diff --git a/CMakeLists.txt b/CMakeLists.txt index 5754992e..96cdadef 100644 --- a/CMakeLists.txt +++ b/CMakeLists.txt @@ -1,13 +1,29 @@ cmake_minimum_required(VERSION 2.6.4) +if (POLICY CMP0048) + cmake_policy(SET CMP0048 NEW) +endif (POLICY CMP0048) + project( googletest-distribution ) enable_testing() +include(CMakeDependentOption) +if (CMAKE_VERSION VERSION_LESS 2.8.5) + set(CMAKE_INSTALL_BINDIR "bin" CACHE STRING "User executables (bin)") + set(CMAKE_INSTALL_LIBDIR "lib${LIB_SUFFIX}" CACHE STRING "Object code libraries (lib)") + set(CMAKE_INSTALL_INCLUDEDIR "include" CACHE STRING "C header files (include)") + mark_as_advanced(CMAKE_INSTALL_BINDIR CMAKE_INSTALL_LIBDIR CMAKE_INSTALL_INCLUDEDIR) +else() + include(GNUInstallDirs) +endif() + option(BUILD_GTEST "Builds the googletest subproject" OFF) +cmake_dependent_option(INSTALL_GTEST "Enable installation of googletest. (Projects embedding googletest may want to turn this OFF.)" ON "BUILD_GTEST OR BUILD_GMOCK" OFF) #Note that googlemock target already builds googletest option(BUILD_GMOCK "Builds the googlemock subproject" ON) +cmake_dependent_option(INSTALL_GMOCK "Enable installation of googlemock. (Projects embedding googlemock may want to turn this OFF.)" ON "BUILD_GMOCK" OFF) if(BUILD_GMOCK) add_subdirectory( googlemock ) diff --git a/README.md b/README.md index 026da075..33df79a8 100644 --- a/README.md +++ b/README.md @@ -13,7 +13,7 @@ maintain and release them together. Please see the project page above for more information as well as the mailing list for questions, discussions, and development. There is -also an IRC channel on OFTC (irc.oftc.net) #gtest available. Please +also an IRC channel on [OFTC](https://webchat.oftc.net/) (irc.oftc.net) #gtest available. Please join us! Getting started information for **Google Test** is available in the @@ -61,9 +61,12 @@ the following notable projects: * [Protocol Buffers](https://github.com/google/protobuf), Google's data interchange format. * The [OpenCV](http://opencv.org/) computer vision library. + * [tiny-dnn](https://github.com/tiny-dnn/tiny-dnn): header only, dependency-free deep learning framework in C++11. ## Related Open Source Projects ## +[GTest Runner](https://github.com/nholthaus/gtest-runner) is a Qt5 based automated test-runner and Graphical User Interface with powerful features for Windows and Linux platforms. + [Google Test UI](https://github.com/ospector/gtest-gbar) is test runner that runs your test binary, allows you to track its progress via a progress bar, and displays a list of test failures. Clicking on one shows failure text. Google @@ -74,6 +77,9 @@ listener for Google Test that implements the [TAP protocol](https://en.wikipedia.org/wiki/Test_Anything_Protocol) for test result output. If your test runner understands TAP, you may find it useful. +[gtest-parallel](https://github.com/google/gtest-parallel) is a test runner that +runs tests from your binary in parallel to provide significant speed-up. + ## Requirements ## Google Test is designed to have fairly minimal requirements to build @@ -83,7 +89,7 @@ effort to support other platforms (e.g. Solaris, AIX, and z/OS). However, since core members of the Google Test project have no access to these platforms, Google Test may have outstanding issues there. If you notice any problems on your platform, please notify -. Patches for fixing them are +[googletestframework@googlegroups.com](https://groups.google.com/forum/#!forum/googletestframework). Patches for fixing them are even more welcome! ### Linux Requirements ### @@ -98,7 +104,7 @@ package (as described below): ### Windows Requirements ### - * Microsoft Visual C++ v7.1 or newer + * Microsoft Visual C++ 2010 or newer ### Cygwin Requirements ### diff --git a/googlemock/CHANGES b/googlemock/CHANGES index d6f2f760..4328ece3 100644 --- a/googlemock/CHANGES +++ b/googlemock/CHANGES @@ -94,7 +94,7 @@ Google Test): * New feature: --gmock_catch_leaked_mocks for detecting leaked mocks. * New feature: ACTION_TEMPLATE for defining templatized actions. * New feature: the .After() clause for specifying expectation order. - * New feature: the .With() clause for for specifying inter-argument + * New feature: the .With() clause for specifying inter-argument constraints. * New feature: actions ReturnArg(), ReturnNew(...), and DeleteArg(). diff --git a/googlemock/CMakeLists.txt b/googlemock/CMakeLists.txt index 9fb96a4b..bd759dfd 100644 --- a/googlemock/CMakeLists.txt +++ b/googlemock/CMakeLists.txt @@ -37,7 +37,12 @@ endif() # as ${gmock_SOURCE_DIR} and to the root binary directory as # ${gmock_BINARY_DIR}. # Language "C" is required for find_package(Threads). -project(gmock CXX C) +if (CMAKE_VERSION VERSION_LESS 3.0) + project(gmock CXX C) +else() + cmake_policy(SET CMP0048 NEW) + project(gmock VERSION 1.9.0 LANGUAGES CXX C) +endif() cmake_minimum_required(VERSION 2.6.4) if (COMMAND set_up_hermetic_build) @@ -103,10 +108,26 @@ endif() ######################################################################## # # Install rules -install(TARGETS gmock gmock_main - DESTINATION lib) -install(DIRECTORY ${gmock_SOURCE_DIR}/include/gmock - DESTINATION include) +if(INSTALL_GMOCK) + install(TARGETS gmock gmock_main + RUNTIME DESTINATION ${CMAKE_INSTALL_BINDIR} + LIBRARY DESTINATION ${CMAKE_INSTALL_LIBDIR} + ARCHIVE DESTINATION ${CMAKE_INSTALL_LIBDIR}) + install(DIRECTORY ${gmock_SOURCE_DIR}/include/gmock + DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}) + + # configure and install pkgconfig files + configure_file( + cmake/gmock.pc.in + "${CMAKE_BINARY_DIR}/gmock.pc" + @ONLY) + configure_file( + cmake/gmock_main.pc.in + "${CMAKE_BINARY_DIR}/gmock_main.pc" + @ONLY) + install(FILES "${CMAKE_BINARY_DIR}/gmock.pc" "${CMAKE_BINARY_DIR}/gmock_main.pc" + DESTINATION "${CMAKE_INSTALL_LIBDIR}/pkgconfig") +endif() ######################################################################## # diff --git a/googlemock/README.md b/googlemock/README.md index 7b13a6d3..f0ea6a0e 100644 --- a/googlemock/README.md +++ b/googlemock/README.md @@ -35,7 +35,7 @@ We hope you find it useful! * Does automatic verification of expectations (no record-and-replay needed). * Allows arbitrary (partial) ordering constraints on function calls to be expressed,. - * Lets a user extend it by defining new matchers and actions. + * Lets an user extend it by defining new matchers and actions. * Does not use exceptions. * Is easy to learn and use. @@ -125,13 +125,46 @@ build Google Mock and its tests, which has further requirements: ### Building Google Mock ### +#### Using CMake #### + If you have CMake available, it is recommended that you follow the [build instructions][gtest_cmakebuild] -as described for Google Test. If are using Google Mock with an +as described for Google Test. + +If are using Google Mock with an existing CMake project, the section [Incorporating Into An Existing CMake Project][gtest_incorpcmake] -may be of particular interest. Otherwise, the following sections -detail how to build Google Mock without CMake. +may be of particular interest. +To make it work for Google Mock you will need to change + + target_link_libraries(example gtest_main) + +to + + target_link_libraries(example gmock_main) + +This works because `gmock_main` library is compiled with Google Test. +However, it does not automatically add Google Test includes. +Therefore you will also have to change + + if (CMAKE_VERSION VERSION_LESS 2.8.11) + include_directories("${gtest_SOURCE_DIR}/include") + endif() + +to + + if (CMAKE_VERSION VERSION_LESS 2.8.11) + include_directories(BEFORE SYSTEM + "${gtest_SOURCE_DIR}/include" "${gmock_SOURCE_DIR}/include") + else() + target_include_directories(gmock_main SYSTEM BEFORE INTERFACE + "${gtest_SOURCE_DIR}/include" "${gmock_SOURCE_DIR}/include") + endif() + +This will addtionally mark Google Mock includes as system, which will +silence compiler warnings when compiling your tests using clang with +`-Wpedantic -Wall -Wextra -Wconversion`. + #### Preparing to Build (Unix only) #### diff --git a/googlemock/cmake/gmock.pc.in b/googlemock/cmake/gmock.pc.in new file mode 100644 index 00000000..c4416426 --- /dev/null +++ b/googlemock/cmake/gmock.pc.in @@ -0,0 +1,9 @@ +libdir=@CMAKE_INSTALL_FULL_LIBDIR@ +includedir=@CMAKE_INSTALL_FULL_INCLUDEDIR@ + +Name: gmock +Description: GoogleMock (without main() function) +Version: @PROJECT_VERSION@ +URL: https://github.com/google/googletest +Libs: -L${libdir} -lgmock @CMAKE_THREAD_LIBS_INIT@ +Cflags: -I${includedir} @GTEST_HAS_PTHREAD_MACRO@ @CMAKE_THREAD_LIBS_INIT@ diff --git a/googlemock/cmake/gmock_main.pc.in b/googlemock/cmake/gmock_main.pc.in new file mode 100644 index 00000000..c377dba1 --- /dev/null +++ b/googlemock/cmake/gmock_main.pc.in @@ -0,0 +1,9 @@ +libdir=@CMAKE_INSTALL_FULL_LIBDIR@ +includedir=@CMAKE_INSTALL_FULL_INCLUDEDIR@ + +Name: gmock_main +Description: GoogleMock (with main() function) +Version: @PROJECT_VERSION@ +URL: https://github.com/google/googletest +Libs: -L${libdir} -lgmock_main @CMAKE_THREAD_LIBS_INIT@ +Cflags: -I${includedir} @GTEST_HAS_PTHREAD_MACRO@ @CMAKE_THREAD_LIBS_INIT@ diff --git a/googlemock/docs/CookBook.md b/googlemock/docs/CookBook.md index 34387c0e..6ea7f3a9 100644 --- a/googlemock/docs/CookBook.md +++ b/googlemock/docs/CookBook.md @@ -18,8 +18,9 @@ You must always put a mock method definition (`MOCK_METHOD*`) in a `public:` section of the mock class, regardless of the method being mocked being `public`, `protected`, or `private` in the base class. This allows `ON_CALL` and `EXPECT_CALL` to reference the mock function -from outside of the mock class. (Yes, C++ allows a subclass to change -the access level of a virtual function in the base class.) Example: +from outside of the mock class. (Yes, C++ allows a subclass to specify +a different access level than the base class on a virtual function.) +Example: ``` class Foo { @@ -1681,7 +1682,7 @@ This also works when the argument is an output iterator: ``` using ::testing::_; -using ::testing::SeArrayArgument; +using ::testing::SetArrayArgument; class MockRolodex : public Rolodex { public: @@ -2366,7 +2367,7 @@ Now there’s one topic we haven’t covered: how do you set expectations on `Sh // When one calls ShareBuzz() on the MockBuzzer like this, the call is // forwarded to DoShareBuzz(), which is mocked. Therefore this statement // will trigger the above EXPECT_CALL. - mock_buzzer_.ShareBuzz(MakeUnique<Buzz>(AccessLevel::kInternal), + mock_buzzer_.ShareBuzz(MakeUnique(AccessLevel::kInternal), ::base::Now()); ``` @@ -2405,7 +2406,7 @@ Now, the mock `DoShareBuzz()` method is free to save the buzz argument for later ``` std::unique_ptr intercepted_buzz; EXPECT_CALL(mock_buzzer_, DoShareBuzz(NotNull(), _)) - .WillOnce(Invoke([&intercepted_buzz](Buzz* buzz, Time timestamp) { + .WillOnce(Invoke([&intercepted_buzz](Buzz* buzz, Time timestamp) { // Save buzz in intercepted_buzz for analysis later. intercepted_buzz.reset(buzz); return false; diff --git a/googlemock/docs/Documentation.md b/googlemock/docs/Documentation.md index 444151ee..a0311871 100644 --- a/googlemock/docs/Documentation.md +++ b/googlemock/docs/Documentation.md @@ -1,5 +1,8 @@ -This page lists all documentation wiki pages for Google Mock **(the SVN trunk version)** -- **if you use a released version of Google Mock, please read the documentation for that specific version instead.** +This page lists all documentation markdown files for Google Mock **(the +current git version)** +-- **if you use a former version of Google Mock, please read the +documentation for that specific version instead (e.g. by checking out +the respective git branch/tag).** * [ForDummies](ForDummies.md) -- start here if you are new to Google Mock. * [CheatSheet](CheatSheet.md) -- a quick reference. @@ -9,4 +12,4 @@ This page lists all documentation wiki pages for Google Mock **(the SVN trunk ve To contribute code to Google Mock, read: * [DevGuide](DevGuide.md) -- read this _before_ writing your first patch. - * [Pump Manual](../googletest/docs/PumpManual.md) -- how we generate some of Google Mock's source files. + * [Pump Manual](../../googletest/docs/PumpManual.md) -- how we generate some of Google Mock's source files. diff --git a/googlemock/docs/ForDummies.md b/googlemock/docs/ForDummies.md index 892f1be6..0bf528e9 100644 --- a/googlemock/docs/ForDummies.md +++ b/googlemock/docs/ForDummies.md @@ -23,8 +23,8 @@ Using Google Mock involves three basic steps: # Why Google Mock? # While mock objects help you remove unnecessary dependencies in tests and make them fast and reliable, using mocks manually in C++ is _hard_: - * Someone has to implement the mocks. The job is usually tedious and error-prone. No wonder people go great distance to avoid it. - * The quality of those manually written mocks is a bit, uh, unpredictable. You may see some really polished ones, but you may also see some that were hacked up in a hurry and have all sorts of ad hoc restrictions. + * Someone has to implement the mocks. The job is usually tedious and error-prone. No wonder people go great distances to avoid it. + * The quality of those manually written mocks is a bit, uh, unpredictable. You may see some really polished ones, but you may also see some that were hacked up in a hurry and have all sorts of ad-hoc restrictions. * The knowledge you gained from using one mock doesn't transfer to the next. In contrast, Java and Python programmers have some fine mock frameworks, which automate the creation of mocks. As a result, mocking is a proven effective technique and widely adopted practice in those communities. Having the right tool absolutely makes the difference. diff --git a/googlemock/docs/v1_5/CheatSheet.md b/googlemock/docs/v1_5/CheatSheet.md deleted file mode 100644 index 3c7bed4c..00000000 --- a/googlemock/docs/v1_5/CheatSheet.md +++ /dev/null @@ -1,525 +0,0 @@ - - -# Defining a Mock Class # - -## Mocking a Normal Class ## - -Given -``` -class Foo { - ... - virtual ~Foo(); - virtual int GetSize() const = 0; - virtual string Describe(const char* name) = 0; - virtual string Describe(int type) = 0; - virtual bool Process(Bar elem, int count) = 0; -}; -``` -(note that `~Foo()` **must** be virtual) we can define its mock as -``` -#include - -class MockFoo : public Foo { - MOCK_CONST_METHOD0(GetSize, int()); - MOCK_METHOD1(Describe, string(const char* name)); - MOCK_METHOD1(Describe, string(int type)); - MOCK_METHOD2(Process, bool(Bar elem, int count)); -}; -``` - -To create a "nice" mock object which ignores all uninteresting calls, -or a "strict" mock object, which treats them as failures: -``` -NiceMock nice_foo; // The type is a subclass of MockFoo. -StrictMock strict_foo; // The type is a subclass of MockFoo. -``` - -## Mocking a Class Template ## - -To mock -``` -template -class StackInterface { - public: - ... - virtual ~StackInterface(); - virtual int GetSize() const = 0; - virtual void Push(const Elem& x) = 0; -}; -``` -(note that `~StackInterface()` **must** be virtual) just append `_T` to the `MOCK_*` macros: -``` -template -class MockStack : public StackInterface { - public: - ... - MOCK_CONST_METHOD0_T(GetSize, int()); - MOCK_METHOD1_T(Push, void(const Elem& x)); -}; -``` - -## Specifying Calling Conventions for Mock Functions ## - -If your mock function doesn't use the default calling convention, you -can specify it by appending `_WITH_CALLTYPE` to any of the macros -described in the previous two sections and supplying the calling -convention as the first argument to the macro. For example, -``` - MOCK_METHOD_1_WITH_CALLTYPE(STDMETHODCALLTYPE, Foo, bool(int n)); - MOCK_CONST_METHOD2_WITH_CALLTYPE(STDMETHODCALLTYPE, Bar, int(double x, double y)); -``` -where `STDMETHODCALLTYPE` is defined by `` on Windows. - -# Using Mocks in Tests # - -The typical flow is: - 1. Import the Google Mock names you need to use. All Google Mock names are in the `testing` namespace unless they are macros or otherwise noted. - 1. Create the mock objects. - 1. Optionally, set the default actions of the mock objects. - 1. Set your expectations on the mock objects (How will they be called? What wil they do?). - 1. Exercise code that uses the mock objects; if necessary, check the result using [Google Test](http://code.google.com/p/googletest/) assertions. - 1. When a mock objects is destructed, Google Mock automatically verifies that all expectations on it have been satisfied. - -Here is an example: -``` -using ::testing::Return; // #1 - -TEST(BarTest, DoesThis) { - MockFoo foo; // #2 - - ON_CALL(foo, GetSize()) // #3 - .WillByDefault(Return(1)); - // ... other default actions ... - - EXPECT_CALL(foo, Describe(5)) // #4 - .Times(3) - .WillRepeatedly(Return("Category 5")); - // ... other expectations ... - - EXPECT_EQ("good", MyProductionFunction(&foo)); // #5 -} // #6 -``` - -# Setting Default Actions # - -Google Mock has a **built-in default action** for any function that -returns `void`, `bool`, a numeric value, or a pointer. - -To customize the default action for functions with return type `T` globally: -``` -using ::testing::DefaultValue; - -DefaultValue::Set(value); // Sets the default value to be returned. -// ... use the mocks ... -DefaultValue::Clear(); // Resets the default value. -``` - -To customize the default action for a particular method, use `ON_CALL()`: -``` -ON_CALL(mock_object, method(matchers)) - .With(multi_argument_matcher) ? - .WillByDefault(action); -``` - -# Setting Expectations # - -`EXPECT_CALL()` sets **expectations** on a mock method (How will it be -called? What will it do?): -``` -EXPECT_CALL(mock_object, method(matchers)) - .With(multi_argument_matcher) ? - .Times(cardinality) ? - .InSequence(sequences) * - .After(expectations) * - .WillOnce(action) * - .WillRepeatedly(action) ? - .RetiresOnSaturation(); ? -``` - -If `Times()` is omitted, the cardinality is assumed to be: - - * `Times(1)` when there is neither `WillOnce()` nor `WillRepeatedly()`; - * `Times(n)` when there are `n WillOnce()`s but no `WillRepeatedly()`, where `n` >= 1; or - * `Times(AtLeast(n))` when there are `n WillOnce()`s and a `WillRepeatedly()`, where `n` >= 0. - -A method with no `EXPECT_CALL()` is free to be invoked _any number of times_, and the default action will be taken each time. - -# Matchers # - -A **matcher** matches a _single_ argument. You can use it inside -`ON_CALL()` or `EXPECT_CALL()`, or use it to validate a value -directly: - -| `EXPECT_THAT(value, matcher)` | Asserts that `value` matches `matcher`. | -|:------------------------------|:----------------------------------------| -| `ASSERT_THAT(value, matcher)` | The same as `EXPECT_THAT(value, matcher)`, except that it generates a **fatal** failure. | - -Built-in matchers (where `argument` is the function argument) are -divided into several categories: - -## Wildcard ## -|`_`|`argument` can be any value of the correct type.| -|:--|:-----------------------------------------------| -|`A()` or `An()`|`argument` can be any value of type `type`. | - -## Generic Comparison ## - -|`Eq(value)` or `value`|`argument == value`| -|:---------------------|:------------------| -|`Ge(value)` |`argument >= value`| -|`Gt(value)` |`argument > value` | -|`Le(value)` |`argument <= value`| -|`Lt(value)` |`argument < value` | -|`Ne(value)` |`argument != value`| -|`IsNull()` |`argument` is a `NULL` pointer (raw or smart).| -|`NotNull()` |`argument` is a non-null pointer (raw or smart).| -|`Ref(variable)` |`argument` is a reference to `variable`.| -|`TypedEq(value)`|`argument` has type `type` and is equal to `value`. You may need to use this instead of `Eq(value)` when the mock function is overloaded.| - -Except `Ref()`, these matchers make a _copy_ of `value` in case it's -modified or destructed later. If the compiler complains that `value` -doesn't have a public copy constructor, try wrap it in `ByRef()`, -e.g. `Eq(ByRef(non_copyable_value))`. If you do that, make sure -`non_copyable_value` is not changed afterwards, or the meaning of your -matcher will be changed. - -## Floating-Point Matchers ## - -|`DoubleEq(a_double)`|`argument` is a `double` value approximately equal to `a_double`, treating two NaNs as unequal.| -|:-------------------|:----------------------------------------------------------------------------------------------| -|`FloatEq(a_float)` |`argument` is a `float` value approximately equal to `a_float`, treating two NaNs as unequal. | -|`NanSensitiveDoubleEq(a_double)`|`argument` is a `double` value approximately equal to `a_double`, treating two NaNs as equal. | -|`NanSensitiveFloatEq(a_float)`|`argument` is a `float` value approximately equal to `a_float`, treating two NaNs as equal. | - -The above matchers use ULP-based comparison (the same as used in -[Google Test](http://code.google.com/p/googletest/)). They -automatically pick a reasonable error bound based on the absolute -value of the expected value. `DoubleEq()` and `FloatEq()` conform to -the IEEE standard, which requires comparing two NaNs for equality to -return false. The `NanSensitive*` version instead treats two NaNs as -equal, which is often what a user wants. - -## String Matchers ## - -The `argument` can be either a C string or a C++ string object: - -|`ContainsRegex(string)`|`argument` matches the given regular expression.| -|:----------------------|:-----------------------------------------------| -|`EndsWith(suffix)` |`argument` ends with string `suffix`. | -|`HasSubstr(string)` |`argument` contains `string` as a sub-string. | -|`MatchesRegex(string)` |`argument` matches the given regular expression with the match starting at the first character and ending at the last character.| -|`StartsWith(prefix)` |`argument` starts with string `prefix`. | -|`StrCaseEq(string)` |`argument` is equal to `string`, ignoring case. | -|`StrCaseNe(string)` |`argument` is not equal to `string`, ignoring case.| -|`StrEq(string)` |`argument` is equal to `string`. | -|`StrNe(string)` |`argument` is not equal to `string`. | - -`StrCaseEq()`, `StrCaseNe()`, `StrEq()`, and `StrNe()` work for wide -strings as well. - -## Container Matchers ## - -Most STL-style containers support `==`, so you can use -`Eq(expected_container)` or simply `expected_container` to match a -container exactly. If you want to write the elements in-line, -match them more flexibly, or get more informative messages, you can use: - -| `Contains(e)` | `argument` contains an element that matches `e`, which can be either a value or a matcher. | -|:--------------|:-------------------------------------------------------------------------------------------| -|`ElementsAre(e0, e1, ..., en)`|`argument` has `n + 1` elements, where the i-th element matches `ei`, which can be a value or a matcher. 0 to 10 arguments are allowed.| -|`ElementsAreArray(array)` or `ElementsAreArray(array, count)`|The same as `ElementsAre()` except that the expected element values/matchers come from a C-style array.| -| `ContainerEq(container)` | The same as `Eq(container)` except that the failure message also includes which elements are in one container but not the other. | - -These matchers can also match: - - 1. a native array passed by reference (e.g. in `Foo(const int (&a)[5])`), and - 1. an array passed as a pointer and a count (e.g. in `Bar(const T* buffer, int len)` -- see [Multi-argument Matchers](#Multiargument_Matchers.md)). - -where the array may be multi-dimensional (i.e. its elements can be arrays). - -## Member Matchers ## - -|`Field(&class::field, m)`|`argument.field` (or `argument->field` when `argument` is a plain pointer) matches matcher `m`, where `argument` is an object of type _class_.| -|:------------------------|:---------------------------------------------------------------------------------------------------------------------------------------------| -|`Key(e)` |`argument.first` matches `e`, which can be either a value or a matcher. E.g. `Contains(Key(Le(5)))` can verify that a `map` contains a key `<= 5`.| -|`Pair(m1, m2)` |`argument` is an `std::pair` whose `first` field matches `m1` and `second` field matches `m2`. | -|`Property(&class::property, m)`|`argument.property()` (or `argument->property()` when `argument` is a plain pointer) matches matcher `m`, where `argument` is an object of type _class_.| - -## Matching the Result of a Function or Functor ## - -|`ResultOf(f, m)`|`f(argument)` matches matcher `m`, where `f` is a function or functor.| -|:---------------|:---------------------------------------------------------------------| - -## Pointer Matchers ## - -|`Pointee(m)`|`argument` (either a smart pointer or a raw pointer) points to a value that matches matcher `m`.| -|:-----------|:-----------------------------------------------------------------------------------------------| - -## Multiargument Matchers ## - -These are matchers on tuple types. They can be used in -`.With()`. The following can be used on functions with two
-arguments `x` and `y`: - -|`Eq()`|`x == y`| -|:-----|:-------| -|`Ge()`|`x >= y`| -|`Gt()`|`x > y` | -|`Le()`|`x <= y`| -|`Lt()`|`x < y` | -|`Ne()`|`x != y`| - -You can use the following selectors to pick a subset of the arguments -(or reorder them) to participate in the matching: - -|`AllArgs(m)`|Equivalent to `m`. Useful as syntactic sugar in `.With(AllArgs(m))`.| -|:-----------|:-------------------------------------------------------------------| -|`Args(m)`|The `k` selected (using 0-based indices) arguments match `m`, e.g. `Args<1, 2>(Contains(5))`.| - -## Composite Matchers ## - -You can make a matcher from one or more other matchers: - -|`AllOf(m1, m2, ..., mn)`|`argument` matches all of the matchers `m1` to `mn`.| -|:-----------------------|:---------------------------------------------------| -|`AnyOf(m1, m2, ..., mn)`|`argument` matches at least one of the matchers `m1` to `mn`.| -|`Not(m)` |`argument` doesn't match matcher `m`. | - -## Adapters for Matchers ## - -|`MatcherCast(m)`|casts matcher `m` to type `Matcher`.| -|:------------------|:--------------------------------------| -|`SafeMatcherCast(m)`| [safely casts](V1_5_CookBook#Casting_Matchers.md) matcher `m` to type `Matcher`. | -|`Truly(predicate)` |`predicate(argument)` returns something considered by C++ to be true, where `predicate` is a function or functor.| - -## Matchers as Predicates ## - -|`Matches(m)`|a unary functor that returns `true` if the argument matches `m`.| -|:-----------|:---------------------------------------------------------------| -|`ExplainMatchResult(m, value, result_listener)`|returns `true` if `value` matches `m`, explaining the result to `result_listener`.| -|`Value(x, m)`|returns `true` if the value of `x` matches `m`. | - -## Defining Matchers ## - -| `MATCHER(IsEven, "") { return (arg % 2) == 0; }` | Defines a matcher `IsEven()` to match an even number. | -|:-------------------------------------------------|:------------------------------------------------------| -| `MATCHER_P(IsDivisibleBy, n, "") { *result_listener << "where the remainder is " << (arg % n); return (arg % n) == 0; }` | Defines a macher `IsDivisibleBy(n)` to match a number divisible by `n`. | -| `MATCHER_P2(IsBetween, a, b, "is between %(a)s and %(b)s") { return a <= arg && arg <= b; }` | Defines a matcher `IsBetween(a, b)` to match a value in the range [`a`, `b`]. | - -**Notes:** - - 1. The `MATCHER*` macros cannot be used inside a function or class. - 1. The matcher body must be _purely functional_ (i.e. it cannot have any side effect, and the result must not depend on anything other than the value being matched and the matcher parameters). - 1. You can use `PrintToString(x)` to convert a value `x` of any type to a string. - -## Matchers as Test Assertions ## - -|`ASSERT_THAT(expression, m)`|Generates a [fatal failure](http://code.google.com/p/googletest/wiki/GoogleTestPrimer#Assertions) if the value of `expression` doesn't match matcher `m`.| -|:---------------------------|:--------------------------------------------------------------------------------------------------------------------------------------------------------| -|`EXPECT_THAT(expression, m)`|Generates a non-fatal failure if the value of `expression` doesn't match matcher `m`. | - -# Actions # - -**Actions** specify what a mock function should do when invoked. - -## Returning a Value ## - -|`Return()`|Return from a `void` mock function.| -|:---------|:----------------------------------| -|`Return(value)`|Return `value`. | -|`ReturnArg()`|Return the `N`-th (0-based) argument.| -|`ReturnNew(a1, ..., ak)`|Return `new T(a1, ..., ak)`; a different object is created each time.| -|`ReturnNull()`|Return a null pointer. | -|`ReturnRef(variable)`|Return a reference to `variable`. | - -## Side Effects ## - -|`Assign(&variable, value)`|Assign `value` to variable.| -|:-------------------------|:--------------------------| -| `DeleteArg()` | Delete the `N`-th (0-based) argument, which must be a pointer. | -| `SaveArg(pointer)` | Save the `N`-th (0-based) argument to `*pointer`. | -| `SetArgReferee(value)` | Assign value to the variable referenced by the `N`-th (0-based) argument. | -|`SetArgumentPointee(value)`|Assign `value` to the variable pointed by the `N`-th (0-based) argument.| -|`SetArrayArgument(first, last)`|Copies the elements in source range [`first`, `last`) to the array pointed to by the `N`-th (0-based) argument, which can be either a pointer or an iterator. The action does not take ownership of the elements in the source range.| -|`SetErrnoAndReturn(error, value)`|Set `errno` to `error` and return `value`.| -|`Throw(exception)` |Throws the given exception, which can be any copyable value. Available since v1.1.0.| - -## Using a Function or a Functor as an Action ## - -|`Invoke(f)`|Invoke `f` with the arguments passed to the mock function, where `f` can be a global/static function or a functor.| -|:----------|:-----------------------------------------------------------------------------------------------------------------| -|`Invoke(object_pointer, &class::method)`|Invoke the {method on the object with the arguments passed to the mock function. | -|`InvokeWithoutArgs(f)`|Invoke `f`, which can be a global/static function or a functor. `f` must take no arguments. | -|`InvokeWithoutArgs(object_pointer, &class::method)`|Invoke the method on the object, which takes no arguments. | -|`InvokeArgument(arg1, arg2, ..., argk)`|Invoke the mock function's `N`-th (0-based) argument, which must be a function or a functor, with the `k` arguments.| - -The return value of the invoked function is used as the return value -of the action. - -When defining a function or functor to be used with `Invoke*()`, you can declare any unused parameters as `Unused`: -``` - double Distance(Unused, double x, double y) { return sqrt(x*x + y*y); } - ... - EXPECT_CALL(mock, Foo("Hi", _, _)).WillOnce(Invoke(Distance)); -``` - -In `InvokeArgument(...)`, if an argument needs to be passed by reference, wrap it inside `ByRef()`. For example, -``` - InvokeArgument<2>(5, string("Hi"), ByRef(foo)) -``` -calls the mock function's #2 argument, passing to it `5` and `string("Hi")` by value, and `foo` by reference. - -## Default Action ## - -|`DoDefault()`|Do the default action (specified by `ON_CALL()` or the built-in one).| -|:------------|:--------------------------------------------------------------------| - -**Note:** due to technical reasons, `DoDefault()` cannot be used inside a composite action - trying to do so will result in a run-time error. - -## Composite Actions ## - -|`DoAll(a1, a2, ..., an)`|Do all actions `a1` to `an` and return the result of `an` in each invocation. The first `n - 1` sub-actions must return void. | -|:-----------------------|:-----------------------------------------------------------------------------------------------------------------------------| -|`IgnoreResult(a)` |Perform action `a` and ignore its result. `a` must not return void. | -|`WithArg(a)` |Pass the `N`-th (0-based) argument of the mock function to action `a` and perform it. | -|`WithArgs(a)`|Pass the selected (0-based) arguments of the mock function to action `a` and perform it. | -|`WithoutArgs(a)` |Perform action `a` without any arguments. | - -## Defining Actions ## - -| `ACTION(Sum) { return arg0 + arg1; }` | Defines an action `Sum()` to return the sum of the mock function's argument #0 and #1. | -|:--------------------------------------|:---------------------------------------------------------------------------------------| -| `ACTION_P(Plus, n) { return arg0 + n; }` | Defines an action `Plus(n)` to return the sum of the mock function's argument #0 and `n`. | -| `ACTION_Pk(Foo, p1, ..., pk) { statements; }` | Defines a parameterized action `Foo(p1, ..., pk)` to execute the given `statements`. | - -The `ACTION*` macros cannot be used inside a function or class. - -# Cardinalities # - -These are used in `Times()` to specify how many times a mock function will be called: - -|`AnyNumber()`|The function can be called any number of times.| -|:------------|:----------------------------------------------| -|`AtLeast(n)` |The call is expected at least `n` times. | -|`AtMost(n)` |The call is expected at most `n` times. | -|`Between(m, n)`|The call is expected between `m` and `n` (inclusive) times.| -|`Exactly(n) or n`|The call is expected exactly `n` times. In particular, the call should never happen when `n` is 0.| - -# Expectation Order # - -By default, the expectations can be matched in _any_ order. If some -or all expectations must be matched in a given order, there are two -ways to specify it. They can be used either independently or -together. - -## The After Clause ## - -``` -using ::testing::Expectation; -... -Expectation init_x = EXPECT_CALL(foo, InitX()); -Expectation init_y = EXPECT_CALL(foo, InitY()); -EXPECT_CALL(foo, Bar()) - .After(init_x, init_y); -``` -says that `Bar()` can be called only after both `InitX()` and -`InitY()` have been called. - -If you don't know how many pre-requisites an expectation has when you -write it, you can use an `ExpectationSet` to collect them: - -``` -using ::testing::ExpectationSet; -... -ExpectationSet all_inits; -for (int i = 0; i < element_count; i++) { - all_inits += EXPECT_CALL(foo, InitElement(i)); -} -EXPECT_CALL(foo, Bar()) - .After(all_inits); -``` -says that `Bar()` can be called only after all elements have been -initialized (but we don't care about which elements get initialized -before the others). - -Modifying an `ExpectationSet` after using it in an `.After()` doesn't -affect the meaning of the `.After()`. - -## Sequences ## - -When you have a long chain of sequential expectations, it's easier to -specify the order using **sequences**, which don't require you to given -each expectation in the chain a different name. All expected
-calls in the same sequence must occur in the order they are -specified. - -``` -using ::testing::Sequence; -Sequence s1, s2; -... -EXPECT_CALL(foo, Reset()) - .InSequence(s1, s2) - .WillOnce(Return(true)); -EXPECT_CALL(foo, GetSize()) - .InSequence(s1) - .WillOnce(Return(1)); -EXPECT_CALL(foo, Describe(A())) - .InSequence(s2) - .WillOnce(Return("dummy")); -``` -says that `Reset()` must be called before _both_ `GetSize()` _and_ -`Describe()`, and the latter two can occur in any order. - -To put many expectations in a sequence conveniently: -``` -using ::testing::InSequence; -{ - InSequence dummy; - - EXPECT_CALL(...)...; - EXPECT_CALL(...)...; - ... - EXPECT_CALL(...)...; -} -``` -says that all expected calls in the scope of `dummy` must occur in -strict order. The name `dummy` is irrelevant.) - -# Verifying and Resetting a Mock # - -Google Mock will verify the expectations on a mock object when it is destructed, or you can do it earlier: -``` -using ::testing::Mock; -... -// Verifies and removes the expectations on mock_obj; -// returns true iff successful. -Mock::VerifyAndClearExpectations(&mock_obj); -... -// Verifies and removes the expectations on mock_obj; -// also removes the default actions set by ON_CALL(); -// returns true iff successful. -Mock::VerifyAndClear(&mock_obj); -``` - -You can also tell Google Mock that a mock object can be leaked and doesn't -need to be verified: -``` -Mock::AllowLeak(&mock_obj); -``` - -# Mock Classes # - -Google Mock defines a convenient mock class template -``` -class MockFunction { - public: - MOCK_METHODn(Call, R(A1, ..., An)); -}; -``` -See this [recipe](V1_5_CookBook#Using_Check_Points.md) for one application of it. - -# Flags # - -| `--gmock_catch_leaked_mocks=0` | Don't report leaked mock objects as failures. | -|:-------------------------------|:----------------------------------------------| -| `--gmock_verbose=LEVEL` | Sets the default verbosity level (`info`, `warning`, or `error`) of Google Mock messages. | \ No newline at end of file diff --git a/googlemock/docs/v1_5/CookBook.md b/googlemock/docs/v1_5/CookBook.md deleted file mode 100644 index 55824bbb..00000000 --- a/googlemock/docs/v1_5/CookBook.md +++ /dev/null @@ -1,3253 +0,0 @@ - - -You can find recipes for using Google Mock here. If you haven't yet, -please read the [ForDummies](V1_5_ForDummies.md) document first to make sure you understand -the basics. - -**Note:** Google Mock lives in the `testing` name space. For -readability, it is recommended to write `using ::testing::Foo;` once in -your file before using the name `Foo` defined by Google Mock. We omit -such `using` statements in this page for brevity, but you should do it -in your own code. - -# Creating Mock Classes # - -## Mocking Private or Protected Methods ## - -You must always put a mock method definition (`MOCK_METHOD*`) in a -`public:` section of the mock class, regardless of the method being -mocked being `public`, `protected`, or `private` in the base class. -This allows `ON_CALL` and `EXPECT_CALL` to reference the mock function -from outside of the mock class. (Yes, C++ allows a subclass to change -the access level of a virtual function in the base class.) Example: - -``` -class Foo { - public: - ... - virtual bool Transform(Gadget* g) = 0; - - protected: - virtual void Resume(); - - private: - virtual int GetTimeOut(); -}; - -class MockFoo : public Foo { - public: - ... - MOCK_METHOD1(Transform, bool(Gadget* g)); - - // The following must be in the public section, even though the - // methods are protected or private in the base class. - MOCK_METHOD0(Resume, void()); - MOCK_METHOD0(GetTimeOut, int()); -}; -``` - -## Mocking Overloaded Methods ## - -You can mock overloaded functions as usual. No special attention is required: - -``` -class Foo { - ... - - // Must be virtual as we'll inherit from Foo. - virtual ~Foo(); - - // Overloaded on the types and/or numbers of arguments. - virtual int Add(Element x); - virtual int Add(int times, Element x); - - // Overloaded on the const-ness of this object. - virtual Bar& GetBar(); - virtual const Bar& GetBar() const; -}; - -class MockFoo : public Foo { - ... - MOCK_METHOD1(Add, int(Element x)); - MOCK_METHOD2(Add, int(int times, Element x); - - MOCK_METHOD0(GetBar, Bar&()); - MOCK_CONST_METHOD0(GetBar, const Bar&()); -}; -``` - -**Note:** if you don't mock all versions of the overloaded method, the -compiler will give you a warning about some methods in the base class -being hidden. To fix that, use `using` to bring them in scope: - -``` -class MockFoo : public Foo { - ... - using Foo::Add; - MOCK_METHOD1(Add, int(Element x)); - // We don't want to mock int Add(int times, Element x); - ... -}; -``` - -## Mocking Class Templates ## - -To mock a class template, append `_T` to the `MOCK_*` macros: - -``` -template -class StackInterface { - ... - // Must be virtual as we'll inherit from StackInterface. - virtual ~StackInterface(); - - virtual int GetSize() const = 0; - virtual void Push(const Elem& x) = 0; -}; - -template -class MockStack : public StackInterface { - ... - MOCK_CONST_METHOD0_T(GetSize, int()); - MOCK_METHOD1_T(Push, void(const Elem& x)); -}; -``` - -## Mocking Nonvirtual Methods ## - -Google Mock can mock non-virtual functions to be used in what we call _hi-perf -dependency injection_. - -In this case, instead of sharing a common base class with the real -class, your mock class will be _unrelated_ to the real class, but -contain methods with the same signatures. The syntax for mocking -non-virtual methods is the _same_ as mocking virtual methods: - -``` -// A simple packet stream class. None of its members is virtual. -class ConcretePacketStream { - public: - void AppendPacket(Packet* new_packet); - const Packet* GetPacket(size_t packet_number) const; - size_t NumberOfPackets() const; - ... -}; - -// A mock packet stream class. It inherits from no other, but defines -// GetPacket() and NumberOfPackets(). -class MockPacketStream { - public: - MOCK_CONST_METHOD1(GetPacket, const Packet*(size_t packet_number)); - MOCK_CONST_METHOD0(NumberOfPackets, size_t()); - ... -}; -``` - -Note that the mock class doesn't define `AppendPacket()`, unlike the -real class. That's fine as long as the test doesn't need to call it. - -Next, you need a way to say that you want to use -`ConcretePacketStream` in production code, and use `MockPacketStream` -in tests. Since the functions are not virtual and the two classes are -unrelated, you must specify your choice at _compile time_ (as opposed -to run time). - -One way to do it is to templatize your code that needs to use a packet -stream. More specifically, you will give your code a template type -argument for the type of the packet stream. In production, you will -instantiate your template with `ConcretePacketStream` as the type -argument. In tests, you will instantiate the same template with -`MockPacketStream`. For example, you may write: - -``` -template -void CreateConnection(PacketStream* stream) { ... } - -template -class PacketReader { - public: - void ReadPackets(PacketStream* stream, size_t packet_num); -}; -``` - -Then you can use `CreateConnection()` and -`PacketReader` in production code, and use -`CreateConnection()` and -`PacketReader` in tests. - -``` - MockPacketStream mock_stream; - EXPECT_CALL(mock_stream, ...)...; - .. set more expectations on mock_stream ... - PacketReader reader(&mock_stream); - ... exercise reader ... -``` - -## Mocking Free Functions ## - -It's possible to use Google Mock to mock a free function (i.e. a -C-style function or a static method). You just need to rewrite your -code to use an interface (abstract class). - -Instead of calling a free function (say, `OpenFile`) directly, -introduce an interface for it and have a concrete subclass that calls -the free function: - -``` -class FileInterface { - public: - ... - virtual bool Open(const char* path, const char* mode) = 0; -}; - -class File : public FileInterface { - public: - ... - virtual bool Open(const char* path, const char* mode) { - return OpenFile(path, mode); - } -}; -``` - -Your code should talk to `FileInterface` to open a file. Now it's -easy to mock out the function. - -This may seem much hassle, but in practice you often have multiple -related functions that you can put in the same interface, so the -per-function syntactic overhead will be much lower. - -If you are concerned about the performance overhead incurred by -virtual functions, and profiling confirms your concern, you can -combine this with the recipe for [mocking non-virtual methods](#Mocking_Nonvirtual_Methods.md). - -## Nice Mocks and Strict Mocks ## - -If a mock method has no `EXPECT_CALL` spec but is called, Google Mock -will print a warning about the "uninteresting call". The rationale is: - - * New methods may be added to an interface after a test is written. We shouldn't fail a test just because a method it doesn't know about is called. - * However, this may also mean there's a bug in the test, so Google Mock shouldn't be silent either. If the user believes these calls are harmless, he can add an `EXPECT_CALL()` to suppress the warning. - -However, sometimes you may want to suppress all "uninteresting call" -warnings, while sometimes you may want the opposite, i.e. to treat all -of them as errors. Google Mock lets you make the decision on a -per-mock-object basis. - -Suppose your test uses a mock class `MockFoo`: - -``` -TEST(...) { - MockFoo mock_foo; - EXPECT_CALL(mock_foo, DoThis()); - ... code that uses mock_foo ... -} -``` - -If a method of `mock_foo` other than `DoThis()` is called, it will be -reported by Google Mock as a warning. However, if you rewrite your -test to use `NiceMock` instead, the warning will be gone, -resulting in a cleaner test output: - -``` -using ::testing::NiceMock; - -TEST(...) { - NiceMock mock_foo; - EXPECT_CALL(mock_foo, DoThis()); - ... code that uses mock_foo ... -} -``` - -`NiceMock` is a subclass of `MockFoo`, so it can be used -wherever `MockFoo` is accepted. - -It also works if `MockFoo`'s constructor takes some arguments, as -`NiceMock` "inherits" `MockFoo`'s constructors: - -``` -using ::testing::NiceMock; - -TEST(...) { - NiceMock mock_foo(5, "hi"); // Calls MockFoo(5, "hi"). - EXPECT_CALL(mock_foo, DoThis()); - ... code that uses mock_foo ... -} -``` - -The usage of `StrictMock` is similar, except that it makes all -uninteresting calls failures: - -``` -using ::testing::StrictMock; - -TEST(...) { - StrictMock mock_foo; - EXPECT_CALL(mock_foo, DoThis()); - ... code that uses mock_foo ... - - // The test will fail if a method of mock_foo other than DoThis() - // is called. -} -``` - -There are some caveats though (I don't like them just as much as the -next guy, but sadly they are side effects of C++'s limitations): - - 1. `NiceMock` and `StrictMock` only work for mock methods defined using the `MOCK_METHOD*` family of macros **directly** in the `MockFoo` class. If a mock method is defined in a **base class** of `MockFoo`, the "nice" or "strict" modifier may not affect it, depending on the compiler. In particular, nesting `NiceMock` and `StrictMock` (e.g. `NiceMock >`) is **not** supported. - 1. The constructors of the base mock (`MockFoo`) cannot have arguments passed by non-const reference, which happens to be banned by the [Google C++ style guide](http://google-styleguide.googlecode.com/svn/trunk/cppguide.xml). - 1. During the constructor or destructor of `MockFoo`, the mock object is _not_ nice or strict. This may cause surprises if the constructor or destructor calls a mock method on `this` object. (This behavior, however, is consistent with C++'s general rule: if a constructor or destructor calls a virtual method of `this` object, that method is treated as non-virtual. In other words, to the base class's constructor or destructor, `this` object behaves like an instance of the base class, not the derived class. This rule is required for safety. Otherwise a base constructor may use members of a derived class before they are initialized, or a base destructor may use members of a derived class after they have been destroyed.) - -Finally, you should be **very cautious** when using this feature, as the -decision you make applies to **all** future changes to the mock -class. If an important change is made in the interface you are mocking -(and thus in the mock class), it could break your tests (if you use -`StrictMock`) or let bugs pass through without a warning (if you use -`NiceMock`). Therefore, try to specify the mock's behavior using -explicit `EXPECT_CALL` first, and only turn to `NiceMock` or -`StrictMock` as the last resort. - -## Simplifying the Interface without Breaking Existing Code ## - -Sometimes a method has a long list of arguments that is mostly -uninteresting. For example, - -``` -class LogSink { - public: - ... - virtual void send(LogSeverity severity, const char* full_filename, - const char* base_filename, int line, - const struct tm* tm_time, - const char* message, size_t message_len) = 0; -}; -``` - -This method's argument list is lengthy and hard to work with (let's -say that the `message` argument is not even 0-terminated). If we mock -it as is, using the mock will be awkward. If, however, we try to -simplify this interface, we'll need to fix all clients depending on -it, which is often infeasible. - -The trick is to re-dispatch the method in the mock class: - -``` -class ScopedMockLog : public LogSink { - public: - ... - virtual void send(LogSeverity severity, const char* full_filename, - const char* base_filename, int line, const tm* tm_time, - const char* message, size_t message_len) { - // We are only interested in the log severity, full file name, and - // log message. - Log(severity, full_filename, std::string(message, message_len)); - } - - // Implements the mock method: - // - // void Log(LogSeverity severity, - // const string& file_path, - // const string& message); - MOCK_METHOD3(Log, void(LogSeverity severity, const string& file_path, - const string& message)); -}; -``` - -By defining a new mock method with a trimmed argument list, we make -the mock class much more user-friendly. - -## Alternative to Mocking Concrete Classes ## - -Often you may find yourself using classes that don't implement -interfaces. In order to test your code that uses such a class (let's -call it `Concrete`), you may be tempted to make the methods of -`Concrete` virtual and then mock it. - -Try not to do that. - -Making a non-virtual function virtual is a big decision. It creates an -extension point where subclasses can tweak your class' behavior. This -weakens your control on the class because now it's harder to maintain -the class' invariants. You should make a function virtual only when -there is a valid reason for a subclass to override it. - -Mocking concrete classes directly is problematic as it creates a tight -coupling between the class and the tests - any small change in the -class may invalidate your tests and make test maintenance a pain. - -To avoid such problems, many programmers have been practicing "coding -to interfaces": instead of talking to the `Concrete` class, your code -would define an interface and talk to it. Then you implement that -interface as an adaptor on top of `Concrete`. In tests, you can easily -mock that interface to observe how your code is doing. - -This technique incurs some overhead: - - * You pay the cost of virtual function calls (usually not a problem). - * There is more abstraction for the programmers to learn. - -However, it can also bring significant benefits in addition to better -testability: - - * `Concrete`'s API may not fit your problem domain very well, as you may not be the only client it tries to serve. By designing your own interface, you have a chance to tailor it to your need - you may add higher-level functionalities, rename stuff, etc instead of just trimming the class. This allows you to write your code (user of the interface) in a more natural way, which means it will be more readable, more maintainable, and you'll be more productive. - * If `Concrete`'s implementation ever has to change, you don't have to rewrite everywhere it is used. Instead, you can absorb the change in your implementation of the interface, and your other code and tests will be insulated from this change. - -Some people worry that if everyone is practicing this technique, they -will end up writing lots of redundant code. This concern is totally -understandable. However, there are two reasons why it may not be the -case: - - * Different projects may need to use `Concrete` in different ways, so the best interfaces for them will be different. Therefore, each of them will have its own domain-specific interface on top of `Concrete`, and they will not be the same code. - * If enough projects want to use the same interface, they can always share it, just like they have been sharing `Concrete`. You can check in the interface and the adaptor somewhere near `Concrete` (perhaps in a `contrib` sub-directory) and let many projects use it. - -You need to weigh the pros and cons carefully for your particular -problem, but I'd like to assure you that the Java community has been -practicing this for a long time and it's a proven effective technique -applicable in a wide variety of situations. :-) - -## Delegating Calls to a Fake ## - -Some times you have a non-trivial fake implementation of an -interface. For example: - -``` -class Foo { - public: - virtual ~Foo() {} - virtual char DoThis(int n) = 0; - virtual void DoThat(const char* s, int* p) = 0; -}; - -class FakeFoo : public Foo { - public: - virtual char DoThis(int n) { - return (n > 0) ? '+' : - (n < 0) ? '-' : '0'; - } - - virtual void DoThat(const char* s, int* p) { - *p = strlen(s); - } -}; -``` - -Now you want to mock this interface such that you can set expectations -on it. However, you also want to use `FakeFoo` for the default -behavior, as duplicating it in the mock object is, well, a lot of -work. - -When you define the mock class using Google Mock, you can have it -delegate its default action to a fake class you already have, using -this pattern: - -``` -using ::testing::_; -using ::testing::Invoke; - -class MockFoo : public Foo { - public: - // Normal mock method definitions using Google Mock. - MOCK_METHOD1(DoThis, char(int n)); - MOCK_METHOD2(DoThat, void(const char* s, int* p)); - - // Delegates the default actions of the methods to a FakeFoo object. - // This must be called *before* the custom ON_CALL() statements. - void DelegateToFake() { - ON_CALL(*this, DoThis(_)) - .WillByDefault(Invoke(&fake_, &FakeFoo::DoThis)); - ON_CALL(*this, DoThat(_, _)) - .WillByDefault(Invoke(&fake_, &FakeFoo::DoThat)); - } - private: - FakeFoo fake_; // Keeps an instance of the fake in the mock. -}; -``` - -With that, you can use `MockFoo` in your tests as usual. Just remember -that if you don't explicitly set an action in an `ON_CALL()` or -`EXPECT_CALL()`, the fake will be called upon to do it: - -``` -using ::testing::_; - -TEST(AbcTest, Xyz) { - MockFoo foo; - foo.DelegateToFake(); // Enables the fake for delegation. - - // Put your ON_CALL(foo, ...)s here, if any. - - // No action specified, meaning to use the default action. - EXPECT_CALL(foo, DoThis(5)); - EXPECT_CALL(foo, DoThat(_, _)); - - int n = 0; - EXPECT_EQ('+', foo.DoThis(5)); // FakeFoo::DoThis() is invoked. - foo.DoThat("Hi", &n); // FakeFoo::DoThat() is invoked. - EXPECT_EQ(2, n); -} -``` - -**Some tips:** - - * If you want, you can still override the default action by providing your own `ON_CALL()` or using `.WillOnce()` / `.WillRepeatedly()` in `EXPECT_CALL()`. - * In `DelegateToFake()`, you only need to delegate the methods whose fake implementation you intend to use. - * The general technique discussed here works for overloaded methods, but you'll need to tell the compiler which version you mean. To disambiguate a mock function (the one you specify inside the parentheses of `ON_CALL()`), see the "Selecting Between Overloaded Functions" section on this page; to disambiguate a fake function (the one you place inside `Invoke()`), use a `static_cast` to specify the function's type. - * Having to mix a mock and a fake is often a sign of something gone wrong. Perhaps you haven't got used to the interaction-based way of testing yet. Or perhaps your interface is taking on too many roles and should be split up. Therefore, **don't abuse this**. We would only recommend to do it as an intermediate step when you are refactoring your code. - -Regarding the tip on mixing a mock and a fake, here's an example on -why it may be a bad sign: Suppose you have a class `System` for -low-level system operations. In particular, it does file and I/O -operations. And suppose you want to test how your code uses `System` -to do I/O, and you just want the file operations to work normally. If -you mock out the entire `System` class, you'll have to provide a fake -implementation for the file operation part, which suggests that -`System` is taking on too many roles. - -Instead, you can define a `FileOps` interface and an `IOOps` interface -and split `System`'s functionalities into the two. Then you can mock -`IOOps` without mocking `FileOps`. - -## Delegating Calls to a Real Object ## - -When using testing doubles (mocks, fakes, stubs, and etc), sometimes -their behaviors will differ from those of the real objects. This -difference could be either intentional (as in simulating an error such -that you can test the error handling code) or unintentional. If your -mocks have different behaviors than the real objects by mistake, you -could end up with code that passes the tests but fails in production. - -You can use the _delegating-to-real_ technique to ensure that your -mock has the same behavior as the real object while retaining the -ability to validate calls. This technique is very similar to the -delegating-to-fake technique, the difference being that we use a real -object instead of a fake. Here's an example: - -``` -using ::testing::_; -using ::testing::AtLeast; -using ::testing::Invoke; - -class MockFoo : public Foo { - public: - MockFoo() { - // By default, all calls are delegated to the real object. - ON_CALL(*this, DoThis()) - .WillByDefault(Invoke(&real_, &Foo::DoThis)); - ON_CALL(*this, DoThat(_)) - .WillByDefault(Invoke(&real_, &Foo::DoThat)); - ... - } - MOCK_METHOD0(DoThis, ...); - MOCK_METHOD1(DoThat, ...); - ... - private: - Foo real_; -}; -... - - MockFoo mock; - - EXPECT_CALL(mock, DoThis()) - .Times(3); - EXPECT_CALL(mock, DoThat("Hi")) - .Times(AtLeast(1)); - ... use mock in test ... -``` - -With this, Google Mock will verify that your code made the right calls -(with the right arguments, in the right order, called the right number -of times, etc), and a real object will answer the calls (so the -behavior will be the same as in production). This gives you the best -of both worlds. - -## Delegating Calls to a Parent Class ## - -Ideally, you should code to interfaces, whose methods are all pure -virtual. In reality, sometimes you do need to mock a virtual method -that is not pure (i.e, it already has an implementation). For example: - -``` -class Foo { - public: - virtual ~Foo(); - - virtual void Pure(int n) = 0; - virtual int Concrete(const char* str) { ... } -}; - -class MockFoo : public Foo { - public: - // Mocking a pure method. - MOCK_METHOD1(Pure, void(int n)); - // Mocking a concrete method. Foo::Concrete() is shadowed. - MOCK_METHOD1(Concrete, int(const char* str)); -}; -``` - -Sometimes you may want to call `Foo::Concrete()` instead of -`MockFoo::Concrete()`. Perhaps you want to do it as part of a stub -action, or perhaps your test doesn't need to mock `Concrete()` at all -(but it would be oh-so painful to have to define a new mock class -whenever you don't need to mock one of its methods). - -The trick is to leave a back door in your mock class for accessing the -real methods in the base class: - -``` -class MockFoo : public Foo { - public: - // Mocking a pure method. - MOCK_METHOD1(Pure, void(int n)); - // Mocking a concrete method. Foo::Concrete() is shadowed. - MOCK_METHOD1(Concrete, int(const char* str)); - - // Use this to call Concrete() defined in Foo. - int FooConcrete(const char* str) { return Foo::Concrete(str); } -}; -``` - -Now, you can call `Foo::Concrete()` inside an action by: - -``` -using ::testing::_; -using ::testing::Invoke; -... - EXPECT_CALL(foo, Concrete(_)) - .WillOnce(Invoke(&foo, &MockFoo::FooConcrete)); -``` - -or tell the mock object that you don't want to mock `Concrete()`: - -``` -using ::testing::Invoke; -... - ON_CALL(foo, Concrete(_)) - .WillByDefault(Invoke(&foo, &MockFoo::FooConcrete)); -``` - -(Why don't we just write `Invoke(&foo, &Foo::Concrete)`? If you do -that, `MockFoo::Concrete()` will be called (and cause an infinite -recursion) since `Foo::Concrete()` is virtual. That's just how C++ -works.) - -# Using Matchers # - -## Matching Argument Values Exactly ## - -You can specify exactly which arguments a mock method is expecting: - -``` -using ::testing::Return; -... - EXPECT_CALL(foo, DoThis(5)) - .WillOnce(Return('a')); - EXPECT_CALL(foo, DoThat("Hello", bar)); -``` - -## Using Simple Matchers ## - -You can use matchers to match arguments that have a certain property: - -``` -using ::testing::Ge; -using ::testing::NotNull; -using ::testing::Return; -... - EXPECT_CALL(foo, DoThis(Ge(5))) // The argument must be >= 5. - .WillOnce(Return('a')); - EXPECT_CALL(foo, DoThat("Hello", NotNull())); - // The second argument must not be NULL. -``` - -A frequently used matcher is `_`, which matches anything: - -``` -using ::testing::_; -using ::testing::NotNull; -... - EXPECT_CALL(foo, DoThat(_, NotNull())); -``` - -## Combining Matchers ## - -You can build complex matchers from existing ones using `AllOf()`, -`AnyOf()`, and `Not()`: - -``` -using ::testing::AllOf; -using ::testing::Gt; -using ::testing::HasSubstr; -using ::testing::Ne; -using ::testing::Not; -... - // The argument must be > 5 and != 10. - EXPECT_CALL(foo, DoThis(AllOf(Gt(5), - Ne(10)))); - - // The first argument must not contain sub-string "blah". - EXPECT_CALL(foo, DoThat(Not(HasSubstr("blah")), - NULL)); -``` - -## Casting Matchers ## - -Google Mock matchers are statically typed, meaning that the compiler -can catch your mistake if you use a matcher of the wrong type (for -example, if you use `Eq(5)` to match a `string` argument). Good for -you! - -Sometimes, however, you know what you're doing and want the compiler -to give you some slack. One example is that you have a matcher for -`long` and the argument you want to match is `int`. While the two -types aren't exactly the same, there is nothing really wrong with -using a `Matcher` to match an `int` - after all, we can first -convert the `int` argument to a `long` before giving it to the -matcher. - -To support this need, Google Mock gives you the -`SafeMatcherCast(m)` function. It casts a matcher `m` to type -`Matcher`. To ensure safety, Google Mock checks that (let `U` be the -type `m` accepts): - - 1. Type `T` can be implicitly cast to type `U`; - 1. When both `T` and `U` are built-in arithmetic types (`bool`, integers, and floating-point numbers), the conversion from `T` to `U` is not lossy (in other words, any value representable by `T` can also be represented by `U`); and - 1. When `U` is a reference, `T` must also be a reference (as the underlying matcher may be interested in the address of the `U` value). - -The code won't compile if any of these conditions isn't met. - -Here's one example: - -``` -using ::testing::SafeMatcherCast; - -// A base class and a child class. -class Base { ... }; -class Derived : public Base { ... }; - -class MockFoo : public Foo { - public: - MOCK_METHOD1(DoThis, void(Derived* derived)); -}; -... - - MockFoo foo; - // m is a Matcher we got from somewhere. - EXPECT_CALL(foo, DoThis(SafeMatcherCast(m))); -``` - -If you find `SafeMatcherCast(m)` too limiting, you can use a similar -function `MatcherCast(m)`. The difference is that `MatcherCast` works -as long as you can `static_cast` type `T` to type `U`. - -`MatcherCast` essentially lets you bypass C++'s type system -(`static_cast` isn't always safe as it could throw away information, -for example), so be careful not to misuse/abuse it. - -## Selecting Between Overloaded Functions ## - -If you expect an overloaded function to be called, the compiler may -need some help on which overloaded version it is. - -To disambiguate functions overloaded on the const-ness of this object, -use the `Const()` argument wrapper. - -``` -using ::testing::ReturnRef; - -class MockFoo : public Foo { - ... - MOCK_METHOD0(GetBar, Bar&()); - MOCK_CONST_METHOD0(GetBar, const Bar&()); -}; -... - - MockFoo foo; - Bar bar1, bar2; - EXPECT_CALL(foo, GetBar()) // The non-const GetBar(). - .WillOnce(ReturnRef(bar1)); - EXPECT_CALL(Const(foo), GetBar()) // The const GetBar(). - .WillOnce(ReturnRef(bar2)); -``` - -(`Const()` is defined by Google Mock and returns a `const` reference -to its argument.) - -To disambiguate overloaded functions with the same number of arguments -but different argument types, you may need to specify the exact type -of a matcher, either by wrapping your matcher in `Matcher()`, or -using a matcher whose type is fixed (`TypedEq`, `An()`, -etc): - -``` -using ::testing::An; -using ::testing::Lt; -using ::testing::Matcher; -using ::testing::TypedEq; - -class MockPrinter : public Printer { - public: - MOCK_METHOD1(Print, void(int n)); - MOCK_METHOD1(Print, void(char c)); -}; - -TEST(PrinterTest, Print) { - MockPrinter printer; - - EXPECT_CALL(printer, Print(An())); // void Print(int); - EXPECT_CALL(printer, Print(Matcher(Lt(5)))); // void Print(int); - EXPECT_CALL(printer, Print(TypedEq('a'))); // void Print(char); - - printer.Print(3); - printer.Print(6); - printer.Print('a'); -} -``` - -## Performing Different Actions Based on the Arguments ## - -When a mock method is called, the _last_ matching expectation that's -still active will be selected (think "newer overrides older"). So, you -can make a method do different things depending on its argument values -like this: - -``` -using ::testing::_; -using ::testing::Lt; -using ::testing::Return; -... - // The default case. - EXPECT_CALL(foo, DoThis(_)) - .WillRepeatedly(Return('b')); - - // The more specific case. - EXPECT_CALL(foo, DoThis(Lt(5))) - .WillRepeatedly(Return('a')); -``` - -Now, if `foo.DoThis()` is called with a value less than 5, `'a'` will -be returned; otherwise `'b'` will be returned. - -## Matching Multiple Arguments as a Whole ## - -Sometimes it's not enough to match the arguments individually. For -example, we may want to say that the first argument must be less than -the second argument. The `With()` clause allows us to match -all arguments of a mock function as a whole. For example, - -``` -using ::testing::_; -using ::testing::Lt; -using ::testing::Ne; -... - EXPECT_CALL(foo, InRange(Ne(0), _)) - .With(Lt()); -``` - -says that the first argument of `InRange()` must not be 0, and must be -less than the second argument. - -The expression inside `With()` must be a matcher of type -`Matcher >`, where `A1`, ..., `An` are the -types of the function arguments. - -You can also write `AllArgs(m)` instead of `m` inside `.With()`. The -two forms are equivalent, but `.With(AllArgs(Lt()))` is more readable -than `.With(Lt())`. - -You can use `Args(m)` to match the `n` selected arguments -against `m`. For example, - -``` -using ::testing::_; -using ::testing::AllOf; -using ::testing::Args; -using ::testing::Lt; -... - EXPECT_CALL(foo, Blah(_, _, _)) - .With(AllOf(Args<0, 1>(Lt()), Args<1, 2>(Lt()))); -``` - -says that `Blah()` will be called with arguments `x`, `y`, and `z` where -`x < y < z`. - -As a convenience and example, Google Mock provides some matchers for -2-tuples, including the `Lt()` matcher above. See the [CheatSheet](V1_5_CheatSheet.md) for -the complete list. - -## Using Matchers as Predicates ## - -Have you noticed that a matcher is just a fancy predicate that also -knows how to describe itself? Many existing algorithms take predicates -as arguments (e.g. those defined in STL's `` header), and -it would be a shame if Google Mock matchers are not allowed to -participate. - -Luckily, you can use a matcher where a unary predicate functor is -expected by wrapping it inside the `Matches()` function. For example, - -``` -#include -#include - -std::vector v; -... -// How many elements in v are >= 10? -const int count = count_if(v.begin(), v.end(), Matches(Ge(10))); -``` - -Since you can build complex matchers from simpler ones easily using -Google Mock, this gives you a way to conveniently construct composite -predicates (doing the same using STL's `` header is just -painful). For example, here's a predicate that's satisfied by any -number that is >= 0, <= 100, and != 50: - -``` -Matches(AllOf(Ge(0), Le(100), Ne(50))) -``` - -## Using Matchers in Google Test Assertions ## - -Since matchers are basically predicates that also know how to describe -themselves, there is a way to take advantage of them in -[Google Test](http://code.google.com/p/googletest/) assertions. It's -called `ASSERT_THAT` and `EXPECT_THAT`: - -``` - ASSERT_THAT(value, matcher); // Asserts that value matches matcher. - EXPECT_THAT(value, matcher); // The non-fatal version. -``` - -For example, in a Google Test test you can write: - -``` -#include - -using ::testing::AllOf; -using ::testing::Ge; -using ::testing::Le; -using ::testing::MatchesRegex; -using ::testing::StartsWith; -... - - EXPECT_THAT(Foo(), StartsWith("Hello")); - EXPECT_THAT(Bar(), MatchesRegex("Line \\d+")); - ASSERT_THAT(Baz(), AllOf(Ge(5), Le(10))); -``` - -which (as you can probably guess) executes `Foo()`, `Bar()`, and -`Baz()`, and verifies that: - - * `Foo()` returns a string that starts with `"Hello"`. - * `Bar()` returns a string that matches regular expression `"Line \\d+"`. - * `Baz()` returns a number in the range [5, 10]. - -The nice thing about these macros is that _they read like -English_. They generate informative messages too. For example, if the -first `EXPECT_THAT()` above fails, the message will be something like: - -``` -Value of: Foo() - Actual: "Hi, world!" -Expected: starts with "Hello" -``` - -**Credit:** The idea of `(ASSERT|EXPECT)_THAT` was stolen from the -[Hamcrest](http://code.google.com/p/hamcrest/) project, which adds -`assertThat()` to JUnit. - -## Using Predicates as Matchers ## - -Google Mock provides a built-in set of matchers. In case you find them -lacking, you can use an arbitray unary predicate function or functor -as a matcher - as long as the predicate accepts a value of the type -you want. You do this by wrapping the predicate inside the `Truly()` -function, for example: - -``` -using ::testing::Truly; - -int IsEven(int n) { return (n % 2) == 0 ? 1 : 0; } -... - - // Bar() must be called with an even number. - EXPECT_CALL(foo, Bar(Truly(IsEven))); -``` - -Note that the predicate function / functor doesn't have to return -`bool`. It works as long as the return value can be used as the -condition in statement `if (condition) ...`. - -## Matching Arguments that Are Not Copyable ## - -When you do an `EXPECT_CALL(mock_obj, Foo(bar))`, Google Mock saves -away a copy of `bar`. When `Foo()` is called later, Google Mock -compares the argument to `Foo()` with the saved copy of `bar`. This -way, you don't need to worry about `bar` being modified or destroyed -after the `EXPECT_CALL()` is executed. The same is true when you use -matchers like `Eq(bar)`, `Le(bar)`, and so on. - -But what if `bar` cannot be copied (i.e. has no copy constructor)? You -could define your own matcher function and use it with `Truly()`, as -the previous couple of recipes have shown. Or, you may be able to get -away from it if you can guarantee that `bar` won't be changed after -the `EXPECT_CALL()` is executed. Just tell Google Mock that it should -save a reference to `bar`, instead of a copy of it. Here's how: - -``` -using ::testing::Eq; -using ::testing::ByRef; -using ::testing::Lt; -... - // Expects that Foo()'s argument == bar. - EXPECT_CALL(mock_obj, Foo(Eq(ByRef(bar)))); - - // Expects that Foo()'s argument < bar. - EXPECT_CALL(mock_obj, Foo(Lt(ByRef(bar)))); -``` - -Remember: if you do this, don't change `bar` after the -`EXPECT_CALL()`, or the result is undefined. - -## Validating a Member of an Object ## - -Often a mock function takes a reference to object as an argument. When -matching the argument, you may not want to compare the entire object -against a fixed object, as that may be over-specification. Instead, -you may need to validate a certain member variable or the result of a -certain getter method of the object. You can do this with `Field()` -and `Property()`. More specifically, - -``` -Field(&Foo::bar, m) -``` - -is a matcher that matches a `Foo` object whose `bar` member variable -satisfies matcher `m`. - -``` -Property(&Foo::baz, m) -``` - -is a matcher that matches a `Foo` object whose `baz()` method returns -a value that satisfies matcher `m`. - -For example: - -| Expression | Description | -|:-----------------------------|:-----------------------------------| -| `Field(&Foo::number, Ge(3))` | Matches `x` where `x.number >= 3`. | -| `Property(&Foo::name, StartsWith("John "))` | Matches `x` where `x.name()` starts with `"John "`. | - -Note that in `Property(&Foo::baz, ...)`, method `baz()` must take no -argument and be declared as `const`. - -BTW, `Field()` and `Property()` can also match plain pointers to -objects. For instance, - -``` -Field(&Foo::number, Ge(3)) -``` - -matches a plain pointer `p` where `p->number >= 3`. If `p` is `NULL`, -the match will always fail regardless of the inner matcher. - -What if you want to validate more than one members at the same time? -Remember that there is `AllOf()`. - -## Validating the Value Pointed to by a Pointer Argument ## - -C++ functions often take pointers as arguments. You can use matchers -like `NULL`, `NotNull()`, and other comparison matchers to match a -pointer, but what if you want to make sure the value _pointed to_ by -the pointer, instead of the pointer itself, has a certain property? -Well, you can use the `Pointee(m)` matcher. - -`Pointee(m)` matches a pointer iff `m` matches the value the pointer -points to. For example: - -``` -using ::testing::Ge; -using ::testing::Pointee; -... - EXPECT_CALL(foo, Bar(Pointee(Ge(3)))); -``` - -expects `foo.Bar()` to be called with a pointer that points to a value -greater than or equal to 3. - -One nice thing about `Pointee()` is that it treats a `NULL` pointer as -a match failure, so you can write `Pointee(m)` instead of - -``` - AllOf(NotNull(), Pointee(m)) -``` - -without worrying that a `NULL` pointer will crash your test. - -Also, did we tell you that `Pointee()` works with both raw pointers -**and** smart pointers (`linked_ptr`, `shared_ptr`, `scoped_ptr`, and -etc)? - -What if you have a pointer to pointer? You guessed it - you can use -nested `Pointee()` to probe deeper inside the value. For example, -`Pointee(Pointee(Lt(3)))` matches a pointer that points to a pointer -that points to a number less than 3 (what a mouthful...). - -## Testing a Certain Property of an Object ## - -Sometimes you want to specify that an object argument has a certain -property, but there is no existing matcher that does this. If you want -good error messages, you should define a matcher. If you want to do it -quick and dirty, you could get away with writing an ordinary function. - -Let's say you have a mock function that takes an object of type `Foo`, -which has an `int bar()` method and an `int baz()` method, and you -want to constrain that the argument's `bar()` value plus its `baz()` -value is a given number. Here's how you can define a matcher to do it: - -``` -using ::testing::MatcherInterface; -using ::testing::MatchResultListener; - -class BarPlusBazEqMatcher : public MatcherInterface { - public: - explicit BarPlusBazEqMatcher(int expected_sum) - : expected_sum_(expected_sum) {} - - virtual bool MatchAndExplain(const Foo& foo, - MatchResultListener* listener) const { - return (foo.bar() + foo.baz()) == expected_sum_; - } - - virtual void DescribeTo(::std::ostream* os) const { - *os << "bar() + baz() equals " << expected_sum_; - } - - virtual void DescribeNegationTo(::std::ostream* os) const { - *os << "bar() + baz() does not equal " << expected_sum_; - } - private: - const int expected_sum_; -}; - -inline Matcher BarPlusBazEq(int expected_sum) { - return MakeMatcher(new BarPlusBazEqMatcher(expected_sum)); -} - -... - - EXPECT_CALL(..., DoThis(BarPlusBazEq(5)))...; -``` - -## Matching Containers ## - -Sometimes an STL container (e.g. list, vector, map, ...) is passed to -a mock function and you may want to validate it. Since most STL -containers support the `==` operator, you can write -`Eq(expected_container)` or simply `expected_container` to match a -container exactly. - -Sometimes, though, you may want to be more flexible (for example, the -first element must be an exact match, but the second element can be -any positive number, and so on). Also, containers used in tests often -have a small number of elements, and having to define the expected -container out-of-line is a bit of a hassle. - -You can use the `ElementsAre()` matcher in such cases: - -``` -using ::testing::_; -using ::testing::ElementsAre; -using ::testing::Gt; -... - - MOCK_METHOD1(Foo, void(const vector& numbers)); -... - - EXPECT_CALL(mock, Foo(ElementsAre(1, Gt(0), _, 5))); -``` - -The above matcher says that the container must have 4 elements, which -must be 1, greater than 0, anything, and 5 respectively. - -`ElementsAre()` is overloaded to take 0 to 10 arguments. If more are -needed, you can place them in a C-style array and use -`ElementsAreArray()` instead: - -``` -using ::testing::ElementsAreArray; -... - - // ElementsAreArray accepts an array of element values. - const int expected_vector1[] = { 1, 5, 2, 4, ... }; - EXPECT_CALL(mock, Foo(ElementsAreArray(expected_vector1))); - - // Or, an array of element matchers. - Matcher expected_vector2 = { 1, Gt(2), _, 3, ... }; - EXPECT_CALL(mock, Foo(ElementsAreArray(expected_vector2))); -``` - -In case the array needs to be dynamically created (and therefore the -array size cannot be inferred by the compiler), you can give -`ElementsAreArray()` an additional argument to specify the array size: - -``` -using ::testing::ElementsAreArray; -... - int* const expected_vector3 = new int[count]; - ... fill expected_vector3 with values ... - EXPECT_CALL(mock, Foo(ElementsAreArray(expected_vector3, count))); -``` - -**Tips:** - - * `ElementAre*()` works with _any_ container that implements the STL iterator concept (i.e. it has a `const_iterator` type and supports `begin()/end()`) and supports `size()`, not just the ones defined in STL. It will even work with container types yet to be written - as long as they follows the above pattern. - * You can use nested `ElementAre*()` to match nested (multi-dimensional) containers. - * If the container is passed by pointer instead of by reference, just write `Pointee(ElementsAre*(...))`. - * The order of elements _matters_ for `ElementsAre*()`. Therefore don't use it with containers whose element order is undefined (e.g. `hash_map`). - -## Sharing Matchers ## - -Under the hood, a Google Mock matcher object consists of a pointer to -a ref-counted implementation object. Copying matchers is allowed and -very efficient, as only the pointer is copied. When the last matcher -that references the implementation object dies, the implementation -object will be deleted. - -Therefore, if you have some complex matcher that you want to use again -and again, there is no need to build it everytime. Just assign it to a -matcher variable and use that variable repeatedly! For example, - -``` - Matcher in_range = AllOf(Gt(5), Le(10)); - ... use in_range as a matcher in multiple EXPECT_CALLs ... -``` - -# Setting Expectations # - -## Ignoring Uninteresting Calls ## - -If you are not interested in how a mock method is called, just don't -say anything about it. In this case, if the method is ever called, -Google Mock will perform its default action to allow the test program -to continue. If you are not happy with the default action taken by -Google Mock, you can override it using `DefaultValue::Set()` -(described later in this document) or `ON_CALL()`. - -Please note that once you expressed interest in a particular mock -method (via `EXPECT_CALL()`), all invocations to it must match some -expectation. If this function is called but the arguments don't match -any `EXPECT_CALL()` statement, it will be an error. - -## Disallowing Unexpected Calls ## - -If a mock method shouldn't be called at all, explicitly say so: - -``` -using ::testing::_; -... - EXPECT_CALL(foo, Bar(_)) - .Times(0); -``` - -If some calls to the method are allowed, but the rest are not, just -list all the expected calls: - -``` -using ::testing::AnyNumber; -using ::testing::Gt; -... - EXPECT_CALL(foo, Bar(5)); - EXPECT_CALL(foo, Bar(Gt(10))) - .Times(AnyNumber()); -``` - -A call to `foo.Bar()` that doesn't match any of the `EXPECT_CALL()` -statements will be an error. - -## Expecting Ordered Calls ## - -Although an `EXPECT_CALL()` statement defined earlier takes precedence -when Google Mock tries to match a function call with an expectation, -by default calls don't have to happen in the order `EXPECT_CALL()` -statements are written. For example, if the arguments match the -matchers in the third `EXPECT_CALL()`, but not those in the first two, -then the third expectation will be used. - -If you would rather have all calls occur in the order of the -expectations, put the `EXPECT_CALL()` statements in a block where you -define a variable of type `InSequence`: - -``` - using ::testing::_; - using ::testing::InSequence; - - { - InSequence s; - - EXPECT_CALL(foo, DoThis(5)); - EXPECT_CALL(bar, DoThat(_)) - .Times(2); - EXPECT_CALL(foo, DoThis(6)); - } -``` - -In this example, we expect a call to `foo.DoThis(5)`, followed by two -calls to `bar.DoThat()` where the argument can be anything, which are -in turn followed by a call to `foo.DoThis(6)`. If a call occurred -out-of-order, Google Mock will report an error. - -## Expecting Partially Ordered Calls ## - -Sometimes requiring everything to occur in a predetermined order can -lead to brittle tests. For example, we may care about `A` occurring -before both `B` and `C`, but aren't interested in the relative order -of `B` and `C`. In this case, the test should reflect our real intent, -instead of being overly constraining. - -Google Mock allows you to impose an arbitrary DAG (directed acyclic -graph) on the calls. One way to express the DAG is to use the -[After](V1_5_CheatSheet#The_After_Clause.md) clause of `EXPECT_CALL`. - -Another way is via the `InSequence()` clause (not the same as the -`InSequence` class), which we borrowed from jMock 2. It's less -flexible than `After()`, but more convenient when you have long chains -of sequential calls, as it doesn't require you to come up with -different names for the expectations in the chains. Here's how it -works: - -If we view `EXPECT_CALL()` statements as nodes in a graph, and add an -edge from node A to node B wherever A must occur before B, we can get -a DAG. We use the term "sequence" to mean a directed path in this -DAG. Now, if we decompose the DAG into sequences, we just need to know -which sequences each `EXPECT_CALL()` belongs to in order to be able to -reconstruct the orginal DAG. - -So, to specify the partial order on the expectations we need to do two -things: first to define some `Sequence` objects, and then for each -`EXPECT_CALL()` say which `Sequence` objects it is part -of. Expectations in the same sequence must occur in the order they are -written. For example, - -``` - using ::testing::Sequence; - - Sequence s1, s2; - - EXPECT_CALL(foo, A()) - .InSequence(s1, s2); - EXPECT_CALL(bar, B()) - .InSequence(s1); - EXPECT_CALL(bar, C()) - .InSequence(s2); - EXPECT_CALL(foo, D()) - .InSequence(s2); -``` - -specifies the following DAG (where `s1` is `A -> B`, and `s2` is `A -> -C -> D`): - -``` - +---> B - | - A ---| - | - +---> C ---> D -``` - -This means that A must occur before B and C, and C must occur before -D. There's no restriction about the order other than these. - -## Controlling When an Expectation Retires ## - -When a mock method is called, Google Mock only consider expectations -that are still active. An expectation is active when created, and -becomes inactive (aka _retires_) when a call that has to occur later -has occurred. For example, in - -``` - using ::testing::_; - using ::testing::Sequence; - - Sequence s1, s2; - - EXPECT_CALL(log, Log(WARNING, _, "File too large.")) // #1 - .Times(AnyNumber()) - .InSequence(s1, s2); - EXPECT_CALL(log, Log(WARNING, _, "Data set is empty.")) // #2 - .InSequence(s1); - EXPECT_CALL(log, Log(WARNING, _, "User not found.")) // #3 - .InSequence(s2); -``` - -as soon as either #2 or #3 is matched, #1 will retire. If a warning -`"File too large."` is logged after this, it will be an error. - -Note that an expectation doesn't retire automatically when it's -saturated. For example, - -``` -using ::testing::_; -... - EXPECT_CALL(log, Log(WARNING, _, _)); // #1 - EXPECT_CALL(log, Log(WARNING, _, "File too large.")); // #2 -``` - -says that there will be exactly one warning with the message `"File -too large."`. If the second warning contains this message too, #2 will -match again and result in an upper-bound-violated error. - -If this is not what you want, you can ask an expectation to retire as -soon as it becomes saturated: - -``` -using ::testing::_; -... - EXPECT_CALL(log, Log(WARNING, _, _)); // #1 - EXPECT_CALL(log, Log(WARNING, _, "File too large.")) // #2 - .RetiresOnSaturation(); -``` - -Here #2 can be used only once, so if you have two warnings with the -message `"File too large."`, the first will match #2 and the second -will match #1 - there will be no error. - -# Using Actions # - -## Returning References from Mock Methods ## - -If a mock function's return type is a reference, you need to use -`ReturnRef()` instead of `Return()` to return a result: - -``` -using ::testing::ReturnRef; - -class MockFoo : public Foo { - public: - MOCK_METHOD0(GetBar, Bar&()); -}; -... - - MockFoo foo; - Bar bar; - EXPECT_CALL(foo, GetBar()) - .WillOnce(ReturnRef(bar)); -``` - -## Combining Actions ## - -Want to do more than one thing when a function is called? That's -fine. `DoAll()` allow you to do sequence of actions every time. Only -the return value of the last action in the sequence will be used. - -``` -using ::testing::DoAll; - -class MockFoo : public Foo { - public: - MOCK_METHOD1(Bar, bool(int n)); -}; -... - - EXPECT_CALL(foo, Bar(_)) - .WillOnce(DoAll(action_1, - action_2, - ... - action_n)); -``` - -## Mocking Side Effects ## - -Sometimes a method exhibits its effect not via returning a value but -via side effects. For example, it may change some global state or -modify an output argument. To mock side effects, in general you can -define your own action by implementing `::testing::ActionInterface`. - -If all you need to do is to change an output argument, the built-in -`SetArgumentPointee()` action is convenient: - -``` -using ::testing::SetArgumentPointee; - -class MockMutator : public Mutator { - public: - MOCK_METHOD2(Mutate, void(bool mutate, int* value)); - ... -}; -... - - MockMutator mutator; - EXPECT_CALL(mutator, Mutate(true, _)) - .WillOnce(SetArgumentPointee<1>(5)); -``` - -In this example, when `mutator.Mutate()` is called, we will assign 5 -to the `int` variable pointed to by argument #1 -(0-based). - -`SetArgumentPointee()` conveniently makes an internal copy of the -value you pass to it, removing the need to keep the value in scope and -alive. The implication however is that the value must have a copy -constructor and assignment operator. - -If the mock method also needs to return a value as well, you can chain -`SetArgumentPointee()` with `Return()` using `DoAll()`: - -``` -using ::testing::_; -using ::testing::Return; -using ::testing::SetArgumentPointee; - -class MockMutator : public Mutator { - public: - ... - MOCK_METHOD1(MutateInt, bool(int* value)); -}; -... - - MockMutator mutator; - EXPECT_CALL(mutator, MutateInt(_)) - .WillOnce(DoAll(SetArgumentPointee<0>(5), - Return(true))); -``` - -If the output argument is an array, use the -`SetArrayArgument(first, last)` action instead. It copies the -elements in source range `[first, last)` to the array pointed to by -the `N`-th (0-based) argument: - -``` -using ::testing::NotNull; -using ::testing::SetArrayArgument; - -class MockArrayMutator : public ArrayMutator { - public: - MOCK_METHOD2(Mutate, void(int* values, int num_values)); - ... -}; -... - - MockArrayMutator mutator; - int values[5] = { 1, 2, 3, 4, 5 }; - EXPECT_CALL(mutator, Mutate(NotNull(), 5)) - .WillOnce(SetArrayArgument<0>(values, values + 5)); -``` - -This also works when the argument is an output iterator: - -``` -using ::testing::_; -using ::testing::SeArrayArgument; - -class MockRolodex : public Rolodex { - public: - MOCK_METHOD1(GetNames, void(std::back_insert_iterator >)); - ... -}; -... - - MockRolodex rolodex; - vector names; - names.push_back("George"); - names.push_back("John"); - names.push_back("Thomas"); - EXPECT_CALL(rolodex, GetNames(_)) - .WillOnce(SetArrayArgument<0>(names.begin(), names.end())); -``` - -## Changing a Mock Object's Behavior Based on the State ## - -If you expect a call to change the behavior of a mock object, you can use `::testing::InSequence` to specify different behaviors before and after the call: - -``` -using ::testing::InSequence; -using ::testing::Return; - -... - { - InSequence seq; - EXPECT_CALL(my_mock, IsDirty()) - .WillRepeatedly(Return(true)); - EXPECT_CALL(my_mock, Flush()); - EXPECT_CALL(my_mock, IsDirty()) - .WillRepeatedly(Return(false)); - } - my_mock.FlushIfDirty(); -``` - -This makes `my_mock.IsDirty()` return `true` before `my_mock.Flush()` is called and return `false` afterwards. - -If the behavior change is more complex, you can store the effects in a variable and make a mock method get its return value from that variable: - -``` -using ::testing::_; -using ::testing::SaveArg; -using ::testing::Return; - -ACTION_P(ReturnPointee, p) { return *p; } -... - int previous_value = 0; - EXPECT_CALL(my_mock, GetPrevValue()) - .WillRepeatedly(ReturnPointee(&previous_value)); - EXPECT_CALL(my_mock, UpdateValue(_)) - .WillRepeatedly(SaveArg<0>(&previous_value)); - my_mock.DoSomethingToUpdateValue(); -``` - -Here `my_mock.GetPrevValue()` will always return the argument of the last `UpdateValue()` call. - -## Setting the Default Value for a Return Type ## - -If a mock method's return type is a built-in C++ type or pointer, by -default it will return 0 when invoked. You only need to specify an -action if this default value doesn't work for you. - -Sometimes, you may want to change this default value, or you may want -to specify a default value for types Google Mock doesn't know -about. You can do this using the `::testing::DefaultValue` class -template: - -``` -class MockFoo : public Foo { - public: - MOCK_METHOD0(CalculateBar, Bar()); -}; -... - - Bar default_bar; - // Sets the default return value for type Bar. - DefaultValue::Set(default_bar); - - MockFoo foo; - - // We don't need to specify an action here, as the default - // return value works for us. - EXPECT_CALL(foo, CalculateBar()); - - foo.CalculateBar(); // This should return default_bar. - - // Unsets the default return value. - DefaultValue::Clear(); -``` - -Please note that changing the default value for a type can make you -tests hard to understand. We recommend you to use this feature -judiciously. For example, you may want to make sure the `Set()` and -`Clear()` calls are right next to the code that uses your mock. - -## Setting the Default Actions for a Mock Method ## - -You've learned how to change the default value of a given -type. However, this may be too coarse for your purpose: perhaps you -have two mock methods with the same return type and you want them to -have different behaviors. The `ON_CALL()` macro allows you to -customize your mock's behavior at the method level: - -``` -using ::testing::_; -using ::testing::AnyNumber; -using ::testing::Gt; -using ::testing::Return; -... - ON_CALL(foo, Sign(_)) - .WillByDefault(Return(-1)); - ON_CALL(foo, Sign(0)) - .WillByDefault(Return(0)); - ON_CALL(foo, Sign(Gt(0))) - .WillByDefault(Return(1)); - - EXPECT_CALL(foo, Sign(_)) - .Times(AnyNumber()); - - foo.Sign(5); // This should return 1. - foo.Sign(-9); // This should return -1. - foo.Sign(0); // This should return 0. -``` - -As you may have guessed, when there are more than one `ON_CALL()` -statements, the news order take precedence over the older ones. In -other words, the **last** one that matches the function arguments will -be used. This matching order allows you to set up the common behavior -in a mock object's constructor or the test fixture's set-up phase and -specialize the mock's behavior later. - -## Using Functions/Methods/Functors as Actions ## - -If the built-in actions don't suit you, you can easily use an existing -function, method, or functor as an action: - -``` -using ::testing::_; -using ::testing::Invoke; - -class MockFoo : public Foo { - public: - MOCK_METHOD2(Sum, int(int x, int y)); - MOCK_METHOD1(ComplexJob, bool(int x)); -}; - -int CalculateSum(int x, int y) { return x + y; } - -class Helper { - public: - bool ComplexJob(int x); -}; -... - - MockFoo foo; - Helper helper; - EXPECT_CALL(foo, Sum(_, _)) - .WillOnce(Invoke(CalculateSum)); - EXPECT_CALL(foo, ComplexJob(_)) - .WillOnce(Invoke(&helper, &Helper::ComplexJob)); - - foo.Sum(5, 6); // Invokes CalculateSum(5, 6). - foo.ComplexJob(10); // Invokes helper.ComplexJob(10); -``` - -The only requirement is that the type of the function, etc must be -_compatible_ with the signature of the mock function, meaning that the -latter's arguments can be implicitly converted to the corresponding -arguments of the former, and the former's return type can be -implicitly converted to that of the latter. So, you can invoke -something whose type is _not_ exactly the same as the mock function, -as long as it's safe to do so - nice, huh? - -## Invoking a Function/Method/Functor Without Arguments ## - -`Invoke()` is very useful for doing actions that are more complex. It -passes the mock function's arguments to the function or functor being -invoked such that the callee has the full context of the call to work -with. If the invoked function is not interested in some or all of the -arguments, it can simply ignore them. - -Yet, a common pattern is that a test author wants to invoke a function -without the arguments of the mock function. `Invoke()` allows her to -do that using a wrapper function that throws away the arguments before -invoking an underlining nullary function. Needless to say, this can be -tedious and obscures the intent of the test. - -`InvokeWithoutArgs()` solves this problem. It's like `Invoke()` except -that it doesn't pass the mock function's arguments to the -callee. Here's an example: - -``` -using ::testing::_; -using ::testing::InvokeWithoutArgs; - -class MockFoo : public Foo { - public: - MOCK_METHOD1(ComplexJob, bool(int n)); -}; - -bool Job1() { ... } -... - - MockFoo foo; - EXPECT_CALL(foo, ComplexJob(_)) - .WillOnce(InvokeWithoutArgs(Job1)); - - foo.ComplexJob(10); // Invokes Job1(). -``` - -## Invoking an Argument of the Mock Function ## - -Sometimes a mock function will receive a function pointer or a functor -(in other words, a "callable") as an argument, e.g. - -``` -class MockFoo : public Foo { - public: - MOCK_METHOD2(DoThis, bool(int n, bool (*fp)(int))); -}; -``` - -and you may want to invoke this callable argument: - -``` -using ::testing::_; -... - MockFoo foo; - EXPECT_CALL(foo, DoThis(_, _)) - .WillOnce(...); - // Will execute (*fp)(5), where fp is the - // second argument DoThis() receives. -``` - -Arghh, you need to refer to a mock function argument but your version -of C++ has no lambdas, so you have to define your own action. :-( -Or do you really? - -Well, Google Mock has an action to solve _exactly_ this problem: - -``` - InvokeArgument(arg_1, arg_2, ..., arg_m) -``` - -will invoke the `N`-th (0-based) argument the mock function receives, -with `arg_1`, `arg_2`, ..., and `arg_m`. No matter if the argument is -a function pointer or a functor, Google Mock handles them both. - -With that, you could write: - -``` -using ::testing::_; -using ::testing::InvokeArgument; -... - EXPECT_CALL(foo, DoThis(_, _)) - .WillOnce(InvokeArgument<1>(5)); - // Will execute (*fp)(5), where fp is the - // second argument DoThis() receives. -``` - -What if the callable takes an argument by reference? No problem - just -wrap it inside `ByRef()`: - -``` -... - MOCK_METHOD1(Bar, bool(bool (*fp)(int, const Helper&))); -... -using ::testing::_; -using ::testing::ByRef; -using ::testing::InvokeArgument; -... - - MockFoo foo; - Helper helper; - ... - EXPECT_CALL(foo, Bar(_)) - .WillOnce(InvokeArgument<0>(5, ByRef(helper))); - // ByRef(helper) guarantees that a reference to helper, not a copy of it, - // will be passed to the callable. -``` - -What if the callable takes an argument by reference and we do **not** -wrap the argument in `ByRef()`? Then `InvokeArgument()` will _make a -copy_ of the argument, and pass a _reference to the copy_, instead of -a reference to the original value, to the callable. This is especially -handy when the argument is a temporary value: - -``` -... - MOCK_METHOD1(DoThat, bool(bool (*f)(const double& x, const string& s))); -... -using ::testing::_; -using ::testing::InvokeArgument; -... - - MockFoo foo; - ... - EXPECT_CALL(foo, DoThat(_)) - .WillOnce(InvokeArgument<0>(5.0, string("Hi"))); - // Will execute (*f)(5.0, string("Hi")), where f is the function pointer - // DoThat() receives. Note that the values 5.0 and string("Hi") are - // temporary and dead once the EXPECT_CALL() statement finishes. Yet - // it's fine to perform this action later, since a copy of the values - // are kept inside the InvokeArgument action. -``` - -## Ignoring an Action's Result ## - -Sometimes you have an action that returns _something_, but you need an -action that returns `void` (perhaps you want to use it in a mock -function that returns `void`, or perhaps it needs to be used in -`DoAll()` and it's not the last in the list). `IgnoreResult()` lets -you do that. For example: - -``` -using ::testing::_; -using ::testing::Invoke; -using ::testing::Return; - -int Process(const MyData& data); -string DoSomething(); - -class MockFoo : public Foo { - public: - MOCK_METHOD1(Abc, void(const MyData& data)); - MOCK_METHOD0(Xyz, bool()); -}; -... - - MockFoo foo; - EXPECT_CALL(foo, Abc(_)) - // .WillOnce(Invoke(Process)); - // The above line won't compile as Process() returns int but Abc() needs - // to return void. - .WillOnce(IgnoreResult(Invoke(Process))); - - EXPECT_CALL(foo, Xyz()) - .WillOnce(DoAll(IgnoreResult(Invoke(DoSomething)), - // Ignores the string DoSomething() returns. - Return(true))); -``` - -Note that you **cannot** use `IgnoreResult()` on an action that already -returns `void`. Doing so will lead to ugly compiler errors. - -## Selecting an Action's Arguments ## - -Say you have a mock function `Foo()` that takes seven arguments, and -you have a custom action that you want to invoke when `Foo()` is -called. Trouble is, the custom action only wants three arguments: - -``` -using ::testing::_; -using ::testing::Invoke; -... - MOCK_METHOD7(Foo, bool(bool visible, const string& name, int x, int y, - const map, double>& weight, - double min_weight, double max_wight)); -... - -bool IsVisibleInQuadrant1(bool visible, int x, int y) { - return visible && x >= 0 && y >= 0; -} -... - - EXPECT_CALL(mock, Foo(_, _, _, _, _, _, _)) - .WillOnce(Invoke(IsVisibleInQuadrant1)); // Uh, won't compile. :-( -``` - -To please the compiler God, you can to define an "adaptor" that has -the same signature as `Foo()` and calls the custom action with the -right arguments: - -``` -using ::testing::_; -using ::testing::Invoke; - -bool MyIsVisibleInQuadrant1(bool visible, const string& name, int x, int y, - const map, double>& weight, - double min_weight, double max_wight) { - return IsVisibleInQuadrant1(visible, x, y); -} -... - - EXPECT_CALL(mock, Foo(_, _, _, _, _, _, _)) - .WillOnce(Invoke(MyIsVisibleInQuadrant1)); // Now it works. -``` - -But isn't this awkward? - -Google Mock provides a generic _action adaptor_, so you can spend your -time minding more important business than writing your own -adaptors. Here's the syntax: - -``` - WithArgs(action) -``` - -creates an action that passes the arguments of the mock function at -the given indices (0-based) to the inner `action` and performs -it. Using `WithArgs`, our original example can be written as: - -``` -using ::testing::_; -using ::testing::Invoke; -using ::testing::WithArgs; -... - EXPECT_CALL(mock, Foo(_, _, _, _, _, _, _)) - .WillOnce(WithArgs<0, 2, 3>(Invoke(IsVisibleInQuadrant1))); - // No need to define your own adaptor. -``` - -For better readability, Google Mock also gives you: - - * `WithoutArgs(action)` when the inner `action` takes _no_ argument, and - * `WithArg(action)` (no `s` after `Arg`) when the inner `action` takes _one_ argument. - -As you may have realized, `InvokeWithoutArgs(...)` is just syntactic -sugar for `WithoutArgs(Inovke(...))`. - -Here are more tips: - - * The inner action used in `WithArgs` and friends does not have to be `Invoke()` -- it can be anything. - * You can repeat an argument in the argument list if necessary, e.g. `WithArgs<2, 3, 3, 5>(...)`. - * You can change the order of the arguments, e.g. `WithArgs<3, 2, 1>(...)`. - * The types of the selected arguments do _not_ have to match the signature of the inner action exactly. It works as long as they can be implicitly converted to the corresponding arguments of the inner action. For example, if the 4-th argument of the mock function is an `int` and `my_action` takes a `double`, `WithArg<4>(my_action)` will work. - -## Ignoring Arguments in Action Functions ## - -The selecting-an-action's-arguments recipe showed us one way to make a -mock function and an action with incompatible argument lists fit -together. The downside is that wrapping the action in -`WithArgs<...>()` can get tedious for people writing the tests. - -If you are defining a function, method, or functor to be used with -`Invoke*()`, and you are not interested in some of its arguments, an -alternative to `WithArgs` is to declare the uninteresting arguments as -`Unused`. This makes the definition less cluttered and less fragile in -case the types of the uninteresting arguments change. It could also -increase the chance the action function can be reused. For example, -given - -``` - MOCK_METHOD3(Foo, double(const string& label, double x, double y)); - MOCK_METHOD3(Bar, double(int index, double x, double y)); -``` - -instead of - -``` -using ::testing::_; -using ::testing::Invoke; - -double DistanceToOriginWithLabel(const string& label, double x, double y) { - return sqrt(x*x + y*y); -} - -double DistanceToOriginWithIndex(int index, double x, double y) { - return sqrt(x*x + y*y); -} -... - - EXEPCT_CALL(mock, Foo("abc", _, _)) - .WillOnce(Invoke(DistanceToOriginWithLabel)); - EXEPCT_CALL(mock, Bar(5, _, _)) - .WillOnce(Invoke(DistanceToOriginWithIndex)); -``` - -you could write - -``` -using ::testing::_; -using ::testing::Invoke; -using ::testing::Unused; - -double DistanceToOrigin(Unused, double x, double y) { - return sqrt(x*x + y*y); -} -... - - EXEPCT_CALL(mock, Foo("abc", _, _)) - .WillOnce(Invoke(DistanceToOrigin)); - EXEPCT_CALL(mock, Bar(5, _, _)) - .WillOnce(Invoke(DistanceToOrigin)); -``` - -## Sharing Actions ## - -Just like matchers, a Google Mock action object consists of a pointer -to a ref-counted implementation object. Therefore copying actions is -also allowed and very efficient. When the last action that references -the implementation object dies, the implementation object will be -deleted. - -If you have some complex action that you want to use again and again, -you may not have to build it from scratch everytime. If the action -doesn't have an internal state (i.e. if it always does the same thing -no matter how many times it has been called), you can assign it to an -action variable and use that variable repeatedly. For example: - -``` - Action set_flag = DoAll(SetArgumentPointee<0>(5), - Return(true)); - ... use set_flag in .WillOnce() and .WillRepeatedly() ... -``` - -However, if the action has its own state, you may be surprised if you -share the action object. Suppose you have an action factory -`IncrementCounter(init)` which creates an action that increments and -returns a counter whose initial value is `init`, using two actions -created from the same expression and using a shared action will -exihibit different behaviors. Example: - -``` - EXPECT_CALL(foo, DoThis()) - .WillRepeatedly(IncrementCounter(0)); - EXPECT_CALL(foo, DoThat()) - .WillRepeatedly(IncrementCounter(0)); - foo.DoThis(); // Returns 1. - foo.DoThis(); // Returns 2. - foo.DoThat(); // Returns 1 - Blah() uses a different - // counter than Bar()'s. -``` - -versus - -``` - Action increment = IncrementCounter(0); - - EXPECT_CALL(foo, DoThis()) - .WillRepeatedly(increment); - EXPECT_CALL(foo, DoThat()) - .WillRepeatedly(increment); - foo.DoThis(); // Returns 1. - foo.DoThis(); // Returns 2. - foo.DoThat(); // Returns 3 - the counter is shared. -``` - -# Misc Recipes on Using Google Mock # - -## Forcing a Verification ## - -When it's being destroyed, your friendly mock object will automatically -verify that all expectations on it have been satisfied, and will -generate [Google Test](http://code.google.com/p/googletest/) failures -if not. This is convenient as it leaves you with one less thing to -worry about. That is, unless you are not sure if your mock object will -be destroyed. - -How could it be that your mock object won't eventually be destroyed? -Well, it might be created on the heap and owned by the code you are -testing. Suppose there's a bug in that code and it doesn't delete the -mock object properly - you could end up with a passing test when -there's actually a bug. - -Using a heap checker is a good idea and can alleviate the concern, but -its implementation may not be 100% reliable. So, sometimes you do want -to _force_ Google Mock to verify a mock object before it is -(hopefully) destructed. You can do this with -`Mock::VerifyAndClearExpectations(&mock_object)`: - -``` -TEST(MyServerTest, ProcessesRequest) { - using ::testing::Mock; - - MockFoo* const foo = new MockFoo; - EXPECT_CALL(*foo, ...)...; - // ... other expectations ... - - // server now owns foo. - MyServer server(foo); - server.ProcessRequest(...); - - // In case that server's destructor will forget to delete foo, - // this will verify the expectations anyway. - Mock::VerifyAndClearExpectations(foo); -} // server is destroyed when it goes out of scope here. -``` - -**Tip:** The `Mock::VerifyAndClearExpectations()` function returns a -`bool` to indicate whether the verification was successful (`true` for -yes), so you can wrap that function call inside a `ASSERT_TRUE()` if -there is no point going further when the verification has failed. - -## Using Check Points ## - -Sometimes you may want to "reset" a mock object at various check -points in your test: at each check point, you verify that all existing -expectations on the mock object have been satisfied, and then you set -some new expectations on it as if it's newly created. This allows you -to work with a mock object in "phases" whose sizes are each -manageable. - -One such scenario is that in your test's `SetUp()` function, you may -want to put the object you are testing into a certain state, with the -help from a mock object. Once in the desired state, you want to clear -all expectations on the mock, such that in the `TEST_F` body you can -set fresh expectations on it. - -As you may have figured out, the `Mock::VerifyAndClearExpectations()` -function we saw in the previous recipe can help you here. Or, if you -are using `ON_CALL()` to set default actions on the mock object and -want to clear the default actions as well, use -`Mock::VerifyAndClear(&mock_object)` instead. This function does what -`Mock::VerifyAndClearExpectations(&mock_object)` does and returns the -same `bool`, **plus** it clears the `ON_CALL()` statements on -`mock_object` too. - -Another trick you can use to achieve the same effect is to put the -expectations in sequences and insert calls to a dummy "check-point" -function at specific places. Then you can verify that the mock -function calls do happen at the right time. For example, if you are -exercising code: - -``` -Foo(1); -Foo(2); -Foo(3); -``` - -and want to verify that `Foo(1)` and `Foo(3)` both invoke -`mock.Bar("a")`, but `Foo(2)` doesn't invoke anything. You can write: - -``` -using ::testing::MockFunction; - -TEST(FooTest, InvokesBarCorrectly) { - MyMock mock; - // Class MockFunction has exactly one mock method. It is named - // Call() and has type F. - MockFunction check; - { - InSequence s; - - EXPECT_CALL(mock, Bar("a")); - EXPECT_CALL(check, Call("1")); - EXPECT_CALL(check, Call("2")); - EXPECT_CALL(mock, Bar("a")); - } - Foo(1); - check.Call("1"); - Foo(2); - check.Call("2"); - Foo(3); -} -``` - -The expectation spec says that the first `Bar("a")` must happen before -check point "1", the second `Bar("a")` must happen after check point "2", -and nothing should happen between the two check points. The explicit -check points make it easy to tell which `Bar("a")` is called by which -call to `Foo()`. - -## Mocking Destructors ## - -Sometimes you want to make sure a mock object is destructed at the -right time, e.g. after `bar->A()` is called but before `bar->B()` is -called. We already know that you can specify constraints on the order -of mock function calls, so all we need to do is to mock the destructor -of the mock function. - -This sounds simple, except for one problem: a destructor is a special -function with special syntax and special semantics, and the -`MOCK_METHOD0` macro doesn't work for it: - -``` - MOCK_METHOD0(~MockFoo, void()); // Won't compile! -``` - -The good news is that you can use a simple pattern to achieve the same -effect. First, add a mock function `Die()` to your mock class and call -it in the destructor, like this: - -``` -class MockFoo : public Foo { - ... - // Add the following two lines to the mock class. - MOCK_METHOD0(Die, void()); - virtual ~MockFoo() { Die(); } -}; -``` - -(If the name `Die()` clashes with an existing symbol, choose another -name.) Now, we have translated the problem of testing when a `MockFoo` -object dies to testing when its `Die()` method is called: - -``` - MockFoo* foo = new MockFoo; - MockBar* bar = new MockBar; - ... - { - InSequence s; - - // Expects *foo to die after bar->A() and before bar->B(). - EXPECT_CALL(*bar, A()); - EXPECT_CALL(*foo, Die()); - EXPECT_CALL(*bar, B()); - } -``` - -And that's that. - -## Using Google Mock and Threads ## - -**IMPORTANT NOTE:** What we describe in this recipe is **NOT** true yet, -as Google Mock is not currently thread-safe. However, all we need to -make it thread-safe is to implement some synchronization operations in -`` - and then the information below will -become true. - -In a **unit** test, it's best if you could isolate and test a piece of -code in a single-threaded context. That avoids race conditions and -dead locks, and makes debugging your test much easier. - -Yet many programs are multi-threaded, and sometimes to test something -we need to pound on it from more than one thread. Google Mock works -for this purpose too. - -Remember the steps for using a mock: - - 1. Create a mock object `foo`. - 1. Set its default actions and expectations using `ON_CALL()` and `EXPECT_CALL()`. - 1. The code under test calls methods of `foo`. - 1. Optionally, verify and reset the mock. - 1. Destroy the mock yourself, or let the code under test destroy it. The destructor will automatically verify it. - -If you follow the following simple rules, your mocks and threads can -live happily togeter: - - * Execute your _test code_ (as opposed to the code being tested) in _one_ thread. This makes your test easy to follow. - * Obviously, you can do step #1 without locking. - * When doing step #2 and #5, make sure no other thread is accessing `foo`. Obvious too, huh? - * #3 and #4 can be done either in one thread or in multiple threads - anyway you want. Google Mock takes care of the locking, so you don't have to do any - unless required by your test logic. - -If you violate the rules (for example, if you set expectations on a -mock while another thread is calling its methods), you get undefined -behavior. That's not fun, so don't do it. - -Google Mock guarantees that the action for a mock function is done in -the same thread that called the mock function. For example, in - -``` - EXPECT_CALL(mock, Foo(1)) - .WillOnce(action1); - EXPECT_CALL(mock, Foo(2)) - .WillOnce(action2); -``` - -if `Foo(1)` is called in thread 1 and `Foo(2)` is called in thread 2, -Google Mock will execute `action1` in thread 1 and `action2` in thread -2. - -Google Mock does _not_ impose a sequence on actions performed in -different threads (doing so may create deadlocks as the actions may -need to cooperate). This means that the execution of `action1` and -`action2` in the above example _may_ interleave. If this is a problem, -you should add proper synchronization logic to `action1` and `action2` -to make the test thread-safe. - - -Also, remember that `DefaultValue` is a global resource that -potentially affects _all_ living mock objects in your -program. Naturally, you won't want to mess with it from multiple -threads or when there still are mocks in action. - -## Controlling How Much Information Google Mock Prints ## - -When Google Mock sees something that has the potential of being an -error (e.g. a mock function with no expectation is called, a.k.a. an -uninteresting call, which is allowed but perhaps you forgot to -explicitly ban the call), it prints some warning messages, including -the arguments of the function and the return value. Hopefully this -will remind you to take a look and see if there is indeed a problem. - -Sometimes you are confident that your tests are correct and may not -appreciate such friendly messages. Some other times, you are debugging -your tests or learning about the behavior of the code you are testing, -and wish you could observe every mock call that happens (including -argument values and the return value). Clearly, one size doesn't fit -all. - -You can control how much Google Mock tells you using the -`--gmock_verbose=LEVEL` command-line flag, where `LEVEL` is a string -with three possible values: - - * `info`: Google Mock will print all informational messages, warnings, and errors (most verbose). At this setting, Google Mock will also log any calls to the `ON_CALL/EXPECT_CALL` macros. - * `warning`: Google Mock will print both warnings and errors (less verbose). This is the default. - * `error`: Google Mock will print errors only (least verbose). - -Alternatively, you can adjust the value of that flag from within your -tests like so: - -``` - ::testing::FLAGS_gmock_verbose = "error"; -``` - -Now, judiciously use the right flag to enable Google Mock serve you better! - -## Running Tests in Emacs ## - -If you build and run your tests in Emacs, the source file locations of -Google Mock and [Google Test](http://code.google.com/p/googletest/) -errors will be highlighted. Just press `` on one of them and -you'll be taken to the offending line. Or, you can just type `C-x `` -to jump to the next error. - -To make it even easier, you can add the following lines to your -`~/.emacs` file: - -``` -(global-set-key "\M-m" 'compile) ; m is for make -(global-set-key [M-down] 'next-error) -(global-set-key [M-up] '(lambda () (interactive) (next-error -1))) -``` - -Then you can type `M-m` to start a build, or `M-up`/`M-down` to move -back and forth between errors. - -## Fusing Google Mock Source Files ## - -Google Mock's implementation consists of dozens of files (excluding -its own tests). Sometimes you may want them to be packaged up in -fewer files instead, such that you can easily copy them to a new -machine and start hacking there. For this we provide an experimental -Python script `fuse_gmock_files.py` in the `scripts/` directory -(starting with release 1.2.0). Assuming you have Python 2.4 or above -installed on your machine, just go to that directory and run -``` -python fuse_gmock_files.py OUTPUT_DIR -``` - -and you should see an `OUTPUT_DIR` directory being created with files -`gtest/gtest.h`, `gmock/gmock.h`, and `gmock-gtest-all.cc` in it. -These three files contain everything you need to use Google Mock (and -Google Test). Just copy them to anywhere you want and you are ready -to write tests and use mocks. You can use the -[scrpts/test/Makefile](http://code.google.com/p/googlemock/source/browse/trunk/scripts/test/Makefile) file as an example on how to compile your tests -against them. - -# Extending Google Mock # - -## Writing New Matchers Quickly ## - -The `MATCHER*` family of macros can be used to define custom matchers -easily. The syntax: - -``` -MATCHER(name, "description string") { statements; } -``` - -will define a matcher with the given name that executes the -statements, which must return a `bool` to indicate if the match -succeeds. Inside the statements, you can refer to the value being -matched by `arg`, and refer to its type by `arg_type`. - -The description string documents what the matcher does, and is used to -generate the failure message when the match fails. Since a -`MATCHER()` is usually defined in a header file shared by multiple C++ -source files, we require the description to be a C-string _literal_ to -avoid possible side effects. It can be empty (`""`), in which case -Google Mock will use the sequence of words in the matcher name as the -description. - -For example: -``` -MATCHER(IsDivisibleBy7, "") { return (arg % 7) == 0; } -``` -allows you to write -``` - // Expects mock_foo.Bar(n) to be called where n is divisible by 7. - EXPECT_CALL(mock_foo, Bar(IsDivisibleBy7())); -``` -or, -``` - // Verifies that the value of some_expression is divisible by 7. - EXPECT_THAT(some_expression, IsDivisibleBy7()); -``` -If the above assertion fails, it will print something like: -``` - Value of: some_expression - Expected: is divisible by 7 - Actual: 27 -``` -where the description `"is divisible by 7"` is automatically calculated from the -matcher name `IsDivisibleBy7`. - -Optionally, you can stream additional information to a hidden argument -named `result_listener` to explain the match result. For example, a -better definition of `IsDivisibleBy7` is: -``` -MATCHER(IsDivisibleBy7, "") { - if ((arg % 7) == 0) - return true; - - *result_listener << "the remainder is " << (arg % 7); - return false; -} -``` - -With this definition, the above assertion will give a better message: -``` - Value of: some_expression - Expected: is divisible by 7 - Actual: 27 (the remainder is 6) -``` - -You should let `MatchAndExplain()` print _any additional information_ -that can help a user understand the match result. Note that it should -explain why the match succeeds in case of a success (unless it's -obvious) - this is useful when the matcher is used inside -`Not()`. There is no need to print the argument value itself, as -Google Mock already prints it for you. - -**Notes:** - - 1. The type of the value being matched (`arg_type`) is determined by the context in which you use the matcher and is supplied to you by the compiler, so you don't need to worry about declaring it (nor can you). This allows the matcher to be polymorphic. For example, `IsDivisibleBy7()` can be used to match any type where the value of `(arg % 7) == 0` can be implicitly converted to a `bool`. In the `Bar(IsDivisibleBy7())` example above, if method `Bar()` takes an `int`, `arg_type` will be `int`; if it takes an `unsigned long`, `arg_type` will be `unsigned long`; and so on. - 1. Google Mock doesn't guarantee when or how many times a matcher will be invoked. Therefore the matcher logic must be _purely functional_ (i.e. it cannot have any side effect, and the result must not depend on anything other than the value being matched and the matcher parameters). This requirement must be satisfied no matter how you define the matcher (e.g. using one of the methods described in the following recipes). In particular, a matcher can never call a mock function, as that will affect the state of the mock object and Google Mock. - -## Writing New Parameterized Matchers Quickly ## - -Sometimes you'll want to define a matcher that has parameters. For that you -can use the macro: -``` -MATCHER_P(name, param_name, "description string") { statements; } -``` - -For example: -``` -MATCHER_P(HasAbsoluteValue, value, "") { return abs(arg) == value; } -``` -will allow you to write: -``` - EXPECT_THAT(Blah("a"), HasAbsoluteValue(n)); -``` -which may lead to this message (assuming `n` is 10): -``` - Value of: Blah("a") - Expected: has absolute value 10 - Actual: -9 -``` - -Note that both the matcher description and its parameter are -printed, making the message human-friendly. - -In the matcher definition body, you can write `foo_type` to -reference the type of a parameter named `foo`. For example, in the -body of `MATCHER_P(HasAbsoluteValue, value)` above, you can write -`value_type` to refer to the type of `value`. - -Google Mock also provides `MATCHER_P2`, `MATCHER_P3`, ..., up to -`MATCHER_P10` to support multi-parameter matchers: -``` -MATCHER_Pk(name, param_1, ..., param_k, "description string") { statements; } -``` - -Please note that the custom description string is for a particular -**instance** of the matcher, where the parameters have been bound to -actual values. Therefore usually you'll want the parameter values to -be part of the description. Google Mock lets you do that using -Python-style interpolations. The following syntaxes are supported -currently: - -| `%%` | a single `%` character | -|:-----|:-----------------------| -| `%(*)s` | all parameters of the matcher printed as a tuple | -| `%(foo)s` | value of the matcher parameter named `foo` | - -For example, -``` - MATCHER_P2(InClosedRange, low, hi, "is in range [%(low)s, %(hi)s]") { - return low <= arg && arg <= hi; - } - ... - EXPECT_THAT(3, InClosedRange(4, 6)); -``` -would generate a failure that contains the message: -``` - Expected: is in range [4, 6] -``` - -If you specify `""` as the description, the failure message will -contain the sequence of words in the matcher name followed by the -parameter values printed as a tuple. For example, -``` - MATCHER_P2(InClosedRange, low, hi, "") { ... } - ... - EXPECT_THAT(3, InClosedRange(4, 6)); -``` -would generate a failure that contains the text: -``` - Expected: in closed range (4, 6) -``` - -For the purpose of typing, you can view -``` -MATCHER_Pk(Foo, p1, ..., pk, "description string") { ... } -``` -as shorthand for -``` -template -FooMatcherPk -Foo(p1_type p1, ..., pk_type pk) { ... } -``` - -When you write `Foo(v1, ..., vk)`, the compiler infers the types of -the parameters `v1`, ..., and `vk` for you. If you are not happy with -the result of the type inference, you can specify the types by -explicitly instantiating the template, as in `Foo(5, false)`. -As said earlier, you don't get to (or need to) specify -`arg_type` as that's determined by the context in which the matcher -is used. - -You can assign the result of expression `Foo(p1, ..., pk)` to a -variable of type `FooMatcherPk`. This can be -useful when composing matchers. Matchers that don't have a parameter -or have only one parameter have special types: you can assign `Foo()` -to a `FooMatcher`-typed variable, and assign `Foo(p)` to a -`FooMatcherP`-typed variable. - -While you can instantiate a matcher template with reference types, -passing the parameters by pointer usually makes your code more -readable. If, however, you still want to pass a parameter by -reference, be aware that in the failure message generated by the -matcher you will see the value of the referenced object but not its -address. - -You can overload matchers with different numbers of parameters: -``` -MATCHER_P(Blah, a, "description string 1") { ... } -MATCHER_P2(Blah, a, b, "description string 2") { ... } -``` - -While it's tempting to always use the `MATCHER*` macros when defining -a new matcher, you should also consider implementing -`MatcherInterface` or using `MakePolymorphicMatcher()` instead (see -the recipes that follow), especially if you need to use the matcher a -lot. While these approaches require more work, they give you more -control on the types of the value being matched and the matcher -parameters, which in general leads to better compiler error messages -that pay off in the long run. They also allow overloading matchers -based on parameter types (as opposed to just based on the number of -parameters). - -## Writing New Monomorphic Matchers ## - -A matcher of argument type `T` implements -`::testing::MatcherInterface` and does two things: it tests whether a -value of type `T` matches the matcher, and can describe what kind of -values it matches. The latter ability is used for generating readable -error messages when expectations are violated. - -The interface looks like this: - -``` -class MatchResultListener { - public: - ... - // Streams x to the underlying ostream; does nothing if the ostream - // is NULL. - template - MatchResultListener& operator<<(const T& x); - - // Returns the underlying ostream. - ::std::ostream* stream(); -}; - -template -class MatcherInterface { - public: - virtual ~MatcherInterface(); - - // Returns true iff the matcher matches x; also explains the match - // result to 'listener'. - virtual bool MatchAndExplain(T x, MatchResultListener* listener) const = 0; - - // Describes this matcher to an ostream. - virtual void DescribeTo(::std::ostream* os) const = 0; - - // Describes the negation of this matcher to an ostream. - virtual void DescribeNegationTo(::std::ostream* os) const; -}; -``` - -If you need a custom matcher but `Truly()` is not a good option (for -example, you may not be happy with the way `Truly(predicate)` -describes itself, or you may want your matcher to be polymorphic as -`Eq(value)` is), you can define a matcher to do whatever you want in -two steps: first implement the matcher interface, and then define a -factory function to create a matcher instance. The second step is not -strictly needed but it makes the syntax of using the matcher nicer. - -For example, you can define a matcher to test whether an `int` is -divisible by 7 and then use it like this: -``` -using ::testing::MakeMatcher; -using ::testing::Matcher; -using ::testing::MatcherInterface; -using ::testing::MatchResultListener; - -class DivisibleBy7Matcher : public MatcherInterface { - public: - virtual bool MatchAndExplain(int n, MatchResultListener* listener) const { - return (n % 7) == 0; - } - - virtual void DescribeTo(::std::ostream* os) const { - *os << "is divisible by 7"; - } - - virtual void DescribeNegationTo(::std::ostream* os) const { - *os << "is not divisible by 7"; - } -}; - -inline Matcher DivisibleBy7() { - return MakeMatcher(new DivisibleBy7Matcher); -} -... - - EXPECT_CALL(foo, Bar(DivisibleBy7())); -``` - -You may improve the matcher message by streaming additional -information to the `listener` argument in `MatchAndExplain()`: - -``` -class DivisibleBy7Matcher : public MatcherInterface { - public: - virtual bool MatchAndExplain(int n, - MatchResultListener* listener) const { - const int remainder = n % 7; - if (remainder != 0) { - *listener << "the remainder is " << remainder; - } - return remainder == 0; - } - ... -}; -``` - -Then, `EXPECT_THAT(x, DivisibleBy7());` may general a message like this: -``` -Value of: x -Expected: is divisible by 7 - Actual: 23 (the remainder is 2) -``` - -## Writing New Polymorphic Matchers ## - -You've learned how to write your own matchers in the previous -recipe. Just one problem: a matcher created using `MakeMatcher()` only -works for one particular type of arguments. If you want a -_polymorphic_ matcher that works with arguments of several types (for -instance, `Eq(x)` can be used to match a `value` as long as `value` == -`x` compiles -- `value` and `x` don't have to share the same type), -you can learn the trick from `` but it's a bit -involved. - -Fortunately, most of the time you can define a polymorphic matcher -easily with the help of `MakePolymorphicMatcher()`. Here's how you can -define `NotNull()` as an example: - -``` -using ::testing::MakePolymorphicMatcher; -using ::testing::MatchResultListener; -using ::testing::NotNull; -using ::testing::PolymorphicMatcher; - -class NotNullMatcher { - public: - // To implement a polymorphic matcher, first define a COPYABLE class - // that has three members MatchAndExplain(), DescribeTo(), and - // DescribeNegationTo(), like the following. - - // In this example, we want to use NotNull() with any pointer, so - // MatchAndExplain() accepts a pointer of any type as its first argument. - // In general, you can define MatchAndExplain() as an ordinary method or - // a method template, or even overload it. - template - bool MatchAndExplain(T* p, - MatchResultListener* /* listener */) const { - return p != NULL; - } - - // Describes the property of a value matching this matcher. - void DescribeTo(::std::ostream* os) const { *os << "is not NULL"; } - - // Describes the property of a value NOT matching this matcher. - void DescribeNegationTo(::std::ostream* os) const { *os << "is NULL"; } -}; - -// To construct a polymorphic matcher, pass an instance of the class -// to MakePolymorphicMatcher(). Note the return type. -inline PolymorphicMatcher NotNull() { - return MakePolymorphicMatcher(NotNullMatcher()); -} -... - - EXPECT_CALL(foo, Bar(NotNull())); // The argument must be a non-NULL pointer. -``` - -**Note:** Your polymorphic matcher class does **not** need to inherit from -`MatcherInterface` or any other class, and its methods do **not** need -to be virtual. - -Like in a monomorphic matcher, you may explain the match result by -streaming additional information to the `listener` argument in -`MatchAndExplain()`. - -## Writing New Cardinalities ## - -A cardinality is used in `Times()` to tell Google Mock how many times -you expect a call to occur. It doesn't have to be exact. For example, -you can say `AtLeast(5)` or `Between(2, 4)`. - -If the built-in set of cardinalities doesn't suit you, you are free to -define your own by implementing the following interface (in namespace -`testing`): - -``` -class CardinalityInterface { - public: - virtual ~CardinalityInterface(); - - // Returns true iff call_count calls will satisfy this cardinality. - virtual bool IsSatisfiedByCallCount(int call_count) const = 0; - - // Returns true iff call_count calls will saturate this cardinality. - virtual bool IsSaturatedByCallCount(int call_count) const = 0; - - // Describes self to an ostream. - virtual void DescribeTo(::std::ostream* os) const = 0; -}; -``` - -For example, to specify that a call must occur even number of times, -you can write - -``` -using ::testing::Cardinality; -using ::testing::CardinalityInterface; -using ::testing::MakeCardinality; - -class EvenNumberCardinality : public CardinalityInterface { - public: - virtual bool IsSatisfiedByCallCount(int call_count) const { - return (call_count % 2) == 0; - } - - virtual bool IsSaturatedByCallCount(int call_count) const { - return false; - } - - virtual void DescribeTo(::std::ostream* os) const { - *os << "called even number of times"; - } -}; - -Cardinality EvenNumber() { - return MakeCardinality(new EvenNumberCardinality); -} -... - - EXPECT_CALL(foo, Bar(3)) - .Times(EvenNumber()); -``` - -## Writing New Actions Quickly ## - -If the built-in actions don't work for you, and you find it -inconvenient to use `Invoke()`, you can use a macro from the `ACTION*` -family to quickly define a new action that can be used in your code as -if it's a built-in action. - -By writing -``` -ACTION(name) { statements; } -``` -in a namespace scope (i.e. not inside a class or function), you will -define an action with the given name that executes the statements. -The value returned by `statements` will be used as the return value of -the action. Inside the statements, you can refer to the K-th -(0-based) argument of the mock function as `argK`. For example: -``` -ACTION(IncrementArg1) { return ++(*arg1); } -``` -allows you to write -``` -... WillOnce(IncrementArg1()); -``` - -Note that you don't need to specify the types of the mock function -arguments. Rest assured that your code is type-safe though: -you'll get a compiler error if `*arg1` doesn't support the `++` -operator, or if the type of `++(*arg1)` isn't compatible with the mock -function's return type. - -Another example: -``` -ACTION(Foo) { - (*arg2)(5); - Blah(); - *arg1 = 0; - return arg0; -} -``` -defines an action `Foo()` that invokes argument #2 (a function pointer) -with 5, calls function `Blah()`, sets the value pointed to by argument -#1 to 0, and returns argument #0. - -For more convenience and flexibility, you can also use the following -pre-defined symbols in the body of `ACTION`: - -| `argK_type` | The type of the K-th (0-based) argument of the mock function | -|:------------|:-------------------------------------------------------------| -| `args` | All arguments of the mock function as a tuple | -| `args_type` | The type of all arguments of the mock function as a tuple | -| `return_type` | The return type of the mock function | -| `function_type` | The type of the mock function | - -For example, when using an `ACTION` as a stub action for mock function: -``` -int DoSomething(bool flag, int* ptr); -``` -we have: - -| **Pre-defined Symbol** | **Is Bound To** | -|:-----------------------|:----------------| -| `arg0` | the value of `flag` | -| `arg0_type` | the type `bool` | -| `arg1` | the value of `ptr` | -| `arg1_type` | the type `int*` | -| `args` | the tuple `(flag, ptr)` | -| `args_type` | the type `std::tr1::tuple` | -| `return_type` | the type `int` | -| `function_type` | the type `int(bool, int*)` | - -## Writing New Parameterized Actions Quickly ## - -Sometimes you'll want to parameterize an action you define. For that -we have another macro -``` -ACTION_P(name, param) { statements; } -``` - -For example, -``` -ACTION_P(Add, n) { return arg0 + n; } -``` -will allow you to write -``` -// Returns argument #0 + 5. -... WillOnce(Add(5)); -``` - -For convenience, we use the term _arguments_ for the values used to -invoke the mock function, and the term _parameters_ for the values -used to instantiate an action. - -Note that you don't need to provide the type of the parameter either. -Suppose the parameter is named `param`, you can also use the -Google-Mock-defined symbol `param_type` to refer to the type of the -parameter as inferred by the compiler. For example, in the body of -`ACTION_P(Add, n)` above, you can write `n_type` for the type of `n`. - -Google Mock also provides `ACTION_P2`, `ACTION_P3`, and etc to support -multi-parameter actions. For example, -``` -ACTION_P2(ReturnDistanceTo, x, y) { - double dx = arg0 - x; - double dy = arg1 - y; - return sqrt(dx*dx + dy*dy); -} -``` -lets you write -``` -... WillOnce(ReturnDistanceTo(5.0, 26.5)); -``` - -You can view `ACTION` as a degenerated parameterized action where the -number of parameters is 0. - -You can also easily define actions overloaded on the number of parameters: -``` -ACTION_P(Plus, a) { ... } -ACTION_P2(Plus, a, b) { ... } -``` - -## Restricting the Type of an Argument or Parameter in an ACTION ## - -For maximum brevity and reusability, the `ACTION*` macros don't ask -you to provide the types of the mock function arguments and the action -parameters. Instead, we let the compiler infer the types for us. - -Sometimes, however, we may want to be more explicit about the types. -There are several tricks to do that. For example: -``` -ACTION(Foo) { - // Makes sure arg0 can be converted to int. - int n = arg0; - ... use n instead of arg0 here ... -} - -ACTION_P(Bar, param) { - // Makes sure the type of arg1 is const char*. - ::testing::StaticAssertTypeEq(); - - // Makes sure param can be converted to bool. - bool flag = param; -} -``` -where `StaticAssertTypeEq` is a compile-time assertion in Google Test -that verifies two types are the same. - -## Writing New Action Templates Quickly ## - -Sometimes you want to give an action explicit template parameters that -cannot be inferred from its value parameters. `ACTION_TEMPLATE()` -supports that and can be viewed as an extension to `ACTION()` and -`ACTION_P*()`. - -The syntax: -``` -ACTION_TEMPLATE(ActionName, - HAS_m_TEMPLATE_PARAMS(kind1, name1, ..., kind_m, name_m), - AND_n_VALUE_PARAMS(p1, ..., p_n)) { statements; } -``` - -defines an action template that takes _m_ explicit template parameters -and _n_ value parameters, where _m_ is between 1 and 10, and _n_ is -between 0 and 10. `name_i` is the name of the i-th template -parameter, and `kind_i` specifies whether it's a `typename`, an -integral constant, or a template. `p_i` is the name of the i-th value -parameter. - -Example: -``` -// DuplicateArg(output) converts the k-th argument of the mock -// function to type T and copies it to *output. -ACTION_TEMPLATE(DuplicateArg, - // Note the comma between int and k: - HAS_2_TEMPLATE_PARAMS(int, k, typename, T), - AND_1_VALUE_PARAMS(output)) { - *output = T(std::tr1::get(args)); -} -``` - -To create an instance of an action template, write: -``` - ActionName(v1, ..., v_n) -``` -where the `t`s are the template arguments and the -`v`s are the value arguments. The value argument -types are inferred by the compiler. For example: -``` -using ::testing::_; -... - int n; - EXPECT_CALL(mock, Foo(_, _)) - .WillOnce(DuplicateArg<1, unsigned char>(&n)); -``` - -If you want to explicitly specify the value argument types, you can -provide additional template arguments: -``` - ActionName(v1, ..., v_n) -``` -where `u_i` is the desired type of `v_i`. - -`ACTION_TEMPLATE` and `ACTION`/`ACTION_P*` can be overloaded on the -number of value parameters, but not on the number of template -parameters. Without the restriction, the meaning of the following is -unclear: - -``` - OverloadedAction(x); -``` - -Are we using a single-template-parameter action where `bool` refers to -the type of `x`, or a two-template-parameter action where the compiler -is asked to infer the type of `x`? - -## Using the ACTION Object's Type ## - -If you are writing a function that returns an `ACTION` object, you'll -need to know its type. The type depends on the macro used to define -the action and the parameter types. The rule is relatively simple: - -| **Given Definition** | **Expression** | **Has Type** | -|:---------------------|:---------------|:-------------| -| `ACTION(Foo)` | `Foo()` | `FooAction` | -| `ACTION_TEMPLATE(Foo, HAS_m_TEMPLATE_PARAMS(...), AND_0_VALUE_PARAMS())` | `Foo()` | `FooAction` | -| `ACTION_P(Bar, param)` | `Bar(int_value)` | `BarActionP` | -| `ACTION_TEMPLATE(Bar, HAS_m_TEMPLATE_PARAMS(...), AND_1_VALUE_PARAMS(p1))` | `Bar(int_value)` | `FooActionP` | -| `ACTION_P2(Baz, p1, p2)` | `Baz(bool_value, int_value)` | `BazActionP2` | -| `ACTION_TEMPLATE(Baz, HAS_m_TEMPLATE_PARAMS(...), AND_2_VALUE_PARAMS(p1, p2))` | `Baz(bool_value, int_value)` | `FooActionP2` | -| ... | ... | ... | - -Note that we have to pick different suffixes (`Action`, `ActionP`, -`ActionP2`, and etc) for actions with different numbers of value -parameters, or the action definitions cannot be overloaded on the -number of them. - -## Writing New Monomorphic Actions ## - -While the `ACTION*` macros are very convenient, sometimes they are -inappropriate. For example, despite the tricks shown in the previous -recipes, they don't let you directly specify the types of the mock -function arguments and the action parameters, which in general leads -to unoptimized compiler error messages that can baffle unfamiliar -users. They also don't allow overloading actions based on parameter -types without jumping through some hoops. - -An alternative to the `ACTION*` macros is to implement -`::testing::ActionInterface`, where `F` is the type of the mock -function in which the action will be used. For example: - -``` -template class ActionInterface { - public: - virtual ~ActionInterface(); - - // Performs the action. Result is the return type of function type - // F, and ArgumentTuple is the tuple of arguments of F. - // - // For example, if F is int(bool, const string&), then Result would - // be int, and ArgumentTuple would be tr1::tuple. - virtual Result Perform(const ArgumentTuple& args) = 0; -}; - -using ::testing::_; -using ::testing::Action; -using ::testing::ActionInterface; -using ::testing::MakeAction; - -typedef int IncrementMethod(int*); - -class IncrementArgumentAction : public ActionInterface { - public: - virtual int Perform(const tr1::tuple& args) { - int* p = tr1::get<0>(args); // Grabs the first argument. - return *p++; - } -}; - -Action IncrementArgument() { - return MakeAction(new IncrementArgumentAction); -} -... - - EXPECT_CALL(foo, Baz(_)) - .WillOnce(IncrementArgument()); - - int n = 5; - foo.Baz(&n); // Should return 5 and change n to 6. -``` - -## Writing New Polymorphic Actions ## - -The previous recipe showed you how to define your own action. This is -all good, except that you need to know the type of the function in -which the action will be used. Sometimes that can be a problem. For -example, if you want to use the action in functions with _different_ -types (e.g. like `Return()` and `SetArgumentPointee()`). - -If an action can be used in several types of mock functions, we say -it's _polymorphic_. The `MakePolymorphicAction()` function template -makes it easy to define such an action: - -``` -namespace testing { - -template -PolymorphicAction MakePolymorphicAction(const Impl& impl); - -} // namespace testing -``` - -As an example, let's define an action that returns the second argument -in the mock function's argument list. The first step is to define an -implementation class: - -``` -class ReturnSecondArgumentAction { - public: - template - Result Perform(const ArgumentTuple& args) const { - // To get the i-th (0-based) argument, use tr1::get(args). - return tr1::get<1>(args); - } -}; -``` - -This implementation class does _not_ need to inherit from any -particular class. What matters is that it must have a `Perform()` -method template. This method template takes the mock function's -arguments as a tuple in a **single** argument, and returns the result of -the action. It can be either `const` or not, but must be invokable -with exactly one template argument, which is the result type. In other -words, you must be able to call `Perform(args)` where `R` is the -mock function's return type and `args` is its arguments in a tuple. - -Next, we use `MakePolymorphicAction()` to turn an instance of the -implementation class into the polymorphic action we need. It will be -convenient to have a wrapper for this: - -``` -using ::testing::MakePolymorphicAction; -using ::testing::PolymorphicAction; - -PolymorphicAction ReturnSecondArgument() { - return MakePolymorphicAction(ReturnSecondArgumentAction()); -} -``` - -Now, you can use this polymorphic action the same way you use the -built-in ones: - -``` -using ::testing::_; - -class MockFoo : public Foo { - public: - MOCK_METHOD2(DoThis, int(bool flag, int n)); - MOCK_METHOD3(DoThat, string(int x, const char* str1, const char* str2)); -}; -... - - MockFoo foo; - EXPECT_CALL(foo, DoThis(_, _)) - .WillOnce(ReturnSecondArgument()); - EXPECT_CALL(foo, DoThat(_, _, _)) - .WillOnce(ReturnSecondArgument()); - ... - foo.DoThis(true, 5); // Will return 5. - foo.DoThat(1, "Hi", "Bye"); // Will return "Hi". -``` - -## Teaching Google Mock How to Print Your Values ## - -When an uninteresting or unexpected call occurs, Google Mock prints -the argument values to help you debug. The `EXPECT_THAT` and -`ASSERT_THAT` assertions also print the value being validated when the -test fails. Google Mock does this using the user-extensible value -printer defined in ``. - -This printer knows how to print the built-in C++ types, native arrays, -STL containers, and any type that supports the `<<` operator. For -other types, it prints the raw bytes in the value and hope you the -user can figure it out. - -Did I say that the printer is `extensible`? That means you can teach -it to do a better job at printing your particular type than to dump -the bytes. To do that, you just need to define `<<` for your type: - -``` -#include - -namespace foo { - -class Foo { ... }; - -// It's important that the << operator is defined in the SAME -// namespace that defines Foo. C++'s look-up rules rely on that. -::std::ostream& operator<<(::std::ostream& os, const Foo& foo) { - return os << foo.DebugString(); // Whatever needed to print foo to os. -} - -} // namespace foo -``` - -Sometimes, this might not be an option. For example, your team may -consider it dangerous or bad style to have a `<<` operator for `Foo`, -or `Foo` may already have a `<<` operator that doesn't do what you -want (and you cannot change it). Don't despair though - Google Mock -gives you a second chance to get it right. Namely, you can define a -`PrintTo()` function like this: - -``` -#include - -namespace foo { - -class Foo { ... }; - -// It's important that PrintTo() is defined in the SAME -// namespace that defines Foo. C++'s look-up rules rely on that. -void PrintTo(const Foo& foo, ::std::ostream* os) { - *os << foo.DebugString(); // Whatever needed to print foo to os. -} - -} // namespace foo -``` - -What if you have both `<<` and `PrintTo()`? In this case, the latter -will override the former when Google Mock is concerned. This allows -you to customize how the value should appear in Google Mock's output -without affecting code that relies on the behavior of its `<<` -operator. - -**Note:** When printing a pointer of type `T*`, Google Mock calls -`PrintTo(T*, std::ostream* os)` instead of `operator<<(std::ostream&, T*)`. -Therefore the only way to affect how a pointer is printed by Google -Mock is to define `PrintTo()` for it. Also note that `T*` and `const T*` -are different types, so you may need to define `PrintTo()` for both. - -Why does Google Mock treat pointers specially? There are several reasons: - - * We cannot use `operator<<` to print a `signed char*` or `unsigned char*`, since it will print the pointer as a NUL-terminated C string, which likely will cause an access violation. - * We want `NULL` pointers to be printed as `"NULL"`, but `operator<<` prints it as `"0"`, `"nullptr"`, or something else, depending on the compiler. - * With some compilers, printing a `NULL` `char*` using `operator<<` will segfault. - * `operator<<` prints a function pointer as a `bool` (hence it always prints `"1"`), which is not very useful. \ No newline at end of file diff --git a/googlemock/docs/v1_5/Documentation.md b/googlemock/docs/v1_5/Documentation.md deleted file mode 100644 index 315b0a29..00000000 --- a/googlemock/docs/v1_5/Documentation.md +++ /dev/null @@ -1,11 +0,0 @@ -This page lists all documentation wiki pages for Google Mock **version 1.5.0** -- **if you use a different version of Google Mock, please read the documentation for that specific version instead.** - - * [ForDummies](V1_5_ForDummies.md) -- start here if you are new to Google Mock. - * [CheatSheet](V1_5_CheatSheet.md) -- a quick reference. - * [CookBook](V1_5_CookBook.md) -- recipes for doing various tasks using Google Mock. - * [FrequentlyAskedQuestions](V1_5_FrequentlyAskedQuestions.md) -- check here before asking a question on the mailing list. - -To contribute code to Google Mock, read: - - * DevGuide -- read this _before_ writing your first patch. - * [Pump Manual](http://code.google.com/p/googletest/wiki/PumpManual) -- how we generate some of Google Mock's source files. \ No newline at end of file diff --git a/googlemock/docs/v1_5/ForDummies.md b/googlemock/docs/v1_5/ForDummies.md deleted file mode 100644 index fcc3b561..00000000 --- a/googlemock/docs/v1_5/ForDummies.md +++ /dev/null @@ -1,439 +0,0 @@ - - -(**Note:** If you get compiler errors that you don't understand, be sure to consult [Google Mock Doctor](V1_5_FrequentlyAskedQuestions#How_am_I_supposed_to_make_sense_of_these_horrible_template_error.md).) - -# What Is Google C++ Mocking Framework? # -When you write a prototype or test, often it's not feasible or wise to rely on real objects entirely. A **mock object** implements the same interface as a real object (so it can be used as one), but lets you specify at run time how it will be used and what it should do (which methods will be called? in which order? how many times? with what arguments? what will they return? etc). - -**Note:** It is easy to confuse the term _fake objects_ with mock objects. Fakes and mocks actually mean very different things in the Test-Driven Development (TDD) community: - - * **Fake** objects have working implementations, but usually take some shortcut (perhaps to make the operations less expensive), which makes them not suitable for production. An in-memory file system would be an example of a fake. - * **Mocks** are objects pre-programmed with _expectations_, which form a specification of the calls they are expected to receive. - -If all this seems too abstract for you, don't worry - the most important thing to remember is that a mock allows you to check the _interaction_ between itself and code that uses it. The difference between fakes and mocks will become much clearer once you start to use mocks. - -**Google C++ Mocking Framework** (or **Google Mock** for short) is a library (sometimes we also call it a "framework" to make it sound cool) for creating mock classes and using them. It does to C++ what [jMock](http://www.jmock.org/) and [EasyMock](http://www.easymock.org/) do to Java. - -Using Google Mock involves three basic steps: - - 1. Use some simple macros to describe the interface you want to mock, and they will expand to the implementation of your mock class; - 1. Create some mock objects and specify its expectations and behavior using an intuitive syntax; - 1. Exercise code that uses the mock objects. Google Mock will catch any violation of the expectations as soon as it arises. - -# Why Google Mock? # -While mock objects help you remove unnecessary dependencies in tests and make them fast and reliable, using mocks manually in C++ is _hard_: - - * Someone has to implement the mocks. The job is usually tedious and error-prone. No wonder people go great distance to avoid it. - * The quality of those manually written mocks is a bit, uh, unpredictable. You may see some really polished ones, but you may also see some that were hacked up in a hurry and have all sorts of ad hoc restrictions. - * The knowledge you gained from using one mock doesn't transfer to the next. - -In contrast, Java and Python programmers have some fine mock frameworks, which automate the creation of mocks. As a result, mocking is a proven effective technique and widely adopted practice in those communities. Having the right tool absolutely makes the difference. - -Google Mock was built to help C++ programmers. It was inspired by [jMock](http://www.jmock.org/) and [EasyMock](http://www.easymock.org/), but designed with C++'s specifics in mind. It is your friend if any of the following problems is bothering you: - - * You are stuck with a sub-optimal design and wish you had done more prototyping before it was too late, but prototyping in C++ is by no means "rapid". - * Your tests are slow as they depend on too many libraries or use expensive resources (e.g. a database). - * Your tests are brittle as some resources they use are unreliable (e.g. the network). - * You want to test how your code handles a failure (e.g. a file checksum error), but it's not easy to cause one. - * You need to make sure that your module interacts with other modules in the right way, but it's hard to observe the interaction; therefore you resort to observing the side effects at the end of the action, which is awkward at best. - * You want to "mock out" your dependencies, except that they don't have mock implementations yet; and, frankly, you aren't thrilled by some of those hand-written mocks. - -We encourage you to use Google Mock as: - - * a _design_ tool, for it lets you experiment with your interface design early and often. More iterations lead to better designs! - * a _testing_ tool to cut your tests' outbound dependencies and probe the interaction between your module and its collaborators. - -# Getting Started # -Using Google Mock is easy! Inside your C++ source file, just `#include` `` and ``, and you are ready to go. - -# A Case for Mock Turtles # -Let's look at an example. Suppose you are developing a graphics program that relies on a LOGO-like API for drawing. How would you test that it does the right thing? Well, you can run it and compare the screen with a golden screen snapshot, but let's admit it: tests like this are expensive to run and fragile (What if you just upgraded to a shiny new graphics card that has better anti-aliasing? Suddenly you have to update all your golden images.). It would be too painful if all your tests are like this. Fortunately, you learned about Dependency Injection and know the right thing to do: instead of having your application talk to the drawing API directly, wrap the API in an interface (say, `Turtle`) and code to that interface: - -``` -class Turtle { - ... - virtual ~Turtle() {} - virtual void PenUp() = 0; - virtual void PenDown() = 0; - virtual void Forward(int distance) = 0; - virtual void Turn(int degrees) = 0; - virtual void GoTo(int x, int y) = 0; - virtual int GetX() const = 0; - virtual int GetY() const = 0; -}; -``` - -(Note that the destructor of `Turtle` **must** be virtual, as is the case for **all** classes you intend to inherit from - otherwise the destructor of the derived class will not be called when you delete an object through a base pointer, and you'll get corrupted program states like memory leaks.) - -You can control whether the turtle's movement will leave a trace using `PenUp()` and `PenDown()`, and control its movement using `Forward()`, `Turn()`, and `GoTo()`. Finally, `GetX()` and `GetY()` tell you the current position of the turtle. - -Your program will normally use a real implementation of this interface. In tests, you can use a mock implementation instead. This allows you to easily check what drawing primitives your program is calling, with what arguments, and in which order. Tests written this way are much more robust (they won't break because your new machine does anti-aliasing differently), easier to read and maintain (the intent of a test is expressed in the code, not in some binary images), and run _much, much faster_. - -# Writing the Mock Class # -If you are lucky, the mocks you need to use have already been implemented by some nice people. If, however, you find yourself in the position to write a mock class, relax - Google Mock turns this task into a fun game! (Well, almost.) - -## How to Define It ## -Using the `Turtle` interface as example, here are the simple steps you need to follow: - - 1. Derive a class `MockTurtle` from `Turtle`. - 1. Take a virtual function of `Turtle`. Count how many arguments it has. - 1. In the `public:` section of the child class, write `MOCK_METHODn();` (or `MOCK_CONST_METHODn();` if you are mocking a `const` method), where `n` is the number of the arguments; if you counted wrong, shame on you, and a compiler error will tell you so. - 1. Now comes the fun part: you take the function signature, cut-and-paste the _function name_ as the _first_ argument to the macro, and leave what's left as the _second_ argument (in case you're curious, this is the _type of the function_). - 1. Repeat until all virtual functions you want to mock are done. - -After the process, you should have something like: - -``` -#include // Brings in Google Mock. -class MockTurtle : public Turtle { - public: - ... - MOCK_METHOD0(PenUp, void()); - MOCK_METHOD0(PenDown, void()); - MOCK_METHOD1(Forward, void(int distance)); - MOCK_METHOD1(Turn, void(int degrees)); - MOCK_METHOD2(GoTo, void(int x, int y)); - MOCK_CONST_METHOD0(GetX, int()); - MOCK_CONST_METHOD0(GetY, int()); -}; -``` - -You don't need to define these mock methods somewhere else - the `MOCK_METHOD*` macros will generate the definitions for you. It's that simple! Once you get the hang of it, you can pump out mock classes faster than your source-control system can handle your check-ins. - -**Tip:** If even this is too much work for you, you'll find the -`gmock_gen.py` tool in Google Mock's `scripts/generator/` directory (courtesy of the [cppclean](http://code.google.com/p/cppclean/) project) useful. This command-line -tool requires that you have Python 2.4 installed. You give it a C++ file and the name of an abstract class defined in it, -and it will print the definition of the mock class for you. Due to the -complexity of the C++ language, this script may not always work, but -it can be quite handy when it does. For more details, read the [user documentation](http://code.google.com/p/googlemock/source/browse/trunk/scripts/generator/README). - -## Where to Put It ## -When you define a mock class, you need to decide where to put its definition. Some people put it in a `*_test.cc`. This is fine when the interface being mocked (say, `Foo`) is owned by the same person or team. Otherwise, when the owner of `Foo` changes it, your test could break. (You can't really expect `Foo`'s maintainer to fix every test that uses `Foo`, can you?) - -So, the rule of thumb is: if you need to mock `Foo` and it's owned by others, define the mock class in `Foo`'s package (better, in a `testing` sub-package such that you can clearly separate production code and testing utilities), and put it in a `mock_foo.h`. Then everyone can reference `mock_foo.h` from their tests. If `Foo` ever changes, there is only one copy of `MockFoo` to change, and only tests that depend on the changed methods need to be fixed. - -Another way to do it: you can introduce a thin layer `FooAdaptor` on top of `Foo` and code to this new interface. Since you own `FooAdaptor`, you can absorb changes in `Foo` much more easily. While this is more work initially, carefully choosing the adaptor interface can make your code easier to write and more readable (a net win in the long run), as you can choose `FooAdaptor` to fit your specific domain much better than `Foo` does. - -# Using Mocks in Tests # -Once you have a mock class, using it is easy. The typical work flow is: - - 1. Import the Google Mock names from the `testing` namespace such that you can use them unqualified (You only have to do it once per file. Remember that namespaces are a good idea and good for your health.). - 1. Create some mock objects. - 1. Specify your expectations on them (How many times will a method be called? With what arguments? What should it do? etc.). - 1. Exercise some code that uses the mocks; optionally, check the result using Google Test assertions. If a mock method is called more than expected or with wrong arguments, you'll get an error immediately. - 1. When a mock is destructed, Google Mock will automatically check whether all expectations on it have been satisfied. - -Here's an example: - -``` -#include "path/to/mock-turtle.h" -#include -#include -using ::testing::AtLeast; // #1 - -TEST(PainterTest, CanDrawSomething) { - MockTurtle turtle; // #2 - EXPECT_CALL(turtle, PenDown()) // #3 - .Times(AtLeast(1)); - - Painter painter(&turtle); // #4 - - EXPECT_TRUE(painter.DrawCircle(0, 0, 10)); -} // #5 - -int main(int argc, char** argv) { - // The following line must be executed to initialize Google Mock - // (and Google Test) before running the tests. - ::testing::InitGoogleMock(&argc, argv); - return RUN_ALL_TESTS(); -} -``` - -As you might have guessed, this test checks that `PenDown()` is called at least once. If the `painter` object didn't call this method, your test will fail with a message like this: - -``` -path/to/my_test.cc:119: Failure -Actual function call count doesn't match this expectation: -Actually: never called; -Expected: called at least once. -``` - -**Tip 1:** If you run the test from an Emacs buffer, you can hit `` on the line number displayed in the error message to jump right to the failed expectation. - -**Tip 2:** If your mock objects are never deleted, the final verification won't happen. Therefore it's a good idea to use a heap leak checker in your tests when you allocate mocks on the heap. - -**Important note:** Google Mock requires expectations to be set **before** the mock functions are called, otherwise the behavior is **undefined**. In particular, you mustn't interleave `EXPECT_CALL()`s and calls to the mock functions. - -This means `EXPECT_CALL()` should be read as expecting that a call will occur _in the future_, not that a call has occurred. Why does Google Mock work like that? Well, specifying the expectation beforehand allows Google Mock to report a violation as soon as it arises, when the context (stack trace, etc) is still available. This makes debugging much easier. - -Admittedly, this test is contrived and doesn't do much. You can easily achieve the same effect without using Google Mock. However, as we shall reveal soon, Google Mock allows you to do _much more_ with the mocks. - -## Using Google Mock with Any Testing Framework ## -If you want to use something other than Google Test (e.g. [CppUnit](http://apps.sourceforge.net/mediawiki/cppunit/index.php?title=Main_Page) or -[CxxTest](http://cxxtest.tigris.org/)) as your testing framework, just change the `main()` function in the previous section to: -``` -int main(int argc, char** argv) { - // The following line causes Google Mock to throw an exception on failure, - // which will be interpreted by your testing framework as a test failure. - ::testing::GTEST_FLAG(throw_on_failure) = true; - ::testing::InitGoogleMock(&argc, argv); - ... whatever your testing framework requires ... -} -``` - -This approach has a catch: it makes Google Mock throw an exception -from a mock object's destructor sometimes. With some compilers, this -sometimes causes the test program to crash. You'll still be able to -notice that the test has failed, but it's not a graceful failure. - -A better solution is to use Google Test's -[event listener API](http://code.google.com/p/googletest/wiki/GoogleTestAdvancedGuide#Extending_Google_Test_by_Handling_Test_Events) -to report a test failure to your testing framework properly. You'll need to -implement the `OnTestPartResult()` method of the event listener interface, but it -should be straightforward. - -If this turns out to be too much work, we suggest that you stick with -Google Test, which works with Google Mock seamlessly (in fact, it is -technically part of Google Mock.). If there is a reason that you -cannot use Google Test, please let us know. - -# Setting Expectations # -The key to using a mock object successfully is to set the _right expectations_ on it. If you set the expectations too strict, your test will fail as the result of unrelated changes. If you set them too loose, bugs can slip through. You want to do it just right such that your test can catch exactly the kind of bugs you intend it to catch. Google Mock provides the necessary means for you to do it "just right." - -## General Syntax ## -In Google Mock we use the `EXPECT_CALL()` macro to set an expectation on a mock method. The general syntax is: - -``` -EXPECT_CALL(mock_object, method(matchers)) - .Times(cardinality) - .WillOnce(action) - .WillRepeatedly(action); -``` - -The macro has two arguments: first the mock object, and then the method and its arguments. Note that the two are separated by a comma (`,`), not a period (`.`). (Why using a comma? The answer is that it was necessary for technical reasons.) - -The macro can be followed by some optional _clauses_ that provide more information about the expectation. We'll discuss how each clause works in the coming sections. - -This syntax is designed to make an expectation read like English. For example, you can probably guess that - -``` -using ::testing::Return;... -EXPECT_CALL(turtle, GetX()) - .Times(5) - .WillOnce(Return(100)) - .WillOnce(Return(150)) - .WillRepeatedly(Return(200)); -``` - -says that the `turtle` object's `GetX()` method will be called five times, it will return 100 the first time, 150 the second time, and then 200 every time. Some people like to call this style of syntax a Domain-Specific Language (DSL). - -**Note:** Why do we use a macro to do this? It serves two purposes: first it makes expectations easily identifiable (either by `grep` or by a human reader), and second it allows Google Mock to include the source file location of a failed expectation in messages, making debugging easier. - -## Matchers: What Arguments Do We Expect? ## -When a mock function takes arguments, we must specify what arguments we are expecting; for example: - -``` -// Expects the turtle to move forward by 100 units. -EXPECT_CALL(turtle, Forward(100)); -``` - -Sometimes you may not want to be too specific (Remember that talk about tests being too rigid? Over specification leads to brittle tests and obscures the intent of tests. Therefore we encourage you to specify only what's necessary - no more, no less.). If you care to check that `Forward()` will be called but aren't interested in its actual argument, write `_` as the argument, which means "anything goes": - -``` -using ::testing::_; -... -// Expects the turtle to move forward. -EXPECT_CALL(turtle, Forward(_)); -``` - -`_` is an instance of what we call **matchers**. A matcher is like a predicate and can test whether an argument is what we'd expect. You can use a matcher inside `EXPECT_CALL()` wherever a function argument is expected. - -A list of built-in matchers can be found in the [CheatSheet](V1_5_CheatSheet.md). For example, here's the `Ge` (greater than or equal) matcher: - -``` -using ::testing::Ge;... -EXPECT_CALL(turtle, Forward(Ge(100))); -``` - -This checks that the turtle will be told to go forward by at least 100 units. - -## Cardinalities: How Many Times Will It Be Called? ## -The first clause we can specify following an `EXPECT_CALL()` is `Times()`. We call its argument a **cardinality** as it tells _how many times_ the call should occur. It allows us to repeat an expectation many times without actually writing it as many times. More importantly, a cardinality can be "fuzzy", just like a matcher can be. This allows a user to express the intent of a test exactly. - -An interesting special case is when we say `Times(0)`. You may have guessed - it means that the function shouldn't be called with the given arguments at all, and Google Mock will report a Google Test failure whenever the function is (wrongfully) called. - -We've seen `AtLeast(n)` as an example of fuzzy cardinalities earlier. For the list of built-in cardinalities you can use, see the [CheatSheet](V1_5_CheatSheet.md). - -The `Times()` clause can be omitted. **If you omit `Times()`, Google Mock will infer the cardinality for you.** The rules are easy to remember: - - * If **neither** `WillOnce()` **nor** `WillRepeatedly()` is in the `EXPECT_CALL()`, the inferred cardinality is `Times(1)`. - * If there are `n WillOnce()`'s but **no** `WillRepeatedly()`, where `n` >= 1, the cardinality is `Times(n)`. - * If there are `n WillOnce()`'s and **one** `WillRepeatedly()`, where `n` >= 0, the cardinality is `Times(AtLeast(n))`. - -**Quick quiz:** what do you think will happen if a function is expected to be called twice but actually called four times? - -## Actions: What Should It Do? ## -Remember that a mock object doesn't really have a working implementation? We as users have to tell it what to do when a method is invoked. This is easy in Google Mock. - -First, if the return type of a mock function is a built-in type or a pointer, the function has a **default action** (a `void` function will just return, a `bool` function will return `false`, and other functions will return 0). If you don't say anything, this behavior will be used. - -Second, if a mock function doesn't have a default action, or the default action doesn't suit you, you can specify the action to be taken each time the expectation matches using a series of `WillOnce()` clauses followed by an optional `WillRepeatedly()`. For example, - -``` -using ::testing::Return;... -EXPECT_CALL(turtle, GetX()) - .WillOnce(Return(100)) - .WillOnce(Return(200)) - .WillOnce(Return(300)); -``` - -This says that `turtle.GetX()` will be called _exactly three times_ (Google Mock inferred this from how many `WillOnce()` clauses we've written, since we didn't explicitly write `Times()`), and will return 100, 200, and 300 respectively. - -``` -using ::testing::Return;... -EXPECT_CALL(turtle, GetY()) - .WillOnce(Return(100)) - .WillOnce(Return(200)) - .WillRepeatedly(Return(300)); -``` - -says that `turtle.GetY()` will be called _at least twice_ (Google Mock knows this as we've written two `WillOnce()` clauses and a `WillRepeatedly()` while having no explicit `Times()`), will return 100 the first time, 200 the second time, and 300 from the third time on. - -Of course, if you explicitly write a `Times()`, Google Mock will not try to infer the cardinality itself. What if the number you specified is larger than there are `WillOnce()` clauses? Well, after all `WillOnce()`s are used up, Google Mock will do the _default_ action for the function every time (unless, of course, you have a `WillRepeatedly()`.). - -What can we do inside `WillOnce()` besides `Return()`? You can return a reference using `ReturnRef(variable)`, or invoke a pre-defined function, among [others](V1_5_CheatSheet#Actions.md). - -**Important note:** The `EXPECT_CALL()` statement evaluates the action clause only once, even though the action may be performed many times. Therefore you must be careful about side effects. The following may not do what you want: - -``` -int n = 100; -EXPECT_CALL(turtle, GetX()) -.Times(4) -.WillOnce(Return(n++)); -``` - -Instead of returning 100, 101, 102, ..., consecutively, this mock function will always return 100 as `n++` is only evaluated once. Similarly, `Return(new Foo)` will create a new `Foo` object when the `EXPECT_CALL()` is executed, and will return the same pointer every time. If you want the side effect to happen every time, you need to define a custom action, which we'll teach in the [CookBook](V1_5_CookBook.md). - -Time for another quiz! What do you think the following means? - -``` -using ::testing::Return;... -EXPECT_CALL(turtle, GetY()) -.Times(4) -.WillOnce(Return(100)); -``` - -Obviously `turtle.GetY()` is expected to be called four times. But if you think it will return 100 every time, think twice! Remember that one `WillOnce()` clause will be consumed each time the function is invoked and the default action will be taken afterwards. So the right answer is that `turtle.GetY()` will return 100 the first time, but **return 0 from the second time on**, as returning 0 is the default action for `int` functions. - -## Using Multiple Expectations ## -So far we've only shown examples where you have a single expectation. More realistically, you're going to specify expectations on multiple mock methods, which may be from multiple mock objects. - -By default, when a mock method is invoked, Google Mock will search the expectations in the **reverse order** they are defined, and stop when an active expectation that matches the arguments is found (you can think of it as "newer rules override older ones."). If the matching expectation cannot take any more calls, you will get an upper-bound-violated failure. Here's an example: - -``` -using ::testing::_;... -EXPECT_CALL(turtle, Forward(_)); // #1 -EXPECT_CALL(turtle, Forward(10)) // #2 - .Times(2); -``` - -If `Forward(10)` is called three times in a row, the third time it will be an error, as the last matching expectation (#2) has been saturated. If, however, the third `Forward(10)` call is replaced by `Forward(20)`, then it would be OK, as now #1 will be the matching expectation. - -**Side note:** Why does Google Mock search for a match in the _reverse_ order of the expectations? The reason is that this allows a user to set up the default expectations in a mock object's constructor or the test fixture's set-up phase and then customize the mock by writing more specific expectations in the test body. So, if you have two expectations on the same method, you want to put the one with more specific matchers **after** the other, or the more specific rule would be shadowed by the more general one that comes after it. - -## Ordered vs Unordered Calls ## -By default, an expectation can match a call even though an earlier expectation hasn't been satisfied. In other words, the calls don't have to occur in the order the expectations are specified. - -Sometimes, you may want all the expected calls to occur in a strict order. To say this in Google Mock is easy: - -``` -using ::testing::InSequence;... -TEST(FooTest, DrawsLineSegment) { - ... - { - InSequence dummy; - - EXPECT_CALL(turtle, PenDown()); - EXPECT_CALL(turtle, Forward(100)); - EXPECT_CALL(turtle, PenUp()); - } - Foo(); -} -``` - -By creating an object of type `InSequence`, all expectations in its scope are put into a _sequence_ and have to occur _sequentially_. Since we are just relying on the constructor and destructor of this object to do the actual work, its name is really irrelevant. - -In this example, we test that `Foo()` calls the three expected functions in the order as written. If a call is made out-of-order, it will be an error. - -(What if you care about the relative order of some of the calls, but not all of them? Can you specify an arbitrary partial order? The answer is ... yes! If you are impatient, the details can be found in the [CookBook](V1_5_CookBook.md).) - -## All Expectations Are Sticky (Unless Said Otherwise) ## -Now let's do a quick quiz to see how well you can use this mock stuff already. How would you test that the turtle is asked to go to the origin _exactly twice_ (you want to ignore any other instructions it receives)? - -After you've come up with your answer, take a look at ours and compare notes (solve it yourself first - don't cheat!): - -``` -using ::testing::_;... -EXPECT_CALL(turtle, GoTo(_, _)) // #1 - .Times(AnyNumber()); -EXPECT_CALL(turtle, GoTo(0, 0)) // #2 - .Times(2); -``` - -Suppose `turtle.GoTo(0, 0)` is called three times. In the third time, Google Mock will see that the arguments match expectation #2 (remember that we always pick the last matching expectation). Now, since we said that there should be only two such calls, Google Mock will report an error immediately. This is basically what we've told you in the "Using Multiple Expectations" section above. - -This example shows that **expectations in Google Mock are "sticky" by default**, in the sense that they remain active even after we have reached their invocation upper bounds. This is an important rule to remember, as it affects the meaning of the spec, and is **different** to how it's done in many other mocking frameworks (Why'd we do that? Because we think our rule makes the common cases easier to express and understand.). - -Simple? Let's see if you've really understood it: what does the following code say? - -``` -using ::testing::Return; -... -for (int i = n; i > 0; i--) { - EXPECT_CALL(turtle, GetX()) - .WillOnce(Return(10*i)); -} -``` - -If you think it says that `turtle.GetX()` will be called `n` times and will return 10, 20, 30, ..., consecutively, think twice! The problem is that, as we said, expectations are sticky. So, the second time `turtle.GetX()` is called, the last (latest) `EXPECT_CALL()` statement will match, and will immediately lead to an "upper bound exceeded" error - this piece of code is not very useful! - -One correct way of saying that `turtle.GetX()` will return 10, 20, 30, ..., is to explicitly say that the expectations are _not_ sticky. In other words, they should _retire_ as soon as they are saturated: - -``` -using ::testing::Return; -... -for (int i = n; i > 0; i--) { - EXPECT_CALL(turtle, GetX()) - .WillOnce(Return(10*i)) - .RetiresOnSaturation(); -} -``` - -And, there's a better way to do it: in this case, we expect the calls to occur in a specific order, and we line up the actions to match the order. Since the order is important here, we should make it explicit using a sequence: - -``` -using ::testing::InSequence; -using ::testing::Return; -... -{ - InSequence s; - - for (int i = 1; i <= n; i++) { - EXPECT_CALL(turtle, GetX()) - .WillOnce(Return(10*i)) - .RetiresOnSaturation(); - } -} -``` - -By the way, the other situation where an expectation may _not_ be sticky is when it's in a sequence - as soon as another expectation that comes after it in the sequence has been used, it automatically retires (and will never be used to match any call). - -## Uninteresting Calls ## -A mock object may have many methods, and not all of them are that interesting. For example, in some tests we may not care about how many times `GetX()` and `GetY()` get called. - -In Google Mock, if you are not interested in a method, just don't say anything about it. If a call to this method occurs, you'll see a warning in the test output, but it won't be a failure. - -# What Now? # -Congratulations! You've learned enough about Google Mock to start using it. Now, you might want to join the [googlemock](http://groups.google.com/group/googlemock) discussion group and actually write some tests using Google Mock - it will be fun. Hey, it may even be addictive - you've been warned. - -Then, if you feel like increasing your mock quotient, you should move on to the [CookBook](V1_5_CookBook.md). You can learn many advanced features of Google Mock there -- and advance your level of enjoyment and testing bliss. \ No newline at end of file diff --git a/googlemock/docs/v1_5/FrequentlyAskedQuestions.md b/googlemock/docs/v1_5/FrequentlyAskedQuestions.md deleted file mode 100644 index 7593243c..00000000 --- a/googlemock/docs/v1_5/FrequentlyAskedQuestions.md +++ /dev/null @@ -1,624 +0,0 @@ - - -Please send your questions to the -[googlemock](http://groups.google.com/group/googlemock) discussion -group. If you need help with compiler errors, make sure you have -tried [Google Mock Doctor](#How_am_I_supposed_to_make_sense_of_these_horrible_template_error.md) first. - -## I wrote some matchers. After I upgraded to a new version of Google Mock, they no longer compile. What's going on? ## - -After version 1.4.0 of Google Mock was released, we had an idea on how -to make it easier to write matchers that can generate informative -messages efficiently. We experimented with this idea and liked what -we saw. Therefore we decided to implement it. - -Unfortunately, this means that if you have defined your own matchers -by implementing `MatcherInterface` or using `MakePolymorphicMatcher()`, -your definitions will no longer compile. Matchers defined using the -`MATCHER*` family of macros are not affected. - -Sorry for the hassle if your matchers are affected. We believe it's -in everyone's long-term interest to make this change sooner than -later. Fortunately, it's usually not hard to migrate an existing -matcher to the new API. Here's what you need to do: - -If you wrote your matcher like this: -``` -// Old matcher definition that doesn't work with the latest -// Google Mock. -using ::testing::MatcherInterface; -... -class MyWonderfulMatcher : public MatcherInterface { - public: - ... - virtual bool Matches(MyType value) const { - // Returns true if value matches. - return value.GetFoo() > 5; - } - ... -}; -``` - -you'll need to change it to: -``` -// New matcher definition that works with the latest Google Mock. -using ::testing::MatcherInterface; -using ::testing::MatchResultListener; -... -class MyWonderfulMatcher : public MatcherInterface { - public: - ... - virtual bool MatchAndExplain(MyType value, - MatchResultListener* listener) const { - // Returns true if value matches. - return value.GetFoo() > 5; - } - ... -}; -``` -(i.e. rename `Matches()` to `MatchAndExplain()` and give it a second -argument of type `MatchResultListener*`.) - -If you were also using `ExplainMatchResultTo()` to improve the matcher -message: -``` -// Old matcher definition that doesn't work with the lastest -// Google Mock. -using ::testing::MatcherInterface; -... -class MyWonderfulMatcher : public MatcherInterface { - public: - ... - virtual bool Matches(MyType value) const { - // Returns true if value matches. - return value.GetFoo() > 5; - } - - virtual void ExplainMatchResultTo(MyType value, - ::std::ostream* os) const { - // Prints some helpful information to os to help - // a user understand why value matches (or doesn't match). - *os << "the Foo property is " << value.GetFoo(); - } - ... -}; -``` - -you should move the logic of `ExplainMatchResultTo()` into -`MatchAndExplain()`, using the `MatchResultListener` argument where -the `::std::ostream` was used: -``` -// New matcher definition that works with the latest Google Mock. -using ::testing::MatcherInterface; -using ::testing::MatchResultListener; -... -class MyWonderfulMatcher : public MatcherInterface { - public: - ... - virtual bool MatchAndExplain(MyType value, - MatchResultListener* listener) const { - // Returns true if value matches. - *listener << "the Foo property is " << value.GetFoo(); - return value.GetFoo() > 5; - } - ... -}; -``` - -If your matcher is defined using `MakePolymorphicMatcher()`: -``` -// Old matcher definition that doesn't work with the latest -// Google Mock. -using ::testing::MakePolymorphicMatcher; -... -class MyGreatMatcher { - public: - ... - bool Matches(MyType value) const { - // Returns true if value matches. - return value.GetBar() < 42; - } - ... -}; -... MakePolymorphicMatcher(MyGreatMatcher()) ... -``` - -you should rename the `Matches()` method to `MatchAndExplain()` and -add a `MatchResultListener*` argument (the same as what you need to do -for matchers defined by implementing `MatcherInterface`): -``` -// New matcher definition that works with the latest Google Mock. -using ::testing::MakePolymorphicMatcher; -using ::testing::MatchResultListener; -... -class MyGreatMatcher { - public: - ... - bool MatchAndExplain(MyType value, - MatchResultListener* listener) const { - // Returns true if value matches. - return value.GetBar() < 42; - } - ... -}; -... MakePolymorphicMatcher(MyGreatMatcher()) ... -``` - -If your polymorphic matcher uses `ExplainMatchResultTo()` for better -failure messages: -``` -// Old matcher definition that doesn't work with the latest -// Google Mock. -using ::testing::MakePolymorphicMatcher; -... -class MyGreatMatcher { - public: - ... - bool Matches(MyType value) const { - // Returns true if value matches. - return value.GetBar() < 42; - } - ... -}; -void ExplainMatchResultTo(const MyGreatMatcher& matcher, - MyType value, - ::std::ostream* os) { - // Prints some helpful information to os to help - // a user understand why value matches (or doesn't match). - *os << "the Bar property is " << value.GetBar(); -} -... MakePolymorphicMatcher(MyGreatMatcher()) ... -``` - -you'll need to move the logic inside `ExplainMatchResultTo()` to -`MatchAndExplain()`: -``` -// New matcher definition that works with the latest Google Mock. -using ::testing::MakePolymorphicMatcher; -using ::testing::MatchResultListener; -... -class MyGreatMatcher { - public: - ... - bool MatchAndExplain(MyType value, - MatchResultListener* listener) const { - // Returns true if value matches. - *listener << "the Bar property is " << value.GetBar(); - return value.GetBar() < 42; - } - ... -}; -... MakePolymorphicMatcher(MyGreatMatcher()) ... -``` - -For more information, you can read these -[two](V1_5_CookBook#Writing_New_Monomorphic_Matchers.md) -[recipes](V1_5_CookBook#Writing_New_Polymorphic_Matchers.md) -from the cookbook. As always, you -are welcome to post questions on `googlemock@googlegroups.com` if you -need any help. - -## When using Google Mock, do I have to use Google Test as the testing framework? I have my favorite testing framework and don't want to switch. ## - -Google Mock works out of the box with Google Test. However, it's easy -to configure it to work with any testing framework of your choice. -[Here](V1_5_ForDummies#Using_Google_Mock_with_Any_Testing_Framework.md) is how. - -## How am I supposed to make sense of these horrible template errors? ## - -If you are confused by the compiler errors gcc threw at you, -try consulting the _Google Mock Doctor_ tool first. What it does is to -scan stdin for gcc error messages, and spit out diagnoses on the -problems (we call them diseases) your code has. - -To "install", run command: -``` -alias gmd='/scripts/gmock_doctor.py' -``` - -To use it, do: -``` - 2>&1 | gmd -``` - -For example: -``` -make my_test 2>&1 | gmd -``` - -Or you can run `gmd` and copy-n-paste gcc's error messages to it. - -## Can I mock a variadic function? ## - -You cannot mock a variadic function (i.e. a function taking ellipsis -(`...`) arguments) directly in Google Mock. - -The problem is that in general, there is _no way_ for a mock object to -know how many arguments are passed to the variadic method, and what -the arguments' types are. Only the _author of the base class_ knows -the protocol, and we cannot look into his head. - -Therefore, to mock such a function, the _user_ must teach the mock -object how to figure out the number of arguments and their types. One -way to do it is to provide overloaded versions of the function. - -Ellipsis arguments are inherited from C and not really a C++ feature. -They are unsafe to use and don't work with arguments that have -constructors or destructors. Therefore we recommend to avoid them in -C++ as much as possible. - -## MSVC gives me warning C4301 or C4373 when I define a mock method with a const parameter. Why? ## - -If you compile this using Microsoft Visual C++ 2005 SP1: -``` -class Foo { - ... - virtual void Bar(const int i) = 0; -}; - -class MockFoo : public Foo { - ... - MOCK_METHOD1(Bar, void(const int i)); -}; -``` -You may get the following warning: -``` -warning C4301: 'MockFoo::Bar': overriding virtual function only differs from 'Foo::Bar' by const/volatile qualifier -``` - -This is a MSVC bug. The same code compiles fine with gcc ,for -example. If you use Visual C++ 2008 SP1, you would get the warning: -``` -warning C4373: 'MockFoo::Bar': virtual function overrides 'Foo::Bar', previous versions of the compiler did not override when parameters only differed by const/volatile qualifiers -``` - -In C++, if you _declare_ a function with a `const` parameter, the -`const` modifier is _ignored_. Therefore, the `Foo` base class above -is equivalent to: -``` -class Foo { - ... - virtual void Bar(int i) = 0; // int or const int? Makes no difference. -}; -``` - -In fact, you can _declare_ Bar() with an `int` parameter, and _define_ -it with a `const int` parameter. The compiler will still match them -up. - -Since making a parameter `const` is meaningless in the method -_declaration_, we recommend to remove it in both `Foo` and `MockFoo`. -That should workaround the VC bug. - -Note that we are talking about the _top-level_ `const` modifier here. -If the function parameter is passed by pointer or reference, declaring -the _pointee_ or _referee_ as `const` is still meaningful. For -example, the following two declarations are _not_ equivalent: -``` -void Bar(int* p); // Neither p nor *p is const. -void Bar(const int* p); // p is not const, but *p is. -``` - -## I have a huge mock class, and Microsoft Visual C++ runs out of memory when compiling it. What can I do? ## - -We've noticed that when the `/clr` compiler flag is used, Visual C++ -uses 5~6 times as much memory when compiling a mock class. We suggest -to avoid `/clr` when compiling native C++ mocks. - -## I can't figure out why Google Mock thinks my expectations are not satisfied. What should I do? ## - -You might want to run your test with -`--gmock_verbose=info`. This flag lets Google Mock print a trace -of every mock function call it receives. By studying the trace, -you'll gain insights on why the expectations you set are not met. - -## How can I assert that a function is NEVER called? ## - -``` -EXPECT_CALL(foo, Bar(_)) - .Times(0); -``` - -## I have a failed test where Google Mock tells me TWICE that a particular expectation is not satisfied. Isn't this redundant? ## - -When Google Mock detects a failure, it prints relevant information -(the mock function arguments, the state of relevant expectations, and -etc) to help the user debug. If another failure is detected, Google -Mock will do the same, including printing the state of relevant -expectations. - -Sometimes an expectation's state didn't change between two failures, -and you'll see the same description of the state twice. They are -however _not_ redundant, as they refer to _different points in time_. -The fact they are the same _is_ interesting information. - -## I get a heap check failure when using a mock object, but using a real object is fine. What can be wrong? ## - -Does the class (hopefully a pure interface) you are mocking have a -virtual destructor? - -Whenever you derive from a base class, make sure its destructor is -virtual. Otherwise Bad Things will happen. Consider the following -code: - -``` -class Base { - public: - // Not virtual, but should be. - ~Base() { ... } - ... -}; - -class Derived : public Base { - public: - ... - private: - std::string value_; -}; - -... - Base* p = new Derived; - ... - delete p; // Surprise! ~Base() will be called, but ~Derived() will not - // - value_ is leaked. -``` - -By changing `~Base()` to virtual, `~Derived()` will be correctly -called when `delete p` is executed, and the heap checker -will be happy. - -## The "newer expectations override older ones" rule makes writing expectations awkward. Why does Google Mock do that? ## - -When people complain about this, often they are referring to code like: - -``` -// foo.Bar() should be called twice, return 1 the first time, and return -// 2 the second time. However, I have to write the expectations in the -// reverse order. This sucks big time!!! -EXPECT_CALL(foo, Bar()) - .WillOnce(Return(2)) - .RetiresOnSaturation(); -EXPECT_CALL(foo, Bar()) - .WillOnce(Return(1)) - .RetiresOnSaturation(); -``` - -The problem is that they didn't pick the **best** way to express the test's -intent. - -By default, expectations don't have to be matched in _any_ particular -order. If you want them to match in a certain order, you need to be -explicit. This is Google Mock's (and jMock's) fundamental philosophy: it's -easy to accidentally over-specify your tests, and we want to make it -harder to do so. - -There are two better ways to write the test spec. You could either -put the expectations in sequence: - -``` -// foo.Bar() should be called twice, return 1 the first time, and return -// 2 the second time. Using a sequence, we can write the expectations -// in their natural order. -{ - InSequence s; - EXPECT_CALL(foo, Bar()) - .WillOnce(Return(1)) - .RetiresOnSaturation(); - EXPECT_CALL(foo, Bar()) - .WillOnce(Return(2)) - .RetiresOnSaturation(); -} -``` - -or you can put the sequence of actions in the same expectation: - -``` -// foo.Bar() should be called twice, return 1 the first time, and return -// 2 the second time. -EXPECT_CALL(foo, Bar()) - .WillOnce(Return(1)) - .WillOnce(Return(2)) - .RetiresOnSaturation(); -``` - -Back to the original questions: why does Google Mock search the -expectations (and `ON_CALL`s) from back to front? Because this -allows a user to set up a mock's behavior for the common case early -(e.g. in the mock's constructor or the test fixture's set-up phase) -and customize it with more specific rules later. If Google Mock -searches from front to back, this very useful pattern won't be -possible. - -## Google Mock prints a warning when a function without EXPECT\_CALL is called, even if I have set its behavior using ON\_CALL. Would it be reasonable not to show the warning in this case? ## - -When choosing between being neat and being safe, we lean toward the -latter. So the answer is that we think it's better to show the -warning. - -Often people write `ON_CALL`s in the mock object's -constructor or `SetUp()`, as the default behavior rarely changes from -test to test. Then in the test body they set the expectations, which -are often different for each test. Having an `ON_CALL` in the set-up -part of a test doesn't mean that the calls are expected. If there's -no `EXPECT_CALL` and the method is called, it's possibly an error. If -we quietly let the call go through without notifying the user, bugs -may creep in unnoticed. - -If, however, you are sure that the calls are OK, you can write - -``` -EXPECT_CALL(foo, Bar(_)) - .WillRepeatedly(...); -``` - -instead of - -``` -ON_CALL(foo, Bar(_)) - .WillByDefault(...); -``` - -This tells Google Mock that you do expect the calls and no warning should be -printed. - -Also, you can control the verbosity using the `--gmock_verbose` flag. -If you find the output too noisy when debugging, just choose a less -verbose level. - -## How can I delete the mock function's argument in an action? ## - -If you find yourself needing to perform some action that's not -supported by Google Mock directly, remember that you can define your own -actions using -[MakeAction()](V1_5_CookBook#Writing_New_Actions.md) or -[MakePolymorphicAction()](V1_5_CookBook#Writing_New_Polymorphic_Actions.md), -or you can write a stub function and invoke it using -[Invoke()](V1_5_CookBook#Using_Functions_Methods_Functors.md). - -## MOCK\_METHODn()'s second argument looks funny. Why don't you use the MOCK\_METHODn(Method, return\_type, arg\_1, ..., arg\_n) syntax? ## - -What?! I think it's beautiful. :-) - -While which syntax looks more natural is a subjective matter to some -extent, Google Mock's syntax was chosen for several practical advantages it -has. - -Try to mock a function that takes a map as an argument: -``` -virtual int GetSize(const map& m); -``` - -Using the proposed syntax, it would be: -``` -MOCK_METHOD1(GetSize, int, const map& m); -``` - -Guess what? You'll get a compiler error as the compiler thinks that -`const map& m` are **two**, not one, arguments. To work -around this you can use `typedef` to give the map type a name, but -that gets in the way of your work. Google Mock's syntax avoids this -problem as the function's argument types are protected inside a pair -of parentheses: -``` -// This compiles fine. -MOCK_METHOD1(GetSize, int(const map& m)); -``` - -You still need a `typedef` if the return type contains an unprotected -comma, but that's much rarer. - -Other advantages include: - 1. `MOCK_METHOD1(Foo, int, bool)` can leave a reader wonder whether the method returns `int` or `bool`, while there won't be such confusion using Google Mock's syntax. - 1. The way Google Mock describes a function type is nothing new, although many people may not be familiar with it. The same syntax was used in C, and the `function` library in `tr1` uses this syntax extensively. Since `tr1` will become a part of the new version of STL, we feel very comfortable to be consistent with it. - 1. The function type syntax is also used in other parts of Google Mock's API (e.g. the action interface) in order to make the implementation tractable. A user needs to learn it anyway in order to utilize Google Mock's more advanced features. We'd as well stick to the same syntax in `MOCK_METHOD*`! - -## My code calls a static/global function. Can I mock it? ## - -You can, but you need to make some changes. - -In general, if you find yourself needing to mock a static function, -it's a sign that your modules are too tightly coupled (and less -flexible, less reusable, less testable, etc). You are probably better -off defining a small interface and call the function through that -interface, which then can be easily mocked. It's a bit of work -initially, but usually pays for itself quickly. - -This Google Testing Blog -[post](http://googletesting.blogspot.com/2008/06/defeat-static-cling.html) -says it excellently. Check it out. - -## My mock object needs to do complex stuff. It's a lot of pain to specify the actions. Google Mock sucks! ## - -I know it's not a question, but you get an answer for free any way. :-) - -With Google Mock, you can create mocks in C++ easily. And people might be -tempted to use them everywhere. Sometimes they work great, and -sometimes you may find them, well, a pain to use. So, what's wrong in -the latter case? - -When you write a test without using mocks, you exercise the code and -assert that it returns the correct value or that the system is in an -expected state. This is sometimes called "state-based testing". - -Mocks are great for what some call "interaction-based" testing: -instead of checking the system state at the very end, mock objects -verify that they are invoked the right way and report an error as soon -as it arises, giving you a handle on the precise context in which the -error was triggered. This is often more effective and economical to -do than state-based testing. - -If you are doing state-based testing and using a test double just to -simulate the real object, you are probably better off using a fake. -Using a mock in this case causes pain, as it's not a strong point for -mocks to perform complex actions. If you experience this and think -that mocks suck, you are just not using the right tool for your -problem. Or, you might be trying to solve the wrong problem. :-) - -## I got a warning "Uninteresting function call encountered - default action taken.." Should I panic? ## - -By all means, NO! It's just an FYI. - -What it means is that you have a mock function, you haven't set any -expectations on it (by Google Mock's rule this means that you are not -interested in calls to this function and therefore it can be called -any number of times), and it is called. That's OK - you didn't say -it's not OK to call the function! - -What if you actually meant to disallow this function to be called, but -forgot to write `EXPECT_CALL(foo, Bar()).Times(0)`? While -one can argue that it's the user's fault, Google Mock tries to be nice and -prints you a note. - -So, when you see the message and believe that there shouldn't be any -uninteresting calls, you should investigate what's going on. To make -your life easier, Google Mock prints the function name and arguments -when an uninteresting call is encountered. - -## I want to define a custom action. Should I use Invoke() or implement the action interface? ## - -Either way is fine - you want to choose the one that's more convenient -for your circumstance. - -Usually, if your action is for a particular function type, defining it -using `Invoke()` should be easier; if your action can be used in -functions of different types (e.g. if you are defining -`Return(value)`), `MakePolymorphicAction()` is -easiest. Sometimes you want precise control on what types of -functions the action can be used in, and implementing -`ActionInterface` is the way to go here. See the implementation of -`Return()` in `include/gmock/gmock-actions.h` for an example. - -## I'm using the set-argument-pointee action, and the compiler complains about "conflicting return type specified". What does it mean? ## - -You got this error as Google Mock has no idea what value it should return -when the mock method is called. `SetArgumentPointee()` says what the -side effect is, but doesn't say what the return value should be. You -need `DoAll()` to chain a `SetArgumentPointee()` with a `Return()`. - -See this [recipe](V1_5_CookBook#Mocking_Side_Effects.md) for more details and an example. - - -## My question is not in your FAQ! ## - -If you cannot find the answer to your question in this FAQ, there are -some other resources you can use: - - 1. read other [wiki pages](http://code.google.com/p/googlemock/w/list), - 1. search the mailing list [archive](http://groups.google.com/group/googlemock/topics), - 1. ask it on [googlemock@googlegroups.com](mailto:googlemock@googlegroups.com) and someone will answer it (to prevent spam, we require you to join the [discussion group](http://groups.google.com/group/googlemock) before you can post.). - -Please note that creating an issue in the -[issue tracker](http://code.google.com/p/googlemock/issues/list) is _not_ -a good way to get your answer, as it is monitored infrequently by a -very small number of people. - -When asking a question, it's helpful to provide as much of the -following information as possible (people cannot help you if there's -not enough information in your question): - - * the version (or the revision number if you check out from SVN directly) of Google Mock you use (Google Mock is under active development, so it's possible that your problem has been solved in a later version), - * your operating system, - * the name and version of your compiler, - * the complete command line flags you give to your compiler, - * the complete compiler error messages (if the question is about compilation), - * the _actual_ code (ideally, a minimal but complete program) that has the problem you encounter. \ No newline at end of file diff --git a/googlemock/docs/v1_6/CheatSheet.md b/googlemock/docs/v1_6/CheatSheet.md deleted file mode 100644 index 91de1d21..00000000 --- a/googlemock/docs/v1_6/CheatSheet.md +++ /dev/null @@ -1,534 +0,0 @@ - - -# Defining a Mock Class # - -## Mocking a Normal Class ## - -Given -``` -class Foo { - ... - virtual ~Foo(); - virtual int GetSize() const = 0; - virtual string Describe(const char* name) = 0; - virtual string Describe(int type) = 0; - virtual bool Process(Bar elem, int count) = 0; -}; -``` -(note that `~Foo()` **must** be virtual) we can define its mock as -``` -#include "gmock/gmock.h" - -class MockFoo : public Foo { - MOCK_CONST_METHOD0(GetSize, int()); - MOCK_METHOD1(Describe, string(const char* name)); - MOCK_METHOD1(Describe, string(int type)); - MOCK_METHOD2(Process, bool(Bar elem, int count)); -}; -``` - -To create a "nice" mock object which ignores all uninteresting calls, -or a "strict" mock object, which treats them as failures: -``` -NiceMock nice_foo; // The type is a subclass of MockFoo. -StrictMock strict_foo; // The type is a subclass of MockFoo. -``` - -## Mocking a Class Template ## - -To mock -``` -template -class StackInterface { - public: - ... - virtual ~StackInterface(); - virtual int GetSize() const = 0; - virtual void Push(const Elem& x) = 0; -}; -``` -(note that `~StackInterface()` **must** be virtual) just append `_T` to the `MOCK_*` macros: -``` -template -class MockStack : public StackInterface { - public: - ... - MOCK_CONST_METHOD0_T(GetSize, int()); - MOCK_METHOD1_T(Push, void(const Elem& x)); -}; -``` - -## Specifying Calling Conventions for Mock Functions ## - -If your mock function doesn't use the default calling convention, you -can specify it by appending `_WITH_CALLTYPE` to any of the macros -described in the previous two sections and supplying the calling -convention as the first argument to the macro. For example, -``` - MOCK_METHOD_1_WITH_CALLTYPE(STDMETHODCALLTYPE, Foo, bool(int n)); - MOCK_CONST_METHOD2_WITH_CALLTYPE(STDMETHODCALLTYPE, Bar, int(double x, double y)); -``` -where `STDMETHODCALLTYPE` is defined by `` on Windows. - -# Using Mocks in Tests # - -The typical flow is: - 1. Import the Google Mock names you need to use. All Google Mock names are in the `testing` namespace unless they are macros or otherwise noted. - 1. Create the mock objects. - 1. Optionally, set the default actions of the mock objects. - 1. Set your expectations on the mock objects (How will they be called? What wil they do?). - 1. Exercise code that uses the mock objects; if necessary, check the result using [Google Test](http://code.google.com/p/googletest/) assertions. - 1. When a mock objects is destructed, Google Mock automatically verifies that all expectations on it have been satisfied. - -Here is an example: -``` -using ::testing::Return; // #1 - -TEST(BarTest, DoesThis) { - MockFoo foo; // #2 - - ON_CALL(foo, GetSize()) // #3 - .WillByDefault(Return(1)); - // ... other default actions ... - - EXPECT_CALL(foo, Describe(5)) // #4 - .Times(3) - .WillRepeatedly(Return("Category 5")); - // ... other expectations ... - - EXPECT_EQ("good", MyProductionFunction(&foo)); // #5 -} // #6 -``` - -# Setting Default Actions # - -Google Mock has a **built-in default action** for any function that -returns `void`, `bool`, a numeric value, or a pointer. - -To customize the default action for functions with return type `T` globally: -``` -using ::testing::DefaultValue; - -DefaultValue::Set(value); // Sets the default value to be returned. -// ... use the mocks ... -DefaultValue::Clear(); // Resets the default value. -``` - -To customize the default action for a particular method, use `ON_CALL()`: -``` -ON_CALL(mock_object, method(matchers)) - .With(multi_argument_matcher) ? - .WillByDefault(action); -``` - -# Setting Expectations # - -`EXPECT_CALL()` sets **expectations** on a mock method (How will it be -called? What will it do?): -``` -EXPECT_CALL(mock_object, method(matchers)) - .With(multi_argument_matcher) ? - .Times(cardinality) ? - .InSequence(sequences) * - .After(expectations) * - .WillOnce(action) * - .WillRepeatedly(action) ? - .RetiresOnSaturation(); ? -``` - -If `Times()` is omitted, the cardinality is assumed to be: - - * `Times(1)` when there is neither `WillOnce()` nor `WillRepeatedly()`; - * `Times(n)` when there are `n WillOnce()`s but no `WillRepeatedly()`, where `n` >= 1; or - * `Times(AtLeast(n))` when there are `n WillOnce()`s and a `WillRepeatedly()`, where `n` >= 0. - -A method with no `EXPECT_CALL()` is free to be invoked _any number of times_, and the default action will be taken each time. - -# Matchers # - -A **matcher** matches a _single_ argument. You can use it inside -`ON_CALL()` or `EXPECT_CALL()`, or use it to validate a value -directly: - -| `EXPECT_THAT(value, matcher)` | Asserts that `value` matches `matcher`. | -|:------------------------------|:----------------------------------------| -| `ASSERT_THAT(value, matcher)` | The same as `EXPECT_THAT(value, matcher)`, except that it generates a **fatal** failure. | - -Built-in matchers (where `argument` is the function argument) are -divided into several categories: - -## Wildcard ## -|`_`|`argument` can be any value of the correct type.| -|:--|:-----------------------------------------------| -|`A()` or `An()`|`argument` can be any value of type `type`. | - -## Generic Comparison ## - -|`Eq(value)` or `value`|`argument == value`| -|:---------------------|:------------------| -|`Ge(value)` |`argument >= value`| -|`Gt(value)` |`argument > value` | -|`Le(value)` |`argument <= value`| -|`Lt(value)` |`argument < value` | -|`Ne(value)` |`argument != value`| -|`IsNull()` |`argument` is a `NULL` pointer (raw or smart).| -|`NotNull()` |`argument` is a non-null pointer (raw or smart).| -|`Ref(variable)` |`argument` is a reference to `variable`.| -|`TypedEq(value)`|`argument` has type `type` and is equal to `value`. You may need to use this instead of `Eq(value)` when the mock function is overloaded.| - -Except `Ref()`, these matchers make a _copy_ of `value` in case it's -modified or destructed later. If the compiler complains that `value` -doesn't have a public copy constructor, try wrap it in `ByRef()`, -e.g. `Eq(ByRef(non_copyable_value))`. If you do that, make sure -`non_copyable_value` is not changed afterwards, or the meaning of your -matcher will be changed. - -## Floating-Point Matchers ## - -|`DoubleEq(a_double)`|`argument` is a `double` value approximately equal to `a_double`, treating two NaNs as unequal.| -|:-------------------|:----------------------------------------------------------------------------------------------| -|`FloatEq(a_float)` |`argument` is a `float` value approximately equal to `a_float`, treating two NaNs as unequal. | -|`NanSensitiveDoubleEq(a_double)`|`argument` is a `double` value approximately equal to `a_double`, treating two NaNs as equal. | -|`NanSensitiveFloatEq(a_float)`|`argument` is a `float` value approximately equal to `a_float`, treating two NaNs as equal. | - -These matchers use ULP-based comparison (the same as used in -[Google Test](http://code.google.com/p/googletest/)). They -automatically pick a reasonable error bound based on the absolute -value of the expected value. `DoubleEq()` and `FloatEq()` conform to -the IEEE standard, which requires comparing two NaNs for equality to -return false. The `NanSensitive*` version instead treats two NaNs as -equal, which is often what a user wants. - -## String Matchers ## - -The `argument` can be either a C string or a C++ string object: - -|`ContainsRegex(string)`|`argument` matches the given regular expression.| -|:----------------------|:-----------------------------------------------| -|`EndsWith(suffix)` |`argument` ends with string `suffix`. | -|`HasSubstr(string)` |`argument` contains `string` as a sub-string. | -|`MatchesRegex(string)` |`argument` matches the given regular expression with the match starting at the first character and ending at the last character.| -|`StartsWith(prefix)` |`argument` starts with string `prefix`. | -|`StrCaseEq(string)` |`argument` is equal to `string`, ignoring case. | -|`StrCaseNe(string)` |`argument` is not equal to `string`, ignoring case.| -|`StrEq(string)` |`argument` is equal to `string`. | -|`StrNe(string)` |`argument` is not equal to `string`. | - -`ContainsRegex()` and `MatchesRegex()` use the regular expression -syntax defined -[here](http://code.google.com/p/googletest/wiki/V1_6_AdvancedGuide#Regular_Expression_Syntax). -`StrCaseEq()`, `StrCaseNe()`, `StrEq()`, and `StrNe()` work for wide -strings as well. - -## Container Matchers ## - -Most STL-style containers support `==`, so you can use -`Eq(expected_container)` or simply `expected_container` to match a -container exactly. If you want to write the elements in-line, -match them more flexibly, or get more informative messages, you can use: - -| `Contains(e)` | `argument` contains an element that matches `e`, which can be either a value or a matcher. | -|:--------------|:-------------------------------------------------------------------------------------------| -| `Each(e)` | `argument` is a container where _every_ element matches `e`, which can be either a value or a matcher. | -| `ElementsAre(e0, e1, ..., en)` | `argument` has `n + 1` elements, where the i-th element matches `ei`, which can be a value or a matcher. 0 to 10 arguments are allowed. | -| `ElementsAreArray(array)` or `ElementsAreArray(array, count)` | The same as `ElementsAre()` except that the expected element values/matchers come from a C-style array. | -| `ContainerEq(container)` | The same as `Eq(container)` except that the failure message also includes which elements are in one container but not the other. | -| `Pointwise(m, container)` | `argument` contains the same number of elements as in `container`, and for all i, (the i-th element in `argument`, the i-th element in `container`) match `m`, which is a matcher on 2-tuples. E.g. `Pointwise(Le(), upper_bounds)` verifies that each element in `argument` doesn't exceed the corresponding element in `upper_bounds`. | - -These matchers can also match: - - 1. a native array passed by reference (e.g. in `Foo(const int (&a)[5])`), and - 1. an array passed as a pointer and a count (e.g. in `Bar(const T* buffer, int len)` -- see [Multi-argument Matchers](#Multiargument_Matchers.md)). - -where the array may be multi-dimensional (i.e. its elements can be arrays). - -## Member Matchers ## - -|`Field(&class::field, m)`|`argument.field` (or `argument->field` when `argument` is a plain pointer) matches matcher `m`, where `argument` is an object of type _class_.| -|:------------------------|:---------------------------------------------------------------------------------------------------------------------------------------------| -|`Key(e)` |`argument.first` matches `e`, which can be either a value or a matcher. E.g. `Contains(Key(Le(5)))` can verify that a `map` contains a key `<= 5`.| -|`Pair(m1, m2)` |`argument` is an `std::pair` whose `first` field matches `m1` and `second` field matches `m2`. | -|`Property(&class::property, m)`|`argument.property()` (or `argument->property()` when `argument` is a plain pointer) matches matcher `m`, where `argument` is an object of type _class_.| - -## Matching the Result of a Function or Functor ## - -|`ResultOf(f, m)`|`f(argument)` matches matcher `m`, where `f` is a function or functor.| -|:---------------|:---------------------------------------------------------------------| - -## Pointer Matchers ## - -|`Pointee(m)`|`argument` (either a smart pointer or a raw pointer) points to a value that matches matcher `m`.| -|:-----------|:-----------------------------------------------------------------------------------------------| - -## Multiargument Matchers ## - -Technically, all matchers match a _single_ value. A "multi-argument" -matcher is just one that matches a _tuple_. The following matchers can -be used to match a tuple `(x, y)`: - -|`Eq()`|`x == y`| -|:-----|:-------| -|`Ge()`|`x >= y`| -|`Gt()`|`x > y` | -|`Le()`|`x <= y`| -|`Lt()`|`x < y` | -|`Ne()`|`x != y`| - -You can use the following selectors to pick a subset of the arguments -(or reorder them) to participate in the matching: - -|`AllArgs(m)`|Equivalent to `m`. Useful as syntactic sugar in `.With(AllArgs(m))`.| -|:-----------|:-------------------------------------------------------------------| -|`Args(m)`|The tuple of the `k` selected (using 0-based indices) arguments matches `m`, e.g. `Args<1, 2>(Eq())`.| - -## Composite Matchers ## - -You can make a matcher from one or more other matchers: - -|`AllOf(m1, m2, ..., mn)`|`argument` matches all of the matchers `m1` to `mn`.| -|:-----------------------|:---------------------------------------------------| -|`AnyOf(m1, m2, ..., mn)`|`argument` matches at least one of the matchers `m1` to `mn`.| -|`Not(m)` |`argument` doesn't match matcher `m`. | - -## Adapters for Matchers ## - -|`MatcherCast(m)`|casts matcher `m` to type `Matcher`.| -|:------------------|:--------------------------------------| -|`SafeMatcherCast(m)`| [safely casts](http://code.google.com/p/googlemock/wiki/V1_6_CookBook#Casting_Matchers) matcher `m` to type `Matcher`. | -|`Truly(predicate)` |`predicate(argument)` returns something considered by C++ to be true, where `predicate` is a function or functor.| - -## Matchers as Predicates ## - -|`Matches(m)(value)`|evaluates to `true` if `value` matches `m`. You can use `Matches(m)` alone as a unary functor.| -|:------------------|:---------------------------------------------------------------------------------------------| -|`ExplainMatchResult(m, value, result_listener)`|evaluates to `true` if `value` matches `m`, explaining the result to `result_listener`. | -|`Value(value, m)` |evaluates to `true` if `value` matches `m`. | - -## Defining Matchers ## - -| `MATCHER(IsEven, "") { return (arg % 2) == 0; }` | Defines a matcher `IsEven()` to match an even number. | -|:-------------------------------------------------|:------------------------------------------------------| -| `MATCHER_P(IsDivisibleBy, n, "") { *result_listener << "where the remainder is " << (arg % n); return (arg % n) == 0; }` | Defines a macher `IsDivisibleBy(n)` to match a number divisible by `n`. | -| `MATCHER_P2(IsBetween, a, b, std::string(negation ? "isn't" : "is") + " between " + PrintToString(a) + " and " + PrintToString(b)) { return a <= arg && arg <= b; }` | Defines a matcher `IsBetween(a, b)` to match a value in the range [`a`, `b`]. | - -**Notes:** - - 1. The `MATCHER*` macros cannot be used inside a function or class. - 1. The matcher body must be _purely functional_ (i.e. it cannot have any side effect, and the result must not depend on anything other than the value being matched and the matcher parameters). - 1. You can use `PrintToString(x)` to convert a value `x` of any type to a string. - -## Matchers as Test Assertions ## - -|`ASSERT_THAT(expression, m)`|Generates a [fatal failure](http://code.google.com/p/googletest/wiki/V1_6_Primer#Assertions) if the value of `expression` doesn't match matcher `m`.| -|:---------------------------|:---------------------------------------------------------------------------------------------------------------------------------------------------| -|`EXPECT_THAT(expression, m)`|Generates a non-fatal failure if the value of `expression` doesn't match matcher `m`. | - -# Actions # - -**Actions** specify what a mock function should do when invoked. - -## Returning a Value ## - -|`Return()`|Return from a `void` mock function.| -|:---------|:----------------------------------| -|`Return(value)`|Return `value`. If the type of `value` is different to the mock function's return type, `value` is converted to the latter type at the time the expectation is set, not when the action is executed.| -|`ReturnArg()`|Return the `N`-th (0-based) argument.| -|`ReturnNew(a1, ..., ak)`|Return `new T(a1, ..., ak)`; a different object is created each time.| -|`ReturnNull()`|Return a null pointer. | -|`ReturnPointee(ptr)`|Return the value pointed to by `ptr`.| -|`ReturnRef(variable)`|Return a reference to `variable`. | -|`ReturnRefOfCopy(value)`|Return a reference to a copy of `value`; the copy lives as long as the action.| - -## Side Effects ## - -|`Assign(&variable, value)`|Assign `value` to variable.| -|:-------------------------|:--------------------------| -| `DeleteArg()` | Delete the `N`-th (0-based) argument, which must be a pointer. | -| `SaveArg(pointer)` | Save the `N`-th (0-based) argument to `*pointer`. | -| `SaveArgPointee(pointer)` | Save the value pointed to by the `N`-th (0-based) argument to `*pointer`. | -| `SetArgReferee(value)` | Assign value to the variable referenced by the `N`-th (0-based) argument. | -|`SetArgPointee(value)` |Assign `value` to the variable pointed by the `N`-th (0-based) argument.| -|`SetArgumentPointee(value)`|Same as `SetArgPointee(value)`. Deprecated. Will be removed in v1.7.0.| -|`SetArrayArgument(first, last)`|Copies the elements in source range [`first`, `last`) to the array pointed to by the `N`-th (0-based) argument, which can be either a pointer or an iterator. The action does not take ownership of the elements in the source range.| -|`SetErrnoAndReturn(error, value)`|Set `errno` to `error` and return `value`.| -|`Throw(exception)` |Throws the given exception, which can be any copyable value. Available since v1.1.0.| - -## Using a Function or a Functor as an Action ## - -|`Invoke(f)`|Invoke `f` with the arguments passed to the mock function, where `f` can be a global/static function or a functor.| -|:----------|:-----------------------------------------------------------------------------------------------------------------| -|`Invoke(object_pointer, &class::method)`|Invoke the {method on the object with the arguments passed to the mock function. | -|`InvokeWithoutArgs(f)`|Invoke `f`, which can be a global/static function or a functor. `f` must take no arguments. | -|`InvokeWithoutArgs(object_pointer, &class::method)`|Invoke the method on the object, which takes no arguments. | -|`InvokeArgument(arg1, arg2, ..., argk)`|Invoke the mock function's `N`-th (0-based) argument, which must be a function or a functor, with the `k` arguments.| - -The return value of the invoked function is used as the return value -of the action. - -When defining a function or functor to be used with `Invoke*()`, you can declare any unused parameters as `Unused`: -``` - double Distance(Unused, double x, double y) { return sqrt(x*x + y*y); } - ... - EXPECT_CALL(mock, Foo("Hi", _, _)).WillOnce(Invoke(Distance)); -``` - -In `InvokeArgument(...)`, if an argument needs to be passed by reference, wrap it inside `ByRef()`. For example, -``` - InvokeArgument<2>(5, string("Hi"), ByRef(foo)) -``` -calls the mock function's #2 argument, passing to it `5` and `string("Hi")` by value, and `foo` by reference. - -## Default Action ## - -|`DoDefault()`|Do the default action (specified by `ON_CALL()` or the built-in one).| -|:------------|:--------------------------------------------------------------------| - -**Note:** due to technical reasons, `DoDefault()` cannot be used inside a composite action - trying to do so will result in a run-time error. - -## Composite Actions ## - -|`DoAll(a1, a2, ..., an)`|Do all actions `a1` to `an` and return the result of `an` in each invocation. The first `n - 1` sub-actions must return void. | -|:-----------------------|:-----------------------------------------------------------------------------------------------------------------------------| -|`IgnoreResult(a)` |Perform action `a` and ignore its result. `a` must not return void. | -|`WithArg(a)` |Pass the `N`-th (0-based) argument of the mock function to action `a` and perform it. | -|`WithArgs(a)`|Pass the selected (0-based) arguments of the mock function to action `a` and perform it. | -|`WithoutArgs(a)` |Perform action `a` without any arguments. | - -## Defining Actions ## - -| `ACTION(Sum) { return arg0 + arg1; }` | Defines an action `Sum()` to return the sum of the mock function's argument #0 and #1. | -|:--------------------------------------|:---------------------------------------------------------------------------------------| -| `ACTION_P(Plus, n) { return arg0 + n; }` | Defines an action `Plus(n)` to return the sum of the mock function's argument #0 and `n`. | -| `ACTION_Pk(Foo, p1, ..., pk) { statements; }` | Defines a parameterized action `Foo(p1, ..., pk)` to execute the given `statements`. | - -The `ACTION*` macros cannot be used inside a function or class. - -# Cardinalities # - -These are used in `Times()` to specify how many times a mock function will be called: - -|`AnyNumber()`|The function can be called any number of times.| -|:------------|:----------------------------------------------| -|`AtLeast(n)` |The call is expected at least `n` times. | -|`AtMost(n)` |The call is expected at most `n` times. | -|`Between(m, n)`|The call is expected between `m` and `n` (inclusive) times.| -|`Exactly(n) or n`|The call is expected exactly `n` times. In particular, the call should never happen when `n` is 0.| - -# Expectation Order # - -By default, the expectations can be matched in _any_ order. If some -or all expectations must be matched in a given order, there are two -ways to specify it. They can be used either independently or -together. - -## The After Clause ## - -``` -using ::testing::Expectation; -... -Expectation init_x = EXPECT_CALL(foo, InitX()); -Expectation init_y = EXPECT_CALL(foo, InitY()); -EXPECT_CALL(foo, Bar()) - .After(init_x, init_y); -``` -says that `Bar()` can be called only after both `InitX()` and -`InitY()` have been called. - -If you don't know how many pre-requisites an expectation has when you -write it, you can use an `ExpectationSet` to collect them: - -``` -using ::testing::ExpectationSet; -... -ExpectationSet all_inits; -for (int i = 0; i < element_count; i++) { - all_inits += EXPECT_CALL(foo, InitElement(i)); -} -EXPECT_CALL(foo, Bar()) - .After(all_inits); -``` -says that `Bar()` can be called only after all elements have been -initialized (but we don't care about which elements get initialized -before the others). - -Modifying an `ExpectationSet` after using it in an `.After()` doesn't -affect the meaning of the `.After()`. - -## Sequences ## - -When you have a long chain of sequential expectations, it's easier to -specify the order using **sequences**, which don't require you to given -each expectation in the chain a different name. All expected
-calls in the same sequence must occur in the order they are -specified. - -``` -using ::testing::Sequence; -Sequence s1, s2; -... -EXPECT_CALL(foo, Reset()) - .InSequence(s1, s2) - .WillOnce(Return(true)); -EXPECT_CALL(foo, GetSize()) - .InSequence(s1) - .WillOnce(Return(1)); -EXPECT_CALL(foo, Describe(A())) - .InSequence(s2) - .WillOnce(Return("dummy")); -``` -says that `Reset()` must be called before _both_ `GetSize()` _and_ -`Describe()`, and the latter two can occur in any order. - -To put many expectations in a sequence conveniently: -``` -using ::testing::InSequence; -{ - InSequence dummy; - - EXPECT_CALL(...)...; - EXPECT_CALL(...)...; - ... - EXPECT_CALL(...)...; -} -``` -says that all expected calls in the scope of `dummy` must occur in -strict order. The name `dummy` is irrelevant.) - -# Verifying and Resetting a Mock # - -Google Mock will verify the expectations on a mock object when it is destructed, or you can do it earlier: -``` -using ::testing::Mock; -... -// Verifies and removes the expectations on mock_obj; -// returns true iff successful. -Mock::VerifyAndClearExpectations(&mock_obj); -... -// Verifies and removes the expectations on mock_obj; -// also removes the default actions set by ON_CALL(); -// returns true iff successful. -Mock::VerifyAndClear(&mock_obj); -``` - -You can also tell Google Mock that a mock object can be leaked and doesn't -need to be verified: -``` -Mock::AllowLeak(&mock_obj); -``` - -# Mock Classes # - -Google Mock defines a convenient mock class template -``` -class MockFunction { - public: - MOCK_METHODn(Call, R(A1, ..., An)); -}; -``` -See this [recipe](http://code.google.com/p/googlemock/wiki/V1_6_CookBook#Using_Check_Points) for one application of it. - -# Flags # - -| `--gmock_catch_leaked_mocks=0` | Don't report leaked mock objects as failures. | -|:-------------------------------|:----------------------------------------------| -| `--gmock_verbose=LEVEL` | Sets the default verbosity level (`info`, `warning`, or `error`) of Google Mock messages. | \ No newline at end of file diff --git a/googlemock/docs/v1_6/CookBook.md b/googlemock/docs/v1_6/CookBook.md deleted file mode 100644 index e77a781c..00000000 --- a/googlemock/docs/v1_6/CookBook.md +++ /dev/null @@ -1,3345 +0,0 @@ - - -You can find recipes for using Google Mock here. If you haven't yet, -please read the [ForDummies](V1_6_ForDummies.md) document first to make sure you understand -the basics. - -**Note:** Google Mock lives in the `testing` name space. For -readability, it is recommended to write `using ::testing::Foo;` once in -your file before using the name `Foo` defined by Google Mock. We omit -such `using` statements in this page for brevity, but you should do it -in your own code. - -# Creating Mock Classes # - -## Mocking Private or Protected Methods ## - -You must always put a mock method definition (`MOCK_METHOD*`) in a -`public:` section of the mock class, regardless of the method being -mocked being `public`, `protected`, or `private` in the base class. -This allows `ON_CALL` and `EXPECT_CALL` to reference the mock function -from outside of the mock class. (Yes, C++ allows a subclass to change -the access level of a virtual function in the base class.) Example: - -``` -class Foo { - public: - ... - virtual bool Transform(Gadget* g) = 0; - - protected: - virtual void Resume(); - - private: - virtual int GetTimeOut(); -}; - -class MockFoo : public Foo { - public: - ... - MOCK_METHOD1(Transform, bool(Gadget* g)); - - // The following must be in the public section, even though the - // methods are protected or private in the base class. - MOCK_METHOD0(Resume, void()); - MOCK_METHOD0(GetTimeOut, int()); -}; -``` - -## Mocking Overloaded Methods ## - -You can mock overloaded functions as usual. No special attention is required: - -``` -class Foo { - ... - - // Must be virtual as we'll inherit from Foo. - virtual ~Foo(); - - // Overloaded on the types and/or numbers of arguments. - virtual int Add(Element x); - virtual int Add(int times, Element x); - - // Overloaded on the const-ness of this object. - virtual Bar& GetBar(); - virtual const Bar& GetBar() const; -}; - -class MockFoo : public Foo { - ... - MOCK_METHOD1(Add, int(Element x)); - MOCK_METHOD2(Add, int(int times, Element x); - - MOCK_METHOD0(GetBar, Bar&()); - MOCK_CONST_METHOD0(GetBar, const Bar&()); -}; -``` - -**Note:** if you don't mock all versions of the overloaded method, the -compiler will give you a warning about some methods in the base class -being hidden. To fix that, use `using` to bring them in scope: - -``` -class MockFoo : public Foo { - ... - using Foo::Add; - MOCK_METHOD1(Add, int(Element x)); - // We don't want to mock int Add(int times, Element x); - ... -}; -``` - -## Mocking Class Templates ## - -To mock a class template, append `_T` to the `MOCK_*` macros: - -``` -template -class StackInterface { - ... - // Must be virtual as we'll inherit from StackInterface. - virtual ~StackInterface(); - - virtual int GetSize() const = 0; - virtual void Push(const Elem& x) = 0; -}; - -template -class MockStack : public StackInterface { - ... - MOCK_CONST_METHOD0_T(GetSize, int()); - MOCK_METHOD1_T(Push, void(const Elem& x)); -}; -``` - -## Mocking Nonvirtual Methods ## - -Google Mock can mock non-virtual functions to be used in what we call _hi-perf -dependency injection_. - -In this case, instead of sharing a common base class with the real -class, your mock class will be _unrelated_ to the real class, but -contain methods with the same signatures. The syntax for mocking -non-virtual methods is the _same_ as mocking virtual methods: - -``` -// A simple packet stream class. None of its members is virtual. -class ConcretePacketStream { - public: - void AppendPacket(Packet* new_packet); - const Packet* GetPacket(size_t packet_number) const; - size_t NumberOfPackets() const; - ... -}; - -// A mock packet stream class. It inherits from no other, but defines -// GetPacket() and NumberOfPackets(). -class MockPacketStream { - public: - MOCK_CONST_METHOD1(GetPacket, const Packet*(size_t packet_number)); - MOCK_CONST_METHOD0(NumberOfPackets, size_t()); - ... -}; -``` - -Note that the mock class doesn't define `AppendPacket()`, unlike the -real class. That's fine as long as the test doesn't need to call it. - -Next, you need a way to say that you want to use -`ConcretePacketStream` in production code, and use `MockPacketStream` -in tests. Since the functions are not virtual and the two classes are -unrelated, you must specify your choice at _compile time_ (as opposed -to run time). - -One way to do it is to templatize your code that needs to use a packet -stream. More specifically, you will give your code a template type -argument for the type of the packet stream. In production, you will -instantiate your template with `ConcretePacketStream` as the type -argument. In tests, you will instantiate the same template with -`MockPacketStream`. For example, you may write: - -``` -template -void CreateConnection(PacketStream* stream) { ... } - -template -class PacketReader { - public: - void ReadPackets(PacketStream* stream, size_t packet_num); -}; -``` - -Then you can use `CreateConnection()` and -`PacketReader` in production code, and use -`CreateConnection()` and -`PacketReader` in tests. - -``` - MockPacketStream mock_stream; - EXPECT_CALL(mock_stream, ...)...; - .. set more expectations on mock_stream ... - PacketReader reader(&mock_stream); - ... exercise reader ... -``` - -## Mocking Free Functions ## - -It's possible to use Google Mock to mock a free function (i.e. a -C-style function or a static method). You just need to rewrite your -code to use an interface (abstract class). - -Instead of calling a free function (say, `OpenFile`) directly, -introduce an interface for it and have a concrete subclass that calls -the free function: - -``` -class FileInterface { - public: - ... - virtual bool Open(const char* path, const char* mode) = 0; -}; - -class File : public FileInterface { - public: - ... - virtual bool Open(const char* path, const char* mode) { - return OpenFile(path, mode); - } -}; -``` - -Your code should talk to `FileInterface` to open a file. Now it's -easy to mock out the function. - -This may seem much hassle, but in practice you often have multiple -related functions that you can put in the same interface, so the -per-function syntactic overhead will be much lower. - -If you are concerned about the performance overhead incurred by -virtual functions, and profiling confirms your concern, you can -combine this with the recipe for [mocking non-virtual methods](#Mocking_Nonvirtual_Methods.md). - -## Nice Mocks and Strict Mocks ## - -If a mock method has no `EXPECT_CALL` spec but is called, Google Mock -will print a warning about the "uninteresting call". The rationale is: - - * New methods may be added to an interface after a test is written. We shouldn't fail a test just because a method it doesn't know about is called. - * However, this may also mean there's a bug in the test, so Google Mock shouldn't be silent either. If the user believes these calls are harmless, he can add an `EXPECT_CALL()` to suppress the warning. - -However, sometimes you may want to suppress all "uninteresting call" -warnings, while sometimes you may want the opposite, i.e. to treat all -of them as errors. Google Mock lets you make the decision on a -per-mock-object basis. - -Suppose your test uses a mock class `MockFoo`: - -``` -TEST(...) { - MockFoo mock_foo; - EXPECT_CALL(mock_foo, DoThis()); - ... code that uses mock_foo ... -} -``` - -If a method of `mock_foo` other than `DoThis()` is called, it will be -reported by Google Mock as a warning. However, if you rewrite your -test to use `NiceMock` instead, the warning will be gone, -resulting in a cleaner test output: - -``` -using ::testing::NiceMock; - -TEST(...) { - NiceMock mock_foo; - EXPECT_CALL(mock_foo, DoThis()); - ... code that uses mock_foo ... -} -``` - -`NiceMock` is a subclass of `MockFoo`, so it can be used -wherever `MockFoo` is accepted. - -It also works if `MockFoo`'s constructor takes some arguments, as -`NiceMock` "inherits" `MockFoo`'s constructors: - -``` -using ::testing::NiceMock; - -TEST(...) { - NiceMock mock_foo(5, "hi"); // Calls MockFoo(5, "hi"). - EXPECT_CALL(mock_foo, DoThis()); - ... code that uses mock_foo ... -} -``` - -The usage of `StrictMock` is similar, except that it makes all -uninteresting calls failures: - -``` -using ::testing::StrictMock; - -TEST(...) { - StrictMock mock_foo; - EXPECT_CALL(mock_foo, DoThis()); - ... code that uses mock_foo ... - - // The test will fail if a method of mock_foo other than DoThis() - // is called. -} -``` - -There are some caveats though (I don't like them just as much as the -next guy, but sadly they are side effects of C++'s limitations): - - 1. `NiceMock` and `StrictMock` only work for mock methods defined using the `MOCK_METHOD*` family of macros **directly** in the `MockFoo` class. If a mock method is defined in a **base class** of `MockFoo`, the "nice" or "strict" modifier may not affect it, depending on the compiler. In particular, nesting `NiceMock` and `StrictMock` (e.g. `NiceMock >`) is **not** supported. - 1. The constructors of the base mock (`MockFoo`) cannot have arguments passed by non-const reference, which happens to be banned by the [Google C++ style guide](http://google-styleguide.googlecode.com/svn/trunk/cppguide.xml). - 1. During the constructor or destructor of `MockFoo`, the mock object is _not_ nice or strict. This may cause surprises if the constructor or destructor calls a mock method on `this` object. (This behavior, however, is consistent with C++'s general rule: if a constructor or destructor calls a virtual method of `this` object, that method is treated as non-virtual. In other words, to the base class's constructor or destructor, `this` object behaves like an instance of the base class, not the derived class. This rule is required for safety. Otherwise a base constructor may use members of a derived class before they are initialized, or a base destructor may use members of a derived class after they have been destroyed.) - -Finally, you should be **very cautious** when using this feature, as the -decision you make applies to **all** future changes to the mock -class. If an important change is made in the interface you are mocking -(and thus in the mock class), it could break your tests (if you use -`StrictMock`) or let bugs pass through without a warning (if you use -`NiceMock`). Therefore, try to specify the mock's behavior using -explicit `EXPECT_CALL` first, and only turn to `NiceMock` or -`StrictMock` as the last resort. - -## Simplifying the Interface without Breaking Existing Code ## - -Sometimes a method has a long list of arguments that is mostly -uninteresting. For example, - -``` -class LogSink { - public: - ... - virtual void send(LogSeverity severity, const char* full_filename, - const char* base_filename, int line, - const struct tm* tm_time, - const char* message, size_t message_len) = 0; -}; -``` - -This method's argument list is lengthy and hard to work with (let's -say that the `message` argument is not even 0-terminated). If we mock -it as is, using the mock will be awkward. If, however, we try to -simplify this interface, we'll need to fix all clients depending on -it, which is often infeasible. - -The trick is to re-dispatch the method in the mock class: - -``` -class ScopedMockLog : public LogSink { - public: - ... - virtual void send(LogSeverity severity, const char* full_filename, - const char* base_filename, int line, const tm* tm_time, - const char* message, size_t message_len) { - // We are only interested in the log severity, full file name, and - // log message. - Log(severity, full_filename, std::string(message, message_len)); - } - - // Implements the mock method: - // - // void Log(LogSeverity severity, - // const string& file_path, - // const string& message); - MOCK_METHOD3(Log, void(LogSeverity severity, const string& file_path, - const string& message)); -}; -``` - -By defining a new mock method with a trimmed argument list, we make -the mock class much more user-friendly. - -## Alternative to Mocking Concrete Classes ## - -Often you may find yourself using classes that don't implement -interfaces. In order to test your code that uses such a class (let's -call it `Concrete`), you may be tempted to make the methods of -`Concrete` virtual and then mock it. - -Try not to do that. - -Making a non-virtual function virtual is a big decision. It creates an -extension point where subclasses can tweak your class' behavior. This -weakens your control on the class because now it's harder to maintain -the class' invariants. You should make a function virtual only when -there is a valid reason for a subclass to override it. - -Mocking concrete classes directly is problematic as it creates a tight -coupling between the class and the tests - any small change in the -class may invalidate your tests and make test maintenance a pain. - -To avoid such problems, many programmers have been practicing "coding -to interfaces": instead of talking to the `Concrete` class, your code -would define an interface and talk to it. Then you implement that -interface as an adaptor on top of `Concrete`. In tests, you can easily -mock that interface to observe how your code is doing. - -This technique incurs some overhead: - - * You pay the cost of virtual function calls (usually not a problem). - * There is more abstraction for the programmers to learn. - -However, it can also bring significant benefits in addition to better -testability: - - * `Concrete`'s API may not fit your problem domain very well, as you may not be the only client it tries to serve. By designing your own interface, you have a chance to tailor it to your need - you may add higher-level functionalities, rename stuff, etc instead of just trimming the class. This allows you to write your code (user of the interface) in a more natural way, which means it will be more readable, more maintainable, and you'll be more productive. - * If `Concrete`'s implementation ever has to change, you don't have to rewrite everywhere it is used. Instead, you can absorb the change in your implementation of the interface, and your other code and tests will be insulated from this change. - -Some people worry that if everyone is practicing this technique, they -will end up writing lots of redundant code. This concern is totally -understandable. However, there are two reasons why it may not be the -case: - - * Different projects may need to use `Concrete` in different ways, so the best interfaces for them will be different. Therefore, each of them will have its own domain-specific interface on top of `Concrete`, and they will not be the same code. - * If enough projects want to use the same interface, they can always share it, just like they have been sharing `Concrete`. You can check in the interface and the adaptor somewhere near `Concrete` (perhaps in a `contrib` sub-directory) and let many projects use it. - -You need to weigh the pros and cons carefully for your particular -problem, but I'd like to assure you that the Java community has been -practicing this for a long time and it's a proven effective technique -applicable in a wide variety of situations. :-) - -## Delegating Calls to a Fake ## - -Some times you have a non-trivial fake implementation of an -interface. For example: - -``` -class Foo { - public: - virtual ~Foo() {} - virtual char DoThis(int n) = 0; - virtual void DoThat(const char* s, int* p) = 0; -}; - -class FakeFoo : public Foo { - public: - virtual char DoThis(int n) { - return (n > 0) ? '+' : - (n < 0) ? '-' : '0'; - } - - virtual void DoThat(const char* s, int* p) { - *p = strlen(s); - } -}; -``` - -Now you want to mock this interface such that you can set expectations -on it. However, you also want to use `FakeFoo` for the default -behavior, as duplicating it in the mock object is, well, a lot of -work. - -When you define the mock class using Google Mock, you can have it -delegate its default action to a fake class you already have, using -this pattern: - -``` -using ::testing::_; -using ::testing::Invoke; - -class MockFoo : public Foo { - public: - // Normal mock method definitions using Google Mock. - MOCK_METHOD1(DoThis, char(int n)); - MOCK_METHOD2(DoThat, void(const char* s, int* p)); - - // Delegates the default actions of the methods to a FakeFoo object. - // This must be called *before* the custom ON_CALL() statements. - void DelegateToFake() { - ON_CALL(*this, DoThis(_)) - .WillByDefault(Invoke(&fake_, &FakeFoo::DoThis)); - ON_CALL(*this, DoThat(_, _)) - .WillByDefault(Invoke(&fake_, &FakeFoo::DoThat)); - } - private: - FakeFoo fake_; // Keeps an instance of the fake in the mock. -}; -``` - -With that, you can use `MockFoo` in your tests as usual. Just remember -that if you don't explicitly set an action in an `ON_CALL()` or -`EXPECT_CALL()`, the fake will be called upon to do it: - -``` -using ::testing::_; - -TEST(AbcTest, Xyz) { - MockFoo foo; - foo.DelegateToFake(); // Enables the fake for delegation. - - // Put your ON_CALL(foo, ...)s here, if any. - - // No action specified, meaning to use the default action. - EXPECT_CALL(foo, DoThis(5)); - EXPECT_CALL(foo, DoThat(_, _)); - - int n = 0; - EXPECT_EQ('+', foo.DoThis(5)); // FakeFoo::DoThis() is invoked. - foo.DoThat("Hi", &n); // FakeFoo::DoThat() is invoked. - EXPECT_EQ(2, n); -} -``` - -**Some tips:** - - * If you want, you can still override the default action by providing your own `ON_CALL()` or using `.WillOnce()` / `.WillRepeatedly()` in `EXPECT_CALL()`. - * In `DelegateToFake()`, you only need to delegate the methods whose fake implementation you intend to use. - * The general technique discussed here works for overloaded methods, but you'll need to tell the compiler which version you mean. To disambiguate a mock function (the one you specify inside the parentheses of `ON_CALL()`), see the "Selecting Between Overloaded Functions" section on this page; to disambiguate a fake function (the one you place inside `Invoke()`), use a `static_cast` to specify the function's type. - * Having to mix a mock and a fake is often a sign of something gone wrong. Perhaps you haven't got used to the interaction-based way of testing yet. Or perhaps your interface is taking on too many roles and should be split up. Therefore, **don't abuse this**. We would only recommend to do it as an intermediate step when you are refactoring your code. - -Regarding the tip on mixing a mock and a fake, here's an example on -why it may be a bad sign: Suppose you have a class `System` for -low-level system operations. In particular, it does file and I/O -operations. And suppose you want to test how your code uses `System` -to do I/O, and you just want the file operations to work normally. If -you mock out the entire `System` class, you'll have to provide a fake -implementation for the file operation part, which suggests that -`System` is taking on too many roles. - -Instead, you can define a `FileOps` interface and an `IOOps` interface -and split `System`'s functionalities into the two. Then you can mock -`IOOps` without mocking `FileOps`. - -## Delegating Calls to a Real Object ## - -When using testing doubles (mocks, fakes, stubs, and etc), sometimes -their behaviors will differ from those of the real objects. This -difference could be either intentional (as in simulating an error such -that you can test the error handling code) or unintentional. If your -mocks have different behaviors than the real objects by mistake, you -could end up with code that passes the tests but fails in production. - -You can use the _delegating-to-real_ technique to ensure that your -mock has the same behavior as the real object while retaining the -ability to validate calls. This technique is very similar to the -delegating-to-fake technique, the difference being that we use a real -object instead of a fake. Here's an example: - -``` -using ::testing::_; -using ::testing::AtLeast; -using ::testing::Invoke; - -class MockFoo : public Foo { - public: - MockFoo() { - // By default, all calls are delegated to the real object. - ON_CALL(*this, DoThis()) - .WillByDefault(Invoke(&real_, &Foo::DoThis)); - ON_CALL(*this, DoThat(_)) - .WillByDefault(Invoke(&real_, &Foo::DoThat)); - ... - } - MOCK_METHOD0(DoThis, ...); - MOCK_METHOD1(DoThat, ...); - ... - private: - Foo real_; -}; -... - - MockFoo mock; - - EXPECT_CALL(mock, DoThis()) - .Times(3); - EXPECT_CALL(mock, DoThat("Hi")) - .Times(AtLeast(1)); - ... use mock in test ... -``` - -With this, Google Mock will verify that your code made the right calls -(with the right arguments, in the right order, called the right number -of times, etc), and a real object will answer the calls (so the -behavior will be the same as in production). This gives you the best -of both worlds. - -## Delegating Calls to a Parent Class ## - -Ideally, you should code to interfaces, whose methods are all pure -virtual. In reality, sometimes you do need to mock a virtual method -that is not pure (i.e, it already has an implementation). For example: - -``` -class Foo { - public: - virtual ~Foo(); - - virtual void Pure(int n) = 0; - virtual int Concrete(const char* str) { ... } -}; - -class MockFoo : public Foo { - public: - // Mocking a pure method. - MOCK_METHOD1(Pure, void(int n)); - // Mocking a concrete method. Foo::Concrete() is shadowed. - MOCK_METHOD1(Concrete, int(const char* str)); -}; -``` - -Sometimes you may want to call `Foo::Concrete()` instead of -`MockFoo::Concrete()`. Perhaps you want to do it as part of a stub -action, or perhaps your test doesn't need to mock `Concrete()` at all -(but it would be oh-so painful to have to define a new mock class -whenever you don't need to mock one of its methods). - -The trick is to leave a back door in your mock class for accessing the -real methods in the base class: - -``` -class MockFoo : public Foo { - public: - // Mocking a pure method. - MOCK_METHOD1(Pure, void(int n)); - // Mocking a concrete method. Foo::Concrete() is shadowed. - MOCK_METHOD1(Concrete, int(const char* str)); - - // Use this to call Concrete() defined in Foo. - int FooConcrete(const char* str) { return Foo::Concrete(str); } -}; -``` - -Now, you can call `Foo::Concrete()` inside an action by: - -``` -using ::testing::_; -using ::testing::Invoke; -... - EXPECT_CALL(foo, Concrete(_)) - .WillOnce(Invoke(&foo, &MockFoo::FooConcrete)); -``` - -or tell the mock object that you don't want to mock `Concrete()`: - -``` -using ::testing::Invoke; -... - ON_CALL(foo, Concrete(_)) - .WillByDefault(Invoke(&foo, &MockFoo::FooConcrete)); -``` - -(Why don't we just write `Invoke(&foo, &Foo::Concrete)`? If you do -that, `MockFoo::Concrete()` will be called (and cause an infinite -recursion) since `Foo::Concrete()` is virtual. That's just how C++ -works.) - -# Using Matchers # - -## Matching Argument Values Exactly ## - -You can specify exactly which arguments a mock method is expecting: - -``` -using ::testing::Return; -... - EXPECT_CALL(foo, DoThis(5)) - .WillOnce(Return('a')); - EXPECT_CALL(foo, DoThat("Hello", bar)); -``` - -## Using Simple Matchers ## - -You can use matchers to match arguments that have a certain property: - -``` -using ::testing::Ge; -using ::testing::NotNull; -using ::testing::Return; -... - EXPECT_CALL(foo, DoThis(Ge(5))) // The argument must be >= 5. - .WillOnce(Return('a')); - EXPECT_CALL(foo, DoThat("Hello", NotNull())); - // The second argument must not be NULL. -``` - -A frequently used matcher is `_`, which matches anything: - -``` -using ::testing::_; -using ::testing::NotNull; -... - EXPECT_CALL(foo, DoThat(_, NotNull())); -``` - -## Combining Matchers ## - -You can build complex matchers from existing ones using `AllOf()`, -`AnyOf()`, and `Not()`: - -``` -using ::testing::AllOf; -using ::testing::Gt; -using ::testing::HasSubstr; -using ::testing::Ne; -using ::testing::Not; -... - // The argument must be > 5 and != 10. - EXPECT_CALL(foo, DoThis(AllOf(Gt(5), - Ne(10)))); - - // The first argument must not contain sub-string "blah". - EXPECT_CALL(foo, DoThat(Not(HasSubstr("blah")), - NULL)); -``` - -## Casting Matchers ## - -Google Mock matchers are statically typed, meaning that the compiler -can catch your mistake if you use a matcher of the wrong type (for -example, if you use `Eq(5)` to match a `string` argument). Good for -you! - -Sometimes, however, you know what you're doing and want the compiler -to give you some slack. One example is that you have a matcher for -`long` and the argument you want to match is `int`. While the two -types aren't exactly the same, there is nothing really wrong with -using a `Matcher` to match an `int` - after all, we can first -convert the `int` argument to a `long` before giving it to the -matcher. - -To support this need, Google Mock gives you the -`SafeMatcherCast(m)` function. It casts a matcher `m` to type -`Matcher`. To ensure safety, Google Mock checks that (let `U` be the -type `m` accepts): - - 1. Type `T` can be implicitly cast to type `U`; - 1. When both `T` and `U` are built-in arithmetic types (`bool`, integers, and floating-point numbers), the conversion from `T` to `U` is not lossy (in other words, any value representable by `T` can also be represented by `U`); and - 1. When `U` is a reference, `T` must also be a reference (as the underlying matcher may be interested in the address of the `U` value). - -The code won't compile if any of these conditions isn't met. - -Here's one example: - -``` -using ::testing::SafeMatcherCast; - -// A base class and a child class. -class Base { ... }; -class Derived : public Base { ... }; - -class MockFoo : public Foo { - public: - MOCK_METHOD1(DoThis, void(Derived* derived)); -}; -... - - MockFoo foo; - // m is a Matcher we got from somewhere. - EXPECT_CALL(foo, DoThis(SafeMatcherCast(m))); -``` - -If you find `SafeMatcherCast(m)` too limiting, you can use a similar -function `MatcherCast(m)`. The difference is that `MatcherCast` works -as long as you can `static_cast` type `T` to type `U`. - -`MatcherCast` essentially lets you bypass C++'s type system -(`static_cast` isn't always safe as it could throw away information, -for example), so be careful not to misuse/abuse it. - -## Selecting Between Overloaded Functions ## - -If you expect an overloaded function to be called, the compiler may -need some help on which overloaded version it is. - -To disambiguate functions overloaded on the const-ness of this object, -use the `Const()` argument wrapper. - -``` -using ::testing::ReturnRef; - -class MockFoo : public Foo { - ... - MOCK_METHOD0(GetBar, Bar&()); - MOCK_CONST_METHOD0(GetBar, const Bar&()); -}; -... - - MockFoo foo; - Bar bar1, bar2; - EXPECT_CALL(foo, GetBar()) // The non-const GetBar(). - .WillOnce(ReturnRef(bar1)); - EXPECT_CALL(Const(foo), GetBar()) // The const GetBar(). - .WillOnce(ReturnRef(bar2)); -``` - -(`Const()` is defined by Google Mock and returns a `const` reference -to its argument.) - -To disambiguate overloaded functions with the same number of arguments -but different argument types, you may need to specify the exact type -of a matcher, either by wrapping your matcher in `Matcher()`, or -using a matcher whose type is fixed (`TypedEq`, `An()`, -etc): - -``` -using ::testing::An; -using ::testing::Lt; -using ::testing::Matcher; -using ::testing::TypedEq; - -class MockPrinter : public Printer { - public: - MOCK_METHOD1(Print, void(int n)); - MOCK_METHOD1(Print, void(char c)); -}; - -TEST(PrinterTest, Print) { - MockPrinter printer; - - EXPECT_CALL(printer, Print(An())); // void Print(int); - EXPECT_CALL(printer, Print(Matcher(Lt(5)))); // void Print(int); - EXPECT_CALL(printer, Print(TypedEq('a'))); // void Print(char); - - printer.Print(3); - printer.Print(6); - printer.Print('a'); -} -``` - -## Performing Different Actions Based on the Arguments ## - -When a mock method is called, the _last_ matching expectation that's -still active will be selected (think "newer overrides older"). So, you -can make a method do different things depending on its argument values -like this: - -``` -using ::testing::_; -using ::testing::Lt; -using ::testing::Return; -... - // The default case. - EXPECT_CALL(foo, DoThis(_)) - .WillRepeatedly(Return('b')); - - // The more specific case. - EXPECT_CALL(foo, DoThis(Lt(5))) - .WillRepeatedly(Return('a')); -``` - -Now, if `foo.DoThis()` is called with a value less than 5, `'a'` will -be returned; otherwise `'b'` will be returned. - -## Matching Multiple Arguments as a Whole ## - -Sometimes it's not enough to match the arguments individually. For -example, we may want to say that the first argument must be less than -the second argument. The `With()` clause allows us to match -all arguments of a mock function as a whole. For example, - -``` -using ::testing::_; -using ::testing::Lt; -using ::testing::Ne; -... - EXPECT_CALL(foo, InRange(Ne(0), _)) - .With(Lt()); -``` - -says that the first argument of `InRange()` must not be 0, and must be -less than the second argument. - -The expression inside `With()` must be a matcher of type -`Matcher >`, where `A1`, ..., `An` are the -types of the function arguments. - -You can also write `AllArgs(m)` instead of `m` inside `.With()`. The -two forms are equivalent, but `.With(AllArgs(Lt()))` is more readable -than `.With(Lt())`. - -You can use `Args(m)` to match the `n` selected arguments -(as a tuple) against `m`. For example, - -``` -using ::testing::_; -using ::testing::AllOf; -using ::testing::Args; -using ::testing::Lt; -... - EXPECT_CALL(foo, Blah(_, _, _)) - .With(AllOf(Args<0, 1>(Lt()), Args<1, 2>(Lt()))); -``` - -says that `Blah()` will be called with arguments `x`, `y`, and `z` where -`x < y < z`. - -As a convenience and example, Google Mock provides some matchers for -2-tuples, including the `Lt()` matcher above. See the [CheatSheet](V1_6_CheatSheet.md) for -the complete list. - -Note that if you want to pass the arguments to a predicate of your own -(e.g. `.With(Args<0, 1>(Truly(&MyPredicate)))`), that predicate MUST be -written to take a `tr1::tuple` as its argument; Google Mock will pass the `n` -selected arguments as _one_ single tuple to the predicate. - -## Using Matchers as Predicates ## - -Have you noticed that a matcher is just a fancy predicate that also -knows how to describe itself? Many existing algorithms take predicates -as arguments (e.g. those defined in STL's `` header), and -it would be a shame if Google Mock matchers are not allowed to -participate. - -Luckily, you can use a matcher where a unary predicate functor is -expected by wrapping it inside the `Matches()` function. For example, - -``` -#include -#include - -std::vector v; -... -// How many elements in v are >= 10? -const int count = count_if(v.begin(), v.end(), Matches(Ge(10))); -``` - -Since you can build complex matchers from simpler ones easily using -Google Mock, this gives you a way to conveniently construct composite -predicates (doing the same using STL's `` header is just -painful). For example, here's a predicate that's satisfied by any -number that is >= 0, <= 100, and != 50: - -``` -Matches(AllOf(Ge(0), Le(100), Ne(50))) -``` - -## Using Matchers in Google Test Assertions ## - -Since matchers are basically predicates that also know how to describe -themselves, there is a way to take advantage of them in -[Google Test](http://code.google.com/p/googletest/) assertions. It's -called `ASSERT_THAT` and `EXPECT_THAT`: - -``` - ASSERT_THAT(value, matcher); // Asserts that value matches matcher. - EXPECT_THAT(value, matcher); // The non-fatal version. -``` - -For example, in a Google Test test you can write: - -``` -#include "gmock/gmock.h" - -using ::testing::AllOf; -using ::testing::Ge; -using ::testing::Le; -using ::testing::MatchesRegex; -using ::testing::StartsWith; -... - - EXPECT_THAT(Foo(), StartsWith("Hello")); - EXPECT_THAT(Bar(), MatchesRegex("Line \\d+")); - ASSERT_THAT(Baz(), AllOf(Ge(5), Le(10))); -``` - -which (as you can probably guess) executes `Foo()`, `Bar()`, and -`Baz()`, and verifies that: - - * `Foo()` returns a string that starts with `"Hello"`. - * `Bar()` returns a string that matches regular expression `"Line \\d+"`. - * `Baz()` returns a number in the range [5, 10]. - -The nice thing about these macros is that _they read like -English_. They generate informative messages too. For example, if the -first `EXPECT_THAT()` above fails, the message will be something like: - -``` -Value of: Foo() - Actual: "Hi, world!" -Expected: starts with "Hello" -``` - -**Credit:** The idea of `(ASSERT|EXPECT)_THAT` was stolen from the -[Hamcrest](http://code.google.com/p/hamcrest/) project, which adds -`assertThat()` to JUnit. - -## Using Predicates as Matchers ## - -Google Mock provides a built-in set of matchers. In case you find them -lacking, you can use an arbitray unary predicate function or functor -as a matcher - as long as the predicate accepts a value of the type -you want. You do this by wrapping the predicate inside the `Truly()` -function, for example: - -``` -using ::testing::Truly; - -int IsEven(int n) { return (n % 2) == 0 ? 1 : 0; } -... - - // Bar() must be called with an even number. - EXPECT_CALL(foo, Bar(Truly(IsEven))); -``` - -Note that the predicate function / functor doesn't have to return -`bool`. It works as long as the return value can be used as the -condition in statement `if (condition) ...`. - -## Matching Arguments that Are Not Copyable ## - -When you do an `EXPECT_CALL(mock_obj, Foo(bar))`, Google Mock saves -away a copy of `bar`. When `Foo()` is called later, Google Mock -compares the argument to `Foo()` with the saved copy of `bar`. This -way, you don't need to worry about `bar` being modified or destroyed -after the `EXPECT_CALL()` is executed. The same is true when you use -matchers like `Eq(bar)`, `Le(bar)`, and so on. - -But what if `bar` cannot be copied (i.e. has no copy constructor)? You -could define your own matcher function and use it with `Truly()`, as -the previous couple of recipes have shown. Or, you may be able to get -away from it if you can guarantee that `bar` won't be changed after -the `EXPECT_CALL()` is executed. Just tell Google Mock that it should -save a reference to `bar`, instead of a copy of it. Here's how: - -``` -using ::testing::Eq; -using ::testing::ByRef; -using ::testing::Lt; -... - // Expects that Foo()'s argument == bar. - EXPECT_CALL(mock_obj, Foo(Eq(ByRef(bar)))); - - // Expects that Foo()'s argument < bar. - EXPECT_CALL(mock_obj, Foo(Lt(ByRef(bar)))); -``` - -Remember: if you do this, don't change `bar` after the -`EXPECT_CALL()`, or the result is undefined. - -## Validating a Member of an Object ## - -Often a mock function takes a reference to object as an argument. When -matching the argument, you may not want to compare the entire object -against a fixed object, as that may be over-specification. Instead, -you may need to validate a certain member variable or the result of a -certain getter method of the object. You can do this with `Field()` -and `Property()`. More specifically, - -``` -Field(&Foo::bar, m) -``` - -is a matcher that matches a `Foo` object whose `bar` member variable -satisfies matcher `m`. - -``` -Property(&Foo::baz, m) -``` - -is a matcher that matches a `Foo` object whose `baz()` method returns -a value that satisfies matcher `m`. - -For example: - -| Expression | Description | -|:-----------------------------|:-----------------------------------| -| `Field(&Foo::number, Ge(3))` | Matches `x` where `x.number >= 3`. | -| `Property(&Foo::name, StartsWith("John "))` | Matches `x` where `x.name()` starts with `"John "`. | - -Note that in `Property(&Foo::baz, ...)`, method `baz()` must take no -argument and be declared as `const`. - -BTW, `Field()` and `Property()` can also match plain pointers to -objects. For instance, - -``` -Field(&Foo::number, Ge(3)) -``` - -matches a plain pointer `p` where `p->number >= 3`. If `p` is `NULL`, -the match will always fail regardless of the inner matcher. - -What if you want to validate more than one members at the same time? -Remember that there is `AllOf()`. - -## Validating the Value Pointed to by a Pointer Argument ## - -C++ functions often take pointers as arguments. You can use matchers -like `NULL`, `NotNull()`, and other comparison matchers to match a -pointer, but what if you want to make sure the value _pointed to_ by -the pointer, instead of the pointer itself, has a certain property? -Well, you can use the `Pointee(m)` matcher. - -`Pointee(m)` matches a pointer iff `m` matches the value the pointer -points to. For example: - -``` -using ::testing::Ge; -using ::testing::Pointee; -... - EXPECT_CALL(foo, Bar(Pointee(Ge(3)))); -``` - -expects `foo.Bar()` to be called with a pointer that points to a value -greater than or equal to 3. - -One nice thing about `Pointee()` is that it treats a `NULL` pointer as -a match failure, so you can write `Pointee(m)` instead of - -``` - AllOf(NotNull(), Pointee(m)) -``` - -without worrying that a `NULL` pointer will crash your test. - -Also, did we tell you that `Pointee()` works with both raw pointers -**and** smart pointers (`linked_ptr`, `shared_ptr`, `scoped_ptr`, and -etc)? - -What if you have a pointer to pointer? You guessed it - you can use -nested `Pointee()` to probe deeper inside the value. For example, -`Pointee(Pointee(Lt(3)))` matches a pointer that points to a pointer -that points to a number less than 3 (what a mouthful...). - -## Testing a Certain Property of an Object ## - -Sometimes you want to specify that an object argument has a certain -property, but there is no existing matcher that does this. If you want -good error messages, you should define a matcher. If you want to do it -quick and dirty, you could get away with writing an ordinary function. - -Let's say you have a mock function that takes an object of type `Foo`, -which has an `int bar()` method and an `int baz()` method, and you -want to constrain that the argument's `bar()` value plus its `baz()` -value is a given number. Here's how you can define a matcher to do it: - -``` -using ::testing::MatcherInterface; -using ::testing::MatchResultListener; - -class BarPlusBazEqMatcher : public MatcherInterface { - public: - explicit BarPlusBazEqMatcher(int expected_sum) - : expected_sum_(expected_sum) {} - - virtual bool MatchAndExplain(const Foo& foo, - MatchResultListener* listener) const { - return (foo.bar() + foo.baz()) == expected_sum_; - } - - virtual void DescribeTo(::std::ostream* os) const { - *os << "bar() + baz() equals " << expected_sum_; - } - - virtual void DescribeNegationTo(::std::ostream* os) const { - *os << "bar() + baz() does not equal " << expected_sum_; - } - private: - const int expected_sum_; -}; - -inline Matcher BarPlusBazEq(int expected_sum) { - return MakeMatcher(new BarPlusBazEqMatcher(expected_sum)); -} - -... - - EXPECT_CALL(..., DoThis(BarPlusBazEq(5)))...; -``` - -## Matching Containers ## - -Sometimes an STL container (e.g. list, vector, map, ...) is passed to -a mock function and you may want to validate it. Since most STL -containers support the `==` operator, you can write -`Eq(expected_container)` or simply `expected_container` to match a -container exactly. - -Sometimes, though, you may want to be more flexible (for example, the -first element must be an exact match, but the second element can be -any positive number, and so on). Also, containers used in tests often -have a small number of elements, and having to define the expected -container out-of-line is a bit of a hassle. - -You can use the `ElementsAre()` matcher in such cases: - -``` -using ::testing::_; -using ::testing::ElementsAre; -using ::testing::Gt; -... - - MOCK_METHOD1(Foo, void(const vector& numbers)); -... - - EXPECT_CALL(mock, Foo(ElementsAre(1, Gt(0), _, 5))); -``` - -The above matcher says that the container must have 4 elements, which -must be 1, greater than 0, anything, and 5 respectively. - -`ElementsAre()` is overloaded to take 0 to 10 arguments. If more are -needed, you can place them in a C-style array and use -`ElementsAreArray()` instead: - -``` -using ::testing::ElementsAreArray; -... - - // ElementsAreArray accepts an array of element values. - const int expected_vector1[] = { 1, 5, 2, 4, ... }; - EXPECT_CALL(mock, Foo(ElementsAreArray(expected_vector1))); - - // Or, an array of element matchers. - Matcher expected_vector2 = { 1, Gt(2), _, 3, ... }; - EXPECT_CALL(mock, Foo(ElementsAreArray(expected_vector2))); -``` - -In case the array needs to be dynamically created (and therefore the -array size cannot be inferred by the compiler), you can give -`ElementsAreArray()` an additional argument to specify the array size: - -``` -using ::testing::ElementsAreArray; -... - int* const expected_vector3 = new int[count]; - ... fill expected_vector3 with values ... - EXPECT_CALL(mock, Foo(ElementsAreArray(expected_vector3, count))); -``` - -**Tips:** - - * `ElementAre*()` works with _any_ container that implements the STL iterator concept (i.e. it has a `const_iterator` type and supports `begin()/end()`) and supports `size()`, not just the ones defined in STL. It will even work with container types yet to be written - as long as they follows the above pattern. - * You can use nested `ElementAre*()` to match nested (multi-dimensional) containers. - * If the container is passed by pointer instead of by reference, just write `Pointee(ElementsAre*(...))`. - * The order of elements _matters_ for `ElementsAre*()`. Therefore don't use it with containers whose element order is undefined (e.g. `hash_map`). - -## Sharing Matchers ## - -Under the hood, a Google Mock matcher object consists of a pointer to -a ref-counted implementation object. Copying matchers is allowed and -very efficient, as only the pointer is copied. When the last matcher -that references the implementation object dies, the implementation -object will be deleted. - -Therefore, if you have some complex matcher that you want to use again -and again, there is no need to build it everytime. Just assign it to a -matcher variable and use that variable repeatedly! For example, - -``` - Matcher in_range = AllOf(Gt(5), Le(10)); - ... use in_range as a matcher in multiple EXPECT_CALLs ... -``` - -# Setting Expectations # - -## Ignoring Uninteresting Calls ## - -If you are not interested in how a mock method is called, just don't -say anything about it. In this case, if the method is ever called, -Google Mock will perform its default action to allow the test program -to continue. If you are not happy with the default action taken by -Google Mock, you can override it using `DefaultValue::Set()` -(described later in this document) or `ON_CALL()`. - -Please note that once you expressed interest in a particular mock -method (via `EXPECT_CALL()`), all invocations to it must match some -expectation. If this function is called but the arguments don't match -any `EXPECT_CALL()` statement, it will be an error. - -## Disallowing Unexpected Calls ## - -If a mock method shouldn't be called at all, explicitly say so: - -``` -using ::testing::_; -... - EXPECT_CALL(foo, Bar(_)) - .Times(0); -``` - -If some calls to the method are allowed, but the rest are not, just -list all the expected calls: - -``` -using ::testing::AnyNumber; -using ::testing::Gt; -... - EXPECT_CALL(foo, Bar(5)); - EXPECT_CALL(foo, Bar(Gt(10))) - .Times(AnyNumber()); -``` - -A call to `foo.Bar()` that doesn't match any of the `EXPECT_CALL()` -statements will be an error. - -## Expecting Ordered Calls ## - -Although an `EXPECT_CALL()` statement defined earlier takes precedence -when Google Mock tries to match a function call with an expectation, -by default calls don't have to happen in the order `EXPECT_CALL()` -statements are written. For example, if the arguments match the -matchers in the third `EXPECT_CALL()`, but not those in the first two, -then the third expectation will be used. - -If you would rather have all calls occur in the order of the -expectations, put the `EXPECT_CALL()` statements in a block where you -define a variable of type `InSequence`: - -``` - using ::testing::_; - using ::testing::InSequence; - - { - InSequence s; - - EXPECT_CALL(foo, DoThis(5)); - EXPECT_CALL(bar, DoThat(_)) - .Times(2); - EXPECT_CALL(foo, DoThis(6)); - } -``` - -In this example, we expect a call to `foo.DoThis(5)`, followed by two -calls to `bar.DoThat()` where the argument can be anything, which are -in turn followed by a call to `foo.DoThis(6)`. If a call occurred -out-of-order, Google Mock will report an error. - -## Expecting Partially Ordered Calls ## - -Sometimes requiring everything to occur in a predetermined order can -lead to brittle tests. For example, we may care about `A` occurring -before both `B` and `C`, but aren't interested in the relative order -of `B` and `C`. In this case, the test should reflect our real intent, -instead of being overly constraining. - -Google Mock allows you to impose an arbitrary DAG (directed acyclic -graph) on the calls. One way to express the DAG is to use the -[After](http://code.google.com/p/googlemock/wiki/V1_6_CheatSheet#The_After_Clause) clause of `EXPECT_CALL`. - -Another way is via the `InSequence()` clause (not the same as the -`InSequence` class), which we borrowed from jMock 2. It's less -flexible than `After()`, but more convenient when you have long chains -of sequential calls, as it doesn't require you to come up with -different names for the expectations in the chains. Here's how it -works: - -If we view `EXPECT_CALL()` statements as nodes in a graph, and add an -edge from node A to node B wherever A must occur before B, we can get -a DAG. We use the term "sequence" to mean a directed path in this -DAG. Now, if we decompose the DAG into sequences, we just need to know -which sequences each `EXPECT_CALL()` belongs to in order to be able to -reconstruct the orginal DAG. - -So, to specify the partial order on the expectations we need to do two -things: first to define some `Sequence` objects, and then for each -`EXPECT_CALL()` say which `Sequence` objects it is part -of. Expectations in the same sequence must occur in the order they are -written. For example, - -``` - using ::testing::Sequence; - - Sequence s1, s2; - - EXPECT_CALL(foo, A()) - .InSequence(s1, s2); - EXPECT_CALL(bar, B()) - .InSequence(s1); - EXPECT_CALL(bar, C()) - .InSequence(s2); - EXPECT_CALL(foo, D()) - .InSequence(s2); -``` - -specifies the following DAG (where `s1` is `A -> B`, and `s2` is `A -> -C -> D`): - -``` - +---> B - | - A ---| - | - +---> C ---> D -``` - -This means that A must occur before B and C, and C must occur before -D. There's no restriction about the order other than these. - -## Controlling When an Expectation Retires ## - -When a mock method is called, Google Mock only consider expectations -that are still active. An expectation is active when created, and -becomes inactive (aka _retires_) when a call that has to occur later -has occurred. For example, in - -``` - using ::testing::_; - using ::testing::Sequence; - - Sequence s1, s2; - - EXPECT_CALL(log, Log(WARNING, _, "File too large.")) // #1 - .Times(AnyNumber()) - .InSequence(s1, s2); - EXPECT_CALL(log, Log(WARNING, _, "Data set is empty.")) // #2 - .InSequence(s1); - EXPECT_CALL(log, Log(WARNING, _, "User not found.")) // #3 - .InSequence(s2); -``` - -as soon as either #2 or #3 is matched, #1 will retire. If a warning -`"File too large."` is logged after this, it will be an error. - -Note that an expectation doesn't retire automatically when it's -saturated. For example, - -``` -using ::testing::_; -... - EXPECT_CALL(log, Log(WARNING, _, _)); // #1 - EXPECT_CALL(log, Log(WARNING, _, "File too large.")); // #2 -``` - -says that there will be exactly one warning with the message `"File -too large."`. If the second warning contains this message too, #2 will -match again and result in an upper-bound-violated error. - -If this is not what you want, you can ask an expectation to retire as -soon as it becomes saturated: - -``` -using ::testing::_; -... - EXPECT_CALL(log, Log(WARNING, _, _)); // #1 - EXPECT_CALL(log, Log(WARNING, _, "File too large.")) // #2 - .RetiresOnSaturation(); -``` - -Here #2 can be used only once, so if you have two warnings with the -message `"File too large."`, the first will match #2 and the second -will match #1 - there will be no error. - -# Using Actions # - -## Returning References from Mock Methods ## - -If a mock function's return type is a reference, you need to use -`ReturnRef()` instead of `Return()` to return a result: - -``` -using ::testing::ReturnRef; - -class MockFoo : public Foo { - public: - MOCK_METHOD0(GetBar, Bar&()); -}; -... - - MockFoo foo; - Bar bar; - EXPECT_CALL(foo, GetBar()) - .WillOnce(ReturnRef(bar)); -``` - -## Returning Live Values from Mock Methods ## - -The `Return(x)` action saves a copy of `x` when the action is -_created_, and always returns the same value whenever it's -executed. Sometimes you may want to instead return the _live_ value of -`x` (i.e. its value at the time when the action is _executed_.). - -If the mock function's return type is a reference, you can do it using -`ReturnRef(x)`, as shown in the previous recipe ("Returning References -from Mock Methods"). However, Google Mock doesn't let you use -`ReturnRef()` in a mock function whose return type is not a reference, -as doing that usually indicates a user error. So, what shall you do? - -You may be tempted to try `ByRef()`: - -``` -using testing::ByRef; -using testing::Return; - -class MockFoo : public Foo { - public: - MOCK_METHOD0(GetValue, int()); -}; -... - int x = 0; - MockFoo foo; - EXPECT_CALL(foo, GetValue()) - .WillRepeatedly(Return(ByRef(x))); - x = 42; - EXPECT_EQ(42, foo.GetValue()); -``` - -Unfortunately, it doesn't work here. The above code will fail with error: - -``` -Value of: foo.GetValue() - Actual: 0 -Expected: 42 -``` - -The reason is that `Return(value)` converts `value` to the actual -return type of the mock function at the time when the action is -_created_, not when it is _executed_. (This behavior was chosen for -the action to be safe when `value` is a proxy object that references -some temporary objects.) As a result, `ByRef(x)` is converted to an -`int` value (instead of a `const int&`) when the expectation is set, -and `Return(ByRef(x))` will always return 0. - -`ReturnPointee(pointer)` was provided to solve this problem -specifically. It returns the value pointed to by `pointer` at the time -the action is _executed_: - -``` -using testing::ReturnPointee; -... - int x = 0; - MockFoo foo; - EXPECT_CALL(foo, GetValue()) - .WillRepeatedly(ReturnPointee(&x)); // Note the & here. - x = 42; - EXPECT_EQ(42, foo.GetValue()); // This will succeed now. -``` - -## Combining Actions ## - -Want to do more than one thing when a function is called? That's -fine. `DoAll()` allow you to do sequence of actions every time. Only -the return value of the last action in the sequence will be used. - -``` -using ::testing::DoAll; - -class MockFoo : public Foo { - public: - MOCK_METHOD1(Bar, bool(int n)); -}; -... - - EXPECT_CALL(foo, Bar(_)) - .WillOnce(DoAll(action_1, - action_2, - ... - action_n)); -``` - -## Mocking Side Effects ## - -Sometimes a method exhibits its effect not via returning a value but -via side effects. For example, it may change some global state or -modify an output argument. To mock side effects, in general you can -define your own action by implementing `::testing::ActionInterface`. - -If all you need to do is to change an output argument, the built-in -`SetArgPointee()` action is convenient: - -``` -using ::testing::SetArgPointee; - -class MockMutator : public Mutator { - public: - MOCK_METHOD2(Mutate, void(bool mutate, int* value)); - ... -}; -... - - MockMutator mutator; - EXPECT_CALL(mutator, Mutate(true, _)) - .WillOnce(SetArgPointee<1>(5)); -``` - -In this example, when `mutator.Mutate()` is called, we will assign 5 -to the `int` variable pointed to by argument #1 -(0-based). - -`SetArgPointee()` conveniently makes an internal copy of the -value you pass to it, removing the need to keep the value in scope and -alive. The implication however is that the value must have a copy -constructor and assignment operator. - -If the mock method also needs to return a value as well, you can chain -`SetArgPointee()` with `Return()` using `DoAll()`: - -``` -using ::testing::_; -using ::testing::Return; -using ::testing::SetArgPointee; - -class MockMutator : public Mutator { - public: - ... - MOCK_METHOD1(MutateInt, bool(int* value)); -}; -... - - MockMutator mutator; - EXPECT_CALL(mutator, MutateInt(_)) - .WillOnce(DoAll(SetArgPointee<0>(5), - Return(true))); -``` - -If the output argument is an array, use the -`SetArrayArgument(first, last)` action instead. It copies the -elements in source range `[first, last)` to the array pointed to by -the `N`-th (0-based) argument: - -``` -using ::testing::NotNull; -using ::testing::SetArrayArgument; - -class MockArrayMutator : public ArrayMutator { - public: - MOCK_METHOD2(Mutate, void(int* values, int num_values)); - ... -}; -... - - MockArrayMutator mutator; - int values[5] = { 1, 2, 3, 4, 5 }; - EXPECT_CALL(mutator, Mutate(NotNull(), 5)) - .WillOnce(SetArrayArgument<0>(values, values + 5)); -``` - -This also works when the argument is an output iterator: - -``` -using ::testing::_; -using ::testing::SeArrayArgument; - -class MockRolodex : public Rolodex { - public: - MOCK_METHOD1(GetNames, void(std::back_insert_iterator >)); - ... -}; -... - - MockRolodex rolodex; - vector names; - names.push_back("George"); - names.push_back("John"); - names.push_back("Thomas"); - EXPECT_CALL(rolodex, GetNames(_)) - .WillOnce(SetArrayArgument<0>(names.begin(), names.end())); -``` - -## Changing a Mock Object's Behavior Based on the State ## - -If you expect a call to change the behavior of a mock object, you can use `::testing::InSequence` to specify different behaviors before and after the call: - -``` -using ::testing::InSequence; -using ::testing::Return; - -... - { - InSequence seq; - EXPECT_CALL(my_mock, IsDirty()) - .WillRepeatedly(Return(true)); - EXPECT_CALL(my_mock, Flush()); - EXPECT_CALL(my_mock, IsDirty()) - .WillRepeatedly(Return(false)); - } - my_mock.FlushIfDirty(); -``` - -This makes `my_mock.IsDirty()` return `true` before `my_mock.Flush()` is called and return `false` afterwards. - -If the behavior change is more complex, you can store the effects in a variable and make a mock method get its return value from that variable: - -``` -using ::testing::_; -using ::testing::SaveArg; -using ::testing::Return; - -ACTION_P(ReturnPointee, p) { return *p; } -... - int previous_value = 0; - EXPECT_CALL(my_mock, GetPrevValue()) - .WillRepeatedly(ReturnPointee(&previous_value)); - EXPECT_CALL(my_mock, UpdateValue(_)) - .WillRepeatedly(SaveArg<0>(&previous_value)); - my_mock.DoSomethingToUpdateValue(); -``` - -Here `my_mock.GetPrevValue()` will always return the argument of the last `UpdateValue()` call. - -## Setting the Default Value for a Return Type ## - -If a mock method's return type is a built-in C++ type or pointer, by -default it will return 0 when invoked. You only need to specify an -action if this default value doesn't work for you. - -Sometimes, you may want to change this default value, or you may want -to specify a default value for types Google Mock doesn't know -about. You can do this using the `::testing::DefaultValue` class -template: - -``` -class MockFoo : public Foo { - public: - MOCK_METHOD0(CalculateBar, Bar()); -}; -... - - Bar default_bar; - // Sets the default return value for type Bar. - DefaultValue::Set(default_bar); - - MockFoo foo; - - // We don't need to specify an action here, as the default - // return value works for us. - EXPECT_CALL(foo, CalculateBar()); - - foo.CalculateBar(); // This should return default_bar. - - // Unsets the default return value. - DefaultValue::Clear(); -``` - -Please note that changing the default value for a type can make you -tests hard to understand. We recommend you to use this feature -judiciously. For example, you may want to make sure the `Set()` and -`Clear()` calls are right next to the code that uses your mock. - -## Setting the Default Actions for a Mock Method ## - -You've learned how to change the default value of a given -type. However, this may be too coarse for your purpose: perhaps you -have two mock methods with the same return type and you want them to -have different behaviors. The `ON_CALL()` macro allows you to -customize your mock's behavior at the method level: - -``` -using ::testing::_; -using ::testing::AnyNumber; -using ::testing::Gt; -using ::testing::Return; -... - ON_CALL(foo, Sign(_)) - .WillByDefault(Return(-1)); - ON_CALL(foo, Sign(0)) - .WillByDefault(Return(0)); - ON_CALL(foo, Sign(Gt(0))) - .WillByDefault(Return(1)); - - EXPECT_CALL(foo, Sign(_)) - .Times(AnyNumber()); - - foo.Sign(5); // This should return 1. - foo.Sign(-9); // This should return -1. - foo.Sign(0); // This should return 0. -``` - -As you may have guessed, when there are more than one `ON_CALL()` -statements, the news order take precedence over the older ones. In -other words, the **last** one that matches the function arguments will -be used. This matching order allows you to set up the common behavior -in a mock object's constructor or the test fixture's set-up phase and -specialize the mock's behavior later. - -## Using Functions/Methods/Functors as Actions ## - -If the built-in actions don't suit you, you can easily use an existing -function, method, or functor as an action: - -``` -using ::testing::_; -using ::testing::Invoke; - -class MockFoo : public Foo { - public: - MOCK_METHOD2(Sum, int(int x, int y)); - MOCK_METHOD1(ComplexJob, bool(int x)); -}; - -int CalculateSum(int x, int y) { return x + y; } - -class Helper { - public: - bool ComplexJob(int x); -}; -... - - MockFoo foo; - Helper helper; - EXPECT_CALL(foo, Sum(_, _)) - .WillOnce(Invoke(CalculateSum)); - EXPECT_CALL(foo, ComplexJob(_)) - .WillOnce(Invoke(&helper, &Helper::ComplexJob)); - - foo.Sum(5, 6); // Invokes CalculateSum(5, 6). - foo.ComplexJob(10); // Invokes helper.ComplexJob(10); -``` - -The only requirement is that the type of the function, etc must be -_compatible_ with the signature of the mock function, meaning that the -latter's arguments can be implicitly converted to the corresponding -arguments of the former, and the former's return type can be -implicitly converted to that of the latter. So, you can invoke -something whose type is _not_ exactly the same as the mock function, -as long as it's safe to do so - nice, huh? - -## Invoking a Function/Method/Functor Without Arguments ## - -`Invoke()` is very useful for doing actions that are more complex. It -passes the mock function's arguments to the function or functor being -invoked such that the callee has the full context of the call to work -with. If the invoked function is not interested in some or all of the -arguments, it can simply ignore them. - -Yet, a common pattern is that a test author wants to invoke a function -without the arguments of the mock function. `Invoke()` allows her to -do that using a wrapper function that throws away the arguments before -invoking an underlining nullary function. Needless to say, this can be -tedious and obscures the intent of the test. - -`InvokeWithoutArgs()` solves this problem. It's like `Invoke()` except -that it doesn't pass the mock function's arguments to the -callee. Here's an example: - -``` -using ::testing::_; -using ::testing::InvokeWithoutArgs; - -class MockFoo : public Foo { - public: - MOCK_METHOD1(ComplexJob, bool(int n)); -}; - -bool Job1() { ... } -... - - MockFoo foo; - EXPECT_CALL(foo, ComplexJob(_)) - .WillOnce(InvokeWithoutArgs(Job1)); - - foo.ComplexJob(10); // Invokes Job1(). -``` - -## Invoking an Argument of the Mock Function ## - -Sometimes a mock function will receive a function pointer or a functor -(in other words, a "callable") as an argument, e.g. - -``` -class MockFoo : public Foo { - public: - MOCK_METHOD2(DoThis, bool(int n, bool (*fp)(int))); -}; -``` - -and you may want to invoke this callable argument: - -``` -using ::testing::_; -... - MockFoo foo; - EXPECT_CALL(foo, DoThis(_, _)) - .WillOnce(...); - // Will execute (*fp)(5), where fp is the - // second argument DoThis() receives. -``` - -Arghh, you need to refer to a mock function argument but your version -of C++ has no lambdas, so you have to define your own action. :-( -Or do you really? - -Well, Google Mock has an action to solve _exactly_ this problem: - -``` - InvokeArgument(arg_1, arg_2, ..., arg_m) -``` - -will invoke the `N`-th (0-based) argument the mock function receives, -with `arg_1`, `arg_2`, ..., and `arg_m`. No matter if the argument is -a function pointer or a functor, Google Mock handles them both. - -With that, you could write: - -``` -using ::testing::_; -using ::testing::InvokeArgument; -... - EXPECT_CALL(foo, DoThis(_, _)) - .WillOnce(InvokeArgument<1>(5)); - // Will execute (*fp)(5), where fp is the - // second argument DoThis() receives. -``` - -What if the callable takes an argument by reference? No problem - just -wrap it inside `ByRef()`: - -``` -... - MOCK_METHOD1(Bar, bool(bool (*fp)(int, const Helper&))); -... -using ::testing::_; -using ::testing::ByRef; -using ::testing::InvokeArgument; -... - - MockFoo foo; - Helper helper; - ... - EXPECT_CALL(foo, Bar(_)) - .WillOnce(InvokeArgument<0>(5, ByRef(helper))); - // ByRef(helper) guarantees that a reference to helper, not a copy of it, - // will be passed to the callable. -``` - -What if the callable takes an argument by reference and we do **not** -wrap the argument in `ByRef()`? Then `InvokeArgument()` will _make a -copy_ of the argument, and pass a _reference to the copy_, instead of -a reference to the original value, to the callable. This is especially -handy when the argument is a temporary value: - -``` -... - MOCK_METHOD1(DoThat, bool(bool (*f)(const double& x, const string& s))); -... -using ::testing::_; -using ::testing::InvokeArgument; -... - - MockFoo foo; - ... - EXPECT_CALL(foo, DoThat(_)) - .WillOnce(InvokeArgument<0>(5.0, string("Hi"))); - // Will execute (*f)(5.0, string("Hi")), where f is the function pointer - // DoThat() receives. Note that the values 5.0 and string("Hi") are - // temporary and dead once the EXPECT_CALL() statement finishes. Yet - // it's fine to perform this action later, since a copy of the values - // are kept inside the InvokeArgument action. -``` - -## Ignoring an Action's Result ## - -Sometimes you have an action that returns _something_, but you need an -action that returns `void` (perhaps you want to use it in a mock -function that returns `void`, or perhaps it needs to be used in -`DoAll()` and it's not the last in the list). `IgnoreResult()` lets -you do that. For example: - -``` -using ::testing::_; -using ::testing::Invoke; -using ::testing::Return; - -int Process(const MyData& data); -string DoSomething(); - -class MockFoo : public Foo { - public: - MOCK_METHOD1(Abc, void(const MyData& data)); - MOCK_METHOD0(Xyz, bool()); -}; -... - - MockFoo foo; - EXPECT_CALL(foo, Abc(_)) - // .WillOnce(Invoke(Process)); - // The above line won't compile as Process() returns int but Abc() needs - // to return void. - .WillOnce(IgnoreResult(Invoke(Process))); - - EXPECT_CALL(foo, Xyz()) - .WillOnce(DoAll(IgnoreResult(Invoke(DoSomething)), - // Ignores the string DoSomething() returns. - Return(true))); -``` - -Note that you **cannot** use `IgnoreResult()` on an action that already -returns `void`. Doing so will lead to ugly compiler errors. - -## Selecting an Action's Arguments ## - -Say you have a mock function `Foo()` that takes seven arguments, and -you have a custom action that you want to invoke when `Foo()` is -called. Trouble is, the custom action only wants three arguments: - -``` -using ::testing::_; -using ::testing::Invoke; -... - MOCK_METHOD7(Foo, bool(bool visible, const string& name, int x, int y, - const map, double>& weight, - double min_weight, double max_wight)); -... - -bool IsVisibleInQuadrant1(bool visible, int x, int y) { - return visible && x >= 0 && y >= 0; -} -... - - EXPECT_CALL(mock, Foo(_, _, _, _, _, _, _)) - .WillOnce(Invoke(IsVisibleInQuadrant1)); // Uh, won't compile. :-( -``` - -To please the compiler God, you can to define an "adaptor" that has -the same signature as `Foo()` and calls the custom action with the -right arguments: - -``` -using ::testing::_; -using ::testing::Invoke; - -bool MyIsVisibleInQuadrant1(bool visible, const string& name, int x, int y, - const map, double>& weight, - double min_weight, double max_wight) { - return IsVisibleInQuadrant1(visible, x, y); -} -... - - EXPECT_CALL(mock, Foo(_, _, _, _, _, _, _)) - .WillOnce(Invoke(MyIsVisibleInQuadrant1)); // Now it works. -``` - -But isn't this awkward? - -Google Mock provides a generic _action adaptor_, so you can spend your -time minding more important business than writing your own -adaptors. Here's the syntax: - -``` - WithArgs(action) -``` - -creates an action that passes the arguments of the mock function at -the given indices (0-based) to the inner `action` and performs -it. Using `WithArgs`, our original example can be written as: - -``` -using ::testing::_; -using ::testing::Invoke; -using ::testing::WithArgs; -... - EXPECT_CALL(mock, Foo(_, _, _, _, _, _, _)) - .WillOnce(WithArgs<0, 2, 3>(Invoke(IsVisibleInQuadrant1))); - // No need to define your own adaptor. -``` - -For better readability, Google Mock also gives you: - - * `WithoutArgs(action)` when the inner `action` takes _no_ argument, and - * `WithArg(action)` (no `s` after `Arg`) when the inner `action` takes _one_ argument. - -As you may have realized, `InvokeWithoutArgs(...)` is just syntactic -sugar for `WithoutArgs(Inovke(...))`. - -Here are more tips: - - * The inner action used in `WithArgs` and friends does not have to be `Invoke()` -- it can be anything. - * You can repeat an argument in the argument list if necessary, e.g. `WithArgs<2, 3, 3, 5>(...)`. - * You can change the order of the arguments, e.g. `WithArgs<3, 2, 1>(...)`. - * The types of the selected arguments do _not_ have to match the signature of the inner action exactly. It works as long as they can be implicitly converted to the corresponding arguments of the inner action. For example, if the 4-th argument of the mock function is an `int` and `my_action` takes a `double`, `WithArg<4>(my_action)` will work. - -## Ignoring Arguments in Action Functions ## - -The selecting-an-action's-arguments recipe showed us one way to make a -mock function and an action with incompatible argument lists fit -together. The downside is that wrapping the action in -`WithArgs<...>()` can get tedious for people writing the tests. - -If you are defining a function, method, or functor to be used with -`Invoke*()`, and you are not interested in some of its arguments, an -alternative to `WithArgs` is to declare the uninteresting arguments as -`Unused`. This makes the definition less cluttered and less fragile in -case the types of the uninteresting arguments change. It could also -increase the chance the action function can be reused. For example, -given - -``` - MOCK_METHOD3(Foo, double(const string& label, double x, double y)); - MOCK_METHOD3(Bar, double(int index, double x, double y)); -``` - -instead of - -``` -using ::testing::_; -using ::testing::Invoke; - -double DistanceToOriginWithLabel(const string& label, double x, double y) { - return sqrt(x*x + y*y); -} - -double DistanceToOriginWithIndex(int index, double x, double y) { - return sqrt(x*x + y*y); -} -... - - EXEPCT_CALL(mock, Foo("abc", _, _)) - .WillOnce(Invoke(DistanceToOriginWithLabel)); - EXEPCT_CALL(mock, Bar(5, _, _)) - .WillOnce(Invoke(DistanceToOriginWithIndex)); -``` - -you could write - -``` -using ::testing::_; -using ::testing::Invoke; -using ::testing::Unused; - -double DistanceToOrigin(Unused, double x, double y) { - return sqrt(x*x + y*y); -} -... - - EXEPCT_CALL(mock, Foo("abc", _, _)) - .WillOnce(Invoke(DistanceToOrigin)); - EXEPCT_CALL(mock, Bar(5, _, _)) - .WillOnce(Invoke(DistanceToOrigin)); -``` - -## Sharing Actions ## - -Just like matchers, a Google Mock action object consists of a pointer -to a ref-counted implementation object. Therefore copying actions is -also allowed and very efficient. When the last action that references -the implementation object dies, the implementation object will be -deleted. - -If you have some complex action that you want to use again and again, -you may not have to build it from scratch everytime. If the action -doesn't have an internal state (i.e. if it always does the same thing -no matter how many times it has been called), you can assign it to an -action variable and use that variable repeatedly. For example: - -``` - Action set_flag = DoAll(SetArgPointee<0>(5), - Return(true)); - ... use set_flag in .WillOnce() and .WillRepeatedly() ... -``` - -However, if the action has its own state, you may be surprised if you -share the action object. Suppose you have an action factory -`IncrementCounter(init)` which creates an action that increments and -returns a counter whose initial value is `init`, using two actions -created from the same expression and using a shared action will -exihibit different behaviors. Example: - -``` - EXPECT_CALL(foo, DoThis()) - .WillRepeatedly(IncrementCounter(0)); - EXPECT_CALL(foo, DoThat()) - .WillRepeatedly(IncrementCounter(0)); - foo.DoThis(); // Returns 1. - foo.DoThis(); // Returns 2. - foo.DoThat(); // Returns 1 - Blah() uses a different - // counter than Bar()'s. -``` - -versus - -``` - Action increment = IncrementCounter(0); - - EXPECT_CALL(foo, DoThis()) - .WillRepeatedly(increment); - EXPECT_CALL(foo, DoThat()) - .WillRepeatedly(increment); - foo.DoThis(); // Returns 1. - foo.DoThis(); // Returns 2. - foo.DoThat(); // Returns 3 - the counter is shared. -``` - -# Misc Recipes on Using Google Mock # - -## Making the Compilation Faster ## - -Believe it or not, the _vast majority_ of the time spent on compiling -a mock class is in generating its constructor and destructor, as they -perform non-trivial tasks (e.g. verification of the -expectations). What's more, mock methods with different signatures -have different types and thus their constructors/destructors need to -be generated by the compiler separately. As a result, if you mock many -different types of methods, compiling your mock class can get really -slow. - -If you are experiencing slow compilation, you can move the definition -of your mock class' constructor and destructor out of the class body -and into a `.cpp` file. This way, even if you `#include` your mock -class in N files, the compiler only needs to generate its constructor -and destructor once, resulting in a much faster compilation. - -Let's illustrate the idea using an example. Here's the definition of a -mock class before applying this recipe: - -``` -// File mock_foo.h. -... -class MockFoo : public Foo { - public: - // Since we don't declare the constructor or the destructor, - // the compiler will generate them in every translation unit - // where this mock class is used. - - MOCK_METHOD0(DoThis, int()); - MOCK_METHOD1(DoThat, bool(const char* str)); - ... more mock methods ... -}; -``` - -After the change, it would look like: - -``` -// File mock_foo.h. -... -class MockFoo : public Foo { - public: - // The constructor and destructor are declared, but not defined, here. - MockFoo(); - virtual ~MockFoo(); - - MOCK_METHOD0(DoThis, int()); - MOCK_METHOD1(DoThat, bool(const char* str)); - ... more mock methods ... -}; -``` -and -``` -// File mock_foo.cpp. -#include "path/to/mock_foo.h" - -// The definitions may appear trivial, but the functions actually do a -// lot of things through the constructors/destructors of the member -// variables used to implement the mock methods. -MockFoo::MockFoo() {} -MockFoo::~MockFoo() {} -``` - -## Forcing a Verification ## - -When it's being destroyed, your friendly mock object will automatically -verify that all expectations on it have been satisfied, and will -generate [Google Test](http://code.google.com/p/googletest/) failures -if not. This is convenient as it leaves you with one less thing to -worry about. That is, unless you are not sure if your mock object will -be destroyed. - -How could it be that your mock object won't eventually be destroyed? -Well, it might be created on the heap and owned by the code you are -testing. Suppose there's a bug in that code and it doesn't delete the -mock object properly - you could end up with a passing test when -there's actually a bug. - -Using a heap checker is a good idea and can alleviate the concern, but -its implementation may not be 100% reliable. So, sometimes you do want -to _force_ Google Mock to verify a mock object before it is -(hopefully) destructed. You can do this with -`Mock::VerifyAndClearExpectations(&mock_object)`: - -``` -TEST(MyServerTest, ProcessesRequest) { - using ::testing::Mock; - - MockFoo* const foo = new MockFoo; - EXPECT_CALL(*foo, ...)...; - // ... other expectations ... - - // server now owns foo. - MyServer server(foo); - server.ProcessRequest(...); - - // In case that server's destructor will forget to delete foo, - // this will verify the expectations anyway. - Mock::VerifyAndClearExpectations(foo); -} // server is destroyed when it goes out of scope here. -``` - -**Tip:** The `Mock::VerifyAndClearExpectations()` function returns a -`bool` to indicate whether the verification was successful (`true` for -yes), so you can wrap that function call inside a `ASSERT_TRUE()` if -there is no point going further when the verification has failed. - -## Using Check Points ## - -Sometimes you may want to "reset" a mock object at various check -points in your test: at each check point, you verify that all existing -expectations on the mock object have been satisfied, and then you set -some new expectations on it as if it's newly created. This allows you -to work with a mock object in "phases" whose sizes are each -manageable. - -One such scenario is that in your test's `SetUp()` function, you may -want to put the object you are testing into a certain state, with the -help from a mock object. Once in the desired state, you want to clear -all expectations on the mock, such that in the `TEST_F` body you can -set fresh expectations on it. - -As you may have figured out, the `Mock::VerifyAndClearExpectations()` -function we saw in the previous recipe can help you here. Or, if you -are using `ON_CALL()` to set default actions on the mock object and -want to clear the default actions as well, use -`Mock::VerifyAndClear(&mock_object)` instead. This function does what -`Mock::VerifyAndClearExpectations(&mock_object)` does and returns the -same `bool`, **plus** it clears the `ON_CALL()` statements on -`mock_object` too. - -Another trick you can use to achieve the same effect is to put the -expectations in sequences and insert calls to a dummy "check-point" -function at specific places. Then you can verify that the mock -function calls do happen at the right time. For example, if you are -exercising code: - -``` -Foo(1); -Foo(2); -Foo(3); -``` - -and want to verify that `Foo(1)` and `Foo(3)` both invoke -`mock.Bar("a")`, but `Foo(2)` doesn't invoke anything. You can write: - -``` -using ::testing::MockFunction; - -TEST(FooTest, InvokesBarCorrectly) { - MyMock mock; - // Class MockFunction has exactly one mock method. It is named - // Call() and has type F. - MockFunction check; - { - InSequence s; - - EXPECT_CALL(mock, Bar("a")); - EXPECT_CALL(check, Call("1")); - EXPECT_CALL(check, Call("2")); - EXPECT_CALL(mock, Bar("a")); - } - Foo(1); - check.Call("1"); - Foo(2); - check.Call("2"); - Foo(3); -} -``` - -The expectation spec says that the first `Bar("a")` must happen before -check point "1", the second `Bar("a")` must happen after check point "2", -and nothing should happen between the two check points. The explicit -check points make it easy to tell which `Bar("a")` is called by which -call to `Foo()`. - -## Mocking Destructors ## - -Sometimes you want to make sure a mock object is destructed at the -right time, e.g. after `bar->A()` is called but before `bar->B()` is -called. We already know that you can specify constraints on the order -of mock function calls, so all we need to do is to mock the destructor -of the mock function. - -This sounds simple, except for one problem: a destructor is a special -function with special syntax and special semantics, and the -`MOCK_METHOD0` macro doesn't work for it: - -``` - MOCK_METHOD0(~MockFoo, void()); // Won't compile! -``` - -The good news is that you can use a simple pattern to achieve the same -effect. First, add a mock function `Die()` to your mock class and call -it in the destructor, like this: - -``` -class MockFoo : public Foo { - ... - // Add the following two lines to the mock class. - MOCK_METHOD0(Die, void()); - virtual ~MockFoo() { Die(); } -}; -``` - -(If the name `Die()` clashes with an existing symbol, choose another -name.) Now, we have translated the problem of testing when a `MockFoo` -object dies to testing when its `Die()` method is called: - -``` - MockFoo* foo = new MockFoo; - MockBar* bar = new MockBar; - ... - { - InSequence s; - - // Expects *foo to die after bar->A() and before bar->B(). - EXPECT_CALL(*bar, A()); - EXPECT_CALL(*foo, Die()); - EXPECT_CALL(*bar, B()); - } -``` - -And that's that. - -## Using Google Mock and Threads ## - -**IMPORTANT NOTE:** What we describe in this recipe is **ONLY** true on -platforms where Google Mock is thread-safe. Currently these are only -platforms that support the pthreads library (this includes Linux and Mac). -To make it thread-safe on other platforms we only need to implement -some synchronization operations in `"gtest/internal/gtest-port.h"`. - -In a **unit** test, it's best if you could isolate and test a piece of -code in a single-threaded context. That avoids race conditions and -dead locks, and makes debugging your test much easier. - -Yet many programs are multi-threaded, and sometimes to test something -we need to pound on it from more than one thread. Google Mock works -for this purpose too. - -Remember the steps for using a mock: - - 1. Create a mock object `foo`. - 1. Set its default actions and expectations using `ON_CALL()` and `EXPECT_CALL()`. - 1. The code under test calls methods of `foo`. - 1. Optionally, verify and reset the mock. - 1. Destroy the mock yourself, or let the code under test destroy it. The destructor will automatically verify it. - -If you follow the following simple rules, your mocks and threads can -live happily togeter: - - * Execute your _test code_ (as opposed to the code being tested) in _one_ thread. This makes your test easy to follow. - * Obviously, you can do step #1 without locking. - * When doing step #2 and #5, make sure no other thread is accessing `foo`. Obvious too, huh? - * #3 and #4 can be done either in one thread or in multiple threads - anyway you want. Google Mock takes care of the locking, so you don't have to do any - unless required by your test logic. - -If you violate the rules (for example, if you set expectations on a -mock while another thread is calling its methods), you get undefined -behavior. That's not fun, so don't do it. - -Google Mock guarantees that the action for a mock function is done in -the same thread that called the mock function. For example, in - -``` - EXPECT_CALL(mock, Foo(1)) - .WillOnce(action1); - EXPECT_CALL(mock, Foo(2)) - .WillOnce(action2); -``` - -if `Foo(1)` is called in thread 1 and `Foo(2)` is called in thread 2, -Google Mock will execute `action1` in thread 1 and `action2` in thread -2. - -Google Mock does _not_ impose a sequence on actions performed in -different threads (doing so may create deadlocks as the actions may -need to cooperate). This means that the execution of `action1` and -`action2` in the above example _may_ interleave. If this is a problem, -you should add proper synchronization logic to `action1` and `action2` -to make the test thread-safe. - - -Also, remember that `DefaultValue` is a global resource that -potentially affects _all_ living mock objects in your -program. Naturally, you won't want to mess with it from multiple -threads or when there still are mocks in action. - -## Controlling How Much Information Google Mock Prints ## - -When Google Mock sees something that has the potential of being an -error (e.g. a mock function with no expectation is called, a.k.a. an -uninteresting call, which is allowed but perhaps you forgot to -explicitly ban the call), it prints some warning messages, including -the arguments of the function and the return value. Hopefully this -will remind you to take a look and see if there is indeed a problem. - -Sometimes you are confident that your tests are correct and may not -appreciate such friendly messages. Some other times, you are debugging -your tests or learning about the behavior of the code you are testing, -and wish you could observe every mock call that happens (including -argument values and the return value). Clearly, one size doesn't fit -all. - -You can control how much Google Mock tells you using the -`--gmock_verbose=LEVEL` command-line flag, where `LEVEL` is a string -with three possible values: - - * `info`: Google Mock will print all informational messages, warnings, and errors (most verbose). At this setting, Google Mock will also log any calls to the `ON_CALL/EXPECT_CALL` macros. - * `warning`: Google Mock will print both warnings and errors (less verbose). This is the default. - * `error`: Google Mock will print errors only (least verbose). - -Alternatively, you can adjust the value of that flag from within your -tests like so: - -``` - ::testing::FLAGS_gmock_verbose = "error"; -``` - -Now, judiciously use the right flag to enable Google Mock serve you better! - -## Running Tests in Emacs ## - -If you build and run your tests in Emacs, the source file locations of -Google Mock and [Google Test](http://code.google.com/p/googletest/) -errors will be highlighted. Just press `` on one of them and -you'll be taken to the offending line. Or, you can just type `C-x `` -to jump to the next error. - -To make it even easier, you can add the following lines to your -`~/.emacs` file: - -``` -(global-set-key "\M-m" 'compile) ; m is for make -(global-set-key [M-down] 'next-error) -(global-set-key [M-up] '(lambda () (interactive) (next-error -1))) -``` - -Then you can type `M-m` to start a build, or `M-up`/`M-down` to move -back and forth between errors. - -## Fusing Google Mock Source Files ## - -Google Mock's implementation consists of dozens of files (excluding -its own tests). Sometimes you may want them to be packaged up in -fewer files instead, such that you can easily copy them to a new -machine and start hacking there. For this we provide an experimental -Python script `fuse_gmock_files.py` in the `scripts/` directory -(starting with release 1.2.0). Assuming you have Python 2.4 or above -installed on your machine, just go to that directory and run -``` -python fuse_gmock_files.py OUTPUT_DIR -``` - -and you should see an `OUTPUT_DIR` directory being created with files -`gtest/gtest.h`, `gmock/gmock.h`, and `gmock-gtest-all.cc` in it. -These three files contain everything you need to use Google Mock (and -Google Test). Just copy them to anywhere you want and you are ready -to write tests and use mocks. You can use the -[scrpts/test/Makefile](http://code.google.com/p/googlemock/source/browse/trunk/scripts/test/Makefile) file as an example on how to compile your tests -against them. - -# Extending Google Mock # - -## Writing New Matchers Quickly ## - -The `MATCHER*` family of macros can be used to define custom matchers -easily. The syntax: - -``` -MATCHER(name, description_string_expression) { statements; } -``` - -will define a matcher with the given name that executes the -statements, which must return a `bool` to indicate if the match -succeeds. Inside the statements, you can refer to the value being -matched by `arg`, and refer to its type by `arg_type`. - -The description string is a `string`-typed expression that documents -what the matcher does, and is used to generate the failure message -when the match fails. It can (and should) reference the special -`bool` variable `negation`, and should evaluate to the description of -the matcher when `negation` is `false`, or that of the matcher's -negation when `negation` is `true`. - -For convenience, we allow the description string to be empty (`""`), -in which case Google Mock will use the sequence of words in the -matcher name as the description. - -For example: -``` -MATCHER(IsDivisibleBy7, "") { return (arg % 7) == 0; } -``` -allows you to write -``` - // Expects mock_foo.Bar(n) to be called where n is divisible by 7. - EXPECT_CALL(mock_foo, Bar(IsDivisibleBy7())); -``` -or, -``` -using ::testing::Not; -... - EXPECT_THAT(some_expression, IsDivisibleBy7()); - EXPECT_THAT(some_other_expression, Not(IsDivisibleBy7())); -``` -If the above assertions fail, they will print something like: -``` - Value of: some_expression - Expected: is divisible by 7 - Actual: 27 -... - Value of: some_other_expression - Expected: not (is divisible by 7) - Actual: 21 -``` -where the descriptions `"is divisible by 7"` and `"not (is divisible -by 7)"` are automatically calculated from the matcher name -`IsDivisibleBy7`. - -As you may have noticed, the auto-generated descriptions (especially -those for the negation) may not be so great. You can always override -them with a string expression of your own: -``` -MATCHER(IsDivisibleBy7, std::string(negation ? "isn't" : "is") + - " divisible by 7") { - return (arg % 7) == 0; -} -``` - -Optionally, you can stream additional information to a hidden argument -named `result_listener` to explain the match result. For example, a -better definition of `IsDivisibleBy7` is: -``` -MATCHER(IsDivisibleBy7, "") { - if ((arg % 7) == 0) - return true; - - *result_listener << "the remainder is " << (arg % 7); - return false; -} -``` - -With this definition, the above assertion will give a better message: -``` - Value of: some_expression - Expected: is divisible by 7 - Actual: 27 (the remainder is 6) -``` - -You should let `MatchAndExplain()` print _any additional information_ -that can help a user understand the match result. Note that it should -explain why the match succeeds in case of a success (unless it's -obvious) - this is useful when the matcher is used inside -`Not()`. There is no need to print the argument value itself, as -Google Mock already prints it for you. - -**Notes:** - - 1. The type of the value being matched (`arg_type`) is determined by the context in which you use the matcher and is supplied to you by the compiler, so you don't need to worry about declaring it (nor can you). This allows the matcher to be polymorphic. For example, `IsDivisibleBy7()` can be used to match any type where the value of `(arg % 7) == 0` can be implicitly converted to a `bool`. In the `Bar(IsDivisibleBy7())` example above, if method `Bar()` takes an `int`, `arg_type` will be `int`; if it takes an `unsigned long`, `arg_type` will be `unsigned long`; and so on. - 1. Google Mock doesn't guarantee when or how many times a matcher will be invoked. Therefore the matcher logic must be _purely functional_ (i.e. it cannot have any side effect, and the result must not depend on anything other than the value being matched and the matcher parameters). This requirement must be satisfied no matter how you define the matcher (e.g. using one of the methods described in the following recipes). In particular, a matcher can never call a mock function, as that will affect the state of the mock object and Google Mock. - -## Writing New Parameterized Matchers Quickly ## - -Sometimes you'll want to define a matcher that has parameters. For that you -can use the macro: -``` -MATCHER_P(name, param_name, description_string) { statements; } -``` -where the description string can be either `""` or a string expression -that references `negation` and `param_name`. - -For example: -``` -MATCHER_P(HasAbsoluteValue, value, "") { return abs(arg) == value; } -``` -will allow you to write: -``` - EXPECT_THAT(Blah("a"), HasAbsoluteValue(n)); -``` -which may lead to this message (assuming `n` is 10): -``` - Value of: Blah("a") - Expected: has absolute value 10 - Actual: -9 -``` - -Note that both the matcher description and its parameter are -printed, making the message human-friendly. - -In the matcher definition body, you can write `foo_type` to -reference the type of a parameter named `foo`. For example, in the -body of `MATCHER_P(HasAbsoluteValue, value)` above, you can write -`value_type` to refer to the type of `value`. - -Google Mock also provides `MATCHER_P2`, `MATCHER_P3`, ..., up to -`MATCHER_P10` to support multi-parameter matchers: -``` -MATCHER_Pk(name, param_1, ..., param_k, description_string) { statements; } -``` - -Please note that the custom description string is for a particular -**instance** of the matcher, where the parameters have been bound to -actual values. Therefore usually you'll want the parameter values to -be part of the description. Google Mock lets you do that by -referencing the matcher parameters in the description string -expression. - -For example, -``` - using ::testing::PrintToString; - MATCHER_P2(InClosedRange, low, hi, - std::string(negation ? "isn't" : "is") + " in range [" + - PrintToString(low) + ", " + PrintToString(hi) + "]") { - return low <= arg && arg <= hi; - } - ... - EXPECT_THAT(3, InClosedRange(4, 6)); -``` -would generate a failure that contains the message: -``` - Expected: is in range [4, 6] -``` - -If you specify `""` as the description, the failure message will -contain the sequence of words in the matcher name followed by the -parameter values printed as a tuple. For example, -``` - MATCHER_P2(InClosedRange, low, hi, "") { ... } - ... - EXPECT_THAT(3, InClosedRange(4, 6)); -``` -would generate a failure that contains the text: -``` - Expected: in closed range (4, 6) -``` - -For the purpose of typing, you can view -``` -MATCHER_Pk(Foo, p1, ..., pk, description_string) { ... } -``` -as shorthand for -``` -template -FooMatcherPk -Foo(p1_type p1, ..., pk_type pk) { ... } -``` - -When you write `Foo(v1, ..., vk)`, the compiler infers the types of -the parameters `v1`, ..., and `vk` for you. If you are not happy with -the result of the type inference, you can specify the types by -explicitly instantiating the template, as in `Foo(5, false)`. -As said earlier, you don't get to (or need to) specify -`arg_type` as that's determined by the context in which the matcher -is used. - -You can assign the result of expression `Foo(p1, ..., pk)` to a -variable of type `FooMatcherPk`. This can be -useful when composing matchers. Matchers that don't have a parameter -or have only one parameter have special types: you can assign `Foo()` -to a `FooMatcher`-typed variable, and assign `Foo(p)` to a -`FooMatcherP`-typed variable. - -While you can instantiate a matcher template with reference types, -passing the parameters by pointer usually makes your code more -readable. If, however, you still want to pass a parameter by -reference, be aware that in the failure message generated by the -matcher you will see the value of the referenced object but not its -address. - -You can overload matchers with different numbers of parameters: -``` -MATCHER_P(Blah, a, description_string_1) { ... } -MATCHER_P2(Blah, a, b, description_string_2) { ... } -``` - -While it's tempting to always use the `MATCHER*` macros when defining -a new matcher, you should also consider implementing -`MatcherInterface` or using `MakePolymorphicMatcher()` instead (see -the recipes that follow), especially if you need to use the matcher a -lot. While these approaches require more work, they give you more -control on the types of the value being matched and the matcher -parameters, which in general leads to better compiler error messages -that pay off in the long run. They also allow overloading matchers -based on parameter types (as opposed to just based on the number of -parameters). - -## Writing New Monomorphic Matchers ## - -A matcher of argument type `T` implements -`::testing::MatcherInterface` and does two things: it tests whether a -value of type `T` matches the matcher, and can describe what kind of -values it matches. The latter ability is used for generating readable -error messages when expectations are violated. - -The interface looks like this: - -``` -class MatchResultListener { - public: - ... - // Streams x to the underlying ostream; does nothing if the ostream - // is NULL. - template - MatchResultListener& operator<<(const T& x); - - // Returns the underlying ostream. - ::std::ostream* stream(); -}; - -template -class MatcherInterface { - public: - virtual ~MatcherInterface(); - - // Returns true iff the matcher matches x; also explains the match - // result to 'listener'. - virtual bool MatchAndExplain(T x, MatchResultListener* listener) const = 0; - - // Describes this matcher to an ostream. - virtual void DescribeTo(::std::ostream* os) const = 0; - - // Describes the negation of this matcher to an ostream. - virtual void DescribeNegationTo(::std::ostream* os) const; -}; -``` - -If you need a custom matcher but `Truly()` is not a good option (for -example, you may not be happy with the way `Truly(predicate)` -describes itself, or you may want your matcher to be polymorphic as -`Eq(value)` is), you can define a matcher to do whatever you want in -two steps: first implement the matcher interface, and then define a -factory function to create a matcher instance. The second step is not -strictly needed but it makes the syntax of using the matcher nicer. - -For example, you can define a matcher to test whether an `int` is -divisible by 7 and then use it like this: -``` -using ::testing::MakeMatcher; -using ::testing::Matcher; -using ::testing::MatcherInterface; -using ::testing::MatchResultListener; - -class DivisibleBy7Matcher : public MatcherInterface { - public: - virtual bool MatchAndExplain(int n, MatchResultListener* listener) const { - return (n % 7) == 0; - } - - virtual void DescribeTo(::std::ostream* os) const { - *os << "is divisible by 7"; - } - - virtual void DescribeNegationTo(::std::ostream* os) const { - *os << "is not divisible by 7"; - } -}; - -inline Matcher DivisibleBy7() { - return MakeMatcher(new DivisibleBy7Matcher); -} -... - - EXPECT_CALL(foo, Bar(DivisibleBy7())); -``` - -You may improve the matcher message by streaming additional -information to the `listener` argument in `MatchAndExplain()`: - -``` -class DivisibleBy7Matcher : public MatcherInterface { - public: - virtual bool MatchAndExplain(int n, - MatchResultListener* listener) const { - const int remainder = n % 7; - if (remainder != 0) { - *listener << "the remainder is " << remainder; - } - return remainder == 0; - } - ... -}; -``` - -Then, `EXPECT_THAT(x, DivisibleBy7());` may general a message like this: -``` -Value of: x -Expected: is divisible by 7 - Actual: 23 (the remainder is 2) -``` - -## Writing New Polymorphic Matchers ## - -You've learned how to write your own matchers in the previous -recipe. Just one problem: a matcher created using `MakeMatcher()` only -works for one particular type of arguments. If you want a -_polymorphic_ matcher that works with arguments of several types (for -instance, `Eq(x)` can be used to match a `value` as long as `value` == -`x` compiles -- `value` and `x` don't have to share the same type), -you can learn the trick from `"gmock/gmock-matchers.h"` but it's a bit -involved. - -Fortunately, most of the time you can define a polymorphic matcher -easily with the help of `MakePolymorphicMatcher()`. Here's how you can -define `NotNull()` as an example: - -``` -using ::testing::MakePolymorphicMatcher; -using ::testing::MatchResultListener; -using ::testing::NotNull; -using ::testing::PolymorphicMatcher; - -class NotNullMatcher { - public: - // To implement a polymorphic matcher, first define a COPYABLE class - // that has three members MatchAndExplain(), DescribeTo(), and - // DescribeNegationTo(), like the following. - - // In this example, we want to use NotNull() with any pointer, so - // MatchAndExplain() accepts a pointer of any type as its first argument. - // In general, you can define MatchAndExplain() as an ordinary method or - // a method template, or even overload it. - template - bool MatchAndExplain(T* p, - MatchResultListener* /* listener */) const { - return p != NULL; - } - - // Describes the property of a value matching this matcher. - void DescribeTo(::std::ostream* os) const { *os << "is not NULL"; } - - // Describes the property of a value NOT matching this matcher. - void DescribeNegationTo(::std::ostream* os) const { *os << "is NULL"; } -}; - -// To construct a polymorphic matcher, pass an instance of the class -// to MakePolymorphicMatcher(). Note the return type. -inline PolymorphicMatcher NotNull() { - return MakePolymorphicMatcher(NotNullMatcher()); -} -... - - EXPECT_CALL(foo, Bar(NotNull())); // The argument must be a non-NULL pointer. -``` - -**Note:** Your polymorphic matcher class does **not** need to inherit from -`MatcherInterface` or any other class, and its methods do **not** need -to be virtual. - -Like in a monomorphic matcher, you may explain the match result by -streaming additional information to the `listener` argument in -`MatchAndExplain()`. - -## Writing New Cardinalities ## - -A cardinality is used in `Times()` to tell Google Mock how many times -you expect a call to occur. It doesn't have to be exact. For example, -you can say `AtLeast(5)` or `Between(2, 4)`. - -If the built-in set of cardinalities doesn't suit you, you are free to -define your own by implementing the following interface (in namespace -`testing`): - -``` -class CardinalityInterface { - public: - virtual ~CardinalityInterface(); - - // Returns true iff call_count calls will satisfy this cardinality. - virtual bool IsSatisfiedByCallCount(int call_count) const = 0; - - // Returns true iff call_count calls will saturate this cardinality. - virtual bool IsSaturatedByCallCount(int call_count) const = 0; - - // Describes self to an ostream. - virtual void DescribeTo(::std::ostream* os) const = 0; -}; -``` - -For example, to specify that a call must occur even number of times, -you can write - -``` -using ::testing::Cardinality; -using ::testing::CardinalityInterface; -using ::testing::MakeCardinality; - -class EvenNumberCardinality : public CardinalityInterface { - public: - virtual bool IsSatisfiedByCallCount(int call_count) const { - return (call_count % 2) == 0; - } - - virtual bool IsSaturatedByCallCount(int call_count) const { - return false; - } - - virtual void DescribeTo(::std::ostream* os) const { - *os << "called even number of times"; - } -}; - -Cardinality EvenNumber() { - return MakeCardinality(new EvenNumberCardinality); -} -... - - EXPECT_CALL(foo, Bar(3)) - .Times(EvenNumber()); -``` - -## Writing New Actions Quickly ## - -If the built-in actions don't work for you, and you find it -inconvenient to use `Invoke()`, you can use a macro from the `ACTION*` -family to quickly define a new action that can be used in your code as -if it's a built-in action. - -By writing -``` -ACTION(name) { statements; } -``` -in a namespace scope (i.e. not inside a class or function), you will -define an action with the given name that executes the statements. -The value returned by `statements` will be used as the return value of -the action. Inside the statements, you can refer to the K-th -(0-based) argument of the mock function as `argK`. For example: -``` -ACTION(IncrementArg1) { return ++(*arg1); } -``` -allows you to write -``` -... WillOnce(IncrementArg1()); -``` - -Note that you don't need to specify the types of the mock function -arguments. Rest assured that your code is type-safe though: -you'll get a compiler error if `*arg1` doesn't support the `++` -operator, or if the type of `++(*arg1)` isn't compatible with the mock -function's return type. - -Another example: -``` -ACTION(Foo) { - (*arg2)(5); - Blah(); - *arg1 = 0; - return arg0; -} -``` -defines an action `Foo()` that invokes argument #2 (a function pointer) -with 5, calls function `Blah()`, sets the value pointed to by argument -#1 to 0, and returns argument #0. - -For more convenience and flexibility, you can also use the following -pre-defined symbols in the body of `ACTION`: - -| `argK_type` | The type of the K-th (0-based) argument of the mock function | -|:------------|:-------------------------------------------------------------| -| `args` | All arguments of the mock function as a tuple | -| `args_type` | The type of all arguments of the mock function as a tuple | -| `return_type` | The return type of the mock function | -| `function_type` | The type of the mock function | - -For example, when using an `ACTION` as a stub action for mock function: -``` -int DoSomething(bool flag, int* ptr); -``` -we have: - -| **Pre-defined Symbol** | **Is Bound To** | -|:-----------------------|:----------------| -| `arg0` | the value of `flag` | -| `arg0_type` | the type `bool` | -| `arg1` | the value of `ptr` | -| `arg1_type` | the type `int*` | -| `args` | the tuple `(flag, ptr)` | -| `args_type` | the type `std::tr1::tuple` | -| `return_type` | the type `int` | -| `function_type` | the type `int(bool, int*)` | - -## Writing New Parameterized Actions Quickly ## - -Sometimes you'll want to parameterize an action you define. For that -we have another macro -``` -ACTION_P(name, param) { statements; } -``` - -For example, -``` -ACTION_P(Add, n) { return arg0 + n; } -``` -will allow you to write -``` -// Returns argument #0 + 5. -... WillOnce(Add(5)); -``` - -For convenience, we use the term _arguments_ for the values used to -invoke the mock function, and the term _parameters_ for the values -used to instantiate an action. - -Note that you don't need to provide the type of the parameter either. -Suppose the parameter is named `param`, you can also use the -Google-Mock-defined symbol `param_type` to refer to the type of the -parameter as inferred by the compiler. For example, in the body of -`ACTION_P(Add, n)` above, you can write `n_type` for the type of `n`. - -Google Mock also provides `ACTION_P2`, `ACTION_P3`, and etc to support -multi-parameter actions. For example, -``` -ACTION_P2(ReturnDistanceTo, x, y) { - double dx = arg0 - x; - double dy = arg1 - y; - return sqrt(dx*dx + dy*dy); -} -``` -lets you write -``` -... WillOnce(ReturnDistanceTo(5.0, 26.5)); -``` - -You can view `ACTION` as a degenerated parameterized action where the -number of parameters is 0. - -You can also easily define actions overloaded on the number of parameters: -``` -ACTION_P(Plus, a) { ... } -ACTION_P2(Plus, a, b) { ... } -``` - -## Restricting the Type of an Argument or Parameter in an ACTION ## - -For maximum brevity and reusability, the `ACTION*` macros don't ask -you to provide the types of the mock function arguments and the action -parameters. Instead, we let the compiler infer the types for us. - -Sometimes, however, we may want to be more explicit about the types. -There are several tricks to do that. For example: -``` -ACTION(Foo) { - // Makes sure arg0 can be converted to int. - int n = arg0; - ... use n instead of arg0 here ... -} - -ACTION_P(Bar, param) { - // Makes sure the type of arg1 is const char*. - ::testing::StaticAssertTypeEq(); - - // Makes sure param can be converted to bool. - bool flag = param; -} -``` -where `StaticAssertTypeEq` is a compile-time assertion in Google Test -that verifies two types are the same. - -## Writing New Action Templates Quickly ## - -Sometimes you want to give an action explicit template parameters that -cannot be inferred from its value parameters. `ACTION_TEMPLATE()` -supports that and can be viewed as an extension to `ACTION()` and -`ACTION_P*()`. - -The syntax: -``` -ACTION_TEMPLATE(ActionName, - HAS_m_TEMPLATE_PARAMS(kind1, name1, ..., kind_m, name_m), - AND_n_VALUE_PARAMS(p1, ..., p_n)) { statements; } -``` - -defines an action template that takes _m_ explicit template parameters -and _n_ value parameters, where _m_ is between 1 and 10, and _n_ is -between 0 and 10. `name_i` is the name of the i-th template -parameter, and `kind_i` specifies whether it's a `typename`, an -integral constant, or a template. `p_i` is the name of the i-th value -parameter. - -Example: -``` -// DuplicateArg(output) converts the k-th argument of the mock -// function to type T and copies it to *output. -ACTION_TEMPLATE(DuplicateArg, - // Note the comma between int and k: - HAS_2_TEMPLATE_PARAMS(int, k, typename, T), - AND_1_VALUE_PARAMS(output)) { - *output = T(std::tr1::get(args)); -} -``` - -To create an instance of an action template, write: -``` - ActionName(v1, ..., v_n) -``` -where the `t`s are the template arguments and the -`v`s are the value arguments. The value argument -types are inferred by the compiler. For example: -``` -using ::testing::_; -... - int n; - EXPECT_CALL(mock, Foo(_, _)) - .WillOnce(DuplicateArg<1, unsigned char>(&n)); -``` - -If you want to explicitly specify the value argument types, you can -provide additional template arguments: -``` - ActionName(v1, ..., v_n) -``` -where `u_i` is the desired type of `v_i`. - -`ACTION_TEMPLATE` and `ACTION`/`ACTION_P*` can be overloaded on the -number of value parameters, but not on the number of template -parameters. Without the restriction, the meaning of the following is -unclear: - -``` - OverloadedAction(x); -``` - -Are we using a single-template-parameter action where `bool` refers to -the type of `x`, or a two-template-parameter action where the compiler -is asked to infer the type of `x`? - -## Using the ACTION Object's Type ## - -If you are writing a function that returns an `ACTION` object, you'll -need to know its type. The type depends on the macro used to define -the action and the parameter types. The rule is relatively simple: - -| **Given Definition** | **Expression** | **Has Type** | -|:---------------------|:---------------|:-------------| -| `ACTION(Foo)` | `Foo()` | `FooAction` | -| `ACTION_TEMPLATE(Foo, HAS_m_TEMPLATE_PARAMS(...), AND_0_VALUE_PARAMS())` | `Foo()` | `FooAction` | -| `ACTION_P(Bar, param)` | `Bar(int_value)` | `BarActionP` | -| `ACTION_TEMPLATE(Bar, HAS_m_TEMPLATE_PARAMS(...), AND_1_VALUE_PARAMS(p1))` | `Bar(int_value)` | `FooActionP` | -| `ACTION_P2(Baz, p1, p2)` | `Baz(bool_value, int_value)` | `BazActionP2` | -| `ACTION_TEMPLATE(Baz, HAS_m_TEMPLATE_PARAMS(...), AND_2_VALUE_PARAMS(p1, p2))` | `Baz(bool_value, int_value)` | `FooActionP2` | -| ... | ... | ... | - -Note that we have to pick different suffixes (`Action`, `ActionP`, -`ActionP2`, and etc) for actions with different numbers of value -parameters, or the action definitions cannot be overloaded on the -number of them. - -## Writing New Monomorphic Actions ## - -While the `ACTION*` macros are very convenient, sometimes they are -inappropriate. For example, despite the tricks shown in the previous -recipes, they don't let you directly specify the types of the mock -function arguments and the action parameters, which in general leads -to unoptimized compiler error messages that can baffle unfamiliar -users. They also don't allow overloading actions based on parameter -types without jumping through some hoops. - -An alternative to the `ACTION*` macros is to implement -`::testing::ActionInterface`, where `F` is the type of the mock -function in which the action will be used. For example: - -``` -template class ActionInterface { - public: - virtual ~ActionInterface(); - - // Performs the action. Result is the return type of function type - // F, and ArgumentTuple is the tuple of arguments of F. - // - // For example, if F is int(bool, const string&), then Result would - // be int, and ArgumentTuple would be tr1::tuple. - virtual Result Perform(const ArgumentTuple& args) = 0; -}; - -using ::testing::_; -using ::testing::Action; -using ::testing::ActionInterface; -using ::testing::MakeAction; - -typedef int IncrementMethod(int*); - -class IncrementArgumentAction : public ActionInterface { - public: - virtual int Perform(const tr1::tuple& args) { - int* p = tr1::get<0>(args); // Grabs the first argument. - return *p++; - } -}; - -Action IncrementArgument() { - return MakeAction(new IncrementArgumentAction); -} -... - - EXPECT_CALL(foo, Baz(_)) - .WillOnce(IncrementArgument()); - - int n = 5; - foo.Baz(&n); // Should return 5 and change n to 6. -``` - -## Writing New Polymorphic Actions ## - -The previous recipe showed you how to define your own action. This is -all good, except that you need to know the type of the function in -which the action will be used. Sometimes that can be a problem. For -example, if you want to use the action in functions with _different_ -types (e.g. like `Return()` and `SetArgPointee()`). - -If an action can be used in several types of mock functions, we say -it's _polymorphic_. The `MakePolymorphicAction()` function template -makes it easy to define such an action: - -``` -namespace testing { - -template -PolymorphicAction MakePolymorphicAction(const Impl& impl); - -} // namespace testing -``` - -As an example, let's define an action that returns the second argument -in the mock function's argument list. The first step is to define an -implementation class: - -``` -class ReturnSecondArgumentAction { - public: - template - Result Perform(const ArgumentTuple& args) const { - // To get the i-th (0-based) argument, use tr1::get(args). - return tr1::get<1>(args); - } -}; -``` - -This implementation class does _not_ need to inherit from any -particular class. What matters is that it must have a `Perform()` -method template. This method template takes the mock function's -arguments as a tuple in a **single** argument, and returns the result of -the action. It can be either `const` or not, but must be invokable -with exactly one template argument, which is the result type. In other -words, you must be able to call `Perform(args)` where `R` is the -mock function's return type and `args` is its arguments in a tuple. - -Next, we use `MakePolymorphicAction()` to turn an instance of the -implementation class into the polymorphic action we need. It will be -convenient to have a wrapper for this: - -``` -using ::testing::MakePolymorphicAction; -using ::testing::PolymorphicAction; - -PolymorphicAction ReturnSecondArgument() { - return MakePolymorphicAction(ReturnSecondArgumentAction()); -} -``` - -Now, you can use this polymorphic action the same way you use the -built-in ones: - -``` -using ::testing::_; - -class MockFoo : public Foo { - public: - MOCK_METHOD2(DoThis, int(bool flag, int n)); - MOCK_METHOD3(DoThat, string(int x, const char* str1, const char* str2)); -}; -... - - MockFoo foo; - EXPECT_CALL(foo, DoThis(_, _)) - .WillOnce(ReturnSecondArgument()); - EXPECT_CALL(foo, DoThat(_, _, _)) - .WillOnce(ReturnSecondArgument()); - ... - foo.DoThis(true, 5); // Will return 5. - foo.DoThat(1, "Hi", "Bye"); // Will return "Hi". -``` - -## Teaching Google Mock How to Print Your Values ## - -When an uninteresting or unexpected call occurs, Google Mock prints the -argument values and the stack trace to help you debug. Assertion -macros like `EXPECT_THAT` and `EXPECT_EQ` also print the values in -question when the assertion fails. Google Mock and Google Test do this using -Google Test's user-extensible value printer. - -This printer knows how to print built-in C++ types, native arrays, STL -containers, and any type that supports the `<<` operator. For other -types, it prints the raw bytes in the value and hopes that you the -user can figure it out. -[Google Test's advanced guide](http://code.google.com/p/googletest/wiki/V1_6_AdvancedGuide#Teaching_Google_Test_How_to_Print_Your_Values) -explains how to extend the printer to do a better job at -printing your particular type than to dump the bytes. \ No newline at end of file diff --git a/googlemock/docs/v1_6/Documentation.md b/googlemock/docs/v1_6/Documentation.md deleted file mode 100644 index dcc9156c..00000000 --- a/googlemock/docs/v1_6/Documentation.md +++ /dev/null @@ -1,12 +0,0 @@ -This page lists all documentation wiki pages for Google Mock **1.6** -- **if you use a released version of Google Mock, please read the documentation for that specific version instead.** - - * [ForDummies](V1_6_ForDummies.md) -- start here if you are new to Google Mock. - * [CheatSheet](V1_6_CheatSheet.md) -- a quick reference. - * [CookBook](V1_6_CookBook.md) -- recipes for doing various tasks using Google Mock. - * [FrequentlyAskedQuestions](V1_6_FrequentlyAskedQuestions.md) -- check here before asking a question on the mailing list. - -To contribute code to Google Mock, read: - - * [DevGuide](DevGuide.md) -- read this _before_ writing your first patch. - * [Pump Manual](http://code.google.com/p/googletest/wiki/V1_6_PumpManual) -- how we generate some of Google Mock's source files. \ No newline at end of file diff --git a/googlemock/docs/v1_6/ForDummies.md b/googlemock/docs/v1_6/ForDummies.md deleted file mode 100644 index 19ee63ab..00000000 --- a/googlemock/docs/v1_6/ForDummies.md +++ /dev/null @@ -1,439 +0,0 @@ - - -(**Note:** If you get compiler errors that you don't understand, be sure to consult [Google Mock Doctor](http://code.google.com/p/googlemock/wiki/V1_6_FrequentlyAskedQuestions#How_am_I_supposed_to_make_sense_of_these_horrible_template_error).) - -# What Is Google C++ Mocking Framework? # -When you write a prototype or test, often it's not feasible or wise to rely on real objects entirely. A **mock object** implements the same interface as a real object (so it can be used as one), but lets you specify at run time how it will be used and what it should do (which methods will be called? in which order? how many times? with what arguments? what will they return? etc). - -**Note:** It is easy to confuse the term _fake objects_ with mock objects. Fakes and mocks actually mean very different things in the Test-Driven Development (TDD) community: - - * **Fake** objects have working implementations, but usually take some shortcut (perhaps to make the operations less expensive), which makes them not suitable for production. An in-memory file system would be an example of a fake. - * **Mocks** are objects pre-programmed with _expectations_, which form a specification of the calls they are expected to receive. - -If all this seems too abstract for you, don't worry - the most important thing to remember is that a mock allows you to check the _interaction_ between itself and code that uses it. The difference between fakes and mocks will become much clearer once you start to use mocks. - -**Google C++ Mocking Framework** (or **Google Mock** for short) is a library (sometimes we also call it a "framework" to make it sound cool) for creating mock classes and using them. It does to C++ what [jMock](http://www.jmock.org/) and [EasyMock](http://www.easymock.org/) do to Java. - -Using Google Mock involves three basic steps: - - 1. Use some simple macros to describe the interface you want to mock, and they will expand to the implementation of your mock class; - 1. Create some mock objects and specify its expectations and behavior using an intuitive syntax; - 1. Exercise code that uses the mock objects. Google Mock will catch any violation of the expectations as soon as it arises. - -# Why Google Mock? # -While mock objects help you remove unnecessary dependencies in tests and make them fast and reliable, using mocks manually in C++ is _hard_: - - * Someone has to implement the mocks. The job is usually tedious and error-prone. No wonder people go great distance to avoid it. - * The quality of those manually written mocks is a bit, uh, unpredictable. You may see some really polished ones, but you may also see some that were hacked up in a hurry and have all sorts of ad hoc restrictions. - * The knowledge you gained from using one mock doesn't transfer to the next. - -In contrast, Java and Python programmers have some fine mock frameworks, which automate the creation of mocks. As a result, mocking is a proven effective technique and widely adopted practice in those communities. Having the right tool absolutely makes the difference. - -Google Mock was built to help C++ programmers. It was inspired by [jMock](http://www.jmock.org/) and [EasyMock](http://www.easymock.org/), but designed with C++'s specifics in mind. It is your friend if any of the following problems is bothering you: - - * You are stuck with a sub-optimal design and wish you had done more prototyping before it was too late, but prototyping in C++ is by no means "rapid". - * Your tests are slow as they depend on too many libraries or use expensive resources (e.g. a database). - * Your tests are brittle as some resources they use are unreliable (e.g. the network). - * You want to test how your code handles a failure (e.g. a file checksum error), but it's not easy to cause one. - * You need to make sure that your module interacts with other modules in the right way, but it's hard to observe the interaction; therefore you resort to observing the side effects at the end of the action, which is awkward at best. - * You want to "mock out" your dependencies, except that they don't have mock implementations yet; and, frankly, you aren't thrilled by some of those hand-written mocks. - -We encourage you to use Google Mock as: - - * a _design_ tool, for it lets you experiment with your interface design early and often. More iterations lead to better designs! - * a _testing_ tool to cut your tests' outbound dependencies and probe the interaction between your module and its collaborators. - -# Getting Started # -Using Google Mock is easy! Inside your C++ source file, just `#include` `"gtest/gtest.h"` and `"gmock/gmock.h"`, and you are ready to go. - -# A Case for Mock Turtles # -Let's look at an example. Suppose you are developing a graphics program that relies on a LOGO-like API for drawing. How would you test that it does the right thing? Well, you can run it and compare the screen with a golden screen snapshot, but let's admit it: tests like this are expensive to run and fragile (What if you just upgraded to a shiny new graphics card that has better anti-aliasing? Suddenly you have to update all your golden images.). It would be too painful if all your tests are like this. Fortunately, you learned about Dependency Injection and know the right thing to do: instead of having your application talk to the drawing API directly, wrap the API in an interface (say, `Turtle`) and code to that interface: - -``` -class Turtle { - ... - virtual ~Turtle() {} - virtual void PenUp() = 0; - virtual void PenDown() = 0; - virtual void Forward(int distance) = 0; - virtual void Turn(int degrees) = 0; - virtual void GoTo(int x, int y) = 0; - virtual int GetX() const = 0; - virtual int GetY() const = 0; -}; -``` - -(Note that the destructor of `Turtle` **must** be virtual, as is the case for **all** classes you intend to inherit from - otherwise the destructor of the derived class will not be called when you delete an object through a base pointer, and you'll get corrupted program states like memory leaks.) - -You can control whether the turtle's movement will leave a trace using `PenUp()` and `PenDown()`, and control its movement using `Forward()`, `Turn()`, and `GoTo()`. Finally, `GetX()` and `GetY()` tell you the current position of the turtle. - -Your program will normally use a real implementation of this interface. In tests, you can use a mock implementation instead. This allows you to easily check what drawing primitives your program is calling, with what arguments, and in which order. Tests written this way are much more robust (they won't break because your new machine does anti-aliasing differently), easier to read and maintain (the intent of a test is expressed in the code, not in some binary images), and run _much, much faster_. - -# Writing the Mock Class # -If you are lucky, the mocks you need to use have already been implemented by some nice people. If, however, you find yourself in the position to write a mock class, relax - Google Mock turns this task into a fun game! (Well, almost.) - -## How to Define It ## -Using the `Turtle` interface as example, here are the simple steps you need to follow: - - 1. Derive a class `MockTurtle` from `Turtle`. - 1. Take a _virtual_ function of `Turtle` (while it's possible to [mock non-virtual methods using templates](http://code.google.com/p/googlemock/wiki/V1_6_CookBook#Mocking_Nonvirtual_Methods), it's much more involved). Count how many arguments it has. - 1. In the `public:` section of the child class, write `MOCK_METHODn();` (or `MOCK_CONST_METHODn();` if you are mocking a `const` method), where `n` is the number of the arguments; if you counted wrong, shame on you, and a compiler error will tell you so. - 1. Now comes the fun part: you take the function signature, cut-and-paste the _function name_ as the _first_ argument to the macro, and leave what's left as the _second_ argument (in case you're curious, this is the _type of the function_). - 1. Repeat until all virtual functions you want to mock are done. - -After the process, you should have something like: - -``` -#include "gmock/gmock.h" // Brings in Google Mock. -class MockTurtle : public Turtle { - public: - ... - MOCK_METHOD0(PenUp, void()); - MOCK_METHOD0(PenDown, void()); - MOCK_METHOD1(Forward, void(int distance)); - MOCK_METHOD1(Turn, void(int degrees)); - MOCK_METHOD2(GoTo, void(int x, int y)); - MOCK_CONST_METHOD0(GetX, int()); - MOCK_CONST_METHOD0(GetY, int()); -}; -``` - -You don't need to define these mock methods somewhere else - the `MOCK_METHOD*` macros will generate the definitions for you. It's that simple! Once you get the hang of it, you can pump out mock classes faster than your source-control system can handle your check-ins. - -**Tip:** If even this is too much work for you, you'll find the -`gmock_gen.py` tool in Google Mock's `scripts/generator/` directory (courtesy of the [cppclean](http://code.google.com/p/cppclean/) project) useful. This command-line -tool requires that you have Python 2.4 installed. You give it a C++ file and the name of an abstract class defined in it, -and it will print the definition of the mock class for you. Due to the -complexity of the C++ language, this script may not always work, but -it can be quite handy when it does. For more details, read the [user documentation](http://code.google.com/p/googlemock/source/browse/trunk/scripts/generator/README). - -## Where to Put It ## -When you define a mock class, you need to decide where to put its definition. Some people put it in a `*_test.cc`. This is fine when the interface being mocked (say, `Foo`) is owned by the same person or team. Otherwise, when the owner of `Foo` changes it, your test could break. (You can't really expect `Foo`'s maintainer to fix every test that uses `Foo`, can you?) - -So, the rule of thumb is: if you need to mock `Foo` and it's owned by others, define the mock class in `Foo`'s package (better, in a `testing` sub-package such that you can clearly separate production code and testing utilities), and put it in a `mock_foo.h`. Then everyone can reference `mock_foo.h` from their tests. If `Foo` ever changes, there is only one copy of `MockFoo` to change, and only tests that depend on the changed methods need to be fixed. - -Another way to do it: you can introduce a thin layer `FooAdaptor` on top of `Foo` and code to this new interface. Since you own `FooAdaptor`, you can absorb changes in `Foo` much more easily. While this is more work initially, carefully choosing the adaptor interface can make your code easier to write and more readable (a net win in the long run), as you can choose `FooAdaptor` to fit your specific domain much better than `Foo` does. - -# Using Mocks in Tests # -Once you have a mock class, using it is easy. The typical work flow is: - - 1. Import the Google Mock names from the `testing` namespace such that you can use them unqualified (You only have to do it once per file. Remember that namespaces are a good idea and good for your health.). - 1. Create some mock objects. - 1. Specify your expectations on them (How many times will a method be called? With what arguments? What should it do? etc.). - 1. Exercise some code that uses the mocks; optionally, check the result using Google Test assertions. If a mock method is called more than expected or with wrong arguments, you'll get an error immediately. - 1. When a mock is destructed, Google Mock will automatically check whether all expectations on it have been satisfied. - -Here's an example: - -``` -#include "path/to/mock-turtle.h" -#include "gmock/gmock.h" -#include "gtest/gtest.h" -using ::testing::AtLeast; // #1 - -TEST(PainterTest, CanDrawSomething) { - MockTurtle turtle; // #2 - EXPECT_CALL(turtle, PenDown()) // #3 - .Times(AtLeast(1)); - - Painter painter(&turtle); // #4 - - EXPECT_TRUE(painter.DrawCircle(0, 0, 10)); -} // #5 - -int main(int argc, char** argv) { - // The following line must be executed to initialize Google Mock - // (and Google Test) before running the tests. - ::testing::InitGoogleMock(&argc, argv); - return RUN_ALL_TESTS(); -} -``` - -As you might have guessed, this test checks that `PenDown()` is called at least once. If the `painter` object didn't call this method, your test will fail with a message like this: - -``` -path/to/my_test.cc:119: Failure -Actual function call count doesn't match this expectation: -Actually: never called; -Expected: called at least once. -``` - -**Tip 1:** If you run the test from an Emacs buffer, you can hit `` on the line number displayed in the error message to jump right to the failed expectation. - -**Tip 2:** If your mock objects are never deleted, the final verification won't happen. Therefore it's a good idea to use a heap leak checker in your tests when you allocate mocks on the heap. - -**Important note:** Google Mock requires expectations to be set **before** the mock functions are called, otherwise the behavior is **undefined**. In particular, you mustn't interleave `EXPECT_CALL()`s and calls to the mock functions. - -This means `EXPECT_CALL()` should be read as expecting that a call will occur _in the future_, not that a call has occurred. Why does Google Mock work like that? Well, specifying the expectation beforehand allows Google Mock to report a violation as soon as it arises, when the context (stack trace, etc) is still available. This makes debugging much easier. - -Admittedly, this test is contrived and doesn't do much. You can easily achieve the same effect without using Google Mock. However, as we shall reveal soon, Google Mock allows you to do _much more_ with the mocks. - -## Using Google Mock with Any Testing Framework ## -If you want to use something other than Google Test (e.g. [CppUnit](http://apps.sourceforge.net/mediawiki/cppunit/index.php?title=Main_Page) or -[CxxTest](http://cxxtest.tigris.org/)) as your testing framework, just change the `main()` function in the previous section to: -``` -int main(int argc, char** argv) { - // The following line causes Google Mock to throw an exception on failure, - // which will be interpreted by your testing framework as a test failure. - ::testing::GTEST_FLAG(throw_on_failure) = true; - ::testing::InitGoogleMock(&argc, argv); - ... whatever your testing framework requires ... -} -``` - -This approach has a catch: it makes Google Mock throw an exception -from a mock object's destructor sometimes. With some compilers, this -sometimes causes the test program to crash. You'll still be able to -notice that the test has failed, but it's not a graceful failure. - -A better solution is to use Google Test's -[event listener API](http://code.google.com/p/googletest/wiki/V1_6_AdvancedGuide#Extending_Google_Test_by_Handling_Test_Events) -to report a test failure to your testing framework properly. You'll need to -implement the `OnTestPartResult()` method of the event listener interface, but it -should be straightforward. - -If this turns out to be too much work, we suggest that you stick with -Google Test, which works with Google Mock seamlessly (in fact, it is -technically part of Google Mock.). If there is a reason that you -cannot use Google Test, please let us know. - -# Setting Expectations # -The key to using a mock object successfully is to set the _right expectations_ on it. If you set the expectations too strict, your test will fail as the result of unrelated changes. If you set them too loose, bugs can slip through. You want to do it just right such that your test can catch exactly the kind of bugs you intend it to catch. Google Mock provides the necessary means for you to do it "just right." - -## General Syntax ## -In Google Mock we use the `EXPECT_CALL()` macro to set an expectation on a mock method. The general syntax is: - -``` -EXPECT_CALL(mock_object, method(matchers)) - .Times(cardinality) - .WillOnce(action) - .WillRepeatedly(action); -``` - -The macro has two arguments: first the mock object, and then the method and its arguments. Note that the two are separated by a comma (`,`), not a period (`.`). (Why using a comma? The answer is that it was necessary for technical reasons.) - -The macro can be followed by some optional _clauses_ that provide more information about the expectation. We'll discuss how each clause works in the coming sections. - -This syntax is designed to make an expectation read like English. For example, you can probably guess that - -``` -using ::testing::Return;... -EXPECT_CALL(turtle, GetX()) - .Times(5) - .WillOnce(Return(100)) - .WillOnce(Return(150)) - .WillRepeatedly(Return(200)); -``` - -says that the `turtle` object's `GetX()` method will be called five times, it will return 100 the first time, 150 the second time, and then 200 every time. Some people like to call this style of syntax a Domain-Specific Language (DSL). - -**Note:** Why do we use a macro to do this? It serves two purposes: first it makes expectations easily identifiable (either by `grep` or by a human reader), and second it allows Google Mock to include the source file location of a failed expectation in messages, making debugging easier. - -## Matchers: What Arguments Do We Expect? ## -When a mock function takes arguments, we must specify what arguments we are expecting; for example: - -``` -// Expects the turtle to move forward by 100 units. -EXPECT_CALL(turtle, Forward(100)); -``` - -Sometimes you may not want to be too specific (Remember that talk about tests being too rigid? Over specification leads to brittle tests and obscures the intent of tests. Therefore we encourage you to specify only what's necessary - no more, no less.). If you care to check that `Forward()` will be called but aren't interested in its actual argument, write `_` as the argument, which means "anything goes": - -``` -using ::testing::_; -... -// Expects the turtle to move forward. -EXPECT_CALL(turtle, Forward(_)); -``` - -`_` is an instance of what we call **matchers**. A matcher is like a predicate and can test whether an argument is what we'd expect. You can use a matcher inside `EXPECT_CALL()` wherever a function argument is expected. - -A list of built-in matchers can be found in the [CheatSheet](V1_6_CheatSheet.md). For example, here's the `Ge` (greater than or equal) matcher: - -``` -using ::testing::Ge;... -EXPECT_CALL(turtle, Forward(Ge(100))); -``` - -This checks that the turtle will be told to go forward by at least 100 units. - -## Cardinalities: How Many Times Will It Be Called? ## -The first clause we can specify following an `EXPECT_CALL()` is `Times()`. We call its argument a **cardinality** as it tells _how many times_ the call should occur. It allows us to repeat an expectation many times without actually writing it as many times. More importantly, a cardinality can be "fuzzy", just like a matcher can be. This allows a user to express the intent of a test exactly. - -An interesting special case is when we say `Times(0)`. You may have guessed - it means that the function shouldn't be called with the given arguments at all, and Google Mock will report a Google Test failure whenever the function is (wrongfully) called. - -We've seen `AtLeast(n)` as an example of fuzzy cardinalities earlier. For the list of built-in cardinalities you can use, see the [CheatSheet](V1_6_CheatSheet.md). - -The `Times()` clause can be omitted. **If you omit `Times()`, Google Mock will infer the cardinality for you.** The rules are easy to remember: - - * If **neither** `WillOnce()` **nor** `WillRepeatedly()` is in the `EXPECT_CALL()`, the inferred cardinality is `Times(1)`. - * If there are `n WillOnce()`'s but **no** `WillRepeatedly()`, where `n` >= 1, the cardinality is `Times(n)`. - * If there are `n WillOnce()`'s and **one** `WillRepeatedly()`, where `n` >= 0, the cardinality is `Times(AtLeast(n))`. - -**Quick quiz:** what do you think will happen if a function is expected to be called twice but actually called four times? - -## Actions: What Should It Do? ## -Remember that a mock object doesn't really have a working implementation? We as users have to tell it what to do when a method is invoked. This is easy in Google Mock. - -First, if the return type of a mock function is a built-in type or a pointer, the function has a **default action** (a `void` function will just return, a `bool` function will return `false`, and other functions will return 0). If you don't say anything, this behavior will be used. - -Second, if a mock function doesn't have a default action, or the default action doesn't suit you, you can specify the action to be taken each time the expectation matches using a series of `WillOnce()` clauses followed by an optional `WillRepeatedly()`. For example, - -``` -using ::testing::Return;... -EXPECT_CALL(turtle, GetX()) - .WillOnce(Return(100)) - .WillOnce(Return(200)) - .WillOnce(Return(300)); -``` - -This says that `turtle.GetX()` will be called _exactly three times_ (Google Mock inferred this from how many `WillOnce()` clauses we've written, since we didn't explicitly write `Times()`), and will return 100, 200, and 300 respectively. - -``` -using ::testing::Return;... -EXPECT_CALL(turtle, GetY()) - .WillOnce(Return(100)) - .WillOnce(Return(200)) - .WillRepeatedly(Return(300)); -``` - -says that `turtle.GetY()` will be called _at least twice_ (Google Mock knows this as we've written two `WillOnce()` clauses and a `WillRepeatedly()` while having no explicit `Times()`), will return 100 the first time, 200 the second time, and 300 from the third time on. - -Of course, if you explicitly write a `Times()`, Google Mock will not try to infer the cardinality itself. What if the number you specified is larger than there are `WillOnce()` clauses? Well, after all `WillOnce()`s are used up, Google Mock will do the _default_ action for the function every time (unless, of course, you have a `WillRepeatedly()`.). - -What can we do inside `WillOnce()` besides `Return()`? You can return a reference using `ReturnRef(variable)`, or invoke a pre-defined function, among [others](http://code.google.com/p/googlemock/wiki/V1_6_CheatSheet#Actions). - -**Important note:** The `EXPECT_CALL()` statement evaluates the action clause only once, even though the action may be performed many times. Therefore you must be careful about side effects. The following may not do what you want: - -``` -int n = 100; -EXPECT_CALL(turtle, GetX()) -.Times(4) -.WillRepeatedly(Return(n++)); -``` - -Instead of returning 100, 101, 102, ..., consecutively, this mock function will always return 100 as `n++` is only evaluated once. Similarly, `Return(new Foo)` will create a new `Foo` object when the `EXPECT_CALL()` is executed, and will return the same pointer every time. If you want the side effect to happen every time, you need to define a custom action, which we'll teach in the [CookBook](V1_6_CookBook.md). - -Time for another quiz! What do you think the following means? - -``` -using ::testing::Return;... -EXPECT_CALL(turtle, GetY()) -.Times(4) -.WillOnce(Return(100)); -``` - -Obviously `turtle.GetY()` is expected to be called four times. But if you think it will return 100 every time, think twice! Remember that one `WillOnce()` clause will be consumed each time the function is invoked and the default action will be taken afterwards. So the right answer is that `turtle.GetY()` will return 100 the first time, but **return 0 from the second time on**, as returning 0 is the default action for `int` functions. - -## Using Multiple Expectations ## -So far we've only shown examples where you have a single expectation. More realistically, you're going to specify expectations on multiple mock methods, which may be from multiple mock objects. - -By default, when a mock method is invoked, Google Mock will search the expectations in the **reverse order** they are defined, and stop when an active expectation that matches the arguments is found (you can think of it as "newer rules override older ones."). If the matching expectation cannot take any more calls, you will get an upper-bound-violated failure. Here's an example: - -``` -using ::testing::_;... -EXPECT_CALL(turtle, Forward(_)); // #1 -EXPECT_CALL(turtle, Forward(10)) // #2 - .Times(2); -``` - -If `Forward(10)` is called three times in a row, the third time it will be an error, as the last matching expectation (#2) has been saturated. If, however, the third `Forward(10)` call is replaced by `Forward(20)`, then it would be OK, as now #1 will be the matching expectation. - -**Side note:** Why does Google Mock search for a match in the _reverse_ order of the expectations? The reason is that this allows a user to set up the default expectations in a mock object's constructor or the test fixture's set-up phase and then customize the mock by writing more specific expectations in the test body. So, if you have two expectations on the same method, you want to put the one with more specific matchers **after** the other, or the more specific rule would be shadowed by the more general one that comes after it. - -## Ordered vs Unordered Calls ## -By default, an expectation can match a call even though an earlier expectation hasn't been satisfied. In other words, the calls don't have to occur in the order the expectations are specified. - -Sometimes, you may want all the expected calls to occur in a strict order. To say this in Google Mock is easy: - -``` -using ::testing::InSequence;... -TEST(FooTest, DrawsLineSegment) { - ... - { - InSequence dummy; - - EXPECT_CALL(turtle, PenDown()); - EXPECT_CALL(turtle, Forward(100)); - EXPECT_CALL(turtle, PenUp()); - } - Foo(); -} -``` - -By creating an object of type `InSequence`, all expectations in its scope are put into a _sequence_ and have to occur _sequentially_. Since we are just relying on the constructor and destructor of this object to do the actual work, its name is really irrelevant. - -In this example, we test that `Foo()` calls the three expected functions in the order as written. If a call is made out-of-order, it will be an error. - -(What if you care about the relative order of some of the calls, but not all of them? Can you specify an arbitrary partial order? The answer is ... yes! If you are impatient, the details can be found in the [CookBook](V1_6_CookBook.md).) - -## All Expectations Are Sticky (Unless Said Otherwise) ## -Now let's do a quick quiz to see how well you can use this mock stuff already. How would you test that the turtle is asked to go to the origin _exactly twice_ (you want to ignore any other instructions it receives)? - -After you've come up with your answer, take a look at ours and compare notes (solve it yourself first - don't cheat!): - -``` -using ::testing::_;... -EXPECT_CALL(turtle, GoTo(_, _)) // #1 - .Times(AnyNumber()); -EXPECT_CALL(turtle, GoTo(0, 0)) // #2 - .Times(2); -``` - -Suppose `turtle.GoTo(0, 0)` is called three times. In the third time, Google Mock will see that the arguments match expectation #2 (remember that we always pick the last matching expectation). Now, since we said that there should be only two such calls, Google Mock will report an error immediately. This is basically what we've told you in the "Using Multiple Expectations" section above. - -This example shows that **expectations in Google Mock are "sticky" by default**, in the sense that they remain active even after we have reached their invocation upper bounds. This is an important rule to remember, as it affects the meaning of the spec, and is **different** to how it's done in many other mocking frameworks (Why'd we do that? Because we think our rule makes the common cases easier to express and understand.). - -Simple? Let's see if you've really understood it: what does the following code say? - -``` -using ::testing::Return; -... -for (int i = n; i > 0; i--) { - EXPECT_CALL(turtle, GetX()) - .WillOnce(Return(10*i)); -} -``` - -If you think it says that `turtle.GetX()` will be called `n` times and will return 10, 20, 30, ..., consecutively, think twice! The problem is that, as we said, expectations are sticky. So, the second time `turtle.GetX()` is called, the last (latest) `EXPECT_CALL()` statement will match, and will immediately lead to an "upper bound exceeded" error - this piece of code is not very useful! - -One correct way of saying that `turtle.GetX()` will return 10, 20, 30, ..., is to explicitly say that the expectations are _not_ sticky. In other words, they should _retire_ as soon as they are saturated: - -``` -using ::testing::Return; -... -for (int i = n; i > 0; i--) { - EXPECT_CALL(turtle, GetX()) - .WillOnce(Return(10*i)) - .RetiresOnSaturation(); -} -``` - -And, there's a better way to do it: in this case, we expect the calls to occur in a specific order, and we line up the actions to match the order. Since the order is important here, we should make it explicit using a sequence: - -``` -using ::testing::InSequence; -using ::testing::Return; -... -{ - InSequence s; - - for (int i = 1; i <= n; i++) { - EXPECT_CALL(turtle, GetX()) - .WillOnce(Return(10*i)) - .RetiresOnSaturation(); - } -} -``` - -By the way, the other situation where an expectation may _not_ be sticky is when it's in a sequence - as soon as another expectation that comes after it in the sequence has been used, it automatically retires (and will never be used to match any call). - -## Uninteresting Calls ## -A mock object may have many methods, and not all of them are that interesting. For example, in some tests we may not care about how many times `GetX()` and `GetY()` get called. - -In Google Mock, if you are not interested in a method, just don't say anything about it. If a call to this method occurs, you'll see a warning in the test output, but it won't be a failure. - -# What Now? # -Congratulations! You've learned enough about Google Mock to start using it. Now, you might want to join the [googlemock](http://groups.google.com/group/googlemock) discussion group and actually write some tests using Google Mock - it will be fun. Hey, it may even be addictive - you've been warned. - -Then, if you feel like increasing your mock quotient, you should move on to the [CookBook](V1_6_CookBook.md). You can learn many advanced features of Google Mock there -- and advance your level of enjoyment and testing bliss. \ No newline at end of file diff --git a/googlemock/docs/v1_6/FrequentlyAskedQuestions.md b/googlemock/docs/v1_6/FrequentlyAskedQuestions.md deleted file mode 100644 index f74715d2..00000000 --- a/googlemock/docs/v1_6/FrequentlyAskedQuestions.md +++ /dev/null @@ -1,628 +0,0 @@ - - -Please send your questions to the -[googlemock](http://groups.google.com/group/googlemock) discussion -group. If you need help with compiler errors, make sure you have -tried [Google Mock Doctor](#How_am_I_supposed_to_make_sense_of_these_horrible_template_error.md) first. - -## When I call a method on my mock object, the method for the real object is invoked instead. What's the problem? ## - -In order for a method to be mocked, it must be _virtual_, unless you use the [high-perf dependency injection technique](http://code.google.com/p/googlemock/wiki/V1_6_CookBook#Mocking_Nonvirtual_Methods). - -## I wrote some matchers. After I upgraded to a new version of Google Mock, they no longer compile. What's going on? ## - -After version 1.4.0 of Google Mock was released, we had an idea on how -to make it easier to write matchers that can generate informative -messages efficiently. We experimented with this idea and liked what -we saw. Therefore we decided to implement it. - -Unfortunately, this means that if you have defined your own matchers -by implementing `MatcherInterface` or using `MakePolymorphicMatcher()`, -your definitions will no longer compile. Matchers defined using the -`MATCHER*` family of macros are not affected. - -Sorry for the hassle if your matchers are affected. We believe it's -in everyone's long-term interest to make this change sooner than -later. Fortunately, it's usually not hard to migrate an existing -matcher to the new API. Here's what you need to do: - -If you wrote your matcher like this: -``` -// Old matcher definition that doesn't work with the latest -// Google Mock. -using ::testing::MatcherInterface; -... -class MyWonderfulMatcher : public MatcherInterface { - public: - ... - virtual bool Matches(MyType value) const { - // Returns true if value matches. - return value.GetFoo() > 5; - } - ... -}; -``` - -you'll need to change it to: -``` -// New matcher definition that works with the latest Google Mock. -using ::testing::MatcherInterface; -using ::testing::MatchResultListener; -... -class MyWonderfulMatcher : public MatcherInterface { - public: - ... - virtual bool MatchAndExplain(MyType value, - MatchResultListener* listener) const { - // Returns true if value matches. - return value.GetFoo() > 5; - } - ... -}; -``` -(i.e. rename `Matches()` to `MatchAndExplain()` and give it a second -argument of type `MatchResultListener*`.) - -If you were also using `ExplainMatchResultTo()` to improve the matcher -message: -``` -// Old matcher definition that doesn't work with the lastest -// Google Mock. -using ::testing::MatcherInterface; -... -class MyWonderfulMatcher : public MatcherInterface { - public: - ... - virtual bool Matches(MyType value) const { - // Returns true if value matches. - return value.GetFoo() > 5; - } - - virtual void ExplainMatchResultTo(MyType value, - ::std::ostream* os) const { - // Prints some helpful information to os to help - // a user understand why value matches (or doesn't match). - *os << "the Foo property is " << value.GetFoo(); - } - ... -}; -``` - -you should move the logic of `ExplainMatchResultTo()` into -`MatchAndExplain()`, using the `MatchResultListener` argument where -the `::std::ostream` was used: -``` -// New matcher definition that works with the latest Google Mock. -using ::testing::MatcherInterface; -using ::testing::MatchResultListener; -... -class MyWonderfulMatcher : public MatcherInterface { - public: - ... - virtual bool MatchAndExplain(MyType value, - MatchResultListener* listener) const { - // Returns true if value matches. - *listener << "the Foo property is " << value.GetFoo(); - return value.GetFoo() > 5; - } - ... -}; -``` - -If your matcher is defined using `MakePolymorphicMatcher()`: -``` -// Old matcher definition that doesn't work with the latest -// Google Mock. -using ::testing::MakePolymorphicMatcher; -... -class MyGreatMatcher { - public: - ... - bool Matches(MyType value) const { - // Returns true if value matches. - return value.GetBar() < 42; - } - ... -}; -... MakePolymorphicMatcher(MyGreatMatcher()) ... -``` - -you should rename the `Matches()` method to `MatchAndExplain()` and -add a `MatchResultListener*` argument (the same as what you need to do -for matchers defined by implementing `MatcherInterface`): -``` -// New matcher definition that works with the latest Google Mock. -using ::testing::MakePolymorphicMatcher; -using ::testing::MatchResultListener; -... -class MyGreatMatcher { - public: - ... - bool MatchAndExplain(MyType value, - MatchResultListener* listener) const { - // Returns true if value matches. - return value.GetBar() < 42; - } - ... -}; -... MakePolymorphicMatcher(MyGreatMatcher()) ... -``` - -If your polymorphic matcher uses `ExplainMatchResultTo()` for better -failure messages: -``` -// Old matcher definition that doesn't work with the latest -// Google Mock. -using ::testing::MakePolymorphicMatcher; -... -class MyGreatMatcher { - public: - ... - bool Matches(MyType value) const { - // Returns true if value matches. - return value.GetBar() < 42; - } - ... -}; -void ExplainMatchResultTo(const MyGreatMatcher& matcher, - MyType value, - ::std::ostream* os) { - // Prints some helpful information to os to help - // a user understand why value matches (or doesn't match). - *os << "the Bar property is " << value.GetBar(); -} -... MakePolymorphicMatcher(MyGreatMatcher()) ... -``` - -you'll need to move the logic inside `ExplainMatchResultTo()` to -`MatchAndExplain()`: -``` -// New matcher definition that works with the latest Google Mock. -using ::testing::MakePolymorphicMatcher; -using ::testing::MatchResultListener; -... -class MyGreatMatcher { - public: - ... - bool MatchAndExplain(MyType value, - MatchResultListener* listener) const { - // Returns true if value matches. - *listener << "the Bar property is " << value.GetBar(); - return value.GetBar() < 42; - } - ... -}; -... MakePolymorphicMatcher(MyGreatMatcher()) ... -``` - -For more information, you can read these -[two](http://code.google.com/p/googlemock/wiki/V1_6_CookBook#Writing_New_Monomorphic_Matchers) -[recipes](http://code.google.com/p/googlemock/wiki/V1_6_CookBook#Writing_New_Polymorphic_Matchers) -from the cookbook. As always, you -are welcome to post questions on `googlemock@googlegroups.com` if you -need any help. - -## When using Google Mock, do I have to use Google Test as the testing framework? I have my favorite testing framework and don't want to switch. ## - -Google Mock works out of the box with Google Test. However, it's easy -to configure it to work with any testing framework of your choice. -[Here](http://code.google.com/p/googlemock/wiki/V1_6_ForDummies#Using_Google_Mock_with_Any_Testing_Framework) is how. - -## How am I supposed to make sense of these horrible template errors? ## - -If you are confused by the compiler errors gcc threw at you, -try consulting the _Google Mock Doctor_ tool first. What it does is to -scan stdin for gcc error messages, and spit out diagnoses on the -problems (we call them diseases) your code has. - -To "install", run command: -``` -alias gmd='/scripts/gmock_doctor.py' -``` - -To use it, do: -``` - 2>&1 | gmd -``` - -For example: -``` -make my_test 2>&1 | gmd -``` - -Or you can run `gmd` and copy-n-paste gcc's error messages to it. - -## Can I mock a variadic function? ## - -You cannot mock a variadic function (i.e. a function taking ellipsis -(`...`) arguments) directly in Google Mock. - -The problem is that in general, there is _no way_ for a mock object to -know how many arguments are passed to the variadic method, and what -the arguments' types are. Only the _author of the base class_ knows -the protocol, and we cannot look into his head. - -Therefore, to mock such a function, the _user_ must teach the mock -object how to figure out the number of arguments and their types. One -way to do it is to provide overloaded versions of the function. - -Ellipsis arguments are inherited from C and not really a C++ feature. -They are unsafe to use and don't work with arguments that have -constructors or destructors. Therefore we recommend to avoid them in -C++ as much as possible. - -## MSVC gives me warning C4301 or C4373 when I define a mock method with a const parameter. Why? ## - -If you compile this using Microsoft Visual C++ 2005 SP1: -``` -class Foo { - ... - virtual void Bar(const int i) = 0; -}; - -class MockFoo : public Foo { - ... - MOCK_METHOD1(Bar, void(const int i)); -}; -``` -You may get the following warning: -``` -warning C4301: 'MockFoo::Bar': overriding virtual function only differs from 'Foo::Bar' by const/volatile qualifier -``` - -This is a MSVC bug. The same code compiles fine with gcc ,for -example. If you use Visual C++ 2008 SP1, you would get the warning: -``` -warning C4373: 'MockFoo::Bar': virtual function overrides 'Foo::Bar', previous versions of the compiler did not override when parameters only differed by const/volatile qualifiers -``` - -In C++, if you _declare_ a function with a `const` parameter, the -`const` modifier is _ignored_. Therefore, the `Foo` base class above -is equivalent to: -``` -class Foo { - ... - virtual void Bar(int i) = 0; // int or const int? Makes no difference. -}; -``` - -In fact, you can _declare_ Bar() with an `int` parameter, and _define_ -it with a `const int` parameter. The compiler will still match them -up. - -Since making a parameter `const` is meaningless in the method -_declaration_, we recommend to remove it in both `Foo` and `MockFoo`. -That should workaround the VC bug. - -Note that we are talking about the _top-level_ `const` modifier here. -If the function parameter is passed by pointer or reference, declaring -the _pointee_ or _referee_ as `const` is still meaningful. For -example, the following two declarations are _not_ equivalent: -``` -void Bar(int* p); // Neither p nor *p is const. -void Bar(const int* p); // p is not const, but *p is. -``` - -## I have a huge mock class, and Microsoft Visual C++ runs out of memory when compiling it. What can I do? ## - -We've noticed that when the `/clr` compiler flag is used, Visual C++ -uses 5~6 times as much memory when compiling a mock class. We suggest -to avoid `/clr` when compiling native C++ mocks. - -## I can't figure out why Google Mock thinks my expectations are not satisfied. What should I do? ## - -You might want to run your test with -`--gmock_verbose=info`. This flag lets Google Mock print a trace -of every mock function call it receives. By studying the trace, -you'll gain insights on why the expectations you set are not met. - -## How can I assert that a function is NEVER called? ## - -``` -EXPECT_CALL(foo, Bar(_)) - .Times(0); -``` - -## I have a failed test where Google Mock tells me TWICE that a particular expectation is not satisfied. Isn't this redundant? ## - -When Google Mock detects a failure, it prints relevant information -(the mock function arguments, the state of relevant expectations, and -etc) to help the user debug. If another failure is detected, Google -Mock will do the same, including printing the state of relevant -expectations. - -Sometimes an expectation's state didn't change between two failures, -and you'll see the same description of the state twice. They are -however _not_ redundant, as they refer to _different points in time_. -The fact they are the same _is_ interesting information. - -## I get a heap check failure when using a mock object, but using a real object is fine. What can be wrong? ## - -Does the class (hopefully a pure interface) you are mocking have a -virtual destructor? - -Whenever you derive from a base class, make sure its destructor is -virtual. Otherwise Bad Things will happen. Consider the following -code: - -``` -class Base { - public: - // Not virtual, but should be. - ~Base() { ... } - ... -}; - -class Derived : public Base { - public: - ... - private: - std::string value_; -}; - -... - Base* p = new Derived; - ... - delete p; // Surprise! ~Base() will be called, but ~Derived() will not - // - value_ is leaked. -``` - -By changing `~Base()` to virtual, `~Derived()` will be correctly -called when `delete p` is executed, and the heap checker -will be happy. - -## The "newer expectations override older ones" rule makes writing expectations awkward. Why does Google Mock do that? ## - -When people complain about this, often they are referring to code like: - -``` -// foo.Bar() should be called twice, return 1 the first time, and return -// 2 the second time. However, I have to write the expectations in the -// reverse order. This sucks big time!!! -EXPECT_CALL(foo, Bar()) - .WillOnce(Return(2)) - .RetiresOnSaturation(); -EXPECT_CALL(foo, Bar()) - .WillOnce(Return(1)) - .RetiresOnSaturation(); -``` - -The problem is that they didn't pick the **best** way to express the test's -intent. - -By default, expectations don't have to be matched in _any_ particular -order. If you want them to match in a certain order, you need to be -explicit. This is Google Mock's (and jMock's) fundamental philosophy: it's -easy to accidentally over-specify your tests, and we want to make it -harder to do so. - -There are two better ways to write the test spec. You could either -put the expectations in sequence: - -``` -// foo.Bar() should be called twice, return 1 the first time, and return -// 2 the second time. Using a sequence, we can write the expectations -// in their natural order. -{ - InSequence s; - EXPECT_CALL(foo, Bar()) - .WillOnce(Return(1)) - .RetiresOnSaturation(); - EXPECT_CALL(foo, Bar()) - .WillOnce(Return(2)) - .RetiresOnSaturation(); -} -``` - -or you can put the sequence of actions in the same expectation: - -``` -// foo.Bar() should be called twice, return 1 the first time, and return -// 2 the second time. -EXPECT_CALL(foo, Bar()) - .WillOnce(Return(1)) - .WillOnce(Return(2)) - .RetiresOnSaturation(); -``` - -Back to the original questions: why does Google Mock search the -expectations (and `ON_CALL`s) from back to front? Because this -allows a user to set up a mock's behavior for the common case early -(e.g. in the mock's constructor or the test fixture's set-up phase) -and customize it with more specific rules later. If Google Mock -searches from front to back, this very useful pattern won't be -possible. - -## Google Mock prints a warning when a function without EXPECT\_CALL is called, even if I have set its behavior using ON\_CALL. Would it be reasonable not to show the warning in this case? ## - -When choosing between being neat and being safe, we lean toward the -latter. So the answer is that we think it's better to show the -warning. - -Often people write `ON_CALL`s in the mock object's -constructor or `SetUp()`, as the default behavior rarely changes from -test to test. Then in the test body they set the expectations, which -are often different for each test. Having an `ON_CALL` in the set-up -part of a test doesn't mean that the calls are expected. If there's -no `EXPECT_CALL` and the method is called, it's possibly an error. If -we quietly let the call go through without notifying the user, bugs -may creep in unnoticed. - -If, however, you are sure that the calls are OK, you can write - -``` -EXPECT_CALL(foo, Bar(_)) - .WillRepeatedly(...); -``` - -instead of - -``` -ON_CALL(foo, Bar(_)) - .WillByDefault(...); -``` - -This tells Google Mock that you do expect the calls and no warning should be -printed. - -Also, you can control the verbosity using the `--gmock_verbose` flag. -If you find the output too noisy when debugging, just choose a less -verbose level. - -## How can I delete the mock function's argument in an action? ## - -If you find yourself needing to perform some action that's not -supported by Google Mock directly, remember that you can define your own -actions using -[MakeAction()](http://code.google.com/p/googlemock/wiki/V1_6_CookBook#Writing_New_Actions) or -[MakePolymorphicAction()](http://code.google.com/p/googlemock/wiki/V1_6_CookBook#Writing_New_Polymorphic_Actions), -or you can write a stub function and invoke it using -[Invoke()](http://code.google.com/p/googlemock/wiki/V1_6_CookBook#Using_Functions_Methods_Functors). - -## MOCK\_METHODn()'s second argument looks funny. Why don't you use the MOCK\_METHODn(Method, return\_type, arg\_1, ..., arg\_n) syntax? ## - -What?! I think it's beautiful. :-) - -While which syntax looks more natural is a subjective matter to some -extent, Google Mock's syntax was chosen for several practical advantages it -has. - -Try to mock a function that takes a map as an argument: -``` -virtual int GetSize(const map& m); -``` - -Using the proposed syntax, it would be: -``` -MOCK_METHOD1(GetSize, int, const map& m); -``` - -Guess what? You'll get a compiler error as the compiler thinks that -`const map& m` are **two**, not one, arguments. To work -around this you can use `typedef` to give the map type a name, but -that gets in the way of your work. Google Mock's syntax avoids this -problem as the function's argument types are protected inside a pair -of parentheses: -``` -// This compiles fine. -MOCK_METHOD1(GetSize, int(const map& m)); -``` - -You still need a `typedef` if the return type contains an unprotected -comma, but that's much rarer. - -Other advantages include: - 1. `MOCK_METHOD1(Foo, int, bool)` can leave a reader wonder whether the method returns `int` or `bool`, while there won't be such confusion using Google Mock's syntax. - 1. The way Google Mock describes a function type is nothing new, although many people may not be familiar with it. The same syntax was used in C, and the `function` library in `tr1` uses this syntax extensively. Since `tr1` will become a part of the new version of STL, we feel very comfortable to be consistent with it. - 1. The function type syntax is also used in other parts of Google Mock's API (e.g. the action interface) in order to make the implementation tractable. A user needs to learn it anyway in order to utilize Google Mock's more advanced features. We'd as well stick to the same syntax in `MOCK_METHOD*`! - -## My code calls a static/global function. Can I mock it? ## - -You can, but you need to make some changes. - -In general, if you find yourself needing to mock a static function, -it's a sign that your modules are too tightly coupled (and less -flexible, less reusable, less testable, etc). You are probably better -off defining a small interface and call the function through that -interface, which then can be easily mocked. It's a bit of work -initially, but usually pays for itself quickly. - -This Google Testing Blog -[post](http://googletesting.blogspot.com/2008/06/defeat-static-cling.html) -says it excellently. Check it out. - -## My mock object needs to do complex stuff. It's a lot of pain to specify the actions. Google Mock sucks! ## - -I know it's not a question, but you get an answer for free any way. :-) - -With Google Mock, you can create mocks in C++ easily. And people might be -tempted to use them everywhere. Sometimes they work great, and -sometimes you may find them, well, a pain to use. So, what's wrong in -the latter case? - -When you write a test without using mocks, you exercise the code and -assert that it returns the correct value or that the system is in an -expected state. This is sometimes called "state-based testing". - -Mocks are great for what some call "interaction-based" testing: -instead of checking the system state at the very end, mock objects -verify that they are invoked the right way and report an error as soon -as it arises, giving you a handle on the precise context in which the -error was triggered. This is often more effective and economical to -do than state-based testing. - -If you are doing state-based testing and using a test double just to -simulate the real object, you are probably better off using a fake. -Using a mock in this case causes pain, as it's not a strong point for -mocks to perform complex actions. If you experience this and think -that mocks suck, you are just not using the right tool for your -problem. Or, you might be trying to solve the wrong problem. :-) - -## I got a warning "Uninteresting function call encountered - default action taken.." Should I panic? ## - -By all means, NO! It's just an FYI. - -What it means is that you have a mock function, you haven't set any -expectations on it (by Google Mock's rule this means that you are not -interested in calls to this function and therefore it can be called -any number of times), and it is called. That's OK - you didn't say -it's not OK to call the function! - -What if you actually meant to disallow this function to be called, but -forgot to write `EXPECT_CALL(foo, Bar()).Times(0)`? While -one can argue that it's the user's fault, Google Mock tries to be nice and -prints you a note. - -So, when you see the message and believe that there shouldn't be any -uninteresting calls, you should investigate what's going on. To make -your life easier, Google Mock prints the function name and arguments -when an uninteresting call is encountered. - -## I want to define a custom action. Should I use Invoke() or implement the action interface? ## - -Either way is fine - you want to choose the one that's more convenient -for your circumstance. - -Usually, if your action is for a particular function type, defining it -using `Invoke()` should be easier; if your action can be used in -functions of different types (e.g. if you are defining -`Return(value)`), `MakePolymorphicAction()` is -easiest. Sometimes you want precise control on what types of -functions the action can be used in, and implementing -`ActionInterface` is the way to go here. See the implementation of -`Return()` in `include/gmock/gmock-actions.h` for an example. - -## I'm using the set-argument-pointee action, and the compiler complains about "conflicting return type specified". What does it mean? ## - -You got this error as Google Mock has no idea what value it should return -when the mock method is called. `SetArgPointee()` says what the -side effect is, but doesn't say what the return value should be. You -need `DoAll()` to chain a `SetArgPointee()` with a `Return()`. - -See this [recipe](http://code.google.com/p/googlemock/wiki/V1_6_CookBook#Mocking_Side_Effects) for more details and an example. - - -## My question is not in your FAQ! ## - -If you cannot find the answer to your question in this FAQ, there are -some other resources you can use: - - 1. read other [wiki pages](http://code.google.com/p/googlemock/w/list), - 1. search the mailing list [archive](http://groups.google.com/group/googlemock/topics), - 1. ask it on [googlemock@googlegroups.com](mailto:googlemock@googlegroups.com) and someone will answer it (to prevent spam, we require you to join the [discussion group](http://groups.google.com/group/googlemock) before you can post.). - -Please note that creating an issue in the -[issue tracker](http://code.google.com/p/googlemock/issues/list) is _not_ -a good way to get your answer, as it is monitored infrequently by a -very small number of people. - -When asking a question, it's helpful to provide as much of the -following information as possible (people cannot help you if there's -not enough information in your question): - - * the version (or the revision number if you check out from SVN directly) of Google Mock you use (Google Mock is under active development, so it's possible that your problem has been solved in a later version), - * your operating system, - * the name and version of your compiler, - * the complete command line flags you give to your compiler, - * the complete compiler error messages (if the question is about compilation), - * the _actual_ code (ideally, a minimal but complete program) that has the problem you encounter. \ No newline at end of file diff --git a/googlemock/docs/v1_7/CheatSheet.md b/googlemock/docs/v1_7/CheatSheet.md deleted file mode 100644 index db421e51..00000000 --- a/googlemock/docs/v1_7/CheatSheet.md +++ /dev/null @@ -1,556 +0,0 @@ - - -# Defining a Mock Class # - -## Mocking a Normal Class ## - -Given -``` -class Foo { - ... - virtual ~Foo(); - virtual int GetSize() const = 0; - virtual string Describe(const char* name) = 0; - virtual string Describe(int type) = 0; - virtual bool Process(Bar elem, int count) = 0; -}; -``` -(note that `~Foo()` **must** be virtual) we can define its mock as -``` -#include "gmock/gmock.h" - -class MockFoo : public Foo { - MOCK_CONST_METHOD0(GetSize, int()); - MOCK_METHOD1(Describe, string(const char* name)); - MOCK_METHOD1(Describe, string(int type)); - MOCK_METHOD2(Process, bool(Bar elem, int count)); -}; -``` - -To create a "nice" mock object which ignores all uninteresting calls, -or a "strict" mock object, which treats them as failures: -``` -NiceMock nice_foo; // The type is a subclass of MockFoo. -StrictMock strict_foo; // The type is a subclass of MockFoo. -``` - -## Mocking a Class Template ## - -To mock -``` -template -class StackInterface { - public: - ... - virtual ~StackInterface(); - virtual int GetSize() const = 0; - virtual void Push(const Elem& x) = 0; -}; -``` -(note that `~StackInterface()` **must** be virtual) just append `_T` to the `MOCK_*` macros: -``` -template -class MockStack : public StackInterface { - public: - ... - MOCK_CONST_METHOD0_T(GetSize, int()); - MOCK_METHOD1_T(Push, void(const Elem& x)); -}; -``` - -## Specifying Calling Conventions for Mock Functions ## - -If your mock function doesn't use the default calling convention, you -can specify it by appending `_WITH_CALLTYPE` to any of the macros -described in the previous two sections and supplying the calling -convention as the first argument to the macro. For example, -``` - MOCK_METHOD_1_WITH_CALLTYPE(STDMETHODCALLTYPE, Foo, bool(int n)); - MOCK_CONST_METHOD2_WITH_CALLTYPE(STDMETHODCALLTYPE, Bar, int(double x, double y)); -``` -where `STDMETHODCALLTYPE` is defined by `` on Windows. - -# Using Mocks in Tests # - -The typical flow is: - 1. Import the Google Mock names you need to use. All Google Mock names are in the `testing` namespace unless they are macros or otherwise noted. - 1. Create the mock objects. - 1. Optionally, set the default actions of the mock objects. - 1. Set your expectations on the mock objects (How will they be called? What wil they do?). - 1. Exercise code that uses the mock objects; if necessary, check the result using [Google Test](http://code.google.com/p/googletest/) assertions. - 1. When a mock objects is destructed, Google Mock automatically verifies that all expectations on it have been satisfied. - -Here is an example: -``` -using ::testing::Return; // #1 - -TEST(BarTest, DoesThis) { - MockFoo foo; // #2 - - ON_CALL(foo, GetSize()) // #3 - .WillByDefault(Return(1)); - // ... other default actions ... - - EXPECT_CALL(foo, Describe(5)) // #4 - .Times(3) - .WillRepeatedly(Return("Category 5")); - // ... other expectations ... - - EXPECT_EQ("good", MyProductionFunction(&foo)); // #5 -} // #6 -``` - -# Setting Default Actions # - -Google Mock has a **built-in default action** for any function that -returns `void`, `bool`, a numeric value, or a pointer. - -To customize the default action for functions with return type `T` globally: -``` -using ::testing::DefaultValue; - -DefaultValue::Set(value); // Sets the default value to be returned. -// ... use the mocks ... -DefaultValue::Clear(); // Resets the default value. -``` - -To customize the default action for a particular method, use `ON_CALL()`: -``` -ON_CALL(mock_object, method(matchers)) - .With(multi_argument_matcher) ? - .WillByDefault(action); -``` - -# Setting Expectations # - -`EXPECT_CALL()` sets **expectations** on a mock method (How will it be -called? What will it do?): -``` -EXPECT_CALL(mock_object, method(matchers)) - .With(multi_argument_matcher) ? - .Times(cardinality) ? - .InSequence(sequences) * - .After(expectations) * - .WillOnce(action) * - .WillRepeatedly(action) ? - .RetiresOnSaturation(); ? -``` - -If `Times()` is omitted, the cardinality is assumed to be: - - * `Times(1)` when there is neither `WillOnce()` nor `WillRepeatedly()`; - * `Times(n)` when there are `n WillOnce()`s but no `WillRepeatedly()`, where `n` >= 1; or - * `Times(AtLeast(n))` when there are `n WillOnce()`s and a `WillRepeatedly()`, where `n` >= 0. - -A method with no `EXPECT_CALL()` is free to be invoked _any number of times_, and the default action will be taken each time. - -# Matchers # - -A **matcher** matches a _single_ argument. You can use it inside -`ON_CALL()` or `EXPECT_CALL()`, or use it to validate a value -directly: - -| `EXPECT_THAT(value, matcher)` | Asserts that `value` matches `matcher`. | -|:------------------------------|:----------------------------------------| -| `ASSERT_THAT(value, matcher)` | The same as `EXPECT_THAT(value, matcher)`, except that it generates a **fatal** failure. | - -Built-in matchers (where `argument` is the function argument) are -divided into several categories: - -## Wildcard ## -|`_`|`argument` can be any value of the correct type.| -|:--|:-----------------------------------------------| -|`A()` or `An()`|`argument` can be any value of type `type`. | - -## Generic Comparison ## - -|`Eq(value)` or `value`|`argument == value`| -|:---------------------|:------------------| -|`Ge(value)` |`argument >= value`| -|`Gt(value)` |`argument > value` | -|`Le(value)` |`argument <= value`| -|`Lt(value)` |`argument < value` | -|`Ne(value)` |`argument != value`| -|`IsNull()` |`argument` is a `NULL` pointer (raw or smart).| -|`NotNull()` |`argument` is a non-null pointer (raw or smart).| -|`Ref(variable)` |`argument` is a reference to `variable`.| -|`TypedEq(value)`|`argument` has type `type` and is equal to `value`. You may need to use this instead of `Eq(value)` when the mock function is overloaded.| - -Except `Ref()`, these matchers make a _copy_ of `value` in case it's -modified or destructed later. If the compiler complains that `value` -doesn't have a public copy constructor, try wrap it in `ByRef()`, -e.g. `Eq(ByRef(non_copyable_value))`. If you do that, make sure -`non_copyable_value` is not changed afterwards, or the meaning of your -matcher will be changed. - -## Floating-Point Matchers ## - -|`DoubleEq(a_double)`|`argument` is a `double` value approximately equal to `a_double`, treating two NaNs as unequal.| -|:-------------------|:----------------------------------------------------------------------------------------------| -|`FloatEq(a_float)` |`argument` is a `float` value approximately equal to `a_float`, treating two NaNs as unequal. | -|`NanSensitiveDoubleEq(a_double)`|`argument` is a `double` value approximately equal to `a_double`, treating two NaNs as equal. | -|`NanSensitiveFloatEq(a_float)`|`argument` is a `float` value approximately equal to `a_float`, treating two NaNs as equal. | - -The above matchers use ULP-based comparison (the same as used in -[Google Test](http://code.google.com/p/googletest/)). They -automatically pick a reasonable error bound based on the absolute -value of the expected value. `DoubleEq()` and `FloatEq()` conform to -the IEEE standard, which requires comparing two NaNs for equality to -return false. The `NanSensitive*` version instead treats two NaNs as -equal, which is often what a user wants. - -|`DoubleNear(a_double, max_abs_error)`|`argument` is a `double` value close to `a_double` (absolute error <= `max_abs_error`), treating two NaNs as unequal.| -|:------------------------------------|:--------------------------------------------------------------------------------------------------------------------| -|`FloatNear(a_float, max_abs_error)` |`argument` is a `float` value close to `a_float` (absolute error <= `max_abs_error`), treating two NaNs as unequal. | -|`NanSensitiveDoubleNear(a_double, max_abs_error)`|`argument` is a `double` value close to `a_double` (absolute error <= `max_abs_error`), treating two NaNs as equal. | -|`NanSensitiveFloatNear(a_float, max_abs_error)`|`argument` is a `float` value close to `a_float` (absolute error <= `max_abs_error`), treating two NaNs as equal. | - -## String Matchers ## - -The `argument` can be either a C string or a C++ string object: - -|`ContainsRegex(string)`|`argument` matches the given regular expression.| -|:----------------------|:-----------------------------------------------| -|`EndsWith(suffix)` |`argument` ends with string `suffix`. | -|`HasSubstr(string)` |`argument` contains `string` as a sub-string. | -|`MatchesRegex(string)` |`argument` matches the given regular expression with the match starting at the first character and ending at the last character.| -|`StartsWith(prefix)` |`argument` starts with string `prefix`. | -|`StrCaseEq(string)` |`argument` is equal to `string`, ignoring case. | -|`StrCaseNe(string)` |`argument` is not equal to `string`, ignoring case.| -|`StrEq(string)` |`argument` is equal to `string`. | -|`StrNe(string)` |`argument` is not equal to `string`. | - -`ContainsRegex()` and `MatchesRegex()` use the regular expression -syntax defined -[here](http://code.google.com/p/googletest/wiki/AdvancedGuide#Regular_Expression_Syntax). -`StrCaseEq()`, `StrCaseNe()`, `StrEq()`, and `StrNe()` work for wide -strings as well. - -## Container Matchers ## - -Most STL-style containers support `==`, so you can use -`Eq(expected_container)` or simply `expected_container` to match a -container exactly. If you want to write the elements in-line, -match them more flexibly, or get more informative messages, you can use: - -| `ContainerEq(container)` | The same as `Eq(container)` except that the failure message also includes which elements are in one container but not the other. | -|:-------------------------|:---------------------------------------------------------------------------------------------------------------------------------| -| `Contains(e)` | `argument` contains an element that matches `e`, which can be either a value or a matcher. | -| `Each(e)` | `argument` is a container where _every_ element matches `e`, which can be either a value or a matcher. | -| `ElementsAre(e0, e1, ..., en)` | `argument` has `n + 1` elements, where the i-th element matches `ei`, which can be a value or a matcher. 0 to 10 arguments are allowed. | -| `ElementsAreArray({ e0, e1, ..., en })`, `ElementsAreArray(array)`, or `ElementsAreArray(array, count)` | The same as `ElementsAre()` except that the expected element values/matchers come from an initializer list, vector, or C-style array. | -| `IsEmpty()` | `argument` is an empty container (`container.empty()`). | -| `Pointwise(m, container)` | `argument` contains the same number of elements as in `container`, and for all i, (the i-th element in `argument`, the i-th element in `container`) match `m`, which is a matcher on 2-tuples. E.g. `Pointwise(Le(), upper_bounds)` verifies that each element in `argument` doesn't exceed the corresponding element in `upper_bounds`. See more detail below. | -| `SizeIs(m)` | `argument` is a container whose size matches `m`. E.g. `SizeIs(2)` or `SizeIs(Lt(2))`. | -| `UnorderedElementsAre(e0, e1, ..., en)` | `argument` has `n + 1` elements, and under some permutation each element matches an `ei` (for a different `i`), which can be a value or a matcher. 0 to 10 arguments are allowed. | -| `UnorderedElementsAreArray({ e0, e1, ..., en })`, `UnorderedElementsAreArray(array)`, or `UnorderedElementsAreArray(array, count)` | The same as `UnorderedElementsAre()` except that the expected element values/matchers come from an initializer list, vector, or C-style array. | -| `WhenSorted(m)` | When `argument` is sorted using the `<` operator, it matches container matcher `m`. E.g. `WhenSorted(UnorderedElementsAre(1, 2, 3))` verifies that `argument` contains elements `1`, `2`, and `3`, ignoring order. | -| `WhenSortedBy(comparator, m)` | The same as `WhenSorted(m)`, except that the given comparator instead of `<` is used to sort `argument`. E.g. `WhenSortedBy(std::greater(), ElementsAre(3, 2, 1))`. | - -Notes: - - * These matchers can also match: - 1. a native array passed by reference (e.g. in `Foo(const int (&a)[5])`), and - 1. an array passed as a pointer and a count (e.g. in `Bar(const T* buffer, int len)` -- see [Multi-argument Matchers](#Multiargument_Matchers.md)). - * The array being matched may be multi-dimensional (i.e. its elements can be arrays). - * `m` in `Pointwise(m, ...)` should be a matcher for `std::tr1::tuple` where `T` and `U` are the element type of the actual container and the expected container, respectively. For example, to compare two `Foo` containers where `Foo` doesn't support `operator==` but has an `Equals()` method, one might write: - -``` -using ::std::tr1::get; -MATCHER(FooEq, "") { - return get<0>(arg).Equals(get<1>(arg)); -} -... -EXPECT_THAT(actual_foos, Pointwise(FooEq(), expected_foos)); -``` - -## Member Matchers ## - -|`Field(&class::field, m)`|`argument.field` (or `argument->field` when `argument` is a plain pointer) matches matcher `m`, where `argument` is an object of type _class_.| -|:------------------------|:---------------------------------------------------------------------------------------------------------------------------------------------| -|`Key(e)` |`argument.first` matches `e`, which can be either a value or a matcher. E.g. `Contains(Key(Le(5)))` can verify that a `map` contains a key `<= 5`.| -|`Pair(m1, m2)` |`argument` is an `std::pair` whose `first` field matches `m1` and `second` field matches `m2`. | -|`Property(&class::property, m)`|`argument.property()` (or `argument->property()` when `argument` is a plain pointer) matches matcher `m`, where `argument` is an object of type _class_.| - -## Matching the Result of a Function or Functor ## - -|`ResultOf(f, m)`|`f(argument)` matches matcher `m`, where `f` is a function or functor.| -|:---------------|:---------------------------------------------------------------------| - -## Pointer Matchers ## - -|`Pointee(m)`|`argument` (either a smart pointer or a raw pointer) points to a value that matches matcher `m`.| -|:-----------|:-----------------------------------------------------------------------------------------------| - -## Multiargument Matchers ## - -Technically, all matchers match a _single_ value. A "multi-argument" -matcher is just one that matches a _tuple_. The following matchers can -be used to match a tuple `(x, y)`: - -|`Eq()`|`x == y`| -|:-----|:-------| -|`Ge()`|`x >= y`| -|`Gt()`|`x > y` | -|`Le()`|`x <= y`| -|`Lt()`|`x < y` | -|`Ne()`|`x != y`| - -You can use the following selectors to pick a subset of the arguments -(or reorder them) to participate in the matching: - -|`AllArgs(m)`|Equivalent to `m`. Useful as syntactic sugar in `.With(AllArgs(m))`.| -|:-----------|:-------------------------------------------------------------------| -|`Args(m)`|The tuple of the `k` selected (using 0-based indices) arguments matches `m`, e.g. `Args<1, 2>(Eq())`.| - -## Composite Matchers ## - -You can make a matcher from one or more other matchers: - -|`AllOf(m1, m2, ..., mn)`|`argument` matches all of the matchers `m1` to `mn`.| -|:-----------------------|:---------------------------------------------------| -|`AnyOf(m1, m2, ..., mn)`|`argument` matches at least one of the matchers `m1` to `mn`.| -|`Not(m)` |`argument` doesn't match matcher `m`. | - -## Adapters for Matchers ## - -|`MatcherCast(m)`|casts matcher `m` to type `Matcher`.| -|:------------------|:--------------------------------------| -|`SafeMatcherCast(m)`| [safely casts](http://code.google.com/p/googlemock/wiki/V1_7_CookBook#Casting_Matchers) matcher `m` to type `Matcher`. | -|`Truly(predicate)` |`predicate(argument)` returns something considered by C++ to be true, where `predicate` is a function or functor.| - -## Matchers as Predicates ## - -|`Matches(m)(value)`|evaluates to `true` if `value` matches `m`. You can use `Matches(m)` alone as a unary functor.| -|:------------------|:---------------------------------------------------------------------------------------------| -|`ExplainMatchResult(m, value, result_listener)`|evaluates to `true` if `value` matches `m`, explaining the result to `result_listener`. | -|`Value(value, m)` |evaluates to `true` if `value` matches `m`. | - -## Defining Matchers ## - -| `MATCHER(IsEven, "") { return (arg % 2) == 0; }` | Defines a matcher `IsEven()` to match an even number. | -|:-------------------------------------------------|:------------------------------------------------------| -| `MATCHER_P(IsDivisibleBy, n, "") { *result_listener << "where the remainder is " << (arg % n); return (arg % n) == 0; }` | Defines a macher `IsDivisibleBy(n)` to match a number divisible by `n`. | -| `MATCHER_P2(IsBetween, a, b, std::string(negation ? "isn't" : "is") + " between " + PrintToString(a) + " and " + PrintToString(b)) { return a <= arg && arg <= b; }` | Defines a matcher `IsBetween(a, b)` to match a value in the range [`a`, `b`]. | - -**Notes:** - - 1. The `MATCHER*` macros cannot be used inside a function or class. - 1. The matcher body must be _purely functional_ (i.e. it cannot have any side effect, and the result must not depend on anything other than the value being matched and the matcher parameters). - 1. You can use `PrintToString(x)` to convert a value `x` of any type to a string. - -## Matchers as Test Assertions ## - -|`ASSERT_THAT(expression, m)`|Generates a [fatal failure](http://code.google.com/p/googletest/wiki/Primer#Assertions) if the value of `expression` doesn't match matcher `m`.| -|:---------------------------|:----------------------------------------------------------------------------------------------------------------------------------------------| -|`EXPECT_THAT(expression, m)`|Generates a non-fatal failure if the value of `expression` doesn't match matcher `m`. | - -# Actions # - -**Actions** specify what a mock function should do when invoked. - -## Returning a Value ## - -|`Return()`|Return from a `void` mock function.| -|:---------|:----------------------------------| -|`Return(value)`|Return `value`. If the type of `value` is different to the mock function's return type, `value` is converted to the latter type at the time the expectation is set, not when the action is executed.| -|`ReturnArg()`|Return the `N`-th (0-based) argument.| -|`ReturnNew(a1, ..., ak)`|Return `new T(a1, ..., ak)`; a different object is created each time.| -|`ReturnNull()`|Return a null pointer. | -|`ReturnPointee(ptr)`|Return the value pointed to by `ptr`.| -|`ReturnRef(variable)`|Return a reference to `variable`. | -|`ReturnRefOfCopy(value)`|Return a reference to a copy of `value`; the copy lives as long as the action.| - -## Side Effects ## - -|`Assign(&variable, value)`|Assign `value` to variable.| -|:-------------------------|:--------------------------| -| `DeleteArg()` | Delete the `N`-th (0-based) argument, which must be a pointer. | -| `SaveArg(pointer)` | Save the `N`-th (0-based) argument to `*pointer`. | -| `SaveArgPointee(pointer)` | Save the value pointed to by the `N`-th (0-based) argument to `*pointer`. | -| `SetArgReferee(value)` | Assign value to the variable referenced by the `N`-th (0-based) argument. | -|`SetArgPointee(value)` |Assign `value` to the variable pointed by the `N`-th (0-based) argument.| -|`SetArgumentPointee(value)`|Same as `SetArgPointee(value)`. Deprecated. Will be removed in v1.7.0.| -|`SetArrayArgument(first, last)`|Copies the elements in source range [`first`, `last`) to the array pointed to by the `N`-th (0-based) argument, which can be either a pointer or an iterator. The action does not take ownership of the elements in the source range.| -|`SetErrnoAndReturn(error, value)`|Set `errno` to `error` and return `value`.| -|`Throw(exception)` |Throws the given exception, which can be any copyable value. Available since v1.1.0.| - -## Using a Function or a Functor as an Action ## - -|`Invoke(f)`|Invoke `f` with the arguments passed to the mock function, where `f` can be a global/static function or a functor.| -|:----------|:-----------------------------------------------------------------------------------------------------------------| -|`Invoke(object_pointer, &class::method)`|Invoke the {method on the object with the arguments passed to the mock function. | -|`InvokeWithoutArgs(f)`|Invoke `f`, which can be a global/static function or a functor. `f` must take no arguments. | -|`InvokeWithoutArgs(object_pointer, &class::method)`|Invoke the method on the object, which takes no arguments. | -|`InvokeArgument(arg1, arg2, ..., argk)`|Invoke the mock function's `N`-th (0-based) argument, which must be a function or a functor, with the `k` arguments.| - -The return value of the invoked function is used as the return value -of the action. - -When defining a function or functor to be used with `Invoke*()`, you can declare any unused parameters as `Unused`: -``` - double Distance(Unused, double x, double y) { return sqrt(x*x + y*y); } - ... - EXPECT_CALL(mock, Foo("Hi", _, _)).WillOnce(Invoke(Distance)); -``` - -In `InvokeArgument(...)`, if an argument needs to be passed by reference, wrap it inside `ByRef()`. For example, -``` - InvokeArgument<2>(5, string("Hi"), ByRef(foo)) -``` -calls the mock function's #2 argument, passing to it `5` and `string("Hi")` by value, and `foo` by reference. - -## Default Action ## - -|`DoDefault()`|Do the default action (specified by `ON_CALL()` or the built-in one).| -|:------------|:--------------------------------------------------------------------| - -**Note:** due to technical reasons, `DoDefault()` cannot be used inside a composite action - trying to do so will result in a run-time error. - -## Composite Actions ## - -|`DoAll(a1, a2, ..., an)`|Do all actions `a1` to `an` and return the result of `an` in each invocation. The first `n - 1` sub-actions must return void. | -|:-----------------------|:-----------------------------------------------------------------------------------------------------------------------------| -|`IgnoreResult(a)` |Perform action `a` and ignore its result. `a` must not return void. | -|`WithArg(a)` |Pass the `N`-th (0-based) argument of the mock function to action `a` and perform it. | -|`WithArgs(a)`|Pass the selected (0-based) arguments of the mock function to action `a` and perform it. | -|`WithoutArgs(a)` |Perform action `a` without any arguments. | - -## Defining Actions ## - -| `ACTION(Sum) { return arg0 + arg1; }` | Defines an action `Sum()` to return the sum of the mock function's argument #0 and #1. | -|:--------------------------------------|:---------------------------------------------------------------------------------------| -| `ACTION_P(Plus, n) { return arg0 + n; }` | Defines an action `Plus(n)` to return the sum of the mock function's argument #0 and `n`. | -| `ACTION_Pk(Foo, p1, ..., pk) { statements; }` | Defines a parameterized action `Foo(p1, ..., pk)` to execute the given `statements`. | - -The `ACTION*` macros cannot be used inside a function or class. - -# Cardinalities # - -These are used in `Times()` to specify how many times a mock function will be called: - -|`AnyNumber()`|The function can be called any number of times.| -|:------------|:----------------------------------------------| -|`AtLeast(n)` |The call is expected at least `n` times. | -|`AtMost(n)` |The call is expected at most `n` times. | -|`Between(m, n)`|The call is expected between `m` and `n` (inclusive) times.| -|`Exactly(n) or n`|The call is expected exactly `n` times. In particular, the call should never happen when `n` is 0.| - -# Expectation Order # - -By default, the expectations can be matched in _any_ order. If some -or all expectations must be matched in a given order, there are two -ways to specify it. They can be used either independently or -together. - -## The After Clause ## - -``` -using ::testing::Expectation; -... -Expectation init_x = EXPECT_CALL(foo, InitX()); -Expectation init_y = EXPECT_CALL(foo, InitY()); -EXPECT_CALL(foo, Bar()) - .After(init_x, init_y); -``` -says that `Bar()` can be called only after both `InitX()` and -`InitY()` have been called. - -If you don't know how many pre-requisites an expectation has when you -write it, you can use an `ExpectationSet` to collect them: - -``` -using ::testing::ExpectationSet; -... -ExpectationSet all_inits; -for (int i = 0; i < element_count; i++) { - all_inits += EXPECT_CALL(foo, InitElement(i)); -} -EXPECT_CALL(foo, Bar()) - .After(all_inits); -``` -says that `Bar()` can be called only after all elements have been -initialized (but we don't care about which elements get initialized -before the others). - -Modifying an `ExpectationSet` after using it in an `.After()` doesn't -affect the meaning of the `.After()`. - -## Sequences ## - -When you have a long chain of sequential expectations, it's easier to -specify the order using **sequences**, which don't require you to given -each expectation in the chain a different name. All expected
-calls in the same sequence must occur in the order they are -specified. - -``` -using ::testing::Sequence; -Sequence s1, s2; -... -EXPECT_CALL(foo, Reset()) - .InSequence(s1, s2) - .WillOnce(Return(true)); -EXPECT_CALL(foo, GetSize()) - .InSequence(s1) - .WillOnce(Return(1)); -EXPECT_CALL(foo, Describe(A())) - .InSequence(s2) - .WillOnce(Return("dummy")); -``` -says that `Reset()` must be called before _both_ `GetSize()` _and_ -`Describe()`, and the latter two can occur in any order. - -To put many expectations in a sequence conveniently: -``` -using ::testing::InSequence; -{ - InSequence dummy; - - EXPECT_CALL(...)...; - EXPECT_CALL(...)...; - ... - EXPECT_CALL(...)...; -} -``` -says that all expected calls in the scope of `dummy` must occur in -strict order. The name `dummy` is irrelevant.) - -# Verifying and Resetting a Mock # - -Google Mock will verify the expectations on a mock object when it is destructed, or you can do it earlier: -``` -using ::testing::Mock; -... -// Verifies and removes the expectations on mock_obj; -// returns true iff successful. -Mock::VerifyAndClearExpectations(&mock_obj); -... -// Verifies and removes the expectations on mock_obj; -// also removes the default actions set by ON_CALL(); -// returns true iff successful. -Mock::VerifyAndClear(&mock_obj); -``` - -You can also tell Google Mock that a mock object can be leaked and doesn't -need to be verified: -``` -Mock::AllowLeak(&mock_obj); -``` - -# Mock Classes # - -Google Mock defines a convenient mock class template -``` -class MockFunction { - public: - MOCK_METHODn(Call, R(A1, ..., An)); -}; -``` -See this [recipe](http://code.google.com/p/googlemock/wiki/V1_7_CookBook#Using_Check_Points) for one application of it. - -# Flags # - -| `--gmock_catch_leaked_mocks=0` | Don't report leaked mock objects as failures. | -|:-------------------------------|:----------------------------------------------| -| `--gmock_verbose=LEVEL` | Sets the default verbosity level (`info`, `warning`, or `error`) of Google Mock messages. | \ No newline at end of file diff --git a/googlemock/docs/v1_7/CookBook.md b/googlemock/docs/v1_7/CookBook.md deleted file mode 100644 index 03994890..00000000 --- a/googlemock/docs/v1_7/CookBook.md +++ /dev/null @@ -1,3435 +0,0 @@ - - -You can find recipes for using Google Mock here. If you haven't yet, -please read the [ForDummies](V1_7_ForDummies.md) document first to make sure you understand -the basics. - -**Note:** Google Mock lives in the `testing` name space. For -readability, it is recommended to write `using ::testing::Foo;` once in -your file before using the name `Foo` defined by Google Mock. We omit -such `using` statements in this page for brevity, but you should do it -in your own code. - -# Creating Mock Classes # - -## Mocking Private or Protected Methods ## - -You must always put a mock method definition (`MOCK_METHOD*`) in a -`public:` section of the mock class, regardless of the method being -mocked being `public`, `protected`, or `private` in the base class. -This allows `ON_CALL` and `EXPECT_CALL` to reference the mock function -from outside of the mock class. (Yes, C++ allows a subclass to change -the access level of a virtual function in the base class.) Example: - -``` -class Foo { - public: - ... - virtual bool Transform(Gadget* g) = 0; - - protected: - virtual void Resume(); - - private: - virtual int GetTimeOut(); -}; - -class MockFoo : public Foo { - public: - ... - MOCK_METHOD1(Transform, bool(Gadget* g)); - - // The following must be in the public section, even though the - // methods are protected or private in the base class. - MOCK_METHOD0(Resume, void()); - MOCK_METHOD0(GetTimeOut, int()); -}; -``` - -## Mocking Overloaded Methods ## - -You can mock overloaded functions as usual. No special attention is required: - -``` -class Foo { - ... - - // Must be virtual as we'll inherit from Foo. - virtual ~Foo(); - - // Overloaded on the types and/or numbers of arguments. - virtual int Add(Element x); - virtual int Add(int times, Element x); - - // Overloaded on the const-ness of this object. - virtual Bar& GetBar(); - virtual const Bar& GetBar() const; -}; - -class MockFoo : public Foo { - ... - MOCK_METHOD1(Add, int(Element x)); - MOCK_METHOD2(Add, int(int times, Element x); - - MOCK_METHOD0(GetBar, Bar&()); - MOCK_CONST_METHOD0(GetBar, const Bar&()); -}; -``` - -**Note:** if you don't mock all versions of the overloaded method, the -compiler will give you a warning about some methods in the base class -being hidden. To fix that, use `using` to bring them in scope: - -``` -class MockFoo : public Foo { - ... - using Foo::Add; - MOCK_METHOD1(Add, int(Element x)); - // We don't want to mock int Add(int times, Element x); - ... -}; -``` - -## Mocking Class Templates ## - -To mock a class template, append `_T` to the `MOCK_*` macros: - -``` -template -class StackInterface { - ... - // Must be virtual as we'll inherit from StackInterface. - virtual ~StackInterface(); - - virtual int GetSize() const = 0; - virtual void Push(const Elem& x) = 0; -}; - -template -class MockStack : public StackInterface { - ... - MOCK_CONST_METHOD0_T(GetSize, int()); - MOCK_METHOD1_T(Push, void(const Elem& x)); -}; -``` - -## Mocking Nonvirtual Methods ## - -Google Mock can mock non-virtual functions to be used in what we call _hi-perf -dependency injection_. - -In this case, instead of sharing a common base class with the real -class, your mock class will be _unrelated_ to the real class, but -contain methods with the same signatures. The syntax for mocking -non-virtual methods is the _same_ as mocking virtual methods: - -``` -// A simple packet stream class. None of its members is virtual. -class ConcretePacketStream { - public: - void AppendPacket(Packet* new_packet); - const Packet* GetPacket(size_t packet_number) const; - size_t NumberOfPackets() const; - ... -}; - -// A mock packet stream class. It inherits from no other, but defines -// GetPacket() and NumberOfPackets(). -class MockPacketStream { - public: - MOCK_CONST_METHOD1(GetPacket, const Packet*(size_t packet_number)); - MOCK_CONST_METHOD0(NumberOfPackets, size_t()); - ... -}; -``` - -Note that the mock class doesn't define `AppendPacket()`, unlike the -real class. That's fine as long as the test doesn't need to call it. - -Next, you need a way to say that you want to use -`ConcretePacketStream` in production code, and use `MockPacketStream` -in tests. Since the functions are not virtual and the two classes are -unrelated, you must specify your choice at _compile time_ (as opposed -to run time). - -One way to do it is to templatize your code that needs to use a packet -stream. More specifically, you will give your code a template type -argument for the type of the packet stream. In production, you will -instantiate your template with `ConcretePacketStream` as the type -argument. In tests, you will instantiate the same template with -`MockPacketStream`. For example, you may write: - -``` -template -void CreateConnection(PacketStream* stream) { ... } - -template -class PacketReader { - public: - void ReadPackets(PacketStream* stream, size_t packet_num); -}; -``` - -Then you can use `CreateConnection()` and -`PacketReader` in production code, and use -`CreateConnection()` and -`PacketReader` in tests. - -``` - MockPacketStream mock_stream; - EXPECT_CALL(mock_stream, ...)...; - .. set more expectations on mock_stream ... - PacketReader reader(&mock_stream); - ... exercise reader ... -``` - -## Mocking Free Functions ## - -It's possible to use Google Mock to mock a free function (i.e. a -C-style function or a static method). You just need to rewrite your -code to use an interface (abstract class). - -Instead of calling a free function (say, `OpenFile`) directly, -introduce an interface for it and have a concrete subclass that calls -the free function: - -``` -class FileInterface { - public: - ... - virtual bool Open(const char* path, const char* mode) = 0; -}; - -class File : public FileInterface { - public: - ... - virtual bool Open(const char* path, const char* mode) { - return OpenFile(path, mode); - } -}; -``` - -Your code should talk to `FileInterface` to open a file. Now it's -easy to mock out the function. - -This may seem much hassle, but in practice you often have multiple -related functions that you can put in the same interface, so the -per-function syntactic overhead will be much lower. - -If you are concerned about the performance overhead incurred by -virtual functions, and profiling confirms your concern, you can -combine this with the recipe for [mocking non-virtual methods](#Mocking_Nonvirtual_Methods.md). - -## The Nice, the Strict, and the Naggy ## - -If a mock method has no `EXPECT_CALL` spec but is called, Google Mock -will print a warning about the "uninteresting call". The rationale is: - - * New methods may be added to an interface after a test is written. We shouldn't fail a test just because a method it doesn't know about is called. - * However, this may also mean there's a bug in the test, so Google Mock shouldn't be silent either. If the user believes these calls are harmless, he can add an `EXPECT_CALL()` to suppress the warning. - -However, sometimes you may want to suppress all "uninteresting call" -warnings, while sometimes you may want the opposite, i.e. to treat all -of them as errors. Google Mock lets you make the decision on a -per-mock-object basis. - -Suppose your test uses a mock class `MockFoo`: - -``` -TEST(...) { - MockFoo mock_foo; - EXPECT_CALL(mock_foo, DoThis()); - ... code that uses mock_foo ... -} -``` - -If a method of `mock_foo` other than `DoThis()` is called, it will be -reported by Google Mock as a warning. However, if you rewrite your -test to use `NiceMock` instead, the warning will be gone, -resulting in a cleaner test output: - -``` -using ::testing::NiceMock; - -TEST(...) { - NiceMock mock_foo; - EXPECT_CALL(mock_foo, DoThis()); - ... code that uses mock_foo ... -} -``` - -`NiceMock` is a subclass of `MockFoo`, so it can be used -wherever `MockFoo` is accepted. - -It also works if `MockFoo`'s constructor takes some arguments, as -`NiceMock` "inherits" `MockFoo`'s constructors: - -``` -using ::testing::NiceMock; - -TEST(...) { - NiceMock mock_foo(5, "hi"); // Calls MockFoo(5, "hi"). - EXPECT_CALL(mock_foo, DoThis()); - ... code that uses mock_foo ... -} -``` - -The usage of `StrictMock` is similar, except that it makes all -uninteresting calls failures: - -``` -using ::testing::StrictMock; - -TEST(...) { - StrictMock mock_foo; - EXPECT_CALL(mock_foo, DoThis()); - ... code that uses mock_foo ... - - // The test will fail if a method of mock_foo other than DoThis() - // is called. -} -``` - -There are some caveats though (I don't like them just as much as the -next guy, but sadly they are side effects of C++'s limitations): - - 1. `NiceMock` and `StrictMock` only work for mock methods defined using the `MOCK_METHOD*` family of macros **directly** in the `MockFoo` class. If a mock method is defined in a **base class** of `MockFoo`, the "nice" or "strict" modifier may not affect it, depending on the compiler. In particular, nesting `NiceMock` and `StrictMock` (e.g. `NiceMock >`) is **not** supported. - 1. The constructors of the base mock (`MockFoo`) cannot have arguments passed by non-const reference, which happens to be banned by the [Google C++ style guide](http://google-styleguide.googlecode.com/svn/trunk/cppguide.xml). - 1. During the constructor or destructor of `MockFoo`, the mock object is _not_ nice or strict. This may cause surprises if the constructor or destructor calls a mock method on `this` object. (This behavior, however, is consistent with C++'s general rule: if a constructor or destructor calls a virtual method of `this` object, that method is treated as non-virtual. In other words, to the base class's constructor or destructor, `this` object behaves like an instance of the base class, not the derived class. This rule is required for safety. Otherwise a base constructor may use members of a derived class before they are initialized, or a base destructor may use members of a derived class after they have been destroyed.) - -Finally, you should be **very cautious** about when to use naggy or strict mocks, as they tend to make tests more brittle and harder to maintain. When you refactor your code without changing its externally visible behavior, ideally you should't need to update any tests. If your code interacts with a naggy mock, however, you may start to get spammed with warnings as the result of your change. Worse, if your code interacts with a strict mock, your tests may start to fail and you'll be forced to fix them. Our general recommendation is to use nice mocks (not yet the default) most of the time, use naggy mocks (the current default) when developing or debugging tests, and use strict mocks only as the last resort. - -## Simplifying the Interface without Breaking Existing Code ## - -Sometimes a method has a long list of arguments that is mostly -uninteresting. For example, - -``` -class LogSink { - public: - ... - virtual void send(LogSeverity severity, const char* full_filename, - const char* base_filename, int line, - const struct tm* tm_time, - const char* message, size_t message_len) = 0; -}; -``` - -This method's argument list is lengthy and hard to work with (let's -say that the `message` argument is not even 0-terminated). If we mock -it as is, using the mock will be awkward. If, however, we try to -simplify this interface, we'll need to fix all clients depending on -it, which is often infeasible. - -The trick is to re-dispatch the method in the mock class: - -``` -class ScopedMockLog : public LogSink { - public: - ... - virtual void send(LogSeverity severity, const char* full_filename, - const char* base_filename, int line, const tm* tm_time, - const char* message, size_t message_len) { - // We are only interested in the log severity, full file name, and - // log message. - Log(severity, full_filename, std::string(message, message_len)); - } - - // Implements the mock method: - // - // void Log(LogSeverity severity, - // const string& file_path, - // const string& message); - MOCK_METHOD3(Log, void(LogSeverity severity, const string& file_path, - const string& message)); -}; -``` - -By defining a new mock method with a trimmed argument list, we make -the mock class much more user-friendly. - -## Alternative to Mocking Concrete Classes ## - -Often you may find yourself using classes that don't implement -interfaces. In order to test your code that uses such a class (let's -call it `Concrete`), you may be tempted to make the methods of -`Concrete` virtual and then mock it. - -Try not to do that. - -Making a non-virtual function virtual is a big decision. It creates an -extension point where subclasses can tweak your class' behavior. This -weakens your control on the class because now it's harder to maintain -the class' invariants. You should make a function virtual only when -there is a valid reason for a subclass to override it. - -Mocking concrete classes directly is problematic as it creates a tight -coupling between the class and the tests - any small change in the -class may invalidate your tests and make test maintenance a pain. - -To avoid such problems, many programmers have been practicing "coding -to interfaces": instead of talking to the `Concrete` class, your code -would define an interface and talk to it. Then you implement that -interface as an adaptor on top of `Concrete`. In tests, you can easily -mock that interface to observe how your code is doing. - -This technique incurs some overhead: - - * You pay the cost of virtual function calls (usually not a problem). - * There is more abstraction for the programmers to learn. - -However, it can also bring significant benefits in addition to better -testability: - - * `Concrete`'s API may not fit your problem domain very well, as you may not be the only client it tries to serve. By designing your own interface, you have a chance to tailor it to your need - you may add higher-level functionalities, rename stuff, etc instead of just trimming the class. This allows you to write your code (user of the interface) in a more natural way, which means it will be more readable, more maintainable, and you'll be more productive. - * If `Concrete`'s implementation ever has to change, you don't have to rewrite everywhere it is used. Instead, you can absorb the change in your implementation of the interface, and your other code and tests will be insulated from this change. - -Some people worry that if everyone is practicing this technique, they -will end up writing lots of redundant code. This concern is totally -understandable. However, there are two reasons why it may not be the -case: - - * Different projects may need to use `Concrete` in different ways, so the best interfaces for them will be different. Therefore, each of them will have its own domain-specific interface on top of `Concrete`, and they will not be the same code. - * If enough projects want to use the same interface, they can always share it, just like they have been sharing `Concrete`. You can check in the interface and the adaptor somewhere near `Concrete` (perhaps in a `contrib` sub-directory) and let many projects use it. - -You need to weigh the pros and cons carefully for your particular -problem, but I'd like to assure you that the Java community has been -practicing this for a long time and it's a proven effective technique -applicable in a wide variety of situations. :-) - -## Delegating Calls to a Fake ## - -Some times you have a non-trivial fake implementation of an -interface. For example: - -``` -class Foo { - public: - virtual ~Foo() {} - virtual char DoThis(int n) = 0; - virtual void DoThat(const char* s, int* p) = 0; -}; - -class FakeFoo : public Foo { - public: - virtual char DoThis(int n) { - return (n > 0) ? '+' : - (n < 0) ? '-' : '0'; - } - - virtual void DoThat(const char* s, int* p) { - *p = strlen(s); - } -}; -``` - -Now you want to mock this interface such that you can set expectations -on it. However, you also want to use `FakeFoo` for the default -behavior, as duplicating it in the mock object is, well, a lot of -work. - -When you define the mock class using Google Mock, you can have it -delegate its default action to a fake class you already have, using -this pattern: - -``` -using ::testing::_; -using ::testing::Invoke; - -class MockFoo : public Foo { - public: - // Normal mock method definitions using Google Mock. - MOCK_METHOD1(DoThis, char(int n)); - MOCK_METHOD2(DoThat, void(const char* s, int* p)); - - // Delegates the default actions of the methods to a FakeFoo object. - // This must be called *before* the custom ON_CALL() statements. - void DelegateToFake() { - ON_CALL(*this, DoThis(_)) - .WillByDefault(Invoke(&fake_, &FakeFoo::DoThis)); - ON_CALL(*this, DoThat(_, _)) - .WillByDefault(Invoke(&fake_, &FakeFoo::DoThat)); - } - private: - FakeFoo fake_; // Keeps an instance of the fake in the mock. -}; -``` - -With that, you can use `MockFoo` in your tests as usual. Just remember -that if you don't explicitly set an action in an `ON_CALL()` or -`EXPECT_CALL()`, the fake will be called upon to do it: - -``` -using ::testing::_; - -TEST(AbcTest, Xyz) { - MockFoo foo; - foo.DelegateToFake(); // Enables the fake for delegation. - - // Put your ON_CALL(foo, ...)s here, if any. - - // No action specified, meaning to use the default action. - EXPECT_CALL(foo, DoThis(5)); - EXPECT_CALL(foo, DoThat(_, _)); - - int n = 0; - EXPECT_EQ('+', foo.DoThis(5)); // FakeFoo::DoThis() is invoked. - foo.DoThat("Hi", &n); // FakeFoo::DoThat() is invoked. - EXPECT_EQ(2, n); -} -``` - -**Some tips:** - - * If you want, you can still override the default action by providing your own `ON_CALL()` or using `.WillOnce()` / `.WillRepeatedly()` in `EXPECT_CALL()`. - * In `DelegateToFake()`, you only need to delegate the methods whose fake implementation you intend to use. - * The general technique discussed here works for overloaded methods, but you'll need to tell the compiler which version you mean. To disambiguate a mock function (the one you specify inside the parentheses of `ON_CALL()`), see the "Selecting Between Overloaded Functions" section on this page; to disambiguate a fake function (the one you place inside `Invoke()`), use a `static_cast` to specify the function's type. For instance, if class `Foo` has methods `char DoThis(int n)` and `bool DoThis(double x) const`, and you want to invoke the latter, you need to write `Invoke(&fake_, static_cast(&FakeFoo::DoThis))` instead of `Invoke(&fake_, &FakeFoo::DoThis)` (The strange-looking thing inside the angled brackets of `static_cast` is the type of a function pointer to the second `DoThis()` method.). - * Having to mix a mock and a fake is often a sign of something gone wrong. Perhaps you haven't got used to the interaction-based way of testing yet. Or perhaps your interface is taking on too many roles and should be split up. Therefore, **don't abuse this**. We would only recommend to do it as an intermediate step when you are refactoring your code. - -Regarding the tip on mixing a mock and a fake, here's an example on -why it may be a bad sign: Suppose you have a class `System` for -low-level system operations. In particular, it does file and I/O -operations. And suppose you want to test how your code uses `System` -to do I/O, and you just want the file operations to work normally. If -you mock out the entire `System` class, you'll have to provide a fake -implementation for the file operation part, which suggests that -`System` is taking on too many roles. - -Instead, you can define a `FileOps` interface and an `IOOps` interface -and split `System`'s functionalities into the two. Then you can mock -`IOOps` without mocking `FileOps`. - -## Delegating Calls to a Real Object ## - -When using testing doubles (mocks, fakes, stubs, and etc), sometimes -their behaviors will differ from those of the real objects. This -difference could be either intentional (as in simulating an error such -that you can test the error handling code) or unintentional. If your -mocks have different behaviors than the real objects by mistake, you -could end up with code that passes the tests but fails in production. - -You can use the _delegating-to-real_ technique to ensure that your -mock has the same behavior as the real object while retaining the -ability to validate calls. This technique is very similar to the -delegating-to-fake technique, the difference being that we use a real -object instead of a fake. Here's an example: - -``` -using ::testing::_; -using ::testing::AtLeast; -using ::testing::Invoke; - -class MockFoo : public Foo { - public: - MockFoo() { - // By default, all calls are delegated to the real object. - ON_CALL(*this, DoThis()) - .WillByDefault(Invoke(&real_, &Foo::DoThis)); - ON_CALL(*this, DoThat(_)) - .WillByDefault(Invoke(&real_, &Foo::DoThat)); - ... - } - MOCK_METHOD0(DoThis, ...); - MOCK_METHOD1(DoThat, ...); - ... - private: - Foo real_; -}; -... - - MockFoo mock; - - EXPECT_CALL(mock, DoThis()) - .Times(3); - EXPECT_CALL(mock, DoThat("Hi")) - .Times(AtLeast(1)); - ... use mock in test ... -``` - -With this, Google Mock will verify that your code made the right calls -(with the right arguments, in the right order, called the right number -of times, etc), and a real object will answer the calls (so the -behavior will be the same as in production). This gives you the best -of both worlds. - -## Delegating Calls to a Parent Class ## - -Ideally, you should code to interfaces, whose methods are all pure -virtual. In reality, sometimes you do need to mock a virtual method -that is not pure (i.e, it already has an implementation). For example: - -``` -class Foo { - public: - virtual ~Foo(); - - virtual void Pure(int n) = 0; - virtual int Concrete(const char* str) { ... } -}; - -class MockFoo : public Foo { - public: - // Mocking a pure method. - MOCK_METHOD1(Pure, void(int n)); - // Mocking a concrete method. Foo::Concrete() is shadowed. - MOCK_METHOD1(Concrete, int(const char* str)); -}; -``` - -Sometimes you may want to call `Foo::Concrete()` instead of -`MockFoo::Concrete()`. Perhaps you want to do it as part of a stub -action, or perhaps your test doesn't need to mock `Concrete()` at all -(but it would be oh-so painful to have to define a new mock class -whenever you don't need to mock one of its methods). - -The trick is to leave a back door in your mock class for accessing the -real methods in the base class: - -``` -class MockFoo : public Foo { - public: - // Mocking a pure method. - MOCK_METHOD1(Pure, void(int n)); - // Mocking a concrete method. Foo::Concrete() is shadowed. - MOCK_METHOD1(Concrete, int(const char* str)); - - // Use this to call Concrete() defined in Foo. - int FooConcrete(const char* str) { return Foo::Concrete(str); } -}; -``` - -Now, you can call `Foo::Concrete()` inside an action by: - -``` -using ::testing::_; -using ::testing::Invoke; -... - EXPECT_CALL(foo, Concrete(_)) - .WillOnce(Invoke(&foo, &MockFoo::FooConcrete)); -``` - -or tell the mock object that you don't want to mock `Concrete()`: - -``` -using ::testing::Invoke; -... - ON_CALL(foo, Concrete(_)) - .WillByDefault(Invoke(&foo, &MockFoo::FooConcrete)); -``` - -(Why don't we just write `Invoke(&foo, &Foo::Concrete)`? If you do -that, `MockFoo::Concrete()` will be called (and cause an infinite -recursion) since `Foo::Concrete()` is virtual. That's just how C++ -works.) - -# Using Matchers # - -## Matching Argument Values Exactly ## - -You can specify exactly which arguments a mock method is expecting: - -``` -using ::testing::Return; -... - EXPECT_CALL(foo, DoThis(5)) - .WillOnce(Return('a')); - EXPECT_CALL(foo, DoThat("Hello", bar)); -``` - -## Using Simple Matchers ## - -You can use matchers to match arguments that have a certain property: - -``` -using ::testing::Ge; -using ::testing::NotNull; -using ::testing::Return; -... - EXPECT_CALL(foo, DoThis(Ge(5))) // The argument must be >= 5. - .WillOnce(Return('a')); - EXPECT_CALL(foo, DoThat("Hello", NotNull())); - // The second argument must not be NULL. -``` - -A frequently used matcher is `_`, which matches anything: - -``` -using ::testing::_; -using ::testing::NotNull; -... - EXPECT_CALL(foo, DoThat(_, NotNull())); -``` - -## Combining Matchers ## - -You can build complex matchers from existing ones using `AllOf()`, -`AnyOf()`, and `Not()`: - -``` -using ::testing::AllOf; -using ::testing::Gt; -using ::testing::HasSubstr; -using ::testing::Ne; -using ::testing::Not; -... - // The argument must be > 5 and != 10. - EXPECT_CALL(foo, DoThis(AllOf(Gt(5), - Ne(10)))); - - // The first argument must not contain sub-string "blah". - EXPECT_CALL(foo, DoThat(Not(HasSubstr("blah")), - NULL)); -``` - -## Casting Matchers ## - -Google Mock matchers are statically typed, meaning that the compiler -can catch your mistake if you use a matcher of the wrong type (for -example, if you use `Eq(5)` to match a `string` argument). Good for -you! - -Sometimes, however, you know what you're doing and want the compiler -to give you some slack. One example is that you have a matcher for -`long` and the argument you want to match is `int`. While the two -types aren't exactly the same, there is nothing really wrong with -using a `Matcher` to match an `int` - after all, we can first -convert the `int` argument to a `long` before giving it to the -matcher. - -To support this need, Google Mock gives you the -`SafeMatcherCast(m)` function. It casts a matcher `m` to type -`Matcher`. To ensure safety, Google Mock checks that (let `U` be the -type `m` accepts): - - 1. Type `T` can be implicitly cast to type `U`; - 1. When both `T` and `U` are built-in arithmetic types (`bool`, integers, and floating-point numbers), the conversion from `T` to `U` is not lossy (in other words, any value representable by `T` can also be represented by `U`); and - 1. When `U` is a reference, `T` must also be a reference (as the underlying matcher may be interested in the address of the `U` value). - -The code won't compile if any of these conditions isn't met. - -Here's one example: - -``` -using ::testing::SafeMatcherCast; - -// A base class and a child class. -class Base { ... }; -class Derived : public Base { ... }; - -class MockFoo : public Foo { - public: - MOCK_METHOD1(DoThis, void(Derived* derived)); -}; -... - - MockFoo foo; - // m is a Matcher we got from somewhere. - EXPECT_CALL(foo, DoThis(SafeMatcherCast(m))); -``` - -If you find `SafeMatcherCast(m)` too limiting, you can use a similar -function `MatcherCast(m)`. The difference is that `MatcherCast` works -as long as you can `static_cast` type `T` to type `U`. - -`MatcherCast` essentially lets you bypass C++'s type system -(`static_cast` isn't always safe as it could throw away information, -for example), so be careful not to misuse/abuse it. - -## Selecting Between Overloaded Functions ## - -If you expect an overloaded function to be called, the compiler may -need some help on which overloaded version it is. - -To disambiguate functions overloaded on the const-ness of this object, -use the `Const()` argument wrapper. - -``` -using ::testing::ReturnRef; - -class MockFoo : public Foo { - ... - MOCK_METHOD0(GetBar, Bar&()); - MOCK_CONST_METHOD0(GetBar, const Bar&()); -}; -... - - MockFoo foo; - Bar bar1, bar2; - EXPECT_CALL(foo, GetBar()) // The non-const GetBar(). - .WillOnce(ReturnRef(bar1)); - EXPECT_CALL(Const(foo), GetBar()) // The const GetBar(). - .WillOnce(ReturnRef(bar2)); -``` - -(`Const()` is defined by Google Mock and returns a `const` reference -to its argument.) - -To disambiguate overloaded functions with the same number of arguments -but different argument types, you may need to specify the exact type -of a matcher, either by wrapping your matcher in `Matcher()`, or -using a matcher whose type is fixed (`TypedEq`, `An()`, -etc): - -``` -using ::testing::An; -using ::testing::Lt; -using ::testing::Matcher; -using ::testing::TypedEq; - -class MockPrinter : public Printer { - public: - MOCK_METHOD1(Print, void(int n)); - MOCK_METHOD1(Print, void(char c)); -}; - -TEST(PrinterTest, Print) { - MockPrinter printer; - - EXPECT_CALL(printer, Print(An())); // void Print(int); - EXPECT_CALL(printer, Print(Matcher(Lt(5)))); // void Print(int); - EXPECT_CALL(printer, Print(TypedEq('a'))); // void Print(char); - - printer.Print(3); - printer.Print(6); - printer.Print('a'); -} -``` - -## Performing Different Actions Based on the Arguments ## - -When a mock method is called, the _last_ matching expectation that's -still active will be selected (think "newer overrides older"). So, you -can make a method do different things depending on its argument values -like this: - -``` -using ::testing::_; -using ::testing::Lt; -using ::testing::Return; -... - // The default case. - EXPECT_CALL(foo, DoThis(_)) - .WillRepeatedly(Return('b')); - - // The more specific case. - EXPECT_CALL(foo, DoThis(Lt(5))) - .WillRepeatedly(Return('a')); -``` - -Now, if `foo.DoThis()` is called with a value less than 5, `'a'` will -be returned; otherwise `'b'` will be returned. - -## Matching Multiple Arguments as a Whole ## - -Sometimes it's not enough to match the arguments individually. For -example, we may want to say that the first argument must be less than -the second argument. The `With()` clause allows us to match -all arguments of a mock function as a whole. For example, - -``` -using ::testing::_; -using ::testing::Lt; -using ::testing::Ne; -... - EXPECT_CALL(foo, InRange(Ne(0), _)) - .With(Lt()); -``` - -says that the first argument of `InRange()` must not be 0, and must be -less than the second argument. - -The expression inside `With()` must be a matcher of type -`Matcher >`, where `A1`, ..., `An` are the -types of the function arguments. - -You can also write `AllArgs(m)` instead of `m` inside `.With()`. The -two forms are equivalent, but `.With(AllArgs(Lt()))` is more readable -than `.With(Lt())`. - -You can use `Args(m)` to match the `n` selected arguments -(as a tuple) against `m`. For example, - -``` -using ::testing::_; -using ::testing::AllOf; -using ::testing::Args; -using ::testing::Lt; -... - EXPECT_CALL(foo, Blah(_, _, _)) - .With(AllOf(Args<0, 1>(Lt()), Args<1, 2>(Lt()))); -``` - -says that `Blah()` will be called with arguments `x`, `y`, and `z` where -`x < y < z`. - -As a convenience and example, Google Mock provides some matchers for -2-tuples, including the `Lt()` matcher above. See the [CheatSheet](V1_7_CheatSheet.md) for -the complete list. - -Note that if you want to pass the arguments to a predicate of your own -(e.g. `.With(Args<0, 1>(Truly(&MyPredicate)))`), that predicate MUST be -written to take a `tr1::tuple` as its argument; Google Mock will pass the `n` -selected arguments as _one_ single tuple to the predicate. - -## Using Matchers as Predicates ## - -Have you noticed that a matcher is just a fancy predicate that also -knows how to describe itself? Many existing algorithms take predicates -as arguments (e.g. those defined in STL's `` header), and -it would be a shame if Google Mock matchers are not allowed to -participate. - -Luckily, you can use a matcher where a unary predicate functor is -expected by wrapping it inside the `Matches()` function. For example, - -``` -#include -#include - -std::vector v; -... -// How many elements in v are >= 10? -const int count = count_if(v.begin(), v.end(), Matches(Ge(10))); -``` - -Since you can build complex matchers from simpler ones easily using -Google Mock, this gives you a way to conveniently construct composite -predicates (doing the same using STL's `` header is just -painful). For example, here's a predicate that's satisfied by any -number that is >= 0, <= 100, and != 50: - -``` -Matches(AllOf(Ge(0), Le(100), Ne(50))) -``` - -## Using Matchers in Google Test Assertions ## - -Since matchers are basically predicates that also know how to describe -themselves, there is a way to take advantage of them in -[Google Test](http://code.google.com/p/googletest/) assertions. It's -called `ASSERT_THAT` and `EXPECT_THAT`: - -``` - ASSERT_THAT(value, matcher); // Asserts that value matches matcher. - EXPECT_THAT(value, matcher); // The non-fatal version. -``` - -For example, in a Google Test test you can write: - -``` -#include "gmock/gmock.h" - -using ::testing::AllOf; -using ::testing::Ge; -using ::testing::Le; -using ::testing::MatchesRegex; -using ::testing::StartsWith; -... - - EXPECT_THAT(Foo(), StartsWith("Hello")); - EXPECT_THAT(Bar(), MatchesRegex("Line \\d+")); - ASSERT_THAT(Baz(), AllOf(Ge(5), Le(10))); -``` - -which (as you can probably guess) executes `Foo()`, `Bar()`, and -`Baz()`, and verifies that: - - * `Foo()` returns a string that starts with `"Hello"`. - * `Bar()` returns a string that matches regular expression `"Line \\d+"`. - * `Baz()` returns a number in the range [5, 10]. - -The nice thing about these macros is that _they read like -English_. They generate informative messages too. For example, if the -first `EXPECT_THAT()` above fails, the message will be something like: - -``` -Value of: Foo() - Actual: "Hi, world!" -Expected: starts with "Hello" -``` - -**Credit:** The idea of `(ASSERT|EXPECT)_THAT` was stolen from the -[Hamcrest](http://code.google.com/p/hamcrest/) project, which adds -`assertThat()` to JUnit. - -## Using Predicates as Matchers ## - -Google Mock provides a built-in set of matchers. In case you find them -lacking, you can use an arbitray unary predicate function or functor -as a matcher - as long as the predicate accepts a value of the type -you want. You do this by wrapping the predicate inside the `Truly()` -function, for example: - -``` -using ::testing::Truly; - -int IsEven(int n) { return (n % 2) == 0 ? 1 : 0; } -... - - // Bar() must be called with an even number. - EXPECT_CALL(foo, Bar(Truly(IsEven))); -``` - -Note that the predicate function / functor doesn't have to return -`bool`. It works as long as the return value can be used as the -condition in statement `if (condition) ...`. - -## Matching Arguments that Are Not Copyable ## - -When you do an `EXPECT_CALL(mock_obj, Foo(bar))`, Google Mock saves -away a copy of `bar`. When `Foo()` is called later, Google Mock -compares the argument to `Foo()` with the saved copy of `bar`. This -way, you don't need to worry about `bar` being modified or destroyed -after the `EXPECT_CALL()` is executed. The same is true when you use -matchers like `Eq(bar)`, `Le(bar)`, and so on. - -But what if `bar` cannot be copied (i.e. has no copy constructor)? You -could define your own matcher function and use it with `Truly()`, as -the previous couple of recipes have shown. Or, you may be able to get -away from it if you can guarantee that `bar` won't be changed after -the `EXPECT_CALL()` is executed. Just tell Google Mock that it should -save a reference to `bar`, instead of a copy of it. Here's how: - -``` -using ::testing::Eq; -using ::testing::ByRef; -using ::testing::Lt; -... - // Expects that Foo()'s argument == bar. - EXPECT_CALL(mock_obj, Foo(Eq(ByRef(bar)))); - - // Expects that Foo()'s argument < bar. - EXPECT_CALL(mock_obj, Foo(Lt(ByRef(bar)))); -``` - -Remember: if you do this, don't change `bar` after the -`EXPECT_CALL()`, or the result is undefined. - -## Validating a Member of an Object ## - -Often a mock function takes a reference to object as an argument. When -matching the argument, you may not want to compare the entire object -against a fixed object, as that may be over-specification. Instead, -you may need to validate a certain member variable or the result of a -certain getter method of the object. You can do this with `Field()` -and `Property()`. More specifically, - -``` -Field(&Foo::bar, m) -``` - -is a matcher that matches a `Foo` object whose `bar` member variable -satisfies matcher `m`. - -``` -Property(&Foo::baz, m) -``` - -is a matcher that matches a `Foo` object whose `baz()` method returns -a value that satisfies matcher `m`. - -For example: - -| Expression | Description | -|:-----------------------------|:-----------------------------------| -| `Field(&Foo::number, Ge(3))` | Matches `x` where `x.number >= 3`. | -| `Property(&Foo::name, StartsWith("John "))` | Matches `x` where `x.name()` starts with `"John "`. | - -Note that in `Property(&Foo::baz, ...)`, method `baz()` must take no -argument and be declared as `const`. - -BTW, `Field()` and `Property()` can also match plain pointers to -objects. For instance, - -``` -Field(&Foo::number, Ge(3)) -``` - -matches a plain pointer `p` where `p->number >= 3`. If `p` is `NULL`, -the match will always fail regardless of the inner matcher. - -What if you want to validate more than one members at the same time? -Remember that there is `AllOf()`. - -## Validating the Value Pointed to by a Pointer Argument ## - -C++ functions often take pointers as arguments. You can use matchers -like `IsNull()`, `NotNull()`, and other comparison matchers to match a -pointer, but what if you want to make sure the value _pointed to_ by -the pointer, instead of the pointer itself, has a certain property? -Well, you can use the `Pointee(m)` matcher. - -`Pointee(m)` matches a pointer iff `m` matches the value the pointer -points to. For example: - -``` -using ::testing::Ge; -using ::testing::Pointee; -... - EXPECT_CALL(foo, Bar(Pointee(Ge(3)))); -``` - -expects `foo.Bar()` to be called with a pointer that points to a value -greater than or equal to 3. - -One nice thing about `Pointee()` is that it treats a `NULL` pointer as -a match failure, so you can write `Pointee(m)` instead of - -``` - AllOf(NotNull(), Pointee(m)) -``` - -without worrying that a `NULL` pointer will crash your test. - -Also, did we tell you that `Pointee()` works with both raw pointers -**and** smart pointers (`linked_ptr`, `shared_ptr`, `scoped_ptr`, and -etc)? - -What if you have a pointer to pointer? You guessed it - you can use -nested `Pointee()` to probe deeper inside the value. For example, -`Pointee(Pointee(Lt(3)))` matches a pointer that points to a pointer -that points to a number less than 3 (what a mouthful...). - -## Testing a Certain Property of an Object ## - -Sometimes you want to specify that an object argument has a certain -property, but there is no existing matcher that does this. If you want -good error messages, you should define a matcher. If you want to do it -quick and dirty, you could get away with writing an ordinary function. - -Let's say you have a mock function that takes an object of type `Foo`, -which has an `int bar()` method and an `int baz()` method, and you -want to constrain that the argument's `bar()` value plus its `baz()` -value is a given number. Here's how you can define a matcher to do it: - -``` -using ::testing::MatcherInterface; -using ::testing::MatchResultListener; - -class BarPlusBazEqMatcher : public MatcherInterface { - public: - explicit BarPlusBazEqMatcher(int expected_sum) - : expected_sum_(expected_sum) {} - - virtual bool MatchAndExplain(const Foo& foo, - MatchResultListener* listener) const { - return (foo.bar() + foo.baz()) == expected_sum_; - } - - virtual void DescribeTo(::std::ostream* os) const { - *os << "bar() + baz() equals " << expected_sum_; - } - - virtual void DescribeNegationTo(::std::ostream* os) const { - *os << "bar() + baz() does not equal " << expected_sum_; - } - private: - const int expected_sum_; -}; - -inline Matcher BarPlusBazEq(int expected_sum) { - return MakeMatcher(new BarPlusBazEqMatcher(expected_sum)); -} - -... - - EXPECT_CALL(..., DoThis(BarPlusBazEq(5)))...; -``` - -## Matching Containers ## - -Sometimes an STL container (e.g. list, vector, map, ...) is passed to -a mock function and you may want to validate it. Since most STL -containers support the `==` operator, you can write -`Eq(expected_container)` or simply `expected_container` to match a -container exactly. - -Sometimes, though, you may want to be more flexible (for example, the -first element must be an exact match, but the second element can be -any positive number, and so on). Also, containers used in tests often -have a small number of elements, and having to define the expected -container out-of-line is a bit of a hassle. - -You can use the `ElementsAre()` or `UnorderedElementsAre()` matcher in -such cases: - -``` -using ::testing::_; -using ::testing::ElementsAre; -using ::testing::Gt; -... - - MOCK_METHOD1(Foo, void(const vector& numbers)); -... - - EXPECT_CALL(mock, Foo(ElementsAre(1, Gt(0), _, 5))); -``` - -The above matcher says that the container must have 4 elements, which -must be 1, greater than 0, anything, and 5 respectively. - -If you instead write: - -``` -using ::testing::_; -using ::testing::Gt; -using ::testing::UnorderedElementsAre; -... - - MOCK_METHOD1(Foo, void(const vector& numbers)); -... - - EXPECT_CALL(mock, Foo(UnorderedElementsAre(1, Gt(0), _, 5))); -``` - -It means that the container must have 4 elements, which under some -permutation must be 1, greater than 0, anything, and 5 respectively. - -`ElementsAre()` and `UnorderedElementsAre()` are overloaded to take 0 -to 10 arguments. If more are needed, you can place them in a C-style -array and use `ElementsAreArray()` or `UnorderedElementsAreArray()` -instead: - -``` -using ::testing::ElementsAreArray; -... - - // ElementsAreArray accepts an array of element values. - const int expected_vector1[] = { 1, 5, 2, 4, ... }; - EXPECT_CALL(mock, Foo(ElementsAreArray(expected_vector1))); - - // Or, an array of element matchers. - Matcher expected_vector2 = { 1, Gt(2), _, 3, ... }; - EXPECT_CALL(mock, Foo(ElementsAreArray(expected_vector2))); -``` - -In case the array needs to be dynamically created (and therefore the -array size cannot be inferred by the compiler), you can give -`ElementsAreArray()` an additional argument to specify the array size: - -``` -using ::testing::ElementsAreArray; -... - int* const expected_vector3 = new int[count]; - ... fill expected_vector3 with values ... - EXPECT_CALL(mock, Foo(ElementsAreArray(expected_vector3, count))); -``` - -**Tips:** - - * `ElementsAre*()` can be used to match _any_ container that implements the STL iterator pattern (i.e. it has a `const_iterator` type and supports `begin()/end()`), not just the ones defined in STL. It will even work with container types yet to be written - as long as they follows the above pattern. - * You can use nested `ElementsAre*()` to match nested (multi-dimensional) containers. - * If the container is passed by pointer instead of by reference, just write `Pointee(ElementsAre*(...))`. - * The order of elements _matters_ for `ElementsAre*()`. Therefore don't use it with containers whose element order is undefined (e.g. `hash_map`). - -## Sharing Matchers ## - -Under the hood, a Google Mock matcher object consists of a pointer to -a ref-counted implementation object. Copying matchers is allowed and -very efficient, as only the pointer is copied. When the last matcher -that references the implementation object dies, the implementation -object will be deleted. - -Therefore, if you have some complex matcher that you want to use again -and again, there is no need to build it everytime. Just assign it to a -matcher variable and use that variable repeatedly! For example, - -``` - Matcher in_range = AllOf(Gt(5), Le(10)); - ... use in_range as a matcher in multiple EXPECT_CALLs ... -``` - -# Setting Expectations # - -## Knowing When to Expect ## - -`ON_CALL` is likely the single most under-utilized construct in Google Mock. - -There are basically two constructs for defining the behavior of a mock object: `ON_CALL` and `EXPECT_CALL`. The difference? `ON_CALL` defines what happens when a mock method is called, but _doesn't imply any expectation on the method being called._ `EXPECT_CALL` not only defines the behavior, but also sets an expectation that _the method will be called with the given arguments, for the given number of times_ (and _in the given order_ when you specify the order too). - -Since `EXPECT_CALL` does more, isn't it better than `ON_CALL`? Not really. Every `EXPECT_CALL` adds a constraint on the behavior of the code under test. Having more constraints than necessary is _baaad_ - even worse than not having enough constraints. - -This may be counter-intuitive. How could tests that verify more be worse than tests that verify less? Isn't verification the whole point of tests? - -The answer, lies in _what_ a test should verify. **A good test verifies the contract of the code.** If a test over-specifies, it doesn't leave enough freedom to the implementation. As a result, changing the implementation without breaking the contract (e.g. refactoring and optimization), which should be perfectly fine to do, can break such tests. Then you have to spend time fixing them, only to see them broken again the next time the implementation is changed. - -Keep in mind that one doesn't have to verify more than one property in one test. In fact, **it's a good style to verify only one thing in one test.** If you do that, a bug will likely break only one or two tests instead of dozens (which case would you rather debug?). If you are also in the habit of giving tests descriptive names that tell what they verify, you can often easily guess what's wrong just from the test log itself. - -So use `ON_CALL` by default, and only use `EXPECT_CALL` when you actually intend to verify that the call is made. For example, you may have a bunch of `ON_CALL`s in your test fixture to set the common mock behavior shared by all tests in the same group, and write (scarcely) different `EXPECT_CALL`s in different `TEST_F`s to verify different aspects of the code's behavior. Compared with the style where each `TEST` has many `EXPECT_CALL`s, this leads to tests that are more resilient to implementational changes (and thus less likely to require maintenance) and makes the intent of the tests more obvious (so they are easier to maintain when you do need to maintain them). - -## Ignoring Uninteresting Calls ## - -If you are not interested in how a mock method is called, just don't -say anything about it. In this case, if the method is ever called, -Google Mock will perform its default action to allow the test program -to continue. If you are not happy with the default action taken by -Google Mock, you can override it using `DefaultValue::Set()` -(described later in this document) or `ON_CALL()`. - -Please note that once you expressed interest in a particular mock -method (via `EXPECT_CALL()`), all invocations to it must match some -expectation. If this function is called but the arguments don't match -any `EXPECT_CALL()` statement, it will be an error. - -## Disallowing Unexpected Calls ## - -If a mock method shouldn't be called at all, explicitly say so: - -``` -using ::testing::_; -... - EXPECT_CALL(foo, Bar(_)) - .Times(0); -``` - -If some calls to the method are allowed, but the rest are not, just -list all the expected calls: - -``` -using ::testing::AnyNumber; -using ::testing::Gt; -... - EXPECT_CALL(foo, Bar(5)); - EXPECT_CALL(foo, Bar(Gt(10))) - .Times(AnyNumber()); -``` - -A call to `foo.Bar()` that doesn't match any of the `EXPECT_CALL()` -statements will be an error. - -## Expecting Ordered Calls ## - -Although an `EXPECT_CALL()` statement defined earlier takes precedence -when Google Mock tries to match a function call with an expectation, -by default calls don't have to happen in the order `EXPECT_CALL()` -statements are written. For example, if the arguments match the -matchers in the third `EXPECT_CALL()`, but not those in the first two, -then the third expectation will be used. - -If you would rather have all calls occur in the order of the -expectations, put the `EXPECT_CALL()` statements in a block where you -define a variable of type `InSequence`: - -``` - using ::testing::_; - using ::testing::InSequence; - - { - InSequence s; - - EXPECT_CALL(foo, DoThis(5)); - EXPECT_CALL(bar, DoThat(_)) - .Times(2); - EXPECT_CALL(foo, DoThis(6)); - } -``` - -In this example, we expect a call to `foo.DoThis(5)`, followed by two -calls to `bar.DoThat()` where the argument can be anything, which are -in turn followed by a call to `foo.DoThis(6)`. If a call occurred -out-of-order, Google Mock will report an error. - -## Expecting Partially Ordered Calls ## - -Sometimes requiring everything to occur in a predetermined order can -lead to brittle tests. For example, we may care about `A` occurring -before both `B` and `C`, but aren't interested in the relative order -of `B` and `C`. In this case, the test should reflect our real intent, -instead of being overly constraining. - -Google Mock allows you to impose an arbitrary DAG (directed acyclic -graph) on the calls. One way to express the DAG is to use the -[After](http://code.google.com/p/googlemock/wiki/V1_7_CheatSheet#The_After_Clause) clause of `EXPECT_CALL`. - -Another way is via the `InSequence()` clause (not the same as the -`InSequence` class), which we borrowed from jMock 2. It's less -flexible than `After()`, but more convenient when you have long chains -of sequential calls, as it doesn't require you to come up with -different names for the expectations in the chains. Here's how it -works: - -If we view `EXPECT_CALL()` statements as nodes in a graph, and add an -edge from node A to node B wherever A must occur before B, we can get -a DAG. We use the term "sequence" to mean a directed path in this -DAG. Now, if we decompose the DAG into sequences, we just need to know -which sequences each `EXPECT_CALL()` belongs to in order to be able to -reconstruct the orginal DAG. - -So, to specify the partial order on the expectations we need to do two -things: first to define some `Sequence` objects, and then for each -`EXPECT_CALL()` say which `Sequence` objects it is part -of. Expectations in the same sequence must occur in the order they are -written. For example, - -``` - using ::testing::Sequence; - - Sequence s1, s2; - - EXPECT_CALL(foo, A()) - .InSequence(s1, s2); - EXPECT_CALL(bar, B()) - .InSequence(s1); - EXPECT_CALL(bar, C()) - .InSequence(s2); - EXPECT_CALL(foo, D()) - .InSequence(s2); -``` - -specifies the following DAG (where `s1` is `A -> B`, and `s2` is `A -> -C -> D`): - -``` - +---> B - | - A ---| - | - +---> C ---> D -``` - -This means that A must occur before B and C, and C must occur before -D. There's no restriction about the order other than these. - -## Controlling When an Expectation Retires ## - -When a mock method is called, Google Mock only consider expectations -that are still active. An expectation is active when created, and -becomes inactive (aka _retires_) when a call that has to occur later -has occurred. For example, in - -``` - using ::testing::_; - using ::testing::Sequence; - - Sequence s1, s2; - - EXPECT_CALL(log, Log(WARNING, _, "File too large.")) // #1 - .Times(AnyNumber()) - .InSequence(s1, s2); - EXPECT_CALL(log, Log(WARNING, _, "Data set is empty.")) // #2 - .InSequence(s1); - EXPECT_CALL(log, Log(WARNING, _, "User not found.")) // #3 - .InSequence(s2); -``` - -as soon as either #2 or #3 is matched, #1 will retire. If a warning -`"File too large."` is logged after this, it will be an error. - -Note that an expectation doesn't retire automatically when it's -saturated. For example, - -``` -using ::testing::_; -... - EXPECT_CALL(log, Log(WARNING, _, _)); // #1 - EXPECT_CALL(log, Log(WARNING, _, "File too large.")); // #2 -``` - -says that there will be exactly one warning with the message `"File -too large."`. If the second warning contains this message too, #2 will -match again and result in an upper-bound-violated error. - -If this is not what you want, you can ask an expectation to retire as -soon as it becomes saturated: - -``` -using ::testing::_; -... - EXPECT_CALL(log, Log(WARNING, _, _)); // #1 - EXPECT_CALL(log, Log(WARNING, _, "File too large.")) // #2 - .RetiresOnSaturation(); -``` - -Here #2 can be used only once, so if you have two warnings with the -message `"File too large."`, the first will match #2 and the second -will match #1 - there will be no error. - -# Using Actions # - -## Returning References from Mock Methods ## - -If a mock function's return type is a reference, you need to use -`ReturnRef()` instead of `Return()` to return a result: - -``` -using ::testing::ReturnRef; - -class MockFoo : public Foo { - public: - MOCK_METHOD0(GetBar, Bar&()); -}; -... - - MockFoo foo; - Bar bar; - EXPECT_CALL(foo, GetBar()) - .WillOnce(ReturnRef(bar)); -``` - -## Returning Live Values from Mock Methods ## - -The `Return(x)` action saves a copy of `x` when the action is -_created_, and always returns the same value whenever it's -executed. Sometimes you may want to instead return the _live_ value of -`x` (i.e. its value at the time when the action is _executed_.). - -If the mock function's return type is a reference, you can do it using -`ReturnRef(x)`, as shown in the previous recipe ("Returning References -from Mock Methods"). However, Google Mock doesn't let you use -`ReturnRef()` in a mock function whose return type is not a reference, -as doing that usually indicates a user error. So, what shall you do? - -You may be tempted to try `ByRef()`: - -``` -using testing::ByRef; -using testing::Return; - -class MockFoo : public Foo { - public: - MOCK_METHOD0(GetValue, int()); -}; -... - int x = 0; - MockFoo foo; - EXPECT_CALL(foo, GetValue()) - .WillRepeatedly(Return(ByRef(x))); - x = 42; - EXPECT_EQ(42, foo.GetValue()); -``` - -Unfortunately, it doesn't work here. The above code will fail with error: - -``` -Value of: foo.GetValue() - Actual: 0 -Expected: 42 -``` - -The reason is that `Return(value)` converts `value` to the actual -return type of the mock function at the time when the action is -_created_, not when it is _executed_. (This behavior was chosen for -the action to be safe when `value` is a proxy object that references -some temporary objects.) As a result, `ByRef(x)` is converted to an -`int` value (instead of a `const int&`) when the expectation is set, -and `Return(ByRef(x))` will always return 0. - -`ReturnPointee(pointer)` was provided to solve this problem -specifically. It returns the value pointed to by `pointer` at the time -the action is _executed_: - -``` -using testing::ReturnPointee; -... - int x = 0; - MockFoo foo; - EXPECT_CALL(foo, GetValue()) - .WillRepeatedly(ReturnPointee(&x)); // Note the & here. - x = 42; - EXPECT_EQ(42, foo.GetValue()); // This will succeed now. -``` - -## Combining Actions ## - -Want to do more than one thing when a function is called? That's -fine. `DoAll()` allow you to do sequence of actions every time. Only -the return value of the last action in the sequence will be used. - -``` -using ::testing::DoAll; - -class MockFoo : public Foo { - public: - MOCK_METHOD1(Bar, bool(int n)); -}; -... - - EXPECT_CALL(foo, Bar(_)) - .WillOnce(DoAll(action_1, - action_2, - ... - action_n)); -``` - -## Mocking Side Effects ## - -Sometimes a method exhibits its effect not via returning a value but -via side effects. For example, it may change some global state or -modify an output argument. To mock side effects, in general you can -define your own action by implementing `::testing::ActionInterface`. - -If all you need to do is to change an output argument, the built-in -`SetArgPointee()` action is convenient: - -``` -using ::testing::SetArgPointee; - -class MockMutator : public Mutator { - public: - MOCK_METHOD2(Mutate, void(bool mutate, int* value)); - ... -}; -... - - MockMutator mutator; - EXPECT_CALL(mutator, Mutate(true, _)) - .WillOnce(SetArgPointee<1>(5)); -``` - -In this example, when `mutator.Mutate()` is called, we will assign 5 -to the `int` variable pointed to by argument #1 -(0-based). - -`SetArgPointee()` conveniently makes an internal copy of the -value you pass to it, removing the need to keep the value in scope and -alive. The implication however is that the value must have a copy -constructor and assignment operator. - -If the mock method also needs to return a value as well, you can chain -`SetArgPointee()` with `Return()` using `DoAll()`: - -``` -using ::testing::_; -using ::testing::Return; -using ::testing::SetArgPointee; - -class MockMutator : public Mutator { - public: - ... - MOCK_METHOD1(MutateInt, bool(int* value)); -}; -... - - MockMutator mutator; - EXPECT_CALL(mutator, MutateInt(_)) - .WillOnce(DoAll(SetArgPointee<0>(5), - Return(true))); -``` - -If the output argument is an array, use the -`SetArrayArgument(first, last)` action instead. It copies the -elements in source range `[first, last)` to the array pointed to by -the `N`-th (0-based) argument: - -``` -using ::testing::NotNull; -using ::testing::SetArrayArgument; - -class MockArrayMutator : public ArrayMutator { - public: - MOCK_METHOD2(Mutate, void(int* values, int num_values)); - ... -}; -... - - MockArrayMutator mutator; - int values[5] = { 1, 2, 3, 4, 5 }; - EXPECT_CALL(mutator, Mutate(NotNull(), 5)) - .WillOnce(SetArrayArgument<0>(values, values + 5)); -``` - -This also works when the argument is an output iterator: - -``` -using ::testing::_; -using ::testing::SeArrayArgument; - -class MockRolodex : public Rolodex { - public: - MOCK_METHOD1(GetNames, void(std::back_insert_iterator >)); - ... -}; -... - - MockRolodex rolodex; - vector names; - names.push_back("George"); - names.push_back("John"); - names.push_back("Thomas"); - EXPECT_CALL(rolodex, GetNames(_)) - .WillOnce(SetArrayArgument<0>(names.begin(), names.end())); -``` - -## Changing a Mock Object's Behavior Based on the State ## - -If you expect a call to change the behavior of a mock object, you can use `::testing::InSequence` to specify different behaviors before and after the call: - -``` -using ::testing::InSequence; -using ::testing::Return; - -... - { - InSequence seq; - EXPECT_CALL(my_mock, IsDirty()) - .WillRepeatedly(Return(true)); - EXPECT_CALL(my_mock, Flush()); - EXPECT_CALL(my_mock, IsDirty()) - .WillRepeatedly(Return(false)); - } - my_mock.FlushIfDirty(); -``` - -This makes `my_mock.IsDirty()` return `true` before `my_mock.Flush()` is called and return `false` afterwards. - -If the behavior change is more complex, you can store the effects in a variable and make a mock method get its return value from that variable: - -``` -using ::testing::_; -using ::testing::SaveArg; -using ::testing::Return; - -ACTION_P(ReturnPointee, p) { return *p; } -... - int previous_value = 0; - EXPECT_CALL(my_mock, GetPrevValue()) - .WillRepeatedly(ReturnPointee(&previous_value)); - EXPECT_CALL(my_mock, UpdateValue(_)) - .WillRepeatedly(SaveArg<0>(&previous_value)); - my_mock.DoSomethingToUpdateValue(); -``` - -Here `my_mock.GetPrevValue()` will always return the argument of the last `UpdateValue()` call. - -## Setting the Default Value for a Return Type ## - -If a mock method's return type is a built-in C++ type or pointer, by -default it will return 0 when invoked. You only need to specify an -action if this default value doesn't work for you. - -Sometimes, you may want to change this default value, or you may want -to specify a default value for types Google Mock doesn't know -about. You can do this using the `::testing::DefaultValue` class -template: - -``` -class MockFoo : public Foo { - public: - MOCK_METHOD0(CalculateBar, Bar()); -}; -... - - Bar default_bar; - // Sets the default return value for type Bar. - DefaultValue::Set(default_bar); - - MockFoo foo; - - // We don't need to specify an action here, as the default - // return value works for us. - EXPECT_CALL(foo, CalculateBar()); - - foo.CalculateBar(); // This should return default_bar. - - // Unsets the default return value. - DefaultValue::Clear(); -``` - -Please note that changing the default value for a type can make you -tests hard to understand. We recommend you to use this feature -judiciously. For example, you may want to make sure the `Set()` and -`Clear()` calls are right next to the code that uses your mock. - -## Setting the Default Actions for a Mock Method ## - -You've learned how to change the default value of a given -type. However, this may be too coarse for your purpose: perhaps you -have two mock methods with the same return type and you want them to -have different behaviors. The `ON_CALL()` macro allows you to -customize your mock's behavior at the method level: - -``` -using ::testing::_; -using ::testing::AnyNumber; -using ::testing::Gt; -using ::testing::Return; -... - ON_CALL(foo, Sign(_)) - .WillByDefault(Return(-1)); - ON_CALL(foo, Sign(0)) - .WillByDefault(Return(0)); - ON_CALL(foo, Sign(Gt(0))) - .WillByDefault(Return(1)); - - EXPECT_CALL(foo, Sign(_)) - .Times(AnyNumber()); - - foo.Sign(5); // This should return 1. - foo.Sign(-9); // This should return -1. - foo.Sign(0); // This should return 0. -``` - -As you may have guessed, when there are more than one `ON_CALL()` -statements, the news order take precedence over the older ones. In -other words, the **last** one that matches the function arguments will -be used. This matching order allows you to set up the common behavior -in a mock object's constructor or the test fixture's set-up phase and -specialize the mock's behavior later. - -## Using Functions/Methods/Functors as Actions ## - -If the built-in actions don't suit you, you can easily use an existing -function, method, or functor as an action: - -``` -using ::testing::_; -using ::testing::Invoke; - -class MockFoo : public Foo { - public: - MOCK_METHOD2(Sum, int(int x, int y)); - MOCK_METHOD1(ComplexJob, bool(int x)); -}; - -int CalculateSum(int x, int y) { return x + y; } - -class Helper { - public: - bool ComplexJob(int x); -}; -... - - MockFoo foo; - Helper helper; - EXPECT_CALL(foo, Sum(_, _)) - .WillOnce(Invoke(CalculateSum)); - EXPECT_CALL(foo, ComplexJob(_)) - .WillOnce(Invoke(&helper, &Helper::ComplexJob)); - - foo.Sum(5, 6); // Invokes CalculateSum(5, 6). - foo.ComplexJob(10); // Invokes helper.ComplexJob(10); -``` - -The only requirement is that the type of the function, etc must be -_compatible_ with the signature of the mock function, meaning that the -latter's arguments can be implicitly converted to the corresponding -arguments of the former, and the former's return type can be -implicitly converted to that of the latter. So, you can invoke -something whose type is _not_ exactly the same as the mock function, -as long as it's safe to do so - nice, huh? - -## Invoking a Function/Method/Functor Without Arguments ## - -`Invoke()` is very useful for doing actions that are more complex. It -passes the mock function's arguments to the function or functor being -invoked such that the callee has the full context of the call to work -with. If the invoked function is not interested in some or all of the -arguments, it can simply ignore them. - -Yet, a common pattern is that a test author wants to invoke a function -without the arguments of the mock function. `Invoke()` allows her to -do that using a wrapper function that throws away the arguments before -invoking an underlining nullary function. Needless to say, this can be -tedious and obscures the intent of the test. - -`InvokeWithoutArgs()` solves this problem. It's like `Invoke()` except -that it doesn't pass the mock function's arguments to the -callee. Here's an example: - -``` -using ::testing::_; -using ::testing::InvokeWithoutArgs; - -class MockFoo : public Foo { - public: - MOCK_METHOD1(ComplexJob, bool(int n)); -}; - -bool Job1() { ... } -... - - MockFoo foo; - EXPECT_CALL(foo, ComplexJob(_)) - .WillOnce(InvokeWithoutArgs(Job1)); - - foo.ComplexJob(10); // Invokes Job1(). -``` - -## Invoking an Argument of the Mock Function ## - -Sometimes a mock function will receive a function pointer or a functor -(in other words, a "callable") as an argument, e.g. - -``` -class MockFoo : public Foo { - public: - MOCK_METHOD2(DoThis, bool(int n, bool (*fp)(int))); -}; -``` - -and you may want to invoke this callable argument: - -``` -using ::testing::_; -... - MockFoo foo; - EXPECT_CALL(foo, DoThis(_, _)) - .WillOnce(...); - // Will execute (*fp)(5), where fp is the - // second argument DoThis() receives. -``` - -Arghh, you need to refer to a mock function argument but your version -of C++ has no lambdas, so you have to define your own action. :-( -Or do you really? - -Well, Google Mock has an action to solve _exactly_ this problem: - -``` - InvokeArgument(arg_1, arg_2, ..., arg_m) -``` - -will invoke the `N`-th (0-based) argument the mock function receives, -with `arg_1`, `arg_2`, ..., and `arg_m`. No matter if the argument is -a function pointer or a functor, Google Mock handles them both. - -With that, you could write: - -``` -using ::testing::_; -using ::testing::InvokeArgument; -... - EXPECT_CALL(foo, DoThis(_, _)) - .WillOnce(InvokeArgument<1>(5)); - // Will execute (*fp)(5), where fp is the - // second argument DoThis() receives. -``` - -What if the callable takes an argument by reference? No problem - just -wrap it inside `ByRef()`: - -``` -... - MOCK_METHOD1(Bar, bool(bool (*fp)(int, const Helper&))); -... -using ::testing::_; -using ::testing::ByRef; -using ::testing::InvokeArgument; -... - - MockFoo foo; - Helper helper; - ... - EXPECT_CALL(foo, Bar(_)) - .WillOnce(InvokeArgument<0>(5, ByRef(helper))); - // ByRef(helper) guarantees that a reference to helper, not a copy of it, - // will be passed to the callable. -``` - -What if the callable takes an argument by reference and we do **not** -wrap the argument in `ByRef()`? Then `InvokeArgument()` will _make a -copy_ of the argument, and pass a _reference to the copy_, instead of -a reference to the original value, to the callable. This is especially -handy when the argument is a temporary value: - -``` -... - MOCK_METHOD1(DoThat, bool(bool (*f)(const double& x, const string& s))); -... -using ::testing::_; -using ::testing::InvokeArgument; -... - - MockFoo foo; - ... - EXPECT_CALL(foo, DoThat(_)) - .WillOnce(InvokeArgument<0>(5.0, string("Hi"))); - // Will execute (*f)(5.0, string("Hi")), where f is the function pointer - // DoThat() receives. Note that the values 5.0 and string("Hi") are - // temporary and dead once the EXPECT_CALL() statement finishes. Yet - // it's fine to perform this action later, since a copy of the values - // are kept inside the InvokeArgument action. -``` - -## Ignoring an Action's Result ## - -Sometimes you have an action that returns _something_, but you need an -action that returns `void` (perhaps you want to use it in a mock -function that returns `void`, or perhaps it needs to be used in -`DoAll()` and it's not the last in the list). `IgnoreResult()` lets -you do that. For example: - -``` -using ::testing::_; -using ::testing::Invoke; -using ::testing::Return; - -int Process(const MyData& data); -string DoSomething(); - -class MockFoo : public Foo { - public: - MOCK_METHOD1(Abc, void(const MyData& data)); - MOCK_METHOD0(Xyz, bool()); -}; -... - - MockFoo foo; - EXPECT_CALL(foo, Abc(_)) - // .WillOnce(Invoke(Process)); - // The above line won't compile as Process() returns int but Abc() needs - // to return void. - .WillOnce(IgnoreResult(Invoke(Process))); - - EXPECT_CALL(foo, Xyz()) - .WillOnce(DoAll(IgnoreResult(Invoke(DoSomething)), - // Ignores the string DoSomething() returns. - Return(true))); -``` - -Note that you **cannot** use `IgnoreResult()` on an action that already -returns `void`. Doing so will lead to ugly compiler errors. - -## Selecting an Action's Arguments ## - -Say you have a mock function `Foo()` that takes seven arguments, and -you have a custom action that you want to invoke when `Foo()` is -called. Trouble is, the custom action only wants three arguments: - -``` -using ::testing::_; -using ::testing::Invoke; -... - MOCK_METHOD7(Foo, bool(bool visible, const string& name, int x, int y, - const map, double>& weight, - double min_weight, double max_wight)); -... - -bool IsVisibleInQuadrant1(bool visible, int x, int y) { - return visible && x >= 0 && y >= 0; -} -... - - EXPECT_CALL(mock, Foo(_, _, _, _, _, _, _)) - .WillOnce(Invoke(IsVisibleInQuadrant1)); // Uh, won't compile. :-( -``` - -To please the compiler God, you can to define an "adaptor" that has -the same signature as `Foo()` and calls the custom action with the -right arguments: - -``` -using ::testing::_; -using ::testing::Invoke; - -bool MyIsVisibleInQuadrant1(bool visible, const string& name, int x, int y, - const map, double>& weight, - double min_weight, double max_wight) { - return IsVisibleInQuadrant1(visible, x, y); -} -... - - EXPECT_CALL(mock, Foo(_, _, _, _, _, _, _)) - .WillOnce(Invoke(MyIsVisibleInQuadrant1)); // Now it works. -``` - -But isn't this awkward? - -Google Mock provides a generic _action adaptor_, so you can spend your -time minding more important business than writing your own -adaptors. Here's the syntax: - -``` - WithArgs(action) -``` - -creates an action that passes the arguments of the mock function at -the given indices (0-based) to the inner `action` and performs -it. Using `WithArgs`, our original example can be written as: - -``` -using ::testing::_; -using ::testing::Invoke; -using ::testing::WithArgs; -... - EXPECT_CALL(mock, Foo(_, _, _, _, _, _, _)) - .WillOnce(WithArgs<0, 2, 3>(Invoke(IsVisibleInQuadrant1))); - // No need to define your own adaptor. -``` - -For better readability, Google Mock also gives you: - - * `WithoutArgs(action)` when the inner `action` takes _no_ argument, and - * `WithArg(action)` (no `s` after `Arg`) when the inner `action` takes _one_ argument. - -As you may have realized, `InvokeWithoutArgs(...)` is just syntactic -sugar for `WithoutArgs(Inovke(...))`. - -Here are more tips: - - * The inner action used in `WithArgs` and friends does not have to be `Invoke()` -- it can be anything. - * You can repeat an argument in the argument list if necessary, e.g. `WithArgs<2, 3, 3, 5>(...)`. - * You can change the order of the arguments, e.g. `WithArgs<3, 2, 1>(...)`. - * The types of the selected arguments do _not_ have to match the signature of the inner action exactly. It works as long as they can be implicitly converted to the corresponding arguments of the inner action. For example, if the 4-th argument of the mock function is an `int` and `my_action` takes a `double`, `WithArg<4>(my_action)` will work. - -## Ignoring Arguments in Action Functions ## - -The selecting-an-action's-arguments recipe showed us one way to make a -mock function and an action with incompatible argument lists fit -together. The downside is that wrapping the action in -`WithArgs<...>()` can get tedious for people writing the tests. - -If you are defining a function, method, or functor to be used with -`Invoke*()`, and you are not interested in some of its arguments, an -alternative to `WithArgs` is to declare the uninteresting arguments as -`Unused`. This makes the definition less cluttered and less fragile in -case the types of the uninteresting arguments change. It could also -increase the chance the action function can be reused. For example, -given - -``` - MOCK_METHOD3(Foo, double(const string& label, double x, double y)); - MOCK_METHOD3(Bar, double(int index, double x, double y)); -``` - -instead of - -``` -using ::testing::_; -using ::testing::Invoke; - -double DistanceToOriginWithLabel(const string& label, double x, double y) { - return sqrt(x*x + y*y); -} - -double DistanceToOriginWithIndex(int index, double x, double y) { - return sqrt(x*x + y*y); -} -... - - EXEPCT_CALL(mock, Foo("abc", _, _)) - .WillOnce(Invoke(DistanceToOriginWithLabel)); - EXEPCT_CALL(mock, Bar(5, _, _)) - .WillOnce(Invoke(DistanceToOriginWithIndex)); -``` - -you could write - -``` -using ::testing::_; -using ::testing::Invoke; -using ::testing::Unused; - -double DistanceToOrigin(Unused, double x, double y) { - return sqrt(x*x + y*y); -} -... - - EXEPCT_CALL(mock, Foo("abc", _, _)) - .WillOnce(Invoke(DistanceToOrigin)); - EXEPCT_CALL(mock, Bar(5, _, _)) - .WillOnce(Invoke(DistanceToOrigin)); -``` - -## Sharing Actions ## - -Just like matchers, a Google Mock action object consists of a pointer -to a ref-counted implementation object. Therefore copying actions is -also allowed and very efficient. When the last action that references -the implementation object dies, the implementation object will be -deleted. - -If you have some complex action that you want to use again and again, -you may not have to build it from scratch everytime. If the action -doesn't have an internal state (i.e. if it always does the same thing -no matter how many times it has been called), you can assign it to an -action variable and use that variable repeatedly. For example: - -``` - Action set_flag = DoAll(SetArgPointee<0>(5), - Return(true)); - ... use set_flag in .WillOnce() and .WillRepeatedly() ... -``` - -However, if the action has its own state, you may be surprised if you -share the action object. Suppose you have an action factory -`IncrementCounter(init)` which creates an action that increments and -returns a counter whose initial value is `init`, using two actions -created from the same expression and using a shared action will -exihibit different behaviors. Example: - -``` - EXPECT_CALL(foo, DoThis()) - .WillRepeatedly(IncrementCounter(0)); - EXPECT_CALL(foo, DoThat()) - .WillRepeatedly(IncrementCounter(0)); - foo.DoThis(); // Returns 1. - foo.DoThis(); // Returns 2. - foo.DoThat(); // Returns 1 - Blah() uses a different - // counter than Bar()'s. -``` - -versus - -``` - Action increment = IncrementCounter(0); - - EXPECT_CALL(foo, DoThis()) - .WillRepeatedly(increment); - EXPECT_CALL(foo, DoThat()) - .WillRepeatedly(increment); - foo.DoThis(); // Returns 1. - foo.DoThis(); // Returns 2. - foo.DoThat(); // Returns 3 - the counter is shared. -``` - -# Misc Recipes on Using Google Mock # - -## Making the Compilation Faster ## - -Believe it or not, the _vast majority_ of the time spent on compiling -a mock class is in generating its constructor and destructor, as they -perform non-trivial tasks (e.g. verification of the -expectations). What's more, mock methods with different signatures -have different types and thus their constructors/destructors need to -be generated by the compiler separately. As a result, if you mock many -different types of methods, compiling your mock class can get really -slow. - -If you are experiencing slow compilation, you can move the definition -of your mock class' constructor and destructor out of the class body -and into a `.cpp` file. This way, even if you `#include` your mock -class in N files, the compiler only needs to generate its constructor -and destructor once, resulting in a much faster compilation. - -Let's illustrate the idea using an example. Here's the definition of a -mock class before applying this recipe: - -``` -// File mock_foo.h. -... -class MockFoo : public Foo { - public: - // Since we don't declare the constructor or the destructor, - // the compiler will generate them in every translation unit - // where this mock class is used. - - MOCK_METHOD0(DoThis, int()); - MOCK_METHOD1(DoThat, bool(const char* str)); - ... more mock methods ... -}; -``` - -After the change, it would look like: - -``` -// File mock_foo.h. -... -class MockFoo : public Foo { - public: - // The constructor and destructor are declared, but not defined, here. - MockFoo(); - virtual ~MockFoo(); - - MOCK_METHOD0(DoThis, int()); - MOCK_METHOD1(DoThat, bool(const char* str)); - ... more mock methods ... -}; -``` -and -``` -// File mock_foo.cpp. -#include "path/to/mock_foo.h" - -// The definitions may appear trivial, but the functions actually do a -// lot of things through the constructors/destructors of the member -// variables used to implement the mock methods. -MockFoo::MockFoo() {} -MockFoo::~MockFoo() {} -``` - -## Forcing a Verification ## - -When it's being destroyed, your friendly mock object will automatically -verify that all expectations on it have been satisfied, and will -generate [Google Test](http://code.google.com/p/googletest/) failures -if not. This is convenient as it leaves you with one less thing to -worry about. That is, unless you are not sure if your mock object will -be destroyed. - -How could it be that your mock object won't eventually be destroyed? -Well, it might be created on the heap and owned by the code you are -testing. Suppose there's a bug in that code and it doesn't delete the -mock object properly - you could end up with a passing test when -there's actually a bug. - -Using a heap checker is a good idea and can alleviate the concern, but -its implementation may not be 100% reliable. So, sometimes you do want -to _force_ Google Mock to verify a mock object before it is -(hopefully) destructed. You can do this with -`Mock::VerifyAndClearExpectations(&mock_object)`: - -``` -TEST(MyServerTest, ProcessesRequest) { - using ::testing::Mock; - - MockFoo* const foo = new MockFoo; - EXPECT_CALL(*foo, ...)...; - // ... other expectations ... - - // server now owns foo. - MyServer server(foo); - server.ProcessRequest(...); - - // In case that server's destructor will forget to delete foo, - // this will verify the expectations anyway. - Mock::VerifyAndClearExpectations(foo); -} // server is destroyed when it goes out of scope here. -``` - -**Tip:** The `Mock::VerifyAndClearExpectations()` function returns a -`bool` to indicate whether the verification was successful (`true` for -yes), so you can wrap that function call inside a `ASSERT_TRUE()` if -there is no point going further when the verification has failed. - -## Using Check Points ## - -Sometimes you may want to "reset" a mock object at various check -points in your test: at each check point, you verify that all existing -expectations on the mock object have been satisfied, and then you set -some new expectations on it as if it's newly created. This allows you -to work with a mock object in "phases" whose sizes are each -manageable. - -One such scenario is that in your test's `SetUp()` function, you may -want to put the object you are testing into a certain state, with the -help from a mock object. Once in the desired state, you want to clear -all expectations on the mock, such that in the `TEST_F` body you can -set fresh expectations on it. - -As you may have figured out, the `Mock::VerifyAndClearExpectations()` -function we saw in the previous recipe can help you here. Or, if you -are using `ON_CALL()` to set default actions on the mock object and -want to clear the default actions as well, use -`Mock::VerifyAndClear(&mock_object)` instead. This function does what -`Mock::VerifyAndClearExpectations(&mock_object)` does and returns the -same `bool`, **plus** it clears the `ON_CALL()` statements on -`mock_object` too. - -Another trick you can use to achieve the same effect is to put the -expectations in sequences and insert calls to a dummy "check-point" -function at specific places. Then you can verify that the mock -function calls do happen at the right time. For example, if you are -exercising code: - -``` -Foo(1); -Foo(2); -Foo(3); -``` - -and want to verify that `Foo(1)` and `Foo(3)` both invoke -`mock.Bar("a")`, but `Foo(2)` doesn't invoke anything. You can write: - -``` -using ::testing::MockFunction; - -TEST(FooTest, InvokesBarCorrectly) { - MyMock mock; - // Class MockFunction has exactly one mock method. It is named - // Call() and has type F. - MockFunction check; - { - InSequence s; - - EXPECT_CALL(mock, Bar("a")); - EXPECT_CALL(check, Call("1")); - EXPECT_CALL(check, Call("2")); - EXPECT_CALL(mock, Bar("a")); - } - Foo(1); - check.Call("1"); - Foo(2); - check.Call("2"); - Foo(3); -} -``` - -The expectation spec says that the first `Bar("a")` must happen before -check point "1", the second `Bar("a")` must happen after check point "2", -and nothing should happen between the two check points. The explicit -check points make it easy to tell which `Bar("a")` is called by which -call to `Foo()`. - -## Mocking Destructors ## - -Sometimes you want to make sure a mock object is destructed at the -right time, e.g. after `bar->A()` is called but before `bar->B()` is -called. We already know that you can specify constraints on the order -of mock function calls, so all we need to do is to mock the destructor -of the mock function. - -This sounds simple, except for one problem: a destructor is a special -function with special syntax and special semantics, and the -`MOCK_METHOD0` macro doesn't work for it: - -``` - MOCK_METHOD0(~MockFoo, void()); // Won't compile! -``` - -The good news is that you can use a simple pattern to achieve the same -effect. First, add a mock function `Die()` to your mock class and call -it in the destructor, like this: - -``` -class MockFoo : public Foo { - ... - // Add the following two lines to the mock class. - MOCK_METHOD0(Die, void()); - virtual ~MockFoo() { Die(); } -}; -``` - -(If the name `Die()` clashes with an existing symbol, choose another -name.) Now, we have translated the problem of testing when a `MockFoo` -object dies to testing when its `Die()` method is called: - -``` - MockFoo* foo = new MockFoo; - MockBar* bar = new MockBar; - ... - { - InSequence s; - - // Expects *foo to die after bar->A() and before bar->B(). - EXPECT_CALL(*bar, A()); - EXPECT_CALL(*foo, Die()); - EXPECT_CALL(*bar, B()); - } -``` - -And that's that. - -## Using Google Mock and Threads ## - -**IMPORTANT NOTE:** What we describe in this recipe is **ONLY** true on -platforms where Google Mock is thread-safe. Currently these are only -platforms that support the pthreads library (this includes Linux and Mac). -To make it thread-safe on other platforms we only need to implement -some synchronization operations in `"gtest/internal/gtest-port.h"`. - -In a **unit** test, it's best if you could isolate and test a piece of -code in a single-threaded context. That avoids race conditions and -dead locks, and makes debugging your test much easier. - -Yet many programs are multi-threaded, and sometimes to test something -we need to pound on it from more than one thread. Google Mock works -for this purpose too. - -Remember the steps for using a mock: - - 1. Create a mock object `foo`. - 1. Set its default actions and expectations using `ON_CALL()` and `EXPECT_CALL()`. - 1. The code under test calls methods of `foo`. - 1. Optionally, verify and reset the mock. - 1. Destroy the mock yourself, or let the code under test destroy it. The destructor will automatically verify it. - -If you follow the following simple rules, your mocks and threads can -live happily togeter: - - * Execute your _test code_ (as opposed to the code being tested) in _one_ thread. This makes your test easy to follow. - * Obviously, you can do step #1 without locking. - * When doing step #2 and #5, make sure no other thread is accessing `foo`. Obvious too, huh? - * #3 and #4 can be done either in one thread or in multiple threads - anyway you want. Google Mock takes care of the locking, so you don't have to do any - unless required by your test logic. - -If you violate the rules (for example, if you set expectations on a -mock while another thread is calling its methods), you get undefined -behavior. That's not fun, so don't do it. - -Google Mock guarantees that the action for a mock function is done in -the same thread that called the mock function. For example, in - -``` - EXPECT_CALL(mock, Foo(1)) - .WillOnce(action1); - EXPECT_CALL(mock, Foo(2)) - .WillOnce(action2); -``` - -if `Foo(1)` is called in thread 1 and `Foo(2)` is called in thread 2, -Google Mock will execute `action1` in thread 1 and `action2` in thread -2. - -Google Mock does _not_ impose a sequence on actions performed in -different threads (doing so may create deadlocks as the actions may -need to cooperate). This means that the execution of `action1` and -`action2` in the above example _may_ interleave. If this is a problem, -you should add proper synchronization logic to `action1` and `action2` -to make the test thread-safe. - - -Also, remember that `DefaultValue` is a global resource that -potentially affects _all_ living mock objects in your -program. Naturally, you won't want to mess with it from multiple -threads or when there still are mocks in action. - -## Controlling How Much Information Google Mock Prints ## - -When Google Mock sees something that has the potential of being an -error (e.g. a mock function with no expectation is called, a.k.a. an -uninteresting call, which is allowed but perhaps you forgot to -explicitly ban the call), it prints some warning messages, including -the arguments of the function and the return value. Hopefully this -will remind you to take a look and see if there is indeed a problem. - -Sometimes you are confident that your tests are correct and may not -appreciate such friendly messages. Some other times, you are debugging -your tests or learning about the behavior of the code you are testing, -and wish you could observe every mock call that happens (including -argument values and the return value). Clearly, one size doesn't fit -all. - -You can control how much Google Mock tells you using the -`--gmock_verbose=LEVEL` command-line flag, where `LEVEL` is a string -with three possible values: - - * `info`: Google Mock will print all informational messages, warnings, and errors (most verbose). At this setting, Google Mock will also log any calls to the `ON_CALL/EXPECT_CALL` macros. - * `warning`: Google Mock will print both warnings and errors (less verbose). This is the default. - * `error`: Google Mock will print errors only (least verbose). - -Alternatively, you can adjust the value of that flag from within your -tests like so: - -``` - ::testing::FLAGS_gmock_verbose = "error"; -``` - -Now, judiciously use the right flag to enable Google Mock serve you better! - -## Gaining Super Vision into Mock Calls ## - -You have a test using Google Mock. It fails: Google Mock tells you -that some expectations aren't satisfied. However, you aren't sure why: -Is there a typo somewhere in the matchers? Did you mess up the order -of the `EXPECT_CALL`s? Or is the code under test doing something -wrong? How can you find out the cause? - -Won't it be nice if you have X-ray vision and can actually see the -trace of all `EXPECT_CALL`s and mock method calls as they are made? -For each call, would you like to see its actual argument values and -which `EXPECT_CALL` Google Mock thinks it matches? - -You can unlock this power by running your test with the -`--gmock_verbose=info` flag. For example, given the test program: - -``` -using testing::_; -using testing::HasSubstr; -using testing::Return; - -class MockFoo { - public: - MOCK_METHOD2(F, void(const string& x, const string& y)); -}; - -TEST(Foo, Bar) { - MockFoo mock; - EXPECT_CALL(mock, F(_, _)).WillRepeatedly(Return()); - EXPECT_CALL(mock, F("a", "b")); - EXPECT_CALL(mock, F("c", HasSubstr("d"))); - - mock.F("a", "good"); - mock.F("a", "b"); -} -``` - -if you run it with `--gmock_verbose=info`, you will see this output: - -``` -[ RUN ] Foo.Bar - -foo_test.cc:14: EXPECT_CALL(mock, F(_, _)) invoked -foo_test.cc:15: EXPECT_CALL(mock, F("a", "b")) invoked -foo_test.cc:16: EXPECT_CALL(mock, F("c", HasSubstr("d"))) invoked -foo_test.cc:14: Mock function call matches EXPECT_CALL(mock, F(_, _))... - Function call: F(@0x7fff7c8dad40"a", @0x7fff7c8dad10"good") -foo_test.cc:15: Mock function call matches EXPECT_CALL(mock, F("a", "b"))... - Function call: F(@0x7fff7c8dada0"a", @0x7fff7c8dad70"b") -foo_test.cc:16: Failure -Actual function call count doesn't match EXPECT_CALL(mock, F("c", HasSubstr("d")))... - Expected: to be called once - Actual: never called - unsatisfied and active -[ FAILED ] Foo.Bar -``` - -Suppose the bug is that the `"c"` in the third `EXPECT_CALL` is a typo -and should actually be `"a"`. With the above message, you should see -that the actual `F("a", "good")` call is matched by the first -`EXPECT_CALL`, not the third as you thought. From that it should be -obvious that the third `EXPECT_CALL` is written wrong. Case solved. - -## Running Tests in Emacs ## - -If you build and run your tests in Emacs, the source file locations of -Google Mock and [Google Test](http://code.google.com/p/googletest/) -errors will be highlighted. Just press `` on one of them and -you'll be taken to the offending line. Or, you can just type `C-x `` -to jump to the next error. - -To make it even easier, you can add the following lines to your -`~/.emacs` file: - -``` -(global-set-key "\M-m" 'compile) ; m is for make -(global-set-key [M-down] 'next-error) -(global-set-key [M-up] '(lambda () (interactive) (next-error -1))) -``` - -Then you can type `M-m` to start a build, or `M-up`/`M-down` to move -back and forth between errors. - -## Fusing Google Mock Source Files ## - -Google Mock's implementation consists of dozens of files (excluding -its own tests). Sometimes you may want them to be packaged up in -fewer files instead, such that you can easily copy them to a new -machine and start hacking there. For this we provide an experimental -Python script `fuse_gmock_files.py` in the `scripts/` directory -(starting with release 1.2.0). Assuming you have Python 2.4 or above -installed on your machine, just go to that directory and run -``` -python fuse_gmock_files.py OUTPUT_DIR -``` - -and you should see an `OUTPUT_DIR` directory being created with files -`gtest/gtest.h`, `gmock/gmock.h`, and `gmock-gtest-all.cc` in it. -These three files contain everything you need to use Google Mock (and -Google Test). Just copy them to anywhere you want and you are ready -to write tests and use mocks. You can use the -[scrpts/test/Makefile](http://code.google.com/p/googlemock/source/browse/trunk/scripts/test/Makefile) file as an example on how to compile your tests -against them. - -# Extending Google Mock # - -## Writing New Matchers Quickly ## - -The `MATCHER*` family of macros can be used to define custom matchers -easily. The syntax: - -``` -MATCHER(name, description_string_expression) { statements; } -``` - -will define a matcher with the given name that executes the -statements, which must return a `bool` to indicate if the match -succeeds. Inside the statements, you can refer to the value being -matched by `arg`, and refer to its type by `arg_type`. - -The description string is a `string`-typed expression that documents -what the matcher does, and is used to generate the failure message -when the match fails. It can (and should) reference the special -`bool` variable `negation`, and should evaluate to the description of -the matcher when `negation` is `false`, or that of the matcher's -negation when `negation` is `true`. - -For convenience, we allow the description string to be empty (`""`), -in which case Google Mock will use the sequence of words in the -matcher name as the description. - -For example: -``` -MATCHER(IsDivisibleBy7, "") { return (arg % 7) == 0; } -``` -allows you to write -``` - // Expects mock_foo.Bar(n) to be called where n is divisible by 7. - EXPECT_CALL(mock_foo, Bar(IsDivisibleBy7())); -``` -or, -``` -using ::testing::Not; -... - EXPECT_THAT(some_expression, IsDivisibleBy7()); - EXPECT_THAT(some_other_expression, Not(IsDivisibleBy7())); -``` -If the above assertions fail, they will print something like: -``` - Value of: some_expression - Expected: is divisible by 7 - Actual: 27 -... - Value of: some_other_expression - Expected: not (is divisible by 7) - Actual: 21 -``` -where the descriptions `"is divisible by 7"` and `"not (is divisible -by 7)"` are automatically calculated from the matcher name -`IsDivisibleBy7`. - -As you may have noticed, the auto-generated descriptions (especially -those for the negation) may not be so great. You can always override -them with a string expression of your own: -``` -MATCHER(IsDivisibleBy7, std::string(negation ? "isn't" : "is") + - " divisible by 7") { - return (arg % 7) == 0; -} -``` - -Optionally, you can stream additional information to a hidden argument -named `result_listener` to explain the match result. For example, a -better definition of `IsDivisibleBy7` is: -``` -MATCHER(IsDivisibleBy7, "") { - if ((arg % 7) == 0) - return true; - - *result_listener << "the remainder is " << (arg % 7); - return false; -} -``` - -With this definition, the above assertion will give a better message: -``` - Value of: some_expression - Expected: is divisible by 7 - Actual: 27 (the remainder is 6) -``` - -You should let `MatchAndExplain()` print _any additional information_ -that can help a user understand the match result. Note that it should -explain why the match succeeds in case of a success (unless it's -obvious) - this is useful when the matcher is used inside -`Not()`. There is no need to print the argument value itself, as -Google Mock already prints it for you. - -**Notes:** - - 1. The type of the value being matched (`arg_type`) is determined by the context in which you use the matcher and is supplied to you by the compiler, so you don't need to worry about declaring it (nor can you). This allows the matcher to be polymorphic. For example, `IsDivisibleBy7()` can be used to match any type where the value of `(arg % 7) == 0` can be implicitly converted to a `bool`. In the `Bar(IsDivisibleBy7())` example above, if method `Bar()` takes an `int`, `arg_type` will be `int`; if it takes an `unsigned long`, `arg_type` will be `unsigned long`; and so on. - 1. Google Mock doesn't guarantee when or how many times a matcher will be invoked. Therefore the matcher logic must be _purely functional_ (i.e. it cannot have any side effect, and the result must not depend on anything other than the value being matched and the matcher parameters). This requirement must be satisfied no matter how you define the matcher (e.g. using one of the methods described in the following recipes). In particular, a matcher can never call a mock function, as that will affect the state of the mock object and Google Mock. - -## Writing New Parameterized Matchers Quickly ## - -Sometimes you'll want to define a matcher that has parameters. For that you -can use the macro: -``` -MATCHER_P(name, param_name, description_string) { statements; } -``` -where the description string can be either `""` or a string expression -that references `negation` and `param_name`. - -For example: -``` -MATCHER_P(HasAbsoluteValue, value, "") { return abs(arg) == value; } -``` -will allow you to write: -``` - EXPECT_THAT(Blah("a"), HasAbsoluteValue(n)); -``` -which may lead to this message (assuming `n` is 10): -``` - Value of: Blah("a") - Expected: has absolute value 10 - Actual: -9 -``` - -Note that both the matcher description and its parameter are -printed, making the message human-friendly. - -In the matcher definition body, you can write `foo_type` to -reference the type of a parameter named `foo`. For example, in the -body of `MATCHER_P(HasAbsoluteValue, value)` above, you can write -`value_type` to refer to the type of `value`. - -Google Mock also provides `MATCHER_P2`, `MATCHER_P3`, ..., up to -`MATCHER_P10` to support multi-parameter matchers: -``` -MATCHER_Pk(name, param_1, ..., param_k, description_string) { statements; } -``` - -Please note that the custom description string is for a particular -**instance** of the matcher, where the parameters have been bound to -actual values. Therefore usually you'll want the parameter values to -be part of the description. Google Mock lets you do that by -referencing the matcher parameters in the description string -expression. - -For example, -``` - using ::testing::PrintToString; - MATCHER_P2(InClosedRange, low, hi, - std::string(negation ? "isn't" : "is") + " in range [" + - PrintToString(low) + ", " + PrintToString(hi) + "]") { - return low <= arg && arg <= hi; - } - ... - EXPECT_THAT(3, InClosedRange(4, 6)); -``` -would generate a failure that contains the message: -``` - Expected: is in range [4, 6] -``` - -If you specify `""` as the description, the failure message will -contain the sequence of words in the matcher name followed by the -parameter values printed as a tuple. For example, -``` - MATCHER_P2(InClosedRange, low, hi, "") { ... } - ... - EXPECT_THAT(3, InClosedRange(4, 6)); -``` -would generate a failure that contains the text: -``` - Expected: in closed range (4, 6) -``` - -For the purpose of typing, you can view -``` -MATCHER_Pk(Foo, p1, ..., pk, description_string) { ... } -``` -as shorthand for -``` -template -FooMatcherPk -Foo(p1_type p1, ..., pk_type pk) { ... } -``` - -When you write `Foo(v1, ..., vk)`, the compiler infers the types of -the parameters `v1`, ..., and `vk` for you. If you are not happy with -the result of the type inference, you can specify the types by -explicitly instantiating the template, as in `Foo(5, false)`. -As said earlier, you don't get to (or need to) specify -`arg_type` as that's determined by the context in which the matcher -is used. - -You can assign the result of expression `Foo(p1, ..., pk)` to a -variable of type `FooMatcherPk`. This can be -useful when composing matchers. Matchers that don't have a parameter -or have only one parameter have special types: you can assign `Foo()` -to a `FooMatcher`-typed variable, and assign `Foo(p)` to a -`FooMatcherP`-typed variable. - -While you can instantiate a matcher template with reference types, -passing the parameters by pointer usually makes your code more -readable. If, however, you still want to pass a parameter by -reference, be aware that in the failure message generated by the -matcher you will see the value of the referenced object but not its -address. - -You can overload matchers with different numbers of parameters: -``` -MATCHER_P(Blah, a, description_string_1) { ... } -MATCHER_P2(Blah, a, b, description_string_2) { ... } -``` - -While it's tempting to always use the `MATCHER*` macros when defining -a new matcher, you should also consider implementing -`MatcherInterface` or using `MakePolymorphicMatcher()` instead (see -the recipes that follow), especially if you need to use the matcher a -lot. While these approaches require more work, they give you more -control on the types of the value being matched and the matcher -parameters, which in general leads to better compiler error messages -that pay off in the long run. They also allow overloading matchers -based on parameter types (as opposed to just based on the number of -parameters). - -## Writing New Monomorphic Matchers ## - -A matcher of argument type `T` implements -`::testing::MatcherInterface` and does two things: it tests whether a -value of type `T` matches the matcher, and can describe what kind of -values it matches. The latter ability is used for generating readable -error messages when expectations are violated. - -The interface looks like this: - -``` -class MatchResultListener { - public: - ... - // Streams x to the underlying ostream; does nothing if the ostream - // is NULL. - template - MatchResultListener& operator<<(const T& x); - - // Returns the underlying ostream. - ::std::ostream* stream(); -}; - -template -class MatcherInterface { - public: - virtual ~MatcherInterface(); - - // Returns true iff the matcher matches x; also explains the match - // result to 'listener'. - virtual bool MatchAndExplain(T x, MatchResultListener* listener) const = 0; - - // Describes this matcher to an ostream. - virtual void DescribeTo(::std::ostream* os) const = 0; - - // Describes the negation of this matcher to an ostream. - virtual void DescribeNegationTo(::std::ostream* os) const; -}; -``` - -If you need a custom matcher but `Truly()` is not a good option (for -example, you may not be happy with the way `Truly(predicate)` -describes itself, or you may want your matcher to be polymorphic as -`Eq(value)` is), you can define a matcher to do whatever you want in -two steps: first implement the matcher interface, and then define a -factory function to create a matcher instance. The second step is not -strictly needed but it makes the syntax of using the matcher nicer. - -For example, you can define a matcher to test whether an `int` is -divisible by 7 and then use it like this: -``` -using ::testing::MakeMatcher; -using ::testing::Matcher; -using ::testing::MatcherInterface; -using ::testing::MatchResultListener; - -class DivisibleBy7Matcher : public MatcherInterface { - public: - virtual bool MatchAndExplain(int n, MatchResultListener* listener) const { - return (n % 7) == 0; - } - - virtual void DescribeTo(::std::ostream* os) const { - *os << "is divisible by 7"; - } - - virtual void DescribeNegationTo(::std::ostream* os) const { - *os << "is not divisible by 7"; - } -}; - -inline Matcher DivisibleBy7() { - return MakeMatcher(new DivisibleBy7Matcher); -} -... - - EXPECT_CALL(foo, Bar(DivisibleBy7())); -``` - -You may improve the matcher message by streaming additional -information to the `listener` argument in `MatchAndExplain()`: - -``` -class DivisibleBy7Matcher : public MatcherInterface { - public: - virtual bool MatchAndExplain(int n, - MatchResultListener* listener) const { - const int remainder = n % 7; - if (remainder != 0) { - *listener << "the remainder is " << remainder; - } - return remainder == 0; - } - ... -}; -``` - -Then, `EXPECT_THAT(x, DivisibleBy7());` may general a message like this: -``` -Value of: x -Expected: is divisible by 7 - Actual: 23 (the remainder is 2) -``` - -## Writing New Polymorphic Matchers ## - -You've learned how to write your own matchers in the previous -recipe. Just one problem: a matcher created using `MakeMatcher()` only -works for one particular type of arguments. If you want a -_polymorphic_ matcher that works with arguments of several types (for -instance, `Eq(x)` can be used to match a `value` as long as `value` == -`x` compiles -- `value` and `x` don't have to share the same type), -you can learn the trick from `"gmock/gmock-matchers.h"` but it's a bit -involved. - -Fortunately, most of the time you can define a polymorphic matcher -easily with the help of `MakePolymorphicMatcher()`. Here's how you can -define `NotNull()` as an example: - -``` -using ::testing::MakePolymorphicMatcher; -using ::testing::MatchResultListener; -using ::testing::NotNull; -using ::testing::PolymorphicMatcher; - -class NotNullMatcher { - public: - // To implement a polymorphic matcher, first define a COPYABLE class - // that has three members MatchAndExplain(), DescribeTo(), and - // DescribeNegationTo(), like the following. - - // In this example, we want to use NotNull() with any pointer, so - // MatchAndExplain() accepts a pointer of any type as its first argument. - // In general, you can define MatchAndExplain() as an ordinary method or - // a method template, or even overload it. - template - bool MatchAndExplain(T* p, - MatchResultListener* /* listener */) const { - return p != NULL; - } - - // Describes the property of a value matching this matcher. - void DescribeTo(::std::ostream* os) const { *os << "is not NULL"; } - - // Describes the property of a value NOT matching this matcher. - void DescribeNegationTo(::std::ostream* os) const { *os << "is NULL"; } -}; - -// To construct a polymorphic matcher, pass an instance of the class -// to MakePolymorphicMatcher(). Note the return type. -inline PolymorphicMatcher NotNull() { - return MakePolymorphicMatcher(NotNullMatcher()); -} -... - - EXPECT_CALL(foo, Bar(NotNull())); // The argument must be a non-NULL pointer. -``` - -**Note:** Your polymorphic matcher class does **not** need to inherit from -`MatcherInterface` or any other class, and its methods do **not** need -to be virtual. - -Like in a monomorphic matcher, you may explain the match result by -streaming additional information to the `listener` argument in -`MatchAndExplain()`. - -## Writing New Cardinalities ## - -A cardinality is used in `Times()` to tell Google Mock how many times -you expect a call to occur. It doesn't have to be exact. For example, -you can say `AtLeast(5)` or `Between(2, 4)`. - -If the built-in set of cardinalities doesn't suit you, you are free to -define your own by implementing the following interface (in namespace -`testing`): - -``` -class CardinalityInterface { - public: - virtual ~CardinalityInterface(); - - // Returns true iff call_count calls will satisfy this cardinality. - virtual bool IsSatisfiedByCallCount(int call_count) const = 0; - - // Returns true iff call_count calls will saturate this cardinality. - virtual bool IsSaturatedByCallCount(int call_count) const = 0; - - // Describes self to an ostream. - virtual void DescribeTo(::std::ostream* os) const = 0; -}; -``` - -For example, to specify that a call must occur even number of times, -you can write - -``` -using ::testing::Cardinality; -using ::testing::CardinalityInterface; -using ::testing::MakeCardinality; - -class EvenNumberCardinality : public CardinalityInterface { - public: - virtual bool IsSatisfiedByCallCount(int call_count) const { - return (call_count % 2) == 0; - } - - virtual bool IsSaturatedByCallCount(int call_count) const { - return false; - } - - virtual void DescribeTo(::std::ostream* os) const { - *os << "called even number of times"; - } -}; - -Cardinality EvenNumber() { - return MakeCardinality(new EvenNumberCardinality); -} -... - - EXPECT_CALL(foo, Bar(3)) - .Times(EvenNumber()); -``` - -## Writing New Actions Quickly ## - -If the built-in actions don't work for you, and you find it -inconvenient to use `Invoke()`, you can use a macro from the `ACTION*` -family to quickly define a new action that can be used in your code as -if it's a built-in action. - -By writing -``` -ACTION(name) { statements; } -``` -in a namespace scope (i.e. not inside a class or function), you will -define an action with the given name that executes the statements. -The value returned by `statements` will be used as the return value of -the action. Inside the statements, you can refer to the K-th -(0-based) argument of the mock function as `argK`. For example: -``` -ACTION(IncrementArg1) { return ++(*arg1); } -``` -allows you to write -``` -... WillOnce(IncrementArg1()); -``` - -Note that you don't need to specify the types of the mock function -arguments. Rest assured that your code is type-safe though: -you'll get a compiler error if `*arg1` doesn't support the `++` -operator, or if the type of `++(*arg1)` isn't compatible with the mock -function's return type. - -Another example: -``` -ACTION(Foo) { - (*arg2)(5); - Blah(); - *arg1 = 0; - return arg0; -} -``` -defines an action `Foo()` that invokes argument #2 (a function pointer) -with 5, calls function `Blah()`, sets the value pointed to by argument -#1 to 0, and returns argument #0. - -For more convenience and flexibility, you can also use the following -pre-defined symbols in the body of `ACTION`: - -| `argK_type` | The type of the K-th (0-based) argument of the mock function | -|:------------|:-------------------------------------------------------------| -| `args` | All arguments of the mock function as a tuple | -| `args_type` | The type of all arguments of the mock function as a tuple | -| `return_type` | The return type of the mock function | -| `function_type` | The type of the mock function | - -For example, when using an `ACTION` as a stub action for mock function: -``` -int DoSomething(bool flag, int* ptr); -``` -we have: - -| **Pre-defined Symbol** | **Is Bound To** | -|:-----------------------|:----------------| -| `arg0` | the value of `flag` | -| `arg0_type` | the type `bool` | -| `arg1` | the value of `ptr` | -| `arg1_type` | the type `int*` | -| `args` | the tuple `(flag, ptr)` | -| `args_type` | the type `std::tr1::tuple` | -| `return_type` | the type `int` | -| `function_type` | the type `int(bool, int*)` | - -## Writing New Parameterized Actions Quickly ## - -Sometimes you'll want to parameterize an action you define. For that -we have another macro -``` -ACTION_P(name, param) { statements; } -``` - -For example, -``` -ACTION_P(Add, n) { return arg0 + n; } -``` -will allow you to write -``` -// Returns argument #0 + 5. -... WillOnce(Add(5)); -``` - -For convenience, we use the term _arguments_ for the values used to -invoke the mock function, and the term _parameters_ for the values -used to instantiate an action. - -Note that you don't need to provide the type of the parameter either. -Suppose the parameter is named `param`, you can also use the -Google-Mock-defined symbol `param_type` to refer to the type of the -parameter as inferred by the compiler. For example, in the body of -`ACTION_P(Add, n)` above, you can write `n_type` for the type of `n`. - -Google Mock also provides `ACTION_P2`, `ACTION_P3`, and etc to support -multi-parameter actions. For example, -``` -ACTION_P2(ReturnDistanceTo, x, y) { - double dx = arg0 - x; - double dy = arg1 - y; - return sqrt(dx*dx + dy*dy); -} -``` -lets you write -``` -... WillOnce(ReturnDistanceTo(5.0, 26.5)); -``` - -You can view `ACTION` as a degenerated parameterized action where the -number of parameters is 0. - -You can also easily define actions overloaded on the number of parameters: -``` -ACTION_P(Plus, a) { ... } -ACTION_P2(Plus, a, b) { ... } -``` - -## Restricting the Type of an Argument or Parameter in an ACTION ## - -For maximum brevity and reusability, the `ACTION*` macros don't ask -you to provide the types of the mock function arguments and the action -parameters. Instead, we let the compiler infer the types for us. - -Sometimes, however, we may want to be more explicit about the types. -There are several tricks to do that. For example: -``` -ACTION(Foo) { - // Makes sure arg0 can be converted to int. - int n = arg0; - ... use n instead of arg0 here ... -} - -ACTION_P(Bar, param) { - // Makes sure the type of arg1 is const char*. - ::testing::StaticAssertTypeEq(); - - // Makes sure param can be converted to bool. - bool flag = param; -} -``` -where `StaticAssertTypeEq` is a compile-time assertion in Google Test -that verifies two types are the same. - -## Writing New Action Templates Quickly ## - -Sometimes you want to give an action explicit template parameters that -cannot be inferred from its value parameters. `ACTION_TEMPLATE()` -supports that and can be viewed as an extension to `ACTION()` and -`ACTION_P*()`. - -The syntax: -``` -ACTION_TEMPLATE(ActionName, - HAS_m_TEMPLATE_PARAMS(kind1, name1, ..., kind_m, name_m), - AND_n_VALUE_PARAMS(p1, ..., p_n)) { statements; } -``` - -defines an action template that takes _m_ explicit template parameters -and _n_ value parameters, where _m_ is between 1 and 10, and _n_ is -between 0 and 10. `name_i` is the name of the i-th template -parameter, and `kind_i` specifies whether it's a `typename`, an -integral constant, or a template. `p_i` is the name of the i-th value -parameter. - -Example: -``` -// DuplicateArg(output) converts the k-th argument of the mock -// function to type T and copies it to *output. -ACTION_TEMPLATE(DuplicateArg, - // Note the comma between int and k: - HAS_2_TEMPLATE_PARAMS(int, k, typename, T), - AND_1_VALUE_PARAMS(output)) { - *output = T(std::tr1::get(args)); -} -``` - -To create an instance of an action template, write: -``` - ActionName(v1, ..., v_n) -``` -where the `t`s are the template arguments and the -`v`s are the value arguments. The value argument -types are inferred by the compiler. For example: -``` -using ::testing::_; -... - int n; - EXPECT_CALL(mock, Foo(_, _)) - .WillOnce(DuplicateArg<1, unsigned char>(&n)); -``` - -If you want to explicitly specify the value argument types, you can -provide additional template arguments: -``` - ActionName(v1, ..., v_n) -``` -where `u_i` is the desired type of `v_i`. - -`ACTION_TEMPLATE` and `ACTION`/`ACTION_P*` can be overloaded on the -number of value parameters, but not on the number of template -parameters. Without the restriction, the meaning of the following is -unclear: - -``` - OverloadedAction(x); -``` - -Are we using a single-template-parameter action where `bool` refers to -the type of `x`, or a two-template-parameter action where the compiler -is asked to infer the type of `x`? - -## Using the ACTION Object's Type ## - -If you are writing a function that returns an `ACTION` object, you'll -need to know its type. The type depends on the macro used to define -the action and the parameter types. The rule is relatively simple: - -| **Given Definition** | **Expression** | **Has Type** | -|:---------------------|:---------------|:-------------| -| `ACTION(Foo)` | `Foo()` | `FooAction` | -| `ACTION_TEMPLATE(Foo, HAS_m_TEMPLATE_PARAMS(...), AND_0_VALUE_PARAMS())` | `Foo()` | `FooAction` | -| `ACTION_P(Bar, param)` | `Bar(int_value)` | `BarActionP` | -| `ACTION_TEMPLATE(Bar, HAS_m_TEMPLATE_PARAMS(...), AND_1_VALUE_PARAMS(p1))` | `Bar(int_value)` | `FooActionP` | -| `ACTION_P2(Baz, p1, p2)` | `Baz(bool_value, int_value)` | `BazActionP2` | -| `ACTION_TEMPLATE(Baz, HAS_m_TEMPLATE_PARAMS(...), AND_2_VALUE_PARAMS(p1, p2))` | `Baz(bool_value, int_value)` | `FooActionP2` | -| ... | ... | ... | - -Note that we have to pick different suffixes (`Action`, `ActionP`, -`ActionP2`, and etc) for actions with different numbers of value -parameters, or the action definitions cannot be overloaded on the -number of them. - -## Writing New Monomorphic Actions ## - -While the `ACTION*` macros are very convenient, sometimes they are -inappropriate. For example, despite the tricks shown in the previous -recipes, they don't let you directly specify the types of the mock -function arguments and the action parameters, which in general leads -to unoptimized compiler error messages that can baffle unfamiliar -users. They also don't allow overloading actions based on parameter -types without jumping through some hoops. - -An alternative to the `ACTION*` macros is to implement -`::testing::ActionInterface`, where `F` is the type of the mock -function in which the action will be used. For example: - -``` -template class ActionInterface { - public: - virtual ~ActionInterface(); - - // Performs the action. Result is the return type of function type - // F, and ArgumentTuple is the tuple of arguments of F. - // - // For example, if F is int(bool, const string&), then Result would - // be int, and ArgumentTuple would be tr1::tuple. - virtual Result Perform(const ArgumentTuple& args) = 0; -}; - -using ::testing::_; -using ::testing::Action; -using ::testing::ActionInterface; -using ::testing::MakeAction; - -typedef int IncrementMethod(int*); - -class IncrementArgumentAction : public ActionInterface { - public: - virtual int Perform(const tr1::tuple& args) { - int* p = tr1::get<0>(args); // Grabs the first argument. - return *p++; - } -}; - -Action IncrementArgument() { - return MakeAction(new IncrementArgumentAction); -} -... - - EXPECT_CALL(foo, Baz(_)) - .WillOnce(IncrementArgument()); - - int n = 5; - foo.Baz(&n); // Should return 5 and change n to 6. -``` - -## Writing New Polymorphic Actions ## - -The previous recipe showed you how to define your own action. This is -all good, except that you need to know the type of the function in -which the action will be used. Sometimes that can be a problem. For -example, if you want to use the action in functions with _different_ -types (e.g. like `Return()` and `SetArgPointee()`). - -If an action can be used in several types of mock functions, we say -it's _polymorphic_. The `MakePolymorphicAction()` function template -makes it easy to define such an action: - -``` -namespace testing { - -template -PolymorphicAction MakePolymorphicAction(const Impl& impl); - -} // namespace testing -``` - -As an example, let's define an action that returns the second argument -in the mock function's argument list. The first step is to define an -implementation class: - -``` -class ReturnSecondArgumentAction { - public: - template - Result Perform(const ArgumentTuple& args) const { - // To get the i-th (0-based) argument, use tr1::get(args). - return tr1::get<1>(args); - } -}; -``` - -This implementation class does _not_ need to inherit from any -particular class. What matters is that it must have a `Perform()` -method template. This method template takes the mock function's -arguments as a tuple in a **single** argument, and returns the result of -the action. It can be either `const` or not, but must be invokable -with exactly one template argument, which is the result type. In other -words, you must be able to call `Perform(args)` where `R` is the -mock function's return type and `args` is its arguments in a tuple. - -Next, we use `MakePolymorphicAction()` to turn an instance of the -implementation class into the polymorphic action we need. It will be -convenient to have a wrapper for this: - -``` -using ::testing::MakePolymorphicAction; -using ::testing::PolymorphicAction; - -PolymorphicAction ReturnSecondArgument() { - return MakePolymorphicAction(ReturnSecondArgumentAction()); -} -``` - -Now, you can use this polymorphic action the same way you use the -built-in ones: - -``` -using ::testing::_; - -class MockFoo : public Foo { - public: - MOCK_METHOD2(DoThis, int(bool flag, int n)); - MOCK_METHOD3(DoThat, string(int x, const char* str1, const char* str2)); -}; -... - - MockFoo foo; - EXPECT_CALL(foo, DoThis(_, _)) - .WillOnce(ReturnSecondArgument()); - EXPECT_CALL(foo, DoThat(_, _, _)) - .WillOnce(ReturnSecondArgument()); - ... - foo.DoThis(true, 5); // Will return 5. - foo.DoThat(1, "Hi", "Bye"); // Will return "Hi". -``` - -## Teaching Google Mock How to Print Your Values ## - -When an uninteresting or unexpected call occurs, Google Mock prints the -argument values and the stack trace to help you debug. Assertion -macros like `EXPECT_THAT` and `EXPECT_EQ` also print the values in -question when the assertion fails. Google Mock and Google Test do this using -Google Test's user-extensible value printer. - -This printer knows how to print built-in C++ types, native arrays, STL -containers, and any type that supports the `<<` operator. For other -types, it prints the raw bytes in the value and hopes that you the -user can figure it out. -[Google Test's advanced guide](http://code.google.com/p/googletest/wiki/AdvancedGuide#Teaching_Google_Test_How_to_Print_Your_Values) -explains how to extend the printer to do a better job at -printing your particular type than to dump the bytes. \ No newline at end of file diff --git a/googlemock/docs/v1_7/Documentation.md b/googlemock/docs/v1_7/Documentation.md deleted file mode 100644 index d9181f28..00000000 --- a/googlemock/docs/v1_7/Documentation.md +++ /dev/null @@ -1,12 +0,0 @@ -This page lists all documentation wiki pages for Google Mock **(the SVN trunk version)** -- **if you use a released version of Google Mock, please read the documentation for that specific version instead.** - - * [ForDummies](V1_7_ForDummies.md) -- start here if you are new to Google Mock. - * [CheatSheet](V1_7_CheatSheet.md) -- a quick reference. - * [CookBook](V1_7_CookBook.md) -- recipes for doing various tasks using Google Mock. - * [FrequentlyAskedQuestions](V1_7_FrequentlyAskedQuestions.md) -- check here before asking a question on the mailing list. - -To contribute code to Google Mock, read: - - * [DevGuide](DevGuide.md) -- read this _before_ writing your first patch. - * [Pump Manual](http://code.google.com/p/googletest/wiki/PumpManual) -- how we generate some of Google Mock's source files. \ No newline at end of file diff --git a/googlemock/docs/v1_7/ForDummies.md b/googlemock/docs/v1_7/ForDummies.md deleted file mode 100644 index ee03c5b9..00000000 --- a/googlemock/docs/v1_7/ForDummies.md +++ /dev/null @@ -1,439 +0,0 @@ - - -(**Note:** If you get compiler errors that you don't understand, be sure to consult [Google Mock Doctor](http://code.google.com/p/googlemock/wiki/V1_7_FrequentlyAskedQuestions#How_am_I_supposed_to_make_sense_of_these_horrible_template_error).) - -# What Is Google C++ Mocking Framework? # -When you write a prototype or test, often it's not feasible or wise to rely on real objects entirely. A **mock object** implements the same interface as a real object (so it can be used as one), but lets you specify at run time how it will be used and what it should do (which methods will be called? in which order? how many times? with what arguments? what will they return? etc). - -**Note:** It is easy to confuse the term _fake objects_ with mock objects. Fakes and mocks actually mean very different things in the Test-Driven Development (TDD) community: - - * **Fake** objects have working implementations, but usually take some shortcut (perhaps to make the operations less expensive), which makes them not suitable for production. An in-memory file system would be an example of a fake. - * **Mocks** are objects pre-programmed with _expectations_, which form a specification of the calls they are expected to receive. - -If all this seems too abstract for you, don't worry - the most important thing to remember is that a mock allows you to check the _interaction_ between itself and code that uses it. The difference between fakes and mocks will become much clearer once you start to use mocks. - -**Google C++ Mocking Framework** (or **Google Mock** for short) is a library (sometimes we also call it a "framework" to make it sound cool) for creating mock classes and using them. It does to C++ what [jMock](http://www.jmock.org/) and [EasyMock](http://www.easymock.org/) do to Java. - -Using Google Mock involves three basic steps: - - 1. Use some simple macros to describe the interface you want to mock, and they will expand to the implementation of your mock class; - 1. Create some mock objects and specify its expectations and behavior using an intuitive syntax; - 1. Exercise code that uses the mock objects. Google Mock will catch any violation of the expectations as soon as it arises. - -# Why Google Mock? # -While mock objects help you remove unnecessary dependencies in tests and make them fast and reliable, using mocks manually in C++ is _hard_: - - * Someone has to implement the mocks. The job is usually tedious and error-prone. No wonder people go great distance to avoid it. - * The quality of those manually written mocks is a bit, uh, unpredictable. You may see some really polished ones, but you may also see some that were hacked up in a hurry and have all sorts of ad hoc restrictions. - * The knowledge you gained from using one mock doesn't transfer to the next. - -In contrast, Java and Python programmers have some fine mock frameworks, which automate the creation of mocks. As a result, mocking is a proven effective technique and widely adopted practice in those communities. Having the right tool absolutely makes the difference. - -Google Mock was built to help C++ programmers. It was inspired by [jMock](http://www.jmock.org/) and [EasyMock](http://www.easymock.org/), but designed with C++'s specifics in mind. It is your friend if any of the following problems is bothering you: - - * You are stuck with a sub-optimal design and wish you had done more prototyping before it was too late, but prototyping in C++ is by no means "rapid". - * Your tests are slow as they depend on too many libraries or use expensive resources (e.g. a database). - * Your tests are brittle as some resources they use are unreliable (e.g. the network). - * You want to test how your code handles a failure (e.g. a file checksum error), but it's not easy to cause one. - * You need to make sure that your module interacts with other modules in the right way, but it's hard to observe the interaction; therefore you resort to observing the side effects at the end of the action, which is awkward at best. - * You want to "mock out" your dependencies, except that they don't have mock implementations yet; and, frankly, you aren't thrilled by some of those hand-written mocks. - -We encourage you to use Google Mock as: - - * a _design_ tool, for it lets you experiment with your interface design early and often. More iterations lead to better designs! - * a _testing_ tool to cut your tests' outbound dependencies and probe the interaction between your module and its collaborators. - -# Getting Started # -Using Google Mock is easy! Inside your C++ source file, just `#include` `"gtest/gtest.h"` and `"gmock/gmock.h"`, and you are ready to go. - -# A Case for Mock Turtles # -Let's look at an example. Suppose you are developing a graphics program that relies on a LOGO-like API for drawing. How would you test that it does the right thing? Well, you can run it and compare the screen with a golden screen snapshot, but let's admit it: tests like this are expensive to run and fragile (What if you just upgraded to a shiny new graphics card that has better anti-aliasing? Suddenly you have to update all your golden images.). It would be too painful if all your tests are like this. Fortunately, you learned about Dependency Injection and know the right thing to do: instead of having your application talk to the drawing API directly, wrap the API in an interface (say, `Turtle`) and code to that interface: - -``` -class Turtle { - ... - virtual ~Turtle() {} - virtual void PenUp() = 0; - virtual void PenDown() = 0; - virtual void Forward(int distance) = 0; - virtual void Turn(int degrees) = 0; - virtual void GoTo(int x, int y) = 0; - virtual int GetX() const = 0; - virtual int GetY() const = 0; -}; -``` - -(Note that the destructor of `Turtle` **must** be virtual, as is the case for **all** classes you intend to inherit from - otherwise the destructor of the derived class will not be called when you delete an object through a base pointer, and you'll get corrupted program states like memory leaks.) - -You can control whether the turtle's movement will leave a trace using `PenUp()` and `PenDown()`, and control its movement using `Forward()`, `Turn()`, and `GoTo()`. Finally, `GetX()` and `GetY()` tell you the current position of the turtle. - -Your program will normally use a real implementation of this interface. In tests, you can use a mock implementation instead. This allows you to easily check what drawing primitives your program is calling, with what arguments, and in which order. Tests written this way are much more robust (they won't break because your new machine does anti-aliasing differently), easier to read and maintain (the intent of a test is expressed in the code, not in some binary images), and run _much, much faster_. - -# Writing the Mock Class # -If you are lucky, the mocks you need to use have already been implemented by some nice people. If, however, you find yourself in the position to write a mock class, relax - Google Mock turns this task into a fun game! (Well, almost.) - -## How to Define It ## -Using the `Turtle` interface as example, here are the simple steps you need to follow: - - 1. Derive a class `MockTurtle` from `Turtle`. - 1. Take a _virtual_ function of `Turtle` (while it's possible to [mock non-virtual methods using templates](http://code.google.com/p/googlemock/wiki/V1_7_CookBook#Mocking_Nonvirtual_Methods), it's much more involved). Count how many arguments it has. - 1. In the `public:` section of the child class, write `MOCK_METHODn();` (or `MOCK_CONST_METHODn();` if you are mocking a `const` method), where `n` is the number of the arguments; if you counted wrong, shame on you, and a compiler error will tell you so. - 1. Now comes the fun part: you take the function signature, cut-and-paste the _function name_ as the _first_ argument to the macro, and leave what's left as the _second_ argument (in case you're curious, this is the _type of the function_). - 1. Repeat until all virtual functions you want to mock are done. - -After the process, you should have something like: - -``` -#include "gmock/gmock.h" // Brings in Google Mock. -class MockTurtle : public Turtle { - public: - ... - MOCK_METHOD0(PenUp, void()); - MOCK_METHOD0(PenDown, void()); - MOCK_METHOD1(Forward, void(int distance)); - MOCK_METHOD1(Turn, void(int degrees)); - MOCK_METHOD2(GoTo, void(int x, int y)); - MOCK_CONST_METHOD0(GetX, int()); - MOCK_CONST_METHOD0(GetY, int()); -}; -``` - -You don't need to define these mock methods somewhere else - the `MOCK_METHOD*` macros will generate the definitions for you. It's that simple! Once you get the hang of it, you can pump out mock classes faster than your source-control system can handle your check-ins. - -**Tip:** If even this is too much work for you, you'll find the -`gmock_gen.py` tool in Google Mock's `scripts/generator/` directory (courtesy of the [cppclean](http://code.google.com/p/cppclean/) project) useful. This command-line -tool requires that you have Python 2.4 installed. You give it a C++ file and the name of an abstract class defined in it, -and it will print the definition of the mock class for you. Due to the -complexity of the C++ language, this script may not always work, but -it can be quite handy when it does. For more details, read the [user documentation](http://code.google.com/p/googlemock/source/browse/trunk/scripts/generator/README). - -## Where to Put It ## -When you define a mock class, you need to decide where to put its definition. Some people put it in a `*_test.cc`. This is fine when the interface being mocked (say, `Foo`) is owned by the same person or team. Otherwise, when the owner of `Foo` changes it, your test could break. (You can't really expect `Foo`'s maintainer to fix every test that uses `Foo`, can you?) - -So, the rule of thumb is: if you need to mock `Foo` and it's owned by others, define the mock class in `Foo`'s package (better, in a `testing` sub-package such that you can clearly separate production code and testing utilities), and put it in a `mock_foo.h`. Then everyone can reference `mock_foo.h` from their tests. If `Foo` ever changes, there is only one copy of `MockFoo` to change, and only tests that depend on the changed methods need to be fixed. - -Another way to do it: you can introduce a thin layer `FooAdaptor` on top of `Foo` and code to this new interface. Since you own `FooAdaptor`, you can absorb changes in `Foo` much more easily. While this is more work initially, carefully choosing the adaptor interface can make your code easier to write and more readable (a net win in the long run), as you can choose `FooAdaptor` to fit your specific domain much better than `Foo` does. - -# Using Mocks in Tests # -Once you have a mock class, using it is easy. The typical work flow is: - - 1. Import the Google Mock names from the `testing` namespace such that you can use them unqualified (You only have to do it once per file. Remember that namespaces are a good idea and good for your health.). - 1. Create some mock objects. - 1. Specify your expectations on them (How many times will a method be called? With what arguments? What should it do? etc.). - 1. Exercise some code that uses the mocks; optionally, check the result using Google Test assertions. If a mock method is called more than expected or with wrong arguments, you'll get an error immediately. - 1. When a mock is destructed, Google Mock will automatically check whether all expectations on it have been satisfied. - -Here's an example: - -``` -#include "path/to/mock-turtle.h" -#include "gmock/gmock.h" -#include "gtest/gtest.h" -using ::testing::AtLeast; // #1 - -TEST(PainterTest, CanDrawSomething) { - MockTurtle turtle; // #2 - EXPECT_CALL(turtle, PenDown()) // #3 - .Times(AtLeast(1)); - - Painter painter(&turtle); // #4 - - EXPECT_TRUE(painter.DrawCircle(0, 0, 10)); -} // #5 - -int main(int argc, char** argv) { - // The following line must be executed to initialize Google Mock - // (and Google Test) before running the tests. - ::testing::InitGoogleMock(&argc, argv); - return RUN_ALL_TESTS(); -} -``` - -As you might have guessed, this test checks that `PenDown()` is called at least once. If the `painter` object didn't call this method, your test will fail with a message like this: - -``` -path/to/my_test.cc:119: Failure -Actual function call count doesn't match this expectation: -Actually: never called; -Expected: called at least once. -``` - -**Tip 1:** If you run the test from an Emacs buffer, you can hit `` on the line number displayed in the error message to jump right to the failed expectation. - -**Tip 2:** If your mock objects are never deleted, the final verification won't happen. Therefore it's a good idea to use a heap leak checker in your tests when you allocate mocks on the heap. - -**Important note:** Google Mock requires expectations to be set **before** the mock functions are called, otherwise the behavior is **undefined**. In particular, you mustn't interleave `EXPECT_CALL()`s and calls to the mock functions. - -This means `EXPECT_CALL()` should be read as expecting that a call will occur _in the future_, not that a call has occurred. Why does Google Mock work like that? Well, specifying the expectation beforehand allows Google Mock to report a violation as soon as it arises, when the context (stack trace, etc) is still available. This makes debugging much easier. - -Admittedly, this test is contrived and doesn't do much. You can easily achieve the same effect without using Google Mock. However, as we shall reveal soon, Google Mock allows you to do _much more_ with the mocks. - -## Using Google Mock with Any Testing Framework ## -If you want to use something other than Google Test (e.g. [CppUnit](http://apps.sourceforge.net/mediawiki/cppunit/index.php?title=Main_Page) or -[CxxTest](http://cxxtest.tigris.org/)) as your testing framework, just change the `main()` function in the previous section to: -``` -int main(int argc, char** argv) { - // The following line causes Google Mock to throw an exception on failure, - // which will be interpreted by your testing framework as a test failure. - ::testing::GTEST_FLAG(throw_on_failure) = true; - ::testing::InitGoogleMock(&argc, argv); - ... whatever your testing framework requires ... -} -``` - -This approach has a catch: it makes Google Mock throw an exception -from a mock object's destructor sometimes. With some compilers, this -sometimes causes the test program to crash. You'll still be able to -notice that the test has failed, but it's not a graceful failure. - -A better solution is to use Google Test's -[event listener API](http://code.google.com/p/googletest/wiki/AdvancedGuide#Extending_Google_Test_by_Handling_Test_Events) -to report a test failure to your testing framework properly. You'll need to -implement the `OnTestPartResult()` method of the event listener interface, but it -should be straightforward. - -If this turns out to be too much work, we suggest that you stick with -Google Test, which works with Google Mock seamlessly (in fact, it is -technically part of Google Mock.). If there is a reason that you -cannot use Google Test, please let us know. - -# Setting Expectations # -The key to using a mock object successfully is to set the _right expectations_ on it. If you set the expectations too strict, your test will fail as the result of unrelated changes. If you set them too loose, bugs can slip through. You want to do it just right such that your test can catch exactly the kind of bugs you intend it to catch. Google Mock provides the necessary means for you to do it "just right." - -## General Syntax ## -In Google Mock we use the `EXPECT_CALL()` macro to set an expectation on a mock method. The general syntax is: - -``` -EXPECT_CALL(mock_object, method(matchers)) - .Times(cardinality) - .WillOnce(action) - .WillRepeatedly(action); -``` - -The macro has two arguments: first the mock object, and then the method and its arguments. Note that the two are separated by a comma (`,`), not a period (`.`). (Why using a comma? The answer is that it was necessary for technical reasons.) - -The macro can be followed by some optional _clauses_ that provide more information about the expectation. We'll discuss how each clause works in the coming sections. - -This syntax is designed to make an expectation read like English. For example, you can probably guess that - -``` -using ::testing::Return;... -EXPECT_CALL(turtle, GetX()) - .Times(5) - .WillOnce(Return(100)) - .WillOnce(Return(150)) - .WillRepeatedly(Return(200)); -``` - -says that the `turtle` object's `GetX()` method will be called five times, it will return 100 the first time, 150 the second time, and then 200 every time. Some people like to call this style of syntax a Domain-Specific Language (DSL). - -**Note:** Why do we use a macro to do this? It serves two purposes: first it makes expectations easily identifiable (either by `grep` or by a human reader), and second it allows Google Mock to include the source file location of a failed expectation in messages, making debugging easier. - -## Matchers: What Arguments Do We Expect? ## -When a mock function takes arguments, we must specify what arguments we are expecting; for example: - -``` -// Expects the turtle to move forward by 100 units. -EXPECT_CALL(turtle, Forward(100)); -``` - -Sometimes you may not want to be too specific (Remember that talk about tests being too rigid? Over specification leads to brittle tests and obscures the intent of tests. Therefore we encourage you to specify only what's necessary - no more, no less.). If you care to check that `Forward()` will be called but aren't interested in its actual argument, write `_` as the argument, which means "anything goes": - -``` -using ::testing::_; -... -// Expects the turtle to move forward. -EXPECT_CALL(turtle, Forward(_)); -``` - -`_` is an instance of what we call **matchers**. A matcher is like a predicate and can test whether an argument is what we'd expect. You can use a matcher inside `EXPECT_CALL()` wherever a function argument is expected. - -A list of built-in matchers can be found in the [CheatSheet](V1_7_CheatSheet.md). For example, here's the `Ge` (greater than or equal) matcher: - -``` -using ::testing::Ge;... -EXPECT_CALL(turtle, Forward(Ge(100))); -``` - -This checks that the turtle will be told to go forward by at least 100 units. - -## Cardinalities: How Many Times Will It Be Called? ## -The first clause we can specify following an `EXPECT_CALL()` is `Times()`. We call its argument a **cardinality** as it tells _how many times_ the call should occur. It allows us to repeat an expectation many times without actually writing it as many times. More importantly, a cardinality can be "fuzzy", just like a matcher can be. This allows a user to express the intent of a test exactly. - -An interesting special case is when we say `Times(0)`. You may have guessed - it means that the function shouldn't be called with the given arguments at all, and Google Mock will report a Google Test failure whenever the function is (wrongfully) called. - -We've seen `AtLeast(n)` as an example of fuzzy cardinalities earlier. For the list of built-in cardinalities you can use, see the [CheatSheet](V1_7_CheatSheet.md). - -The `Times()` clause can be omitted. **If you omit `Times()`, Google Mock will infer the cardinality for you.** The rules are easy to remember: - - * If **neither** `WillOnce()` **nor** `WillRepeatedly()` is in the `EXPECT_CALL()`, the inferred cardinality is `Times(1)`. - * If there are `n WillOnce()`'s but **no** `WillRepeatedly()`, where `n` >= 1, the cardinality is `Times(n)`. - * If there are `n WillOnce()`'s and **one** `WillRepeatedly()`, where `n` >= 0, the cardinality is `Times(AtLeast(n))`. - -**Quick quiz:** what do you think will happen if a function is expected to be called twice but actually called four times? - -## Actions: What Should It Do? ## -Remember that a mock object doesn't really have a working implementation? We as users have to tell it what to do when a method is invoked. This is easy in Google Mock. - -First, if the return type of a mock function is a built-in type or a pointer, the function has a **default action** (a `void` function will just return, a `bool` function will return `false`, and other functions will return 0). If you don't say anything, this behavior will be used. - -Second, if a mock function doesn't have a default action, or the default action doesn't suit you, you can specify the action to be taken each time the expectation matches using a series of `WillOnce()` clauses followed by an optional `WillRepeatedly()`. For example, - -``` -using ::testing::Return;... -EXPECT_CALL(turtle, GetX()) - .WillOnce(Return(100)) - .WillOnce(Return(200)) - .WillOnce(Return(300)); -``` - -This says that `turtle.GetX()` will be called _exactly three times_ (Google Mock inferred this from how many `WillOnce()` clauses we've written, since we didn't explicitly write `Times()`), and will return 100, 200, and 300 respectively. - -``` -using ::testing::Return;... -EXPECT_CALL(turtle, GetY()) - .WillOnce(Return(100)) - .WillOnce(Return(200)) - .WillRepeatedly(Return(300)); -``` - -says that `turtle.GetY()` will be called _at least twice_ (Google Mock knows this as we've written two `WillOnce()` clauses and a `WillRepeatedly()` while having no explicit `Times()`), will return 100 the first time, 200 the second time, and 300 from the third time on. - -Of course, if you explicitly write a `Times()`, Google Mock will not try to infer the cardinality itself. What if the number you specified is larger than there are `WillOnce()` clauses? Well, after all `WillOnce()`s are used up, Google Mock will do the _default_ action for the function every time (unless, of course, you have a `WillRepeatedly()`.). - -What can we do inside `WillOnce()` besides `Return()`? You can return a reference using `ReturnRef(variable)`, or invoke a pre-defined function, among [others](http://code.google.com/p/googlemock/wiki/V1_7_CheatSheet#Actions). - -**Important note:** The `EXPECT_CALL()` statement evaluates the action clause only once, even though the action may be performed many times. Therefore you must be careful about side effects. The following may not do what you want: - -``` -int n = 100; -EXPECT_CALL(turtle, GetX()) -.Times(4) -.WillRepeatedly(Return(n++)); -``` - -Instead of returning 100, 101, 102, ..., consecutively, this mock function will always return 100 as `n++` is only evaluated once. Similarly, `Return(new Foo)` will create a new `Foo` object when the `EXPECT_CALL()` is executed, and will return the same pointer every time. If you want the side effect to happen every time, you need to define a custom action, which we'll teach in the [CookBook](V1_7_CookBook.md). - -Time for another quiz! What do you think the following means? - -``` -using ::testing::Return;... -EXPECT_CALL(turtle, GetY()) -.Times(4) -.WillOnce(Return(100)); -``` - -Obviously `turtle.GetY()` is expected to be called four times. But if you think it will return 100 every time, think twice! Remember that one `WillOnce()` clause will be consumed each time the function is invoked and the default action will be taken afterwards. So the right answer is that `turtle.GetY()` will return 100 the first time, but **return 0 from the second time on**, as returning 0 is the default action for `int` functions. - -## Using Multiple Expectations ## -So far we've only shown examples where you have a single expectation. More realistically, you're going to specify expectations on multiple mock methods, which may be from multiple mock objects. - -By default, when a mock method is invoked, Google Mock will search the expectations in the **reverse order** they are defined, and stop when an active expectation that matches the arguments is found (you can think of it as "newer rules override older ones."). If the matching expectation cannot take any more calls, you will get an upper-bound-violated failure. Here's an example: - -``` -using ::testing::_;... -EXPECT_CALL(turtle, Forward(_)); // #1 -EXPECT_CALL(turtle, Forward(10)) // #2 - .Times(2); -``` - -If `Forward(10)` is called three times in a row, the third time it will be an error, as the last matching expectation (#2) has been saturated. If, however, the third `Forward(10)` call is replaced by `Forward(20)`, then it would be OK, as now #1 will be the matching expectation. - -**Side note:** Why does Google Mock search for a match in the _reverse_ order of the expectations? The reason is that this allows a user to set up the default expectations in a mock object's constructor or the test fixture's set-up phase and then customize the mock by writing more specific expectations in the test body. So, if you have two expectations on the same method, you want to put the one with more specific matchers **after** the other, or the more specific rule would be shadowed by the more general one that comes after it. - -## Ordered vs Unordered Calls ## -By default, an expectation can match a call even though an earlier expectation hasn't been satisfied. In other words, the calls don't have to occur in the order the expectations are specified. - -Sometimes, you may want all the expected calls to occur in a strict order. To say this in Google Mock is easy: - -``` -using ::testing::InSequence;... -TEST(FooTest, DrawsLineSegment) { - ... - { - InSequence dummy; - - EXPECT_CALL(turtle, PenDown()); - EXPECT_CALL(turtle, Forward(100)); - EXPECT_CALL(turtle, PenUp()); - } - Foo(); -} -``` - -By creating an object of type `InSequence`, all expectations in its scope are put into a _sequence_ and have to occur _sequentially_. Since we are just relying on the constructor and destructor of this object to do the actual work, its name is really irrelevant. - -In this example, we test that `Foo()` calls the three expected functions in the order as written. If a call is made out-of-order, it will be an error. - -(What if you care about the relative order of some of the calls, but not all of them? Can you specify an arbitrary partial order? The answer is ... yes! If you are impatient, the details can be found in the [CookBook](V1_7_CookBook#Expecting_Partially_Ordered_Calls.md).) - -## All Expectations Are Sticky (Unless Said Otherwise) ## -Now let's do a quick quiz to see how well you can use this mock stuff already. How would you test that the turtle is asked to go to the origin _exactly twice_ (you want to ignore any other instructions it receives)? - -After you've come up with your answer, take a look at ours and compare notes (solve it yourself first - don't cheat!): - -``` -using ::testing::_;... -EXPECT_CALL(turtle, GoTo(_, _)) // #1 - .Times(AnyNumber()); -EXPECT_CALL(turtle, GoTo(0, 0)) // #2 - .Times(2); -``` - -Suppose `turtle.GoTo(0, 0)` is called three times. In the third time, Google Mock will see that the arguments match expectation #2 (remember that we always pick the last matching expectation). Now, since we said that there should be only two such calls, Google Mock will report an error immediately. This is basically what we've told you in the "Using Multiple Expectations" section above. - -This example shows that **expectations in Google Mock are "sticky" by default**, in the sense that they remain active even after we have reached their invocation upper bounds. This is an important rule to remember, as it affects the meaning of the spec, and is **different** to how it's done in many other mocking frameworks (Why'd we do that? Because we think our rule makes the common cases easier to express and understand.). - -Simple? Let's see if you've really understood it: what does the following code say? - -``` -using ::testing::Return; -... -for (int i = n; i > 0; i--) { - EXPECT_CALL(turtle, GetX()) - .WillOnce(Return(10*i)); -} -``` - -If you think it says that `turtle.GetX()` will be called `n` times and will return 10, 20, 30, ..., consecutively, think twice! The problem is that, as we said, expectations are sticky. So, the second time `turtle.GetX()` is called, the last (latest) `EXPECT_CALL()` statement will match, and will immediately lead to an "upper bound exceeded" error - this piece of code is not very useful! - -One correct way of saying that `turtle.GetX()` will return 10, 20, 30, ..., is to explicitly say that the expectations are _not_ sticky. In other words, they should _retire_ as soon as they are saturated: - -``` -using ::testing::Return; -... -for (int i = n; i > 0; i--) { - EXPECT_CALL(turtle, GetX()) - .WillOnce(Return(10*i)) - .RetiresOnSaturation(); -} -``` - -And, there's a better way to do it: in this case, we expect the calls to occur in a specific order, and we line up the actions to match the order. Since the order is important here, we should make it explicit using a sequence: - -``` -using ::testing::InSequence; -using ::testing::Return; -... -{ - InSequence s; - - for (int i = 1; i <= n; i++) { - EXPECT_CALL(turtle, GetX()) - .WillOnce(Return(10*i)) - .RetiresOnSaturation(); - } -} -``` - -By the way, the other situation where an expectation may _not_ be sticky is when it's in a sequence - as soon as another expectation that comes after it in the sequence has been used, it automatically retires (and will never be used to match any call). - -## Uninteresting Calls ## -A mock object may have many methods, and not all of them are that interesting. For example, in some tests we may not care about how many times `GetX()` and `GetY()` get called. - -In Google Mock, if you are not interested in a method, just don't say anything about it. If a call to this method occurs, you'll see a warning in the test output, but it won't be a failure. - -# What Now? # -Congratulations! You've learned enough about Google Mock to start using it. Now, you might want to join the [googlemock](http://groups.google.com/group/googlemock) discussion group and actually write some tests using Google Mock - it will be fun. Hey, it may even be addictive - you've been warned. - -Then, if you feel like increasing your mock quotient, you should move on to the [CookBook](V1_7_CookBook.md). You can learn many advanced features of Google Mock there -- and advance your level of enjoyment and testing bliss. \ No newline at end of file diff --git a/googlemock/docs/v1_7/FrequentlyAskedQuestions.md b/googlemock/docs/v1_7/FrequentlyAskedQuestions.md deleted file mode 100644 index fa21233a..00000000 --- a/googlemock/docs/v1_7/FrequentlyAskedQuestions.md +++ /dev/null @@ -1,628 +0,0 @@ - - -Please send your questions to the -[googlemock](http://groups.google.com/group/googlemock) discussion -group. If you need help with compiler errors, make sure you have -tried [Google Mock Doctor](#How_am_I_supposed_to_make_sense_of_these_horrible_template_error.md) first. - -## When I call a method on my mock object, the method for the real object is invoked instead. What's the problem? ## - -In order for a method to be mocked, it must be _virtual_, unless you use the [high-perf dependency injection technique](http://code.google.com/p/googlemock/wiki/V1_7_CookBook#Mocking_Nonvirtual_Methods). - -## I wrote some matchers. After I upgraded to a new version of Google Mock, they no longer compile. What's going on? ## - -After version 1.4.0 of Google Mock was released, we had an idea on how -to make it easier to write matchers that can generate informative -messages efficiently. We experimented with this idea and liked what -we saw. Therefore we decided to implement it. - -Unfortunately, this means that if you have defined your own matchers -by implementing `MatcherInterface` or using `MakePolymorphicMatcher()`, -your definitions will no longer compile. Matchers defined using the -`MATCHER*` family of macros are not affected. - -Sorry for the hassle if your matchers are affected. We believe it's -in everyone's long-term interest to make this change sooner than -later. Fortunately, it's usually not hard to migrate an existing -matcher to the new API. Here's what you need to do: - -If you wrote your matcher like this: -``` -// Old matcher definition that doesn't work with the latest -// Google Mock. -using ::testing::MatcherInterface; -... -class MyWonderfulMatcher : public MatcherInterface { - public: - ... - virtual bool Matches(MyType value) const { - // Returns true if value matches. - return value.GetFoo() > 5; - } - ... -}; -``` - -you'll need to change it to: -``` -// New matcher definition that works with the latest Google Mock. -using ::testing::MatcherInterface; -using ::testing::MatchResultListener; -... -class MyWonderfulMatcher : public MatcherInterface { - public: - ... - virtual bool MatchAndExplain(MyType value, - MatchResultListener* listener) const { - // Returns true if value matches. - return value.GetFoo() > 5; - } - ... -}; -``` -(i.e. rename `Matches()` to `MatchAndExplain()` and give it a second -argument of type `MatchResultListener*`.) - -If you were also using `ExplainMatchResultTo()` to improve the matcher -message: -``` -// Old matcher definition that doesn't work with the lastest -// Google Mock. -using ::testing::MatcherInterface; -... -class MyWonderfulMatcher : public MatcherInterface { - public: - ... - virtual bool Matches(MyType value) const { - // Returns true if value matches. - return value.GetFoo() > 5; - } - - virtual void ExplainMatchResultTo(MyType value, - ::std::ostream* os) const { - // Prints some helpful information to os to help - // a user understand why value matches (or doesn't match). - *os << "the Foo property is " << value.GetFoo(); - } - ... -}; -``` - -you should move the logic of `ExplainMatchResultTo()` into -`MatchAndExplain()`, using the `MatchResultListener` argument where -the `::std::ostream` was used: -``` -// New matcher definition that works with the latest Google Mock. -using ::testing::MatcherInterface; -using ::testing::MatchResultListener; -... -class MyWonderfulMatcher : public MatcherInterface { - public: - ... - virtual bool MatchAndExplain(MyType value, - MatchResultListener* listener) const { - // Returns true if value matches. - *listener << "the Foo property is " << value.GetFoo(); - return value.GetFoo() > 5; - } - ... -}; -``` - -If your matcher is defined using `MakePolymorphicMatcher()`: -``` -// Old matcher definition that doesn't work with the latest -// Google Mock. -using ::testing::MakePolymorphicMatcher; -... -class MyGreatMatcher { - public: - ... - bool Matches(MyType value) const { - // Returns true if value matches. - return value.GetBar() < 42; - } - ... -}; -... MakePolymorphicMatcher(MyGreatMatcher()) ... -``` - -you should rename the `Matches()` method to `MatchAndExplain()` and -add a `MatchResultListener*` argument (the same as what you need to do -for matchers defined by implementing `MatcherInterface`): -``` -// New matcher definition that works with the latest Google Mock. -using ::testing::MakePolymorphicMatcher; -using ::testing::MatchResultListener; -... -class MyGreatMatcher { - public: - ... - bool MatchAndExplain(MyType value, - MatchResultListener* listener) const { - // Returns true if value matches. - return value.GetBar() < 42; - } - ... -}; -... MakePolymorphicMatcher(MyGreatMatcher()) ... -``` - -If your polymorphic matcher uses `ExplainMatchResultTo()` for better -failure messages: -``` -// Old matcher definition that doesn't work with the latest -// Google Mock. -using ::testing::MakePolymorphicMatcher; -... -class MyGreatMatcher { - public: - ... - bool Matches(MyType value) const { - // Returns true if value matches. - return value.GetBar() < 42; - } - ... -}; -void ExplainMatchResultTo(const MyGreatMatcher& matcher, - MyType value, - ::std::ostream* os) { - // Prints some helpful information to os to help - // a user understand why value matches (or doesn't match). - *os << "the Bar property is " << value.GetBar(); -} -... MakePolymorphicMatcher(MyGreatMatcher()) ... -``` - -you'll need to move the logic inside `ExplainMatchResultTo()` to -`MatchAndExplain()`: -``` -// New matcher definition that works with the latest Google Mock. -using ::testing::MakePolymorphicMatcher; -using ::testing::MatchResultListener; -... -class MyGreatMatcher { - public: - ... - bool MatchAndExplain(MyType value, - MatchResultListener* listener) const { - // Returns true if value matches. - *listener << "the Bar property is " << value.GetBar(); - return value.GetBar() < 42; - } - ... -}; -... MakePolymorphicMatcher(MyGreatMatcher()) ... -``` - -For more information, you can read these -[two](http://code.google.com/p/googlemock/wiki/V1_7_CookBook#Writing_New_Monomorphic_Matchers) -[recipes](http://code.google.com/p/googlemock/wiki/V1_7_CookBook#Writing_New_Polymorphic_Matchers) -from the cookbook. As always, you -are welcome to post questions on `googlemock@googlegroups.com` if you -need any help. - -## When using Google Mock, do I have to use Google Test as the testing framework? I have my favorite testing framework and don't want to switch. ## - -Google Mock works out of the box with Google Test. However, it's easy -to configure it to work with any testing framework of your choice. -[Here](http://code.google.com/p/googlemock/wiki/V1_7_ForDummies#Using_Google_Mock_with_Any_Testing_Framework) is how. - -## How am I supposed to make sense of these horrible template errors? ## - -If you are confused by the compiler errors gcc threw at you, -try consulting the _Google Mock Doctor_ tool first. What it does is to -scan stdin for gcc error messages, and spit out diagnoses on the -problems (we call them diseases) your code has. - -To "install", run command: -``` -alias gmd='/scripts/gmock_doctor.py' -``` - -To use it, do: -``` - 2>&1 | gmd -``` - -For example: -``` -make my_test 2>&1 | gmd -``` - -Or you can run `gmd` and copy-n-paste gcc's error messages to it. - -## Can I mock a variadic function? ## - -You cannot mock a variadic function (i.e. a function taking ellipsis -(`...`) arguments) directly in Google Mock. - -The problem is that in general, there is _no way_ for a mock object to -know how many arguments are passed to the variadic method, and what -the arguments' types are. Only the _author of the base class_ knows -the protocol, and we cannot look into his head. - -Therefore, to mock such a function, the _user_ must teach the mock -object how to figure out the number of arguments and their types. One -way to do it is to provide overloaded versions of the function. - -Ellipsis arguments are inherited from C and not really a C++ feature. -They are unsafe to use and don't work with arguments that have -constructors or destructors. Therefore we recommend to avoid them in -C++ as much as possible. - -## MSVC gives me warning C4301 or C4373 when I define a mock method with a const parameter. Why? ## - -If you compile this using Microsoft Visual C++ 2005 SP1: -``` -class Foo { - ... - virtual void Bar(const int i) = 0; -}; - -class MockFoo : public Foo { - ... - MOCK_METHOD1(Bar, void(const int i)); -}; -``` -You may get the following warning: -``` -warning C4301: 'MockFoo::Bar': overriding virtual function only differs from 'Foo::Bar' by const/volatile qualifier -``` - -This is a MSVC bug. The same code compiles fine with gcc ,for -example. If you use Visual C++ 2008 SP1, you would get the warning: -``` -warning C4373: 'MockFoo::Bar': virtual function overrides 'Foo::Bar', previous versions of the compiler did not override when parameters only differed by const/volatile qualifiers -``` - -In C++, if you _declare_ a function with a `const` parameter, the -`const` modifier is _ignored_. Therefore, the `Foo` base class above -is equivalent to: -``` -class Foo { - ... - virtual void Bar(int i) = 0; // int or const int? Makes no difference. -}; -``` - -In fact, you can _declare_ Bar() with an `int` parameter, and _define_ -it with a `const int` parameter. The compiler will still match them -up. - -Since making a parameter `const` is meaningless in the method -_declaration_, we recommend to remove it in both `Foo` and `MockFoo`. -That should workaround the VC bug. - -Note that we are talking about the _top-level_ `const` modifier here. -If the function parameter is passed by pointer or reference, declaring -the _pointee_ or _referee_ as `const` is still meaningful. For -example, the following two declarations are _not_ equivalent: -``` -void Bar(int* p); // Neither p nor *p is const. -void Bar(const int* p); // p is not const, but *p is. -``` - -## I have a huge mock class, and Microsoft Visual C++ runs out of memory when compiling it. What can I do? ## - -We've noticed that when the `/clr` compiler flag is used, Visual C++ -uses 5~6 times as much memory when compiling a mock class. We suggest -to avoid `/clr` when compiling native C++ mocks. - -## I can't figure out why Google Mock thinks my expectations are not satisfied. What should I do? ## - -You might want to run your test with -`--gmock_verbose=info`. This flag lets Google Mock print a trace -of every mock function call it receives. By studying the trace, -you'll gain insights on why the expectations you set are not met. - -## How can I assert that a function is NEVER called? ## - -``` -EXPECT_CALL(foo, Bar(_)) - .Times(0); -``` - -## I have a failed test where Google Mock tells me TWICE that a particular expectation is not satisfied. Isn't this redundant? ## - -When Google Mock detects a failure, it prints relevant information -(the mock function arguments, the state of relevant expectations, and -etc) to help the user debug. If another failure is detected, Google -Mock will do the same, including printing the state of relevant -expectations. - -Sometimes an expectation's state didn't change between two failures, -and you'll see the same description of the state twice. They are -however _not_ redundant, as they refer to _different points in time_. -The fact they are the same _is_ interesting information. - -## I get a heap check failure when using a mock object, but using a real object is fine. What can be wrong? ## - -Does the class (hopefully a pure interface) you are mocking have a -virtual destructor? - -Whenever you derive from a base class, make sure its destructor is -virtual. Otherwise Bad Things will happen. Consider the following -code: - -``` -class Base { - public: - // Not virtual, but should be. - ~Base() { ... } - ... -}; - -class Derived : public Base { - public: - ... - private: - std::string value_; -}; - -... - Base* p = new Derived; - ... - delete p; // Surprise! ~Base() will be called, but ~Derived() will not - // - value_ is leaked. -``` - -By changing `~Base()` to virtual, `~Derived()` will be correctly -called when `delete p` is executed, and the heap checker -will be happy. - -## The "newer expectations override older ones" rule makes writing expectations awkward. Why does Google Mock do that? ## - -When people complain about this, often they are referring to code like: - -``` -// foo.Bar() should be called twice, return 1 the first time, and return -// 2 the second time. However, I have to write the expectations in the -// reverse order. This sucks big time!!! -EXPECT_CALL(foo, Bar()) - .WillOnce(Return(2)) - .RetiresOnSaturation(); -EXPECT_CALL(foo, Bar()) - .WillOnce(Return(1)) - .RetiresOnSaturation(); -``` - -The problem is that they didn't pick the **best** way to express the test's -intent. - -By default, expectations don't have to be matched in _any_ particular -order. If you want them to match in a certain order, you need to be -explicit. This is Google Mock's (and jMock's) fundamental philosophy: it's -easy to accidentally over-specify your tests, and we want to make it -harder to do so. - -There are two better ways to write the test spec. You could either -put the expectations in sequence: - -``` -// foo.Bar() should be called twice, return 1 the first time, and return -// 2 the second time. Using a sequence, we can write the expectations -// in their natural order. -{ - InSequence s; - EXPECT_CALL(foo, Bar()) - .WillOnce(Return(1)) - .RetiresOnSaturation(); - EXPECT_CALL(foo, Bar()) - .WillOnce(Return(2)) - .RetiresOnSaturation(); -} -``` - -or you can put the sequence of actions in the same expectation: - -``` -// foo.Bar() should be called twice, return 1 the first time, and return -// 2 the second time. -EXPECT_CALL(foo, Bar()) - .WillOnce(Return(1)) - .WillOnce(Return(2)) - .RetiresOnSaturation(); -``` - -Back to the original questions: why does Google Mock search the -expectations (and `ON_CALL`s) from back to front? Because this -allows a user to set up a mock's behavior for the common case early -(e.g. in the mock's constructor or the test fixture's set-up phase) -and customize it with more specific rules later. If Google Mock -searches from front to back, this very useful pattern won't be -possible. - -## Google Mock prints a warning when a function without EXPECT\_CALL is called, even if I have set its behavior using ON\_CALL. Would it be reasonable not to show the warning in this case? ## - -When choosing between being neat and being safe, we lean toward the -latter. So the answer is that we think it's better to show the -warning. - -Often people write `ON_CALL`s in the mock object's -constructor or `SetUp()`, as the default behavior rarely changes from -test to test. Then in the test body they set the expectations, which -are often different for each test. Having an `ON_CALL` in the set-up -part of a test doesn't mean that the calls are expected. If there's -no `EXPECT_CALL` and the method is called, it's possibly an error. If -we quietly let the call go through without notifying the user, bugs -may creep in unnoticed. - -If, however, you are sure that the calls are OK, you can write - -``` -EXPECT_CALL(foo, Bar(_)) - .WillRepeatedly(...); -``` - -instead of - -``` -ON_CALL(foo, Bar(_)) - .WillByDefault(...); -``` - -This tells Google Mock that you do expect the calls and no warning should be -printed. - -Also, you can control the verbosity using the `--gmock_verbose` flag. -If you find the output too noisy when debugging, just choose a less -verbose level. - -## How can I delete the mock function's argument in an action? ## - -If you find yourself needing to perform some action that's not -supported by Google Mock directly, remember that you can define your own -actions using -[MakeAction()](http://code.google.com/p/googlemock/wiki/V1_7_CookBook#Writing_New_Actions) or -[MakePolymorphicAction()](http://code.google.com/p/googlemock/wiki/V1_7_CookBook#Writing_New_Polymorphic_Actions), -or you can write a stub function and invoke it using -[Invoke()](http://code.google.com/p/googlemock/wiki/V1_7_CookBook#Using_Functions_Methods_Functors). - -## MOCK\_METHODn()'s second argument looks funny. Why don't you use the MOCK\_METHODn(Method, return\_type, arg\_1, ..., arg\_n) syntax? ## - -What?! I think it's beautiful. :-) - -While which syntax looks more natural is a subjective matter to some -extent, Google Mock's syntax was chosen for several practical advantages it -has. - -Try to mock a function that takes a map as an argument: -``` -virtual int GetSize(const map& m); -``` - -Using the proposed syntax, it would be: -``` -MOCK_METHOD1(GetSize, int, const map& m); -``` - -Guess what? You'll get a compiler error as the compiler thinks that -`const map& m` are **two**, not one, arguments. To work -around this you can use `typedef` to give the map type a name, but -that gets in the way of your work. Google Mock's syntax avoids this -problem as the function's argument types are protected inside a pair -of parentheses: -``` -// This compiles fine. -MOCK_METHOD1(GetSize, int(const map& m)); -``` - -You still need a `typedef` if the return type contains an unprotected -comma, but that's much rarer. - -Other advantages include: - 1. `MOCK_METHOD1(Foo, int, bool)` can leave a reader wonder whether the method returns `int` or `bool`, while there won't be such confusion using Google Mock's syntax. - 1. The way Google Mock describes a function type is nothing new, although many people may not be familiar with it. The same syntax was used in C, and the `function` library in `tr1` uses this syntax extensively. Since `tr1` will become a part of the new version of STL, we feel very comfortable to be consistent with it. - 1. The function type syntax is also used in other parts of Google Mock's API (e.g. the action interface) in order to make the implementation tractable. A user needs to learn it anyway in order to utilize Google Mock's more advanced features. We'd as well stick to the same syntax in `MOCK_METHOD*`! - -## My code calls a static/global function. Can I mock it? ## - -You can, but you need to make some changes. - -In general, if you find yourself needing to mock a static function, -it's a sign that your modules are too tightly coupled (and less -flexible, less reusable, less testable, etc). You are probably better -off defining a small interface and call the function through that -interface, which then can be easily mocked. It's a bit of work -initially, but usually pays for itself quickly. - -This Google Testing Blog -[post](http://googletesting.blogspot.com/2008/06/defeat-static-cling.html) -says it excellently. Check it out. - -## My mock object needs to do complex stuff. It's a lot of pain to specify the actions. Google Mock sucks! ## - -I know it's not a question, but you get an answer for free any way. :-) - -With Google Mock, you can create mocks in C++ easily. And people might be -tempted to use them everywhere. Sometimes they work great, and -sometimes you may find them, well, a pain to use. So, what's wrong in -the latter case? - -When you write a test without using mocks, you exercise the code and -assert that it returns the correct value or that the system is in an -expected state. This is sometimes called "state-based testing". - -Mocks are great for what some call "interaction-based" testing: -instead of checking the system state at the very end, mock objects -verify that they are invoked the right way and report an error as soon -as it arises, giving you a handle on the precise context in which the -error was triggered. This is often more effective and economical to -do than state-based testing. - -If you are doing state-based testing and using a test double just to -simulate the real object, you are probably better off using a fake. -Using a mock in this case causes pain, as it's not a strong point for -mocks to perform complex actions. If you experience this and think -that mocks suck, you are just not using the right tool for your -problem. Or, you might be trying to solve the wrong problem. :-) - -## I got a warning "Uninteresting function call encountered - default action taken.." Should I panic? ## - -By all means, NO! It's just an FYI. - -What it means is that you have a mock function, you haven't set any -expectations on it (by Google Mock's rule this means that you are not -interested in calls to this function and therefore it can be called -any number of times), and it is called. That's OK - you didn't say -it's not OK to call the function! - -What if you actually meant to disallow this function to be called, but -forgot to write `EXPECT_CALL(foo, Bar()).Times(0)`? While -one can argue that it's the user's fault, Google Mock tries to be nice and -prints you a note. - -So, when you see the message and believe that there shouldn't be any -uninteresting calls, you should investigate what's going on. To make -your life easier, Google Mock prints the function name and arguments -when an uninteresting call is encountered. - -## I want to define a custom action. Should I use Invoke() or implement the action interface? ## - -Either way is fine - you want to choose the one that's more convenient -for your circumstance. - -Usually, if your action is for a particular function type, defining it -using `Invoke()` should be easier; if your action can be used in -functions of different types (e.g. if you are defining -`Return(value)`), `MakePolymorphicAction()` is -easiest. Sometimes you want precise control on what types of -functions the action can be used in, and implementing -`ActionInterface` is the way to go here. See the implementation of -`Return()` in `include/gmock/gmock-actions.h` for an example. - -## I'm using the set-argument-pointee action, and the compiler complains about "conflicting return type specified". What does it mean? ## - -You got this error as Google Mock has no idea what value it should return -when the mock method is called. `SetArgPointee()` says what the -side effect is, but doesn't say what the return value should be. You -need `DoAll()` to chain a `SetArgPointee()` with a `Return()`. - -See this [recipe](http://code.google.com/p/googlemock/wiki/V1_7_CookBook#Mocking_Side_Effects) for more details and an example. - - -## My question is not in your FAQ! ## - -If you cannot find the answer to your question in this FAQ, there are -some other resources you can use: - - 1. read other [wiki pages](http://code.google.com/p/googlemock/w/list), - 1. search the mailing list [archive](http://groups.google.com/group/googlemock/topics), - 1. ask it on [googlemock@googlegroups.com](mailto:googlemock@googlegroups.com) and someone will answer it (to prevent spam, we require you to join the [discussion group](http://groups.google.com/group/googlemock) before you can post.). - -Please note that creating an issue in the -[issue tracker](http://code.google.com/p/googlemock/issues/list) is _not_ -a good way to get your answer, as it is monitored infrequently by a -very small number of people. - -When asking a question, it's helpful to provide as much of the -following information as possible (people cannot help you if there's -not enough information in your question): - - * the version (or the revision number if you check out from SVN directly) of Google Mock you use (Google Mock is under active development, so it's possible that your problem has been solved in a later version), - * your operating system, - * the name and version of your compiler, - * the complete command line flags you give to your compiler, - * the complete compiler error messages (if the question is about compilation), - * the _actual_ code (ideally, a minimal but complete program) that has the problem you encounter. \ No newline at end of file diff --git a/googlemock/include/gmock/gmock-actions.h b/googlemock/include/gmock/gmock-actions.h index b3f654af..845c8232 100644 --- a/googlemock/include/gmock/gmock-actions.h +++ b/googlemock/include/gmock/gmock-actions.h @@ -1029,9 +1029,9 @@ class DoBothAction { // return sqrt(x*x + y*y); // } // ... -// EXEPCT_CALL(mock, Foo("abc", _, _)) +// EXPECT_CALL(mock, Foo("abc", _, _)) // .WillOnce(Invoke(DistanceToOriginWithLabel)); -// EXEPCT_CALL(mock, Bar(5, _, _)) +// EXPECT_CALL(mock, Bar(5, _, _)) // .WillOnce(Invoke(DistanceToOriginWithIndex)); // // you could write @@ -1041,8 +1041,8 @@ class DoBothAction { // return sqrt(x*x + y*y); // } // ... -// EXEPCT_CALL(mock, Foo("abc", _, _)).WillOnce(Invoke(DistanceToOrigin)); -// EXEPCT_CALL(mock, Bar(5, _, _)).WillOnce(Invoke(DistanceToOrigin)); +// EXPECT_CALL(mock, Foo("abc", _, _)).WillOnce(Invoke(DistanceToOrigin)); +// EXPECT_CALL(mock, Bar(5, _, _)).WillOnce(Invoke(DistanceToOrigin)); typedef internal::IgnoredValue Unused; // This constructor allows us to turn an Action object into an diff --git a/googlemock/include/gmock/gmock-matchers.h b/googlemock/include/gmock/gmock-matchers.h index 9ade5b64..3a97c438 100644 --- a/googlemock/include/gmock/gmock-matchers.h +++ b/googlemock/include/gmock/gmock-matchers.h @@ -646,7 +646,7 @@ class SafeMatcherCastImpl { // type U. GTEST_COMPILE_ASSERT_( internal::is_reference::value || !internal::is_reference::value, - cannot_convert_non_referentce_arg_to_reference); + cannot_convert_non_reference_arg_to_reference); // In case both T and U are arithmetic types, enforce that the // conversion is not lossy. typedef GTEST_REMOVE_REFERENCE_AND_CONST_(T) RawT; diff --git a/googlemock/src/gmock-matchers.cc b/googlemock/src/gmock-matchers.cc index e0de25cb..6e40e5e8 100644 --- a/googlemock/src/gmock-matchers.cc +++ b/googlemock/src/gmock-matchers.cc @@ -288,7 +288,7 @@ class MaxBipartiteMatchState { // Each element of the left_ vector represents a left hand side node // (i.e. an element) and each element of right_ is a right hand side // node (i.e. a matcher). The values in the left_ vector indicate - // outflow from that node to a node on the the right_ side. The values + // outflow from that node to a node on the right_ side. The values // in the right_ indicate inflow, and specify which left_ node is // feeding that right_ node, if any. For example, left_[3] == 1 means // there's a flow from element #3 to matcher #1. Such a flow would also diff --git a/googlemock/test/gmock-generated-actions_test.cc b/googlemock/test/gmock-generated-actions_test.cc index 58d45728..80bcb31c 100644 --- a/googlemock/test/gmock-generated-actions_test.cc +++ b/googlemock/test/gmock-generated-actions_test.cc @@ -1120,7 +1120,7 @@ TEST(ActionTemplateTest, WorksForIntegralTemplateParams) { EXPECT_FALSE(b); // Verifies that resetter is deleted. } -// Tests that ACTION_TEMPLATES works for template template parameters. +// Tests that ACTION_TEMPLATE works for a template with template parameters. ACTION_TEMPLATE(ReturnSmartPointer, HAS_1_TEMPLATE_PARAMS(template class, Pointer), diff --git a/googletest/CMakeLists.txt b/googletest/CMakeLists.txt index 36d0a9ec..b5414608 100644 --- a/googletest/CMakeLists.txt +++ b/googletest/CMakeLists.txt @@ -44,7 +44,12 @@ endif() # as ${gtest_SOURCE_DIR} and to the root binary directory as # ${gtest_BINARY_DIR}. # Language "C" is required for find_package(Threads). -project(gtest CXX C) +if (CMAKE_VERSION VERSION_LESS 3.0) + project(gtest CXX C) +else() + cmake_policy(SET CMP0048 NEW) + project(gtest VERSION 1.9.0 LANGUAGES CXX C) +endif() cmake_minimum_required(VERSION 2.6.4) if (COMMAND set_up_hermetic_build) @@ -102,10 +107,26 @@ endif() ######################################################################## # # Install rules -install(TARGETS gtest gtest_main - DESTINATION lib) -install(DIRECTORY ${gtest_SOURCE_DIR}/include/gtest - DESTINATION include) +if(INSTALL_GTEST) + install(TARGETS gtest gtest_main + RUNTIME DESTINATION ${CMAKE_INSTALL_BINDIR} + ARCHIVE DESTINATION ${CMAKE_INSTALL_LIBDIR} + LIBRARY DESTINATION ${CMAKE_INSTALL_LIBDIR}) + install(DIRECTORY ${gtest_SOURCE_DIR}/include/gtest + DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}) + + # configure and install pkgconfig files + configure_file( + cmake/gtest.pc.in + "${CMAKE_BINARY_DIR}/gtest.pc" + @ONLY) + configure_file( + cmake/gtest_main.pc.in + "${CMAKE_BINARY_DIR}/gtest_main.pc" + @ONLY) + install(FILES "${CMAKE_BINARY_DIR}/gtest.pc" "${CMAKE_BINARY_DIR}/gtest_main.pc" + DESTINATION "${CMAKE_INSTALL_LIBDIR}/pkgconfig") +endif() ######################################################################## # diff --git a/googletest/Makefile.am b/googletest/Makefile.am index 29797e4e..dbc004de 100644 --- a/googletest/Makefile.am +++ b/googletest/Makefile.am @@ -216,7 +216,7 @@ pkginclude_internal_HEADERS = \ lib_libgtest_main_la_SOURCES = src/gtest_main.cc lib_libgtest_main_la_LIBADD = lib/libgtest.la -# Bulid rules for samples and tests. Automake's naming for some of +# Build rules for samples and tests. Automake's naming for some of # these variables isn't terribly obvious, so this is a brief # reference: # diff --git a/googletest/cmake/gtest.pc.in b/googletest/cmake/gtest.pc.in new file mode 100644 index 00000000..e7967ad5 --- /dev/null +++ b/googletest/cmake/gtest.pc.in @@ -0,0 +1,9 @@ +libdir=@CMAKE_INSTALL_FULL_LIBDIR@ +includedir=@CMAKE_INSTALL_FULL_INCLUDEDIR@ + +Name: gtest +Description: GoogleTest (without main() function) +Version: @PROJECT_VERSION@ +URL: https://github.com/google/googletest +Libs: -L${libdir} -lgtest @CMAKE_THREAD_LIBS_INIT@ +Cflags: -I${includedir} @GTEST_HAS_PTHREAD_MACRO@ @CMAKE_THREAD_LIBS_INIT@ diff --git a/googletest/cmake/gtest_main.pc.in b/googletest/cmake/gtest_main.pc.in new file mode 100644 index 00000000..fe25d9c7 --- /dev/null +++ b/googletest/cmake/gtest_main.pc.in @@ -0,0 +1,10 @@ +libdir=@CMAKE_INSTALL_FULL_LIBDIR@ +includedir=@CMAKE_INSTALL_FULL_INCLUDEDIR@ + +Name: gtest_main +Description: GoogleTest (with main() function) +Version: @PROJECT_VERSION@ +URL: https://github.com/google/googletest +Requires: gtest +Libs: -L${libdir} -lgtest_main @CMAKE_THREAD_LIBS_INIT@ +Cflags: -I${includedir} @GTEST_HAS_PTHREAD_MACRO@ @CMAKE_THREAD_LIBS_INIT@ diff --git a/googletest/cmake/internal_utils.cmake b/googletest/cmake/internal_utils.cmake index 8878dc1a..f0f54d02 100644 --- a/googletest/cmake/internal_utils.cmake +++ b/googletest/cmake/internal_utils.cmake @@ -50,6 +50,7 @@ macro(config_compiler_and_linker) # instead, we use windows threading primitives if (NOT gtest_disable_pthreads AND NOT MINGW) # Defines CMAKE_USE_PTHREADS_INIT and CMAKE_THREAD_LIBS_INIT. + set(THREADS_PREFER_PTHREAD_FLAG ON) find_package(Threads) endif() @@ -126,10 +127,11 @@ macro(config_compiler_and_linker) endif() if (CMAKE_USE_PTHREADS_INIT) # The pthreads library is available and allowed. - set(cxx_base_flags "${cxx_base_flags} -DGTEST_HAS_PTHREAD=1") + set(GTEST_HAS_PTHREAD_MACRO "-DGTEST_HAS_PTHREAD=1") else() - set(cxx_base_flags "${cxx_base_flags} -DGTEST_HAS_PTHREAD=0") + set(GTEST_HAS_PTHREAD_MACRO "-DGTEST_HAS_PTHREAD=0") endif() + set(cxx_base_flags "${cxx_base_flags} ${GTEST_HAS_PTHREAD_MACRO}") # For building gtest's own tests and samples. set(cxx_exception "${CMAKE_CXX_FLAGS} ${cxx_base_flags} ${cxx_exception_flags}") diff --git a/googletest/docs/AdvancedGuide.md b/googletest/docs/AdvancedGuide.md index fc27d1d0..a454bf45 100644 --- a/googletest/docs/AdvancedGuide.md +++ b/googletest/docs/AdvancedGuide.md @@ -32,7 +32,7 @@ output in the future. `FAIL()` generates a fatal failure, while `ADD_FAILURE()` and `ADD_FAILURE_AT()` generate a nonfatal failure. These are useful when control flow, rather than a Boolean expression, -deteremines the test's success or failure. For example, you might want to write +determines the test's success or failure. For example, you might want to write something like: ``` @@ -128,7 +128,7 @@ c is 10
1. If you see a compiler error "no matching function to call" when using `ASSERT_PRED*` or `EXPECT_PRED*`, please see [this FAQ](FAQ.md#the-compiler-complains-no-matching-function-to-call-when-i-use-assert_predn-how-do-i-fix-it) for how to resolve it. 1. Currently we only provide predicate assertions of arity <= 5. If you need a higher-arity assertion, let us know. -_Availability_: Linux, Windows, Mac +_Availability_: Linux, Windows, Mac. ### Using a Function That Returns an AssertionResult ### @@ -675,7 +675,7 @@ syntax only. ## How It Works ## Under the hood, `ASSERT_EXIT()` spawns a new process and executes the -death test statement in that process. The details of of how precisely +death test statement in that process. The details of how precisely that happens depend on the platform and the variable `::testing::GTEST_FLAG(death_test_style)` (which is initialized from the command-line flag `--gtest_death_test_style`). @@ -1344,7 +1344,7 @@ TYPED_TEST(FooTest, DoesBlah) { TYPED_TEST(FooTest, HasPropertyA) { ... } ``` -You can see `samples/sample6_unittest.cc` for a complete example. +You can see [`samples/sample6_unittest.cc`](../samples/sample6_unittest.cc) for a complete example. _Availability:_ Linux, Windows (requires MSVC 8.0 or above), Mac; since version 1.1.0. @@ -1444,7 +1444,7 @@ absolutely have to test non-public interface code though, you can. There are two cases to consider: * Static functions (_not_ the same as static member functions!) or unnamed namespaces, and - * Private or protected class members + * Private or protected class members. ## Static Functions ## @@ -1551,7 +1551,7 @@ exception, you could catch the exception and assert on it. But Google Test doesn't use exceptions, so how do we test that a piece of code generates an expected failure? -`"gtest/gtest-spi.h"` contains some constructs to do this. After +`"gtest/gtest-spi.h"` contains some constructs to do this. After `#include`ing this header, you can use | `EXPECT_FATAL_FAILURE(`_statement, substring_`);` | diff --git a/googletest/docs/Documentation.md b/googletest/docs/Documentation.md index 8ca1aac7..1e4c5c54 100644 --- a/googletest/docs/Documentation.md +++ b/googletest/docs/Documentation.md @@ -1,6 +1,8 @@ -This page lists all documentation wiki pages for Google Test **(the SVN trunk version)** --- **if you use a released version of Google Test, please read the -documentation for that specific version instead.** +This page lists all documentation markdown files for Google Test **(the +current git version)** +-- **if you use a former version of Google Test, please read the +documentation for that specific version instead (e.g. by checking out +the respective git branch/tag).** * [Primer](Primer.md) -- start here if you are new to Google Test. * [Samples](Samples.md) -- learn from examples. @@ -11,4 +13,4 @@ documentation for that specific version instead.** To contribute code to Google Test, read: * [DevGuide](DevGuide.md) -- read this _before_ writing your first patch. - * [PumpManual](PumpManual.md) -- how we generate some of Google Test's source files. \ No newline at end of file + * [PumpManual](PumpManual.md) -- how we generate some of Google Test's source files. diff --git a/googletest/docs/FAQ.md b/googletest/docs/FAQ.md index 7d1caf6a..36f5f7fb 100644 --- a/googletest/docs/FAQ.md +++ b/googletest/docs/FAQ.md @@ -960,12 +960,11 @@ Have you read a the Google Test Primer page? ## I want to use Google Test with Visual Studio but don't know where to start. ## -Many people are in your position and one of the posted his solution to -our mailing list. +Many people are in your position and one of them posted his solution to our mailing list. ## I am seeing compile errors mentioning std::type\_traits when I try to use Google Test on Solaris. ## Google Test uses parts of the standard C++ library that SunStudio does not support. -Our users reported success using alternative implementations. Try running the build after runing this commad: +Our users reported success using alternative implementations. Try running the build after running this command: `export CC=cc CXX=CC CXXFLAGS='-library=stlport4'` @@ -1015,7 +1014,7 @@ instead of ``` in order to define a test. -Currently, the following `TEST`, `FAIL`, `SUCCEED`, and the basic comparison assertion macros can have alternative names. You can see the full list of covered macros [here](http://www.google.com/codesearch?q=if+!GTEST_DONT_DEFINE_\w%2B+package:http://googletest\.googlecode\.com+file:/include/gtest/gtest.h). More information can be found in the "Avoiding Macro Name Clashes" section of the README file. +Currently, the following `TEST`, `FAIL`, `SUCCEED`, and the basic comparison assertion macros can have . You can see the full list of covered macros [here](../include/gtest/gtest.h). More information can be found in the "Avoiding Macro Name Clashes" section of the README file. ## Is it OK if I have two separate `TEST(Foo, Bar)` test methods defined in different namespaces? ## @@ -1061,6 +1060,12 @@ TEST_F(CoolTest, DoSomething) { If you try to build Google Test's Xcode project with Xcode 4.0 or later, you may encounter an error message that looks like "Missing SDK in target gtest\_framework: /Developer/SDKs/MacOSX10.4u.sdk". That means that Xcode does not support the SDK the project is targeting. See the Xcode section in the [README](../README.md) file on how to resolve this. +## How do I easily discover the flags needed for GoogleTest? ## + +GoogleTest (and GoogleMock) now support discovering all necessary flags using pkg-config. +See the [pkg-config guide](Pkgconfig.md) on how you can easily discover all compiler and +linker flags using pkg-config. + ## My question is not covered in your FAQ! ## If you cannot find the answer to your question in this FAQ, there are diff --git a/googletest/docs/Pkgconfig.md b/googletest/docs/Pkgconfig.md new file mode 100644 index 00000000..97612894 --- /dev/null +++ b/googletest/docs/Pkgconfig.md @@ -0,0 +1,146 @@ +## Using GoogleTest from various build systems ## + +GoogleTest comes with pkg-config files that can be used to determine all +necessary flags for compiling and linking to GoogleTest (and GoogleMock). +Pkg-config is a standardised plain-text format containing + + * the includedir (-I) path + * necessary macro (-D) definitions + * further required flags (-pthread) + * the library (-L) path + * the library (-l) to link to + +All current build systems support pkg-config in one way or another. For +all examples here we assume you want to compile the sample +`samples/sample3_unittest.cc`. + + +### CMake ### + +Using `pkg-config` in CMake is fairly easy: + +``` +cmake_minimum_required(VERSION 3.0) + +cmake_policy(SET CMP0048 NEW) +project(my_gtest_pkgconfig VERSION 0.0.1 LANGUAGES CXX) + +find_package(PkgConfig) +pkg_search_module(GTEST REQUIRED gtest_main) + +add_executable(testapp samples/sample3_unittest.cc) +target_link_libraries(testapp ${GTEST_LDFLAGS}) +target_compile_options(testapp PUBLIC ${GTEST_CFLAGS}) + +include(CTest) +add_test(first_and_only_test testapp) +``` + +It is generally recommended that you use `target_compile_options` + `_CFLAGS` +over `target_include_directories` + `_INCLUDE_DIRS` as the former includes not +just -I flags (GoogleTest might require a macro indicating to internal headers +that all libraries have been compiled with threading enabled. In addition, +GoogleTest might also require `-pthread` in the compiling step, and as such +splitting the pkg-config `Cflags` variable into include dirs and macros for +`target_compile_definitions()` might still miss this). The same recommendation +goes for using `_LDFLAGS` over the more commonplace `_LIBRARIES`, which +happens to discard `-L` flags and `-pthread`. + + +### Autotools ### + +Finding GoogleTest in Autoconf and using it from Automake is also fairly easy: + +In your `configure.ac`: + +``` +AC_PREREQ([2.69]) +AC_INIT([my_gtest_pkgconfig], [0.0.1]) +AC_CONFIG_SRCDIR([samples/sample3_unittest.cc]) +AC_PROG_CXX + +PKG_CHECK_MODULES([GTEST], [gtest_main]) + +AM_INIT_AUTOMAKE([foreign subdir-objects]) +AC_CONFIG_FILES([Makefile]) +AC_OUTPUT +``` + +and in your `Makefile.am`: + +``` +check_PROGRAMS = testapp +TESTS = $(check_PROGRAMS) + +testapp_SOURCES = samples/sample3_unittest.cc +testapp_CXXFLAGS = $(GTEST_CFLAGS) +testapp_LDADD = $(GTEST_LIBS) +``` + + +### Meson ### + +Meson natively uses pkgconfig to query dependencies: + +``` +project('my_gtest_pkgconfig', 'cpp', version : '0.0.1') + +gtest_dep = dependency('gtest_main') + +testapp = executable( + 'testapp', + files(['samples/sample3_unittest.cc']), + dependencies : gtest_dep, + install : false) + +test('first_and_only_test', testapp) +``` + + +### Plain Makefiles ### + +Since `pkg-config` is a small Unix command-line utility, it can be used +in handwritten `Makefile`s too: + +``` +GTEST_CFLAGS = `pkg-config --cflags gtest_main` +GTEST_LIBS = `pkg-config --libs gtest_main` + +.PHONY: tests all + +tests: all + ./testapp + +all: testapp + +testapp: testapp.o + $(CXX) $(CXXFLAGS) $(LDFLAGS) $< -o $@ $(GTEST_LIBS) + +testapp.o: samples/sample3_unittest.cc + $(CXX) $(CPPFLAGS) $(CXXFLAGS) $< -c -o $@ $(GTEST_CFLAGS) +``` + + +### Help! pkg-config can't find GoogleTest! ### + +Let's say you have a `CMakeLists.txt` along the lines of the one in this +tutorial and you try to run `cmake`. It is very possible that you get a +failure along the lines of: + +``` +-- Checking for one of the modules 'gtest_main' +CMake Error at /usr/share/cmake/Modules/FindPkgConfig.cmake:640 (message): + None of the required 'gtest_main' found +``` + +These failures are common if you installed GoogleTest yourself and have not +sourced it from a distro or other package manager. If so, you need to tell +pkg-config where it can find the `.pc` files containing the information. +Say you installed GoogleTest to `/usr/local`, then it might be that the +`.pc` files are installed under `/usr/local/lib64/pkgconfig`. If you set + +``` +export PKG_CONFIG_PATH=/usr/local/lib64/pkgconfig +``` + +pkg-config will also try to look in `PKG_CONFIG_PATH` to find `gtest_main.pc`. diff --git a/googletest/docs/Primer.md b/googletest/docs/Primer.md index 474c1d2a..384d4d6e 100644 --- a/googletest/docs/Primer.md +++ b/googletest/docs/Primer.md @@ -23,6 +23,40 @@ So let's go! _Note:_ We sometimes refer to Google C++ Testing Framework informally as _Google Test_. +# Beware of the nomenclature # + +_Note:_ There might be some confusion of idea due to different +definitions of the terms _Test_, _Test Case_ and _Test Suite_, so beware +of misunderstanding these. + +Historically, the Google C++ Testing Framework started to use the term +_Test Case_ for grouping related tests, whereas current publications +including the International Software Testing Qualifications Board +([ISTQB](http://www.istqb.org/)) and various textbooks on Software +Quality use the term _[Test +Suite](http://glossary.istqb.org/search/test%20suite)_ for this. + +The related term _Test_, as it is used in the Google C++ Testing +Framework, is corresponding to the term _[Test +Case](http://glossary.istqb.org/search/test%20case)_ of ISTQB and +others. + +The term _Test_ is commonly of broad enough sense, including ISTQB's +definition of _Test Case_, so it's not much of a problem here. But the +term _Test Case_ as used in Google Test is of contradictory sense and thus confusing. + +Unfortunately replacing the term _Test Case_ by _Test Suite_ throughout +the Google C++ Testing Framework is not easy without breaking dependent +projects, as `TestCase` is part of the public API at various places. + +So for the time being, please be aware of the different definitions of +the terms: + +Meaning | Google Test Term | [ISTQB](http://www.istqb.org/) Term +------- | ---------------- | ----------------------------------- +Exercise a particular program path with specific input values and verify the results | [TEST()](#simple-tests) | [Test Case](http://glossary.istqb.org/search/test%20case) +A set of several tests related to one component | [Test Case](#basic-concepts) | [Test Suite](http://glossary.istqb.org/search/test%20suite) + # Setting up a New Test Project # To write a test program using Google Test, you need to compile Google @@ -179,7 +213,7 @@ two `string` objects, use `EXPECT_EQ`, `EXPECT_NE`, and etc instead. | **Fatal assertion** | **Nonfatal assertion** | **Verifies** | |:--------------------|:-----------------------|:-------------| -| `ASSERT_STREQ(`_str1_`, `_str2_`);` | `EXPECT_STREQ(`_str1_`, `_str_2`);` | the two C strings have the same content | +| `ASSERT_STREQ(`_str1_`, `_str2_`);` | `EXPECT_STREQ(`_str1_`, `_str2_`);` | the two C strings have the same content | | `ASSERT_STRNE(`_str1_`, `_str2_`);` | `EXPECT_STRNE(`_str1_`, `_str2_`);` | the two C strings have different content | | `ASSERT_STRCASEEQ(`_str1_`, `_str2_`);`| `EXPECT_STRCASEEQ(`_str1_`, `_str2_`);` | the two C strings have the same content, ignoring case | | `ASSERT_STRCASENE(`_str1_`, `_str2_`);`| `EXPECT_STRCASENE(`_str1_`, `_str2_`);` | the two C strings have different content, ignoring case | @@ -281,7 +315,7 @@ declaration`". For each test defined with `TEST_F()`, Google Test will: 1. Create a _fresh_ test fixture at runtime - 1. Immediately initialize it via `SetUp()` , + 1. Immediately initialize it via `SetUp()` 1. Run the test 1. Clean up by calling `TearDown()` 1. Delete the test fixture. Note that different tests in the same test case have different test fixture objects, and Google Test always deletes a test fixture before it creates the next one. Google Test does not reuse the same test fixture for multiple tests. Any changes one test makes to the fixture do not affect other tests. @@ -382,7 +416,7 @@ When invoked, the `RUN_ALL_TESTS()` macro: 1. Restores the state of all Google Test flags. 1. Repeats the above steps for the next test, until all tests have run. -In addition, if the text fixture's constructor generates a fatal failure in +In addition, if the test fixture's constructor generates a fatal failure in step 2, there is no point for step 3 - 5 and they are thus skipped. Similarly, if step 3 generates a fatal failure, step 4 will be skipped. diff --git a/googletest/docs/PumpManual.md b/googletest/docs/PumpManual.md index 8184f153..109c7f2c 100644 --- a/googletest/docs/PumpManual.md +++ b/googletest/docs/PumpManual.md @@ -169,7 +169,7 @@ improving Pump. ## Real Examples ## -You can find real-world applications of Pump in [Google Test](http://www.google.com/codesearch?q=file%3A\.pump%24+package%3Ahttp%3A%2F%2Fgoogletest\.googlecode\.com) and [Google Mock](http://www.google.com/codesearch?q=file%3A\.pump%24+package%3Ahttp%3A%2F%2Fgooglemock\.googlecode\.com). The source file `foo.h.pump` generates `foo.h`. +You can find real-world applications of Pump in [Google Test](https://github.com/google/googletest/tree/master/googletest) and [Google Mock](https://github.com/google/googletest/tree/master/googlemock). The source file `foo.h.pump` generates `foo.h`. ## Tips ## diff --git a/googletest/docs/V1_5_AdvancedGuide.md b/googletest/docs/V1_5_AdvancedGuide.md deleted file mode 100644 index 34e19c26..00000000 --- a/googletest/docs/V1_5_AdvancedGuide.md +++ /dev/null @@ -1,2096 +0,0 @@ - - -Now that you have read [Primer](V1_5_Primer.md) and learned how to write tests -using Google Test, it's time to learn some new tricks. This document -will show you more assertions as well as how to construct complex -failure messages, propagate fatal failures, reuse and speed up your -test fixtures, and use various flags with your tests. - -# More Assertions # - -This section covers some less frequently used, but still significant, -assertions. - -## Explicit Success and Failure ## - -These three assertions do not actually test a value or expression. Instead, -they generate a success or failure directly. Like the macros that actually -perform a test, you may stream a custom failure message into the them. - -| `SUCCEED();` | -|:-------------| - -Generates a success. This does NOT make the overall test succeed. A test is -considered successful only if none of its assertions fail during its execution. - -Note: `SUCCEED()` is purely documentary and currently doesn't generate any -user-visible output. However, we may add `SUCCEED()` messages to Google Test's -output in the future. - -| `FAIL();` | `ADD_FAILURE();` | -|:-----------|:-----------------| - -`FAIL*` generates a fatal failure while `ADD_FAILURE*` generates a nonfatal -failure. These are useful when control flow, rather than a Boolean expression, -deteremines the test's success or failure. For example, you might want to write -something like: - -``` -switch(expression) { - case 1: ... some checks ... - case 2: ... some other checks - ... - default: FAIL() << "We shouldn't get here."; -} -``` - -_Availability_: Linux, Windows, Mac. - -## Exception Assertions ## - -These are for verifying that a piece of code throws (or does not -throw) an exception of the given type: - -| **Fatal assertion** | **Nonfatal assertion** | **Verifies** | -|:--------------------|:-----------------------|:-------------| -| `ASSERT_THROW(`_statement_, _exception\_type_`);` | `EXPECT_THROW(`_statement_, _exception\_type_`);` | _statement_ throws an exception of the given type | -| `ASSERT_ANY_THROW(`_statement_`);` | `EXPECT_ANY_THROW(`_statement_`);` | _statement_ throws an exception of any type | -| `ASSERT_NO_THROW(`_statement_`);` | `EXPECT_NO_THROW(`_statement_`);` | _statement_ doesn't throw any exception | - -Examples: - -``` -ASSERT_THROW(Foo(5), bar_exception); - -EXPECT_NO_THROW({ - int n = 5; - Bar(&n); -}); -``` - -_Availability_: Linux, Windows, Mac; since version 1.1.0. - -## Predicate Assertions for Better Error Messages ## - -Even though Google Test has a rich set of assertions, they can never be -complete, as it's impossible (nor a good idea) to anticipate all the scenarios -a user might run into. Therefore, sometimes a user has to use `EXPECT_TRUE()` -to check a complex expression, for lack of a better macro. This has the problem -of not showing you the values of the parts of the expression, making it hard to -understand what went wrong. As a workaround, some users choose to construct the -failure message by themselves, streaming it into `EXPECT_TRUE()`. However, this -is awkward especially when the expression has side-effects or is expensive to -evaluate. - -Google Test gives you three different options to solve this problem: - -### Using an Existing Boolean Function ### - -If you already have a function or a functor that returns `bool` (or a type -that can be implicitly converted to `bool`), you can use it in a _predicate -assertion_ to get the function arguments printed for free: - -| **Fatal assertion** | **Nonfatal assertion** | **Verifies** | -|:--------------------|:-----------------------|:-------------| -| `ASSERT_PRED1(`_pred1, val1_`);` | `EXPECT_PRED1(`_pred1, val1_`);` | _pred1(val1)_ returns true | -| `ASSERT_PRED2(`_pred2, val1, val2_`);` | `EXPECT_PRED2(`_pred2, val1, val2_`);` | _pred2(val1, val2)_ returns true | -| ... | ... | ... | - -In the above, _predn_ is an _n_-ary predicate function or functor, where -_val1_, _val2_, ..., and _valn_ are its arguments. The assertion succeeds -if the predicate returns `true` when applied to the given arguments, and fails -otherwise. When the assertion fails, it prints the value of each argument. In -either case, the arguments are evaluated exactly once. - -Here's an example. Given - -``` -// Returns true iff m and n have no common divisors except 1. -bool MutuallyPrime(int m, int n) { ... } -const int a = 3; -const int b = 4; -const int c = 10; -``` - -the assertion `EXPECT_PRED2(MutuallyPrime, a, b);` will succeed, while the -assertion `EXPECT_PRED2(MutuallyPrime, b, c);` will fail with the message - -
-!MutuallyPrime(b, c) is false, where

-b is 4

-c is 10

-
- -**Notes:** - - 1. If you see a compiler error "no matching function to call" when using `ASSERT_PRED*` or `EXPECT_PRED*`, please see [this](V1_5_FAQ.md#the-compiler-complains-about-undefined-references-to-some-static-const-member-variables-but-i-did-define-them-in-the-class-body-whats-wrong) for how to resolve it. - 1. Currently we only provide predicate assertions of arity <= 5. If you need a higher-arity assertion, let us know. - -_Availability_: Linux, Windows, Mac - -### Using a Function That Returns an AssertionResult ### - -While `EXPECT_PRED*()` and friends are handy for a quick job, the -syntax is not satisfactory: you have to use different macros for -different arities, and it feels more like Lisp than C++. The -`::testing::AssertionResult` class solves this problem. - -An `AssertionResult` object represents the result of an assertion -(whether it's a success or a failure, and an associated message). You -can create an `AssertionResult` using one of these factory -functions: - -``` -namespace testing { - -// Returns an AssertionResult object to indicate that an assertion has -// succeeded. -AssertionResult AssertionSuccess(); - -// Returns an AssertionResult object to indicate that an assertion has -// failed. -AssertionResult AssertionFailure(); - -} -``` - -You can then use the `<<` operator to stream messages to the -`AssertionResult` object. - -To provide more readable messages in Boolean assertions -(e.g. `EXPECT_TRUE()`), write a predicate function that returns -`AssertionResult` instead of `bool`. For example, if you define -`IsEven()` as: - -``` -::testing::AssertionResult IsEven(int n) { - if ((n % 2) == 0) - return ::testing::AssertionSuccess(); - else - return ::testing::AssertionFailure() << n << " is odd"; -} -``` - -instead of: - -``` -bool IsEven(int n) { - return (n % 2) == 0; -} -``` - -the failed assertion `EXPECT_TRUE(IsEven(Fib(4)))` will print: - -
-Value of: !IsEven(Fib(4))

-Actual: false (*3 is odd*)

-Expected: true

-
- -instead of a more opaque - -
-Value of: !IsEven(Fib(4))

-Actual: false

-Expected: true

-
- -If you want informative messages in `EXPECT_FALSE` and `ASSERT_FALSE` -as well, and are fine with making the predicate slower in the success -case, you can supply a success message: - -``` -::testing::AssertionResult IsEven(int n) { - if ((n % 2) == 0) - return ::testing::AssertionSuccess() << n << " is even"; - else - return ::testing::AssertionFailure() << n << " is odd"; -} -``` - -Then the statement `EXPECT_FALSE(IsEven(Fib(6)))` will print - -
-Value of: !IsEven(Fib(6))

-Actual: true (8 is even)

-Expected: false

-
- -_Availability_: Linux, Windows, Mac; since version 1.4.1. - -### Using a Predicate-Formatter ### - -If you find the default message generated by `(ASSERT|EXPECT)_PRED*` and -`(ASSERT|EXPECT)_(TRUE|FALSE)` unsatisfactory, or some arguments to your -predicate do not support streaming to `ostream`, you can instead use the -following _predicate-formatter assertions_ to _fully_ customize how the -message is formatted: - -| **Fatal assertion** | **Nonfatal assertion** | **Verifies** | -|:--------------------|:-----------------------|:-------------| -| `ASSERT_PRED_FORMAT1(`_pred\_format1, val1_`);` | `EXPECT_PRED_FORMAT1(`_pred\_format1, val1_`); | _pred\_format1(val1)_ is successful | -| `ASSERT_PRED_FORMAT2(`_pred\_format2, val1, val2_`);` | `EXPECT_PRED_FORMAT2(`_pred\_format2, val1, val2_`);` | _pred\_format2(val1, val2)_ is successful | -| `...` | `...` | `...` | - -The difference between this and the previous two groups of macros is that instead of -a predicate, `(ASSERT|EXPECT)_PRED_FORMAT*` take a _predicate-formatter_ -(_pred\_formatn_), which is a function or functor with the signature: - -`::testing::AssertionResult PredicateFormattern(const char* `_expr1_`, const char* `_expr2_`, ... const char* `_exprn_`, T1 `_val1_`, T2 `_val2_`, ... Tn `_valn_`);` - -where _val1_, _val2_, ..., and _valn_ are the values of the predicate -arguments, and _expr1_, _expr2_, ..., and _exprn_ are the corresponding -expressions as they appear in the source code. The types `T1`, `T2`, ..., and -`Tn` can be either value types or reference types. For example, if an -argument has type `Foo`, you can declare it as either `Foo` or `const Foo&`, -whichever is appropriate. - -A predicate-formatter returns a `::testing::AssertionResult` object to indicate -whether the assertion has succeeded or not. The only way to create such an -object is to call one of these factory functions: - -As an example, let's improve the failure message in the previous example, which uses `EXPECT_PRED2()`: - -``` -// Returns the smallest prime common divisor of m and n, -// or 1 when m and n are mutually prime. -int SmallestPrimeCommonDivisor(int m, int n) { ... } - -// A predicate-formatter for asserting that two integers are mutually prime. -::testing::AssertionResult AssertMutuallyPrime(const char* m_expr, - const char* n_expr, - int m, - int n) { - if (MutuallyPrime(m, n)) - return ::testing::AssertionSuccess(); - - return ::testing::AssertionFailure() - << m_expr << " and " << n_expr << " (" << m << " and " << n - << ") are not mutually prime, " << "as they have a common divisor " - << SmallestPrimeCommonDivisor(m, n); -} -``` - -With this predicate-formatter, we can use - -``` -EXPECT_PRED_FORMAT2(AssertMutuallyPrime, b, c); -``` - -to generate the message - -
-b and c (4 and 10) are not mutually prime, as they have a common divisor 2.

-
- -As you may have realized, many of the assertions we introduced earlier are -special cases of `(EXPECT|ASSERT)_PRED_FORMAT*`. In fact, most of them are -indeed defined using `(EXPECT|ASSERT)_PRED_FORMAT*`. - -_Availability_: Linux, Windows, Mac. - - -## Floating-Point Comparison ## - -Comparing floating-point numbers is tricky. Due to round-off errors, it is -very unlikely that two floating-points will match exactly. Therefore, -`ASSERT_EQ` 's naive comparison usually doesn't work. And since floating-points -can have a wide value range, no single fixed error bound works. It's better to -compare by a fixed relative error bound, except for values close to 0 due to -the loss of precision there. - -In general, for floating-point comparison to make sense, the user needs to -carefully choose the error bound. If they don't want or care to, comparing in -terms of Units in the Last Place (ULPs) is a good default, and Google Test -provides assertions to do this. Full details about ULPs are quite long; if you -want to learn more, see -[this article on float comparison](http://www.cygnus-software.com/papers/comparingfloats/comparingfloats.htm). - -### Floating-Point Macros ### - -| **Fatal assertion** | **Nonfatal assertion** | **Verifies** | -|:--------------------|:-----------------------|:-------------| -| `ASSERT_FLOAT_EQ(`_expected, actual_`);` | `EXPECT_FLOAT_EQ(`_expected, actual_`);` | the two `float` values are almost equal | -| `ASSERT_DOUBLE_EQ(`_expected, actual_`);` | `EXPECT_DOUBLE_EQ(`_expected, actual_`);` | the two `double` values are almost equal | - -By "almost equal", we mean the two values are within 4 ULP's from each -other. - -The following assertions allow you to choose the acceptable error bound: - -| **Fatal assertion** | **Nonfatal assertion** | **Verifies** | -|:--------------------|:-----------------------|:-------------| -| `ASSERT_NEAR(`_val1, val2, abs\_error_`);` | `EXPECT_NEAR`_(val1, val2, abs\_error_`);` | the difference between _val1_ and _val2_ doesn't exceed the given absolute error | - -_Availability_: Linux, Windows, Mac. - -### Floating-Point Predicate-Format Functions ### - -Some floating-point operations are useful, but not that often used. In order -to avoid an explosion of new macros, we provide them as predicate-format -functions that can be used in predicate assertion macros (e.g. -`EXPECT_PRED_FORMAT2`, etc). - -``` -EXPECT_PRED_FORMAT2(::testing::FloatLE, val1, val2); -EXPECT_PRED_FORMAT2(::testing::DoubleLE, val1, val2); -``` - -Verifies that _val1_ is less than, or almost equal to, _val2_. You can -replace `EXPECT_PRED_FORMAT2` in the above table with `ASSERT_PRED_FORMAT2`. - -_Availability_: Linux, Windows, Mac. - -## Windows HRESULT assertions ## - -These assertions test for `HRESULT` success or failure. - -| **Fatal assertion** | **Nonfatal assertion** | **Verifies** | -|:--------------------|:-----------------------|:-------------| -| `ASSERT_HRESULT_SUCCEEDED(`_expression_`);` | `EXPECT_HRESULT_SUCCEEDED(`_expression_`);` | _expression_ is a success `HRESULT` | -| `ASSERT_HRESULT_FAILED(`_expression_`);` | `EXPECT_HRESULT_FAILED(`_expression_`);` | _expression_ is a failure `HRESULT` | - -The generated output contains the human-readable error message -associated with the `HRESULT` code returned by _expression_. - -You might use them like this: - -``` -CComPtr shell; -ASSERT_HRESULT_SUCCEEDED(shell.CoCreateInstance(L"Shell.Application")); -CComVariant empty; -ASSERT_HRESULT_SUCCEEDED(shell->ShellExecute(CComBSTR(url), empty, empty, empty, empty)); -``` - -_Availability_: Windows. - -## Type Assertions ## - -You can call the function -``` -::testing::StaticAssertTypeEq(); -``` -to assert that types `T1` and `T2` are the same. The function does -nothing if the assertion is satisfied. If the types are different, -the function call will fail to compile, and the compiler error message -will likely (depending on the compiler) show you the actual values of -`T1` and `T2`. This is mainly useful inside template code. - -_Caveat:_ When used inside a member function of a class template or a -function template, `StaticAssertTypeEq()` is effective _only if_ -the function is instantiated. For example, given: -``` -template class Foo { - public: - void Bar() { ::testing::StaticAssertTypeEq(); } -}; -``` -the code: -``` -void Test1() { Foo foo; } -``` -will _not_ generate a compiler error, as `Foo::Bar()` is never -actually instantiated. Instead, you need: -``` -void Test2() { Foo foo; foo.Bar(); } -``` -to cause a compiler error. - -_Availability:_ Linux, Windows, Mac; since version 1.3.0. - -## Assertion Placement ## - -You can use assertions in any C++ function. In particular, it doesn't -have to be a method of the test fixture class. The one constraint is -that assertions that generate a fatal failure (`FAIL*` and `ASSERT_*`) -can only be used in void-returning functions. This is a consequence of -Google Test not using exceptions. By placing it in a non-void function -you'll get a confusing compile error like -`"error: void value not ignored as it ought to be"`. - -If you need to use assertions in a function that returns non-void, one option -is to make the function return the value in an out parameter instead. For -example, you can rewrite `T2 Foo(T1 x)` to `void Foo(T1 x, T2* result)`. You -need to make sure that `*result` contains some sensible value even when the -function returns prematurely. As the function now returns `void`, you can use -any assertion inside of it. - -If changing the function's type is not an option, you should just use -assertions that generate non-fatal failures, such as `ADD_FAILURE*` and -`EXPECT_*`. - -_Note_: Constructors and destructors are not considered void-returning -functions, according to the C++ language specification, and so you may not use -fatal assertions in them. You'll get a compilation error if you try. A simple -workaround is to transfer the entire body of the constructor or destructor to a -private void-returning method. However, you should be aware that a fatal -assertion failure in a constructor does not terminate the current test, as your -intuition might suggest; it merely returns from the constructor early, possibly -leaving your object in a partially-constructed state. Likewise, a fatal -assertion failure in a destructor may leave your object in a -partially-destructed state. Use assertions carefully in these situations! - -# Death Tests # - -In many applications, there are assertions that can cause application failure -if a condition is not met. These sanity checks, which ensure that the program -is in a known good state, are there to fail at the earliest possible time after -some program state is corrupted. If the assertion checks the wrong condition, -then the program may proceed in an erroneous state, which could lead to memory -corruption, security holes, or worse. Hence it is vitally important to test -that such assertion statements work as expected. - -Since these precondition checks cause the processes to die, we call such tests -_death tests_. More generally, any test that checks that a program terminates -in an expected fashion is also a death test. - -If you want to test `EXPECT_*()/ASSERT_*()` failures in your test code, see [Catching Failures](#catching-failures). - -## How to Write a Death Test ## - -Google Test has the following macros to support death tests: - -| **Fatal assertion** | **Nonfatal assertion** | **Verifies** | -|:--------------------|:-----------------------|:-------------| -| `ASSERT_DEATH(`_statement, regex_`); | `EXPECT_DEATH(`_statement, regex_`); | _statement_ crashes with the given error | -| `ASSERT_DEATH_IF_SUPPORTED(`_statement, regex_`); | `EXPECT_DEATH_IF_SUPPORTED(`_statement, regex_`); | if death tests are supported, verifies that _statement_ crashes with the given error; otherwise verifies nothing | -| `ASSERT_EXIT(`_statement, predicate, regex_`); | `EXPECT_EXIT(`_statement, predicate, regex_`); |_statement_ exits with the given error and its exit code matches _predicate_ | - -where _statement_ is a statement that is expected to cause the process to -die, _predicate_ is a function or function object that evaluates an integer -exit status, and _regex_ is a regular expression that the stderr output of -_statement_ is expected to match. Note that _statement_ can be _any valid -statement_ (including _compound statement_) and doesn't have to be an -expression. - -As usual, the `ASSERT` variants abort the current test function, while the -`EXPECT` variants do not. - -**Note:** We use the word "crash" here to mean that the process -terminates with a _non-zero_ exit status code. There are two -possibilities: either the process has called `exit()` or `_exit()` -with a non-zero value, or it may be killed by a signal. - -This means that if _statement_ terminates the process with a 0 exit -code, it is _not_ considered a crash by `EXPECT_DEATH`. Use -`EXPECT_EXIT` instead if this is the case, or if you want to restrict -the exit code more precisely. - -A predicate here must accept an `int` and return a `bool`. The death test -succeeds only if the predicate returns `true`. Google Test defines a few -predicates that handle the most common cases: - -``` -::testing::ExitedWithCode(exit_code) -``` - -This expression is `true` if the program exited normally with the given exit -code. - -``` -::testing::KilledBySignal(signal_number) // Not available on Windows. -``` - -This expression is `true` if the program was killed by the given signal. - -The `*_DEATH` macros are convenient wrappers for `*_EXIT` that use a predicate -that verifies the process' exit code is non-zero. - -Note that a death test only cares about three things: - - 1. does _statement_ abort or exit the process? - 1. (in the case of `ASSERT_EXIT` and `EXPECT_EXIT`) does the exit status satisfy _predicate_? Or (in the case of `ASSERT_DEATH` and `EXPECT_DEATH`) is the exit status non-zero? And - 1. does the stderr output match _regex_? - -In particular, if _statement_ generates an `ASSERT_*` or `EXPECT_*` failure, it will **not** cause the death test to fail, as Google Test assertions don't abort the process. - -To write a death test, simply use one of the above macros inside your test -function. For example, - -``` -TEST(My*DeathTest*, Foo) { - // This death test uses a compound statement. - ASSERT_DEATH({ int n = 5; Foo(&n); }, "Error on line .* of Foo()"); -} -TEST(MyDeathTest, NormalExit) { - EXPECT_EXIT(NormalExit(), ::testing::ExitedWithCode(0), "Success"); -} -TEST(MyDeathTest, KillMyself) { - EXPECT_EXIT(KillMyself(), ::testing::KilledBySignal(SIGKILL), "Sending myself unblockable signal"); -} -``` - -verifies that: - - * calling `Foo(5)` causes the process to die with the given error message, - * calling `NormalExit()` causes the process to print `"Success"` to stderr and exit with exit code 0, and - * calling `KillMyself()` kills the process with signal `SIGKILL`. - -The test function body may contain other assertions and statements as well, if -necessary. - -_Important:_ We strongly recommend you to follow the convention of naming your -test case (not test) `*DeathTest` when it contains a death test, as -demonstrated in the above example. The `Death Tests And Threads` section below -explains why. - -If a test fixture class is shared by normal tests and death tests, you -can use typedef to introduce an alias for the fixture class and avoid -duplicating its code: -``` -class FooTest : public ::testing::Test { ... }; - -typedef FooTest FooDeathTest; - -TEST_F(FooTest, DoesThis) { - // normal test -} - -TEST_F(FooDeathTest, DoesThat) { - // death test -} -``` - -_Availability:_ Linux, Windows (requires MSVC 8.0 or above), Cygwin, and Mac (the latter three are supported since v1.3.0). `(ASSERT|EXPECT)_DEATH_IF_SUPPORTED` are new in v1.4.0. - -## Regular Expression Syntax ## - -On POSIX systems (e.g. Linux, Cygwin, and Mac), Google Test uses the -[POSIX extended regular expression](http://www.opengroup.org/onlinepubs/009695399/basedefs/xbd_chap09.html#tag_09_04) -syntax in death tests. To learn about this syntax, you may want to read this [Wikipedia entry](http://en.wikipedia.org/wiki/Regular_expression#POSIX_Extended_Regular_Expressions). - -On Windows, Google Test uses its own simple regular expression -implementation. It lacks many features you can find in POSIX extended -regular expressions. For example, we don't support union (`"x|y"`), -grouping (`"(xy)"`), brackets (`"[xy]"`), and repetition count -(`"x{5,7}"`), among others. Below is what we do support (`A` denotes a -literal character, period (`.`), or a single `\\` escape sequence; `x` -and `y` denote regular expressions.): - -| `c` | matches any literal character `c` | -|:----|:----------------------------------| -| `\\d` | matches any decimal digit | -| `\\D` | matches any character that's not a decimal digit | -| `\\f` | matches `\f` | -| `\\n` | matches `\n` | -| `\\r` | matches `\r` | -| `\\s` | matches any ASCII whitespace, including `\n` | -| `\\S` | matches any character that's not a whitespace | -| `\\t` | matches `\t` | -| `\\v` | matches `\v` | -| `\\w` | matches any letter, `_`, or decimal digit | -| `\\W` | matches any character that `\\w` doesn't match | -| `\\c` | matches any literal character `c`, which must be a punctuation | -| `.` | matches any single character except `\n` | -| `A?` | matches 0 or 1 occurrences of `A` | -| `A*` | matches 0 or many occurrences of `A` | -| `A+` | matches 1 or many occurrences of `A` | -| `^` | matches the beginning of a string (not that of each line) | -| `$` | matches the end of a string (not that of each line) | -| `xy` | matches `x` followed by `y` | - -To help you determine which capability is available on your system, -Google Test defines macro `GTEST_USES_POSIX_RE=1` when it uses POSIX -extended regular expressions, or `GTEST_USES_SIMPLE_RE=1` when it uses -the simple version. If you want your death tests to work in both -cases, you can either `#if` on these macros or use the more limited -syntax only. - -## How It Works ## - -Under the hood, `ASSERT_EXIT()` spawns a new process and executes the -death test statement in that process. The details of of how precisely -that happens depend on the platform and the variable -`::testing::GTEST_FLAG(death_test_style)` (which is initialized from the -command-line flag `--gtest_death_test_style`). - - * On POSIX systems, `fork()` (or `clone()` on Linux) is used to spawn the child, after which: - * If the variable's value is `"fast"`, the death test statement is immediately executed. - * If the variable's value is `"threadsafe"`, the child process re-executes the unit test binary just as it was originally invoked, but with some extra flags to cause just the single death test under consideration to be run. - * On Windows, the child is spawned using the `CreateProcess()` API, and re-executes the binary to cause just the single death test under consideration to be run - much like the `threadsafe` mode on POSIX. - -Other values for the variable are illegal and will cause the death test to -fail. Currently, the flag's default value is `"fast"`. However, we reserve the -right to change it in the future. Therefore, your tests should not depend on -this. - -In either case, the parent process waits for the child process to complete, and checks that - - 1. the child's exit status satisfies the predicate, and - 1. the child's stderr matches the regular expression. - -If the death test statement runs to completion without dying, the child -process will nonetheless terminate, and the assertion fails. - -## Death Tests And Threads ## - -The reason for the two death test styles has to do with thread safety. Due to -well-known problems with forking in the presence of threads, death tests should -be run in a single-threaded context. Sometimes, however, it isn't feasible to -arrange that kind of environment. For example, statically-initialized modules -may start threads before main is ever reached. Once threads have been created, -it may be difficult or impossible to clean them up. - -Google Test has three features intended to raise awareness of threading issues. - - 1. A warning is emitted if multiple threads are running when a death test is encountered. - 1. Test cases with a name ending in "DeathTest" are run before all other tests. - 1. It uses `clone()` instead of `fork()` to spawn the child process on Linux (`clone()` is not available on Cygwin and Mac), as `fork()` is more likely to cause the child to hang when the parent process has multiple threads. - -It's perfectly fine to create threads inside a death test statement; they are -executed in a separate process and cannot affect the parent. - -## Death Test Styles ## - -The "threadsafe" death test style was introduced in order to help mitigate the -risks of testing in a possibly multithreaded environment. It trades increased -test execution time (potentially dramatically so) for improved thread safety. -We suggest using the faster, default "fast" style unless your test has specific -problems with it. - -You can choose a particular style of death tests by setting the flag -programmatically: - -``` -::testing::FLAGS_gtest_death_test_style = "threadsafe"; -``` - -You can do this in `main()` to set the style for all death tests in the -binary, or in individual tests. Recall that flags are saved before running each -test and restored afterwards, so you need not do that yourself. For example: - -``` -TEST(MyDeathTest, TestOne) { - ::testing::FLAGS_gtest_death_test_style = "threadsafe"; - // This test is run in the "threadsafe" style: - ASSERT_DEATH(ThisShouldDie(), ""); -} - -TEST(MyDeathTest, TestTwo) { - // This test is run in the "fast" style: - ASSERT_DEATH(ThisShouldDie(), ""); -} - -int main(int argc, char** argv) { - ::testing::InitGoogleTest(&argc, argv); - ::testing::FLAGS_gtest_death_test_style = "fast"; - return RUN_ALL_TESTS(); -} -``` - -## Caveats ## - -The _statement_ argument of `ASSERT_EXIT()` can be any valid C++ statement -except that it can not return from the current function. This means -_statement_ should not contain `return` or a macro that might return (e.g. -`ASSERT_TRUE()` ). If _statement_ returns before it crashes, Google Test will -print an error message, and the test will fail. - -Since _statement_ runs in the child process, any in-memory side effect (e.g. -modifying a variable, releasing memory, etc) it causes will _not_ be observable -in the parent process. In particular, if you release memory in a death test, -your program will fail the heap check as the parent process will never see the -memory reclaimed. To solve this problem, you can - - 1. try not to free memory in a death test; - 1. free the memory again in the parent process; or - 1. do not use the heap checker in your program. - -Due to an implementation detail, you cannot place multiple death test -assertions on the same line; otherwise, compilation will fail with an unobvious -error message. - -Despite the improved thread safety afforded by the "threadsafe" style of death -test, thread problems such as deadlock are still possible in the presence of -handlers registered with `pthread_atfork(3)`. - -# Using Assertions in Sub-routines # - -## Adding Traces to Assertions ## - -If a test sub-routine is called from several places, when an assertion -inside it fails, it can be hard to tell which invocation of the -sub-routine the failure is from. You can alleviate this problem using -extra logging or custom failure messages, but that usually clutters up -your tests. A better solution is to use the `SCOPED_TRACE` macro: - -| `SCOPED_TRACE(`_message_`);` | -|:-----------------------------| - -where _message_ can be anything streamable to `std::ostream`. This -macro will cause the current file name, line number, and the given -message to be added in every failure message. The effect will be -undone when the control leaves the current lexical scope. - -For example, - -``` -10: void Sub1(int n) { -11: EXPECT_EQ(1, Bar(n)); -12: EXPECT_EQ(2, Bar(n + 1)); -13: } -14: -15: TEST(FooTest, Bar) { -16: { -17: SCOPED_TRACE("A"); // This trace point will be included in -18: // every failure in this scope. -19: Sub1(1); -20: } -21: // Now it won't. -22: Sub1(9); -23: } -``` - -could result in messages like these: - -``` -path/to/foo_test.cc:11: Failure -Value of: Bar(n) -Expected: 1 - Actual: 2 - Trace: -path/to/foo_test.cc:17: A - -path/to/foo_test.cc:12: Failure -Value of: Bar(n + 1) -Expected: 2 - Actual: 3 -``` - -Without the trace, it would've been difficult to know which invocation -of `Sub1()` the two failures come from respectively. (You could add an -extra message to each assertion in `Sub1()` to indicate the value of -`n`, but that's tedious.) - -Some tips on using `SCOPED_TRACE`: - - 1. With a suitable message, it's often enough to use `SCOPED_TRACE` at the beginning of a sub-routine, instead of at each call site. - 1. When calling sub-routines inside a loop, make the loop iterator part of the message in `SCOPED_TRACE` such that you can know which iteration the failure is from. - 1. Sometimes the line number of the trace point is enough for identifying the particular invocation of a sub-routine. In this case, you don't have to choose a unique message for `SCOPED_TRACE`. You can simply use `""`. - 1. You can use `SCOPED_TRACE` in an inner scope when there is one in the outer scope. In this case, all active trace points will be included in the failure messages, in reverse order they are encountered. - 1. The trace dump is clickable in Emacs' compilation buffer - hit return on a line number and you'll be taken to that line in the source file! - -_Availability:_ Linux, Windows, Mac. - -## Propagating Fatal Failures ## - -A common pitfall when using `ASSERT_*` and `FAIL*` is not understanding that -when they fail they only abort the _current function_, not the entire test. For -example, the following test will segfault: -``` -void Subroutine() { - // Generates a fatal failure and aborts the current function. - ASSERT_EQ(1, 2); - // The following won't be executed. - ... -} - -TEST(FooTest, Bar) { - Subroutine(); - // The intended behavior is for the fatal failure - // in Subroutine() to abort the entire test. - // The actual behavior: the function goes on after Subroutine() returns. - int* p = NULL; - *p = 3; // Segfault! -} -``` - -Since we don't use exceptions, it is technically impossible to -implement the intended behavior here. To alleviate this, Google Test -provides two solutions. You could use either the -`(ASSERT|EXPECT)_NO_FATAL_FAILURE` assertions or the -`HasFatalFailure()` function. They are described in the following two -subsections. - - - -### Asserting on Subroutines ### - -As shown above, if your test calls a subroutine that has an `ASSERT_*` -failure in it, the test will continue after the subroutine -returns. This may not be what you want. - -Often people want fatal failures to propagate like exceptions. For -that Google Test offers the following macros: - -| **Fatal assertion** | **Nonfatal assertion** | **Verifies** | -|:--------------------|:-----------------------|:-------------| -| `ASSERT_NO_FATAL_FAILURE(`_statement_`);` | `EXPECT_NO_FATAL_FAILURE(`_statement_`);` | _statement_ doesn't generate any new fatal failures in the current thread. | - -Only failures in the thread that executes the assertion are checked to -determine the result of this type of assertions. If _statement_ -creates new threads, failures in these threads are ignored. - -Examples: - -``` -ASSERT_NO_FATAL_FAILURE(Foo()); - -int i; -EXPECT_NO_FATAL_FAILURE({ - i = Bar(); -}); -``` - -_Availability:_ Linux, Windows, Mac. Assertions from multiple threads -are currently not supported. - -### Checking for Failures in the Current Test ### - -`HasFatalFailure()` in the `::testing::Test` class returns `true` if an -assertion in the current test has suffered a fatal failure. This -allows functions to catch fatal failures in a sub-routine and return -early. - -``` -class Test { - public: - ... - static bool HasFatalFailure(); -}; -``` - -The typical usage, which basically simulates the behavior of a thrown -exception, is: - -``` -TEST(FooTest, Bar) { - Subroutine(); - // Aborts if Subroutine() had a fatal failure. - if (HasFatalFailure()) - return; - // The following won't be executed. - ... -} -``` - -If `HasFatalFailure()` is used outside of `TEST()` , `TEST_F()` , or a test -fixture, you must add the `::testing::Test::` prefix, as in: - -``` -if (::testing::Test::HasFatalFailure()) - return; -``` - -Similarly, `HasNonfatalFailure()` returns `true` if the current test -has at least one non-fatal failure, and `HasFailure()` returns `true` -if the current test has at least one failure of either kind. - -_Availability:_ Linux, Windows, Mac. `HasNonfatalFailure()` and -`HasFailure()` are available since version 1.4.0. - -# Logging Additional Information # - -In your test code, you can call `RecordProperty("key", value)` to log -additional information, where `value` can be either a C string or a 32-bit -integer. The _last_ value recorded for a key will be emitted to the XML output -if you specify one. For example, the test - -``` -TEST_F(WidgetUsageTest, MinAndMaxWidgets) { - RecordProperty("MaximumWidgets", ComputeMaxUsage()); - RecordProperty("MinimumWidgets", ComputeMinUsage()); -} -``` - -will output XML like this: - -``` -... - -... -``` - -_Note_: - * `RecordProperty()` is a static member of the `Test` class. Therefore it needs to be prefixed with `::testing::Test::` if used outside of the `TEST` body and the test fixture class. - * `key` must be a valid XML attribute name, and cannot conflict with the ones already used by Google Test (`name`, `status`, `time`, and `classname`). - -_Availability_: Linux, Windows, Mac. - -# Sharing Resources Between Tests in the Same Test Case # - - - -Google Test creates a new test fixture object for each test in order to make -tests independent and easier to debug. However, sometimes tests use resources -that are expensive to set up, making the one-copy-per-test model prohibitively -expensive. - -If the tests don't change the resource, there's no harm in them sharing a -single resource copy. So, in addition to per-test set-up/tear-down, Google Test -also supports per-test-case set-up/tear-down. To use it: - - 1. In your test fixture class (say `FooTest` ), define as `static` some member variables to hold the shared resources. - 1. In the same test fixture class, define a `static void SetUpTestCase()` function (remember not to spell it as **`SetupTestCase`** with a small `u`!) to set up the shared resources and a `static void TearDownTestCase()` function to tear them down. - -That's it! Google Test automatically calls `SetUpTestCase()` before running the -_first test_ in the `FooTest` test case (i.e. before creating the first -`FooTest` object), and calls `TearDownTestCase()` after running the _last test_ -in it (i.e. after deleting the last `FooTest` object). In between, the tests -can use the shared resources. - -Remember that the test order is undefined, so your code can't depend on a test -preceding or following another. Also, the tests must either not modify the -state of any shared resource, or, if they do modify the state, they must -restore the state to its original value before passing control to the next -test. - -Here's an example of per-test-case set-up and tear-down: -``` -class FooTest : public ::testing::Test { - protected: - // Per-test-case set-up. - // Called before the first test in this test case. - // Can be omitted if not needed. - static void SetUpTestCase() { - shared_resource_ = new ...; - } - - // Per-test-case tear-down. - // Called after the last test in this test case. - // Can be omitted if not needed. - static void TearDownTestCase() { - delete shared_resource_; - shared_resource_ = NULL; - } - - // You can define per-test set-up and tear-down logic as usual. - virtual void SetUp() { ... } - virtual void TearDown() { ... } - - // Some expensive resource shared by all tests. - static T* shared_resource_; -}; - -T* FooTest::shared_resource_ = NULL; - -TEST_F(FooTest, Test1) { - ... you can refer to shared_resource here ... -} -TEST_F(FooTest, Test2) { - ... you can refer to shared_resource here ... -} -``` - -_Availability:_ Linux, Windows, Mac. - -# Global Set-Up and Tear-Down # - -Just as you can do set-up and tear-down at the test level and the test case -level, you can also do it at the test program level. Here's how. - -First, you subclass the `::testing::Environment` class to define a test -environment, which knows how to set-up and tear-down: - -``` -class Environment { - public: - virtual ~Environment() {} - // Override this to define how to set up the environment. - virtual void SetUp() {} - // Override this to define how to tear down the environment. - virtual void TearDown() {} -}; -``` - -Then, you register an instance of your environment class with Google Test by -calling the `::testing::AddGlobalTestEnvironment()` function: - -``` -Environment* AddGlobalTestEnvironment(Environment* env); -``` - -Now, when `RUN_ALL_TESTS()` is called, it first calls the `SetUp()` method of -the environment object, then runs the tests if there was no fatal failures, and -finally calls `TearDown()` of the environment object. - -It's OK to register multiple environment objects. In this case, their `SetUp()` -will be called in the order they are registered, and their `TearDown()` will be -called in the reverse order. - -Note that Google Test takes ownership of the registered environment objects. -Therefore **do not delete them** by yourself. - -You should call `AddGlobalTestEnvironment()` before `RUN_ALL_TESTS()` is -called, probably in `main()`. If you use `gtest_main`, you need to call -this before `main()` starts for it to take effect. One way to do this is to -define a global variable like this: - -``` -::testing::Environment* const foo_env = ::testing::AddGlobalTestEnvironment(new FooEnvironment); -``` - -However, we strongly recommend you to write your own `main()` and call -`AddGlobalTestEnvironment()` there, as relying on initialization of global -variables makes the code harder to read and may cause problems when you -register multiple environments from different translation units and the -environments have dependencies among them (remember that the compiler doesn't -guarantee the order in which global variables from different translation units -are initialized). - -_Availability:_ Linux, Windows, Mac. - - -# Value Parameterized Tests # - -_Value-parameterized tests_ allow you to test your code with different -parameters without writing multiple copies of the same test. - -Suppose you write a test for your code and then realize that your code is affected by a presence of a Boolean command line flag. - -``` -TEST(MyCodeTest, TestFoo) { - // A code to test foo(). -} -``` - -Usually people factor their test code into a function with a Boolean parameter in such situations. The function sets the flag, then executes the testing code. - -``` -void TestFooHelper(bool flag_value) { - flag = flag_value; - // A code to test foo(). -} - -TEST(MyCodeTest, TestFooo) { - TestFooHelper(false); - TestFooHelper(true); -} -``` - -But this setup has serious drawbacks. First, when a test assertion fails in your tests, it becomes unclear what value of the parameter caused it to fail. You can stream a clarifying message into your `EXPECT`/`ASSERT` statements, but it you'll have to do it with all of them. Second, you have to add one such helper function per test. What if you have ten tests? Twenty? A hundred? - -Value-parameterized tests will let you write your test only once and then easily instantiate and run it with an arbitrary number of parameter values. - -Here are some other situations when value-parameterized tests come handy: - - * You wan to test different implementations of an OO interface. - * You want to test your code over various inputs (a.k.a. data-driven testing). This feature is easy to abuse, so please exercise your good sense when doing it! - -## How to Write Value-Parameterized Tests ## - -To write value-parameterized tests, first you should define a fixture -class. It must be derived from `::testing::TestWithParam`, where `T` -is the type of your parameter values. `TestWithParam` is itself -derived from `::testing::Test`. `T` can be any copyable type. If it's -a raw pointer, you are responsible for managing the lifespan of the -pointed values. - -``` -class FooTest : public ::testing::TestWithParam { - // You can implement all the usual fixture class members here. - // To access the test parameter, call GetParam() from class - // TestWithParam. -}; -``` - -Then, use the `TEST_P` macro to define as many test patterns using -this fixture as you want. The `_P` suffix is for "parameterized" or -"pattern", whichever you prefer to think. - -``` -TEST_P(FooTest, DoesBlah) { - // Inside a test, access the test parameter with the GetParam() method - // of the TestWithParam class: - EXPECT_TRUE(foo.Blah(GetParam())); - ... -} - -TEST_P(FooTest, HasBlahBlah) { - ... -} -``` - -Finally, you can use `INSTANTIATE_TEST_CASE_P` to instantiate the test -case with any set of parameters you want. Google Test defines a number of -functions for generating test parameters. They return what we call -(surprise!) _parameter generators_. Here is a summary of them, -which are all in the `testing` namespace: - -| `Range(begin, end[, step])` | Yields values `{begin, begin+step, begin+step+step, ...}`. The values do not include `end`. `step` defaults to 1. | -|:----------------------------|:------------------------------------------------------------------------------------------------------------------| -| `Values(v1, v2, ..., vN)` | Yields values `{v1, v2, ..., vN}`. | -| `ValuesIn(container)` and `ValuesIn(begin, end)` | Yields values from a C-style array, an STL-style container, or an iterator range `[begin, end)`. | -| `Bool()` | Yields sequence `{false, true}`. | -| `Combine(g1, g2, ..., gN)` | Yields all combinations (the Cartesian product for the math savvy) of the values generated by the `N` generators. This is only available if your system provides the `` header. If you are sure your system does, and Google Test disagrees, you can override it by defining `GTEST_HAS_TR1_TUPLE=1`. See comments in [include/gtest/internal/gtest-port.h](../include/gtest/internal/gtest-port.h) for more information. | - -For more details, see the comments at the definitions of these functions in the [source code](../include/gtest/gtest-param-test.h). - -The following statement will instantiate tests from the `FooTest` test case -each with parameter values `"meeny"`, `"miny"`, and `"moe"`. - -``` -INSTANTIATE_TEST_CASE_P(InstantiationName, - FooTest, - ::testing::Values("meeny", "miny", "moe")); -``` - -To distinguish different instances of the pattern (yes, you can -instantiate it more than once), the first argument to -`INSTANTIATE_TEST_CASE_P` is a prefix that will be added to the actual -test case name. Remember to pick unique prefixes for different -instantiations. The tests from the instantiation above will have these -names: - - * `InstantiationName/FooTest.DoesBlah/0` for `"meeny"` - * `InstantiationName/FooTest.DoesBlah/1` for `"miny"` - * `InstantiationName/FooTest.DoesBlah/2` for `"moe"` - * `InstantiationName/FooTest.HasBlahBlah/0` for `"meeny"` - * `InstantiationName/FooTest.HasBlahBlah/1` for `"miny"` - * `InstantiationName/FooTest.HasBlahBlah/2` for `"moe"` - -You can use these names in [--gtest\-filter](#running-a-subset-of-the-tests). - -This statement will instantiate all tests from `FooTest` again, each -with parameter values `"cat"` and `"dog"`: - -``` -const char* pets[] = {"cat", "dog"}; -INSTANTIATE_TEST_CASE_P(AnotherInstantiationName, FooTest, - ::testing::ValuesIn(pets)); -``` - -The tests from the instantiation above will have these names: - - * `AnotherInstantiationName/FooTest.DoesBlah/0` for `"cat"` - * `AnotherInstantiationName/FooTest.DoesBlah/1` for `"dog"` - * `AnotherInstantiationName/FooTest.HasBlahBlah/0` for `"cat"` - * `AnotherInstantiationName/FooTest.HasBlahBlah/1` for `"dog"` - -Please note that `INSTANTIATE_TEST_CASE_P` will instantiate _all_ -tests in the given test case, whether their definitions come before or -_after_ the `INSTANTIATE_TEST_CASE_P` statement. - -You can see -[these](../samples/sample7_unittest.cc) -[files](../samples/sample8_unittest.cc) for more examples. - -_Availability_: Linux, Windows (requires MSVC 8.0 or above), Mac; since version 1.2.0. - -## Creating Value-Parameterized Abstract Tests ## - -In the above, we define and instantiate `FooTest` in the same source -file. Sometimes you may want to define value-parameterized tests in a -library and let other people instantiate them later. This pattern is -known as abstract tests. As an example of its application, when you -are designing an interface you can write a standard suite of abstract -tests (perhaps using a factory function as the test parameter) that -all implementations of the interface are expected to pass. When -someone implements the interface, he can instantiate your suite to get -all the interface-conformance tests for free. - -To define abstract tests, you should organize your code like this: - - 1. Put the definition of the parameterized test fixture class (e.g. `FooTest`) in a header file, say `foo_param_test.h`. Think of this as _declaring_ your abstract tests. - 1. Put the `TEST_P` definitions in `foo_param_test.cc`, which includes `foo_param_test.h`. Think of this as _implementing_ your abstract tests. - -Once they are defined, you can instantiate them by including -`foo_param_test.h`, invoking `INSTANTIATE_TEST_CASE_P()`, and linking -with `foo_param_test.cc`. You can instantiate the same abstract test -case multiple times, possibly in different source files. - -# Typed Tests # - -Suppose you have multiple implementations of the same interface and -want to make sure that all of them satisfy some common requirements. -Or, you may have defined several types that are supposed to conform to -the same "concept" and you want to verify it. In both cases, you want -the same test logic repeated for different types. - -While you can write one `TEST` or `TEST_F` for each type you want to -test (and you may even factor the test logic into a function template -that you invoke from the `TEST`), it's tedious and doesn't scale: -if you want _m_ tests over _n_ types, you'll end up writing _m\*n_ -`TEST`s. - -_Typed tests_ allow you to repeat the same test logic over a list of -types. You only need to write the test logic once, although you must -know the type list when writing typed tests. Here's how you do it: - -First, define a fixture class template. It should be parameterized -by a type. Remember to derive it from `::testing::Test`: - -``` -template -class FooTest : public ::testing::Test { - public: - ... - typedef std::list List; - static T shared_; - T value_; -}; -``` - -Next, associate a list of types with the test case, which will be -repeated for each type in the list: - -``` -typedef ::testing::Types MyTypes; -TYPED_TEST_CASE(FooTest, MyTypes); -``` - -The `typedef` is necessary for the `TYPED_TEST_CASE` macro to parse -correctly. Otherwise the compiler will think that each comma in the -type list introduces a new macro argument. - -Then, use `TYPED_TEST()` instead of `TEST_F()` to define a typed test -for this test case. You can repeat this as many times as you want: - -``` -TYPED_TEST(FooTest, DoesBlah) { - // Inside a test, refer to the special name TypeParam to get the type - // parameter. Since we are inside a derived class template, C++ requires - // us to visit the members of FooTest via 'this'. - TypeParam n = this->value_; - - // To visit static members of the fixture, add the 'TestFixture::' - // prefix. - n += TestFixture::shared_; - - // To refer to typedefs in the fixture, add the 'typename TestFixture::' - // prefix. The 'typename' is required to satisfy the compiler. - typename TestFixture::List values; - values.push_back(n); - ... -} - -TYPED_TEST(FooTest, HasPropertyA) { ... } -``` - -You can see `samples/sample6_unittest.cc` for a complete example. - -_Availability:_ Linux, Windows (requires MSVC 8.0 or above), Mac; -since version 1.1.0. - -# Type-Parameterized Tests # - -_Type-parameterized tests_ are like typed tests, except that they -don't require you to know the list of types ahead of time. Instead, -you can define the test logic first and instantiate it with different -type lists later. You can even instantiate it more than once in the -same program. - -If you are designing an interface or concept, you can define a suite -of type-parameterized tests to verify properties that any valid -implementation of the interface/concept should have. Then, the author -of each implementation can just instantiate the test suite with his -type to verify that it conforms to the requirements, without having to -write similar tests repeatedly. Here's an example: - -First, define a fixture class template, as we did with typed tests: - -``` -template -class FooTest : public ::testing::Test { - ... -}; -``` - -Next, declare that you will define a type-parameterized test case: - -``` -TYPED_TEST_CASE_P(FooTest); -``` - -The `_P` suffix is for "parameterized" or "pattern", whichever you -prefer to think. - -Then, use `TYPED_TEST_P()` to define a type-parameterized test. You -can repeat this as many times as you want: - -``` -TYPED_TEST_P(FooTest, DoesBlah) { - // Inside a test, refer to TypeParam to get the type parameter. - TypeParam n = 0; - ... -} - -TYPED_TEST_P(FooTest, HasPropertyA) { ... } -``` - -Now the tricky part: you need to register all test patterns using the -`REGISTER_TYPED_TEST_CASE_P` macro before you can instantiate them. -The first argument of the macro is the test case name; the rest are -the names of the tests in this test case: - -``` -REGISTER_TYPED_TEST_CASE_P(FooTest, - DoesBlah, HasPropertyA); -``` - -Finally, you are free to instantiate the pattern with the types you -want. If you put the above code in a header file, you can `#include` -it in multiple C++ source files and instantiate it multiple times. - -``` -typedef ::testing::Types MyTypes; -INSTANTIATE_TYPED_TEST_CASE_P(My, FooTest, MyTypes); -``` - -To distinguish different instances of the pattern, the first argument -to the `INSTANTIATE_TYPED_TEST_CASE_P` macro is a prefix that will be -added to the actual test case name. Remember to pick unique prefixes -for different instances. - -In the special case where the type list contains only one type, you -can write that type directly without `::testing::Types<...>`, like this: - -``` -INSTANTIATE_TYPED_TEST_CASE_P(My, FooTest, int); -``` - -You can see `samples/sample6_unittest.cc` for a complete example. - -_Availability:_ Linux, Windows (requires MSVC 8.0 or above), Mac; -since version 1.1.0. - -# Testing Private Code # - -If you change your software's internal implementation, your tests should not -break as long as the change is not observable by users. Therefore, per the -_black-box testing principle_, most of the time you should test your code -through its public interfaces. - -If you still find yourself needing to test internal implementation code, -consider if there's a better design that wouldn't require you to do so. If you -absolutely have to test non-public interface code though, you can. There are -two cases to consider: - - * Static functions (_not_ the same as static member functions!) or unnamed namespaces, and - * Private or protected class members - -## Static Functions ## - -Both static functions and definitions/declarations in an unnamed namespace are -only visible within the same translation unit. To test them, you can `#include` -the entire `.cc` file being tested in your `*_test.cc` file. (`#include`ing `.cc` -files is not a good way to reuse code - you should not do this in production -code!) - -However, a better approach is to move the private code into the -`foo::internal` namespace, where `foo` is the namespace your project normally -uses, and put the private declarations in a `*-internal.h` file. Your -production `.cc` files and your tests are allowed to include this internal -header, but your clients are not. This way, you can fully test your internal -implementation without leaking it to your clients. - -## Private Class Members ## - -Private class members are only accessible from within the class or by friends. -To access a class' private members, you can declare your test fixture as a -friend to the class and define accessors in your fixture. Tests using the -fixture can then access the private members of your production class via the -accessors in the fixture. Note that even though your fixture is a friend to -your production class, your tests are not automatically friends to it, as they -are technically defined in sub-classes of the fixture. - -Another way to test private members is to refactor them into an implementation -class, which is then declared in a `*-internal.h` file. Your clients aren't -allowed to include this header but your tests can. Such is called the Pimpl -(Private Implementation) idiom. - -Or, you can declare an individual test as a friend of your class by adding this -line in the class body: - -``` -FRIEND_TEST(TestCaseName, TestName); -``` - -For example, -``` -// foo.h -#include - -// Defines FRIEND_TEST. -class Foo { - ... - private: - FRIEND_TEST(FooTest, BarReturnsZeroOnNull); - int Bar(void* x); -}; - -// foo_test.cc -... -TEST(FooTest, BarReturnsZeroOnNull) { - Foo foo; - EXPECT_EQ(0, foo.Bar(NULL)); - // Uses Foo's private member Bar(). -} -``` - -Pay special attention when your class is defined in a namespace, as you should -define your test fixtures and tests in the same namespace if you want them to -be friends of your class. For example, if the code to be tested looks like: - -``` -namespace my_namespace { - -class Foo { - friend class FooTest; - FRIEND_TEST(FooTest, Bar); - FRIEND_TEST(FooTest, Baz); - ... - definition of the class Foo - ... -}; - -} // namespace my_namespace -``` - -Your test code should be something like: - -``` -namespace my_namespace { -class FooTest : public ::testing::Test { - protected: - ... -}; - -TEST_F(FooTest, Bar) { ... } -TEST_F(FooTest, Baz) { ... } - -} // namespace my_namespace -``` - -# Catching Failures # - -If you are building a testing utility on top of Google Test, you'll -want to test your utility. What framework would you use to test it? -Google Test, of course. - -The challenge is to verify that your testing utility reports failures -correctly. In frameworks that report a failure by throwing an -exception, you could catch the exception and assert on it. But Google -Test doesn't use exceptions, so how do we test that a piece of code -generates an expected failure? - -`` contains some constructs to do this. After -`#include`ing this header, you can use - -| `EXPECT_FATAL_FAILURE(`_statement, substring_`);` | -|:--------------------------------------------------| - -to assert that _statement_ generates a fatal (e.g. `ASSERT_*`) failure -whose message contains the given _substring_, or use - -| `EXPECT_NONFATAL_FAILURE(`_statement, substring_`);` | -|:-----------------------------------------------------| - -if you are expecting a non-fatal (e.g. `EXPECT_*`) failure. - -For technical reasons, there are some caveats: - - 1. You cannot stream a failure message to either macro. - 1. _statement_ in `EXPECT_FATAL_FAILURE()` cannot reference local non-static variables or non-static members of `this` object. - 1. _statement_ in `EXPECT_FATAL_FAILURE()` cannot return a value. - -_Note:_ Google Test is designed with threads in mind. Once the -synchronization primitives in `` have -been implemented, Google Test will become thread-safe, meaning that -you can then use assertions in multiple threads concurrently. Before - -that, however, Google Test only supports single-threaded usage. Once -thread-safe, `EXPECT_FATAL_FAILURE()` and `EXPECT_NONFATAL_FAILURE()` -will capture failures in the current thread only. If _statement_ -creates new threads, failures in these threads will be ignored. If -you want to capture failures from all threads instead, you should use -the following macros: - -| `EXPECT_FATAL_FAILURE_ON_ALL_THREADS(`_statement, substring_`);` | -|:-----------------------------------------------------------------| -| `EXPECT_NONFATAL_FAILURE_ON_ALL_THREADS(`_statement, substring_`);` | - -# Getting the Current Test's Name # - -Sometimes a function may need to know the name of the currently running test. -For example, you may be using the `SetUp()` method of your test fixture to set -the golden file name based on which test is running. The `::testing::TestInfo` -class has this information: - -``` -namespace testing { - -class TestInfo { - public: - // Returns the test case name and the test name, respectively. - // - // Do NOT delete or free the return value - it's managed by the - // TestInfo class. - const char* test_case_name() const; - const char* name() const; -}; - -} // namespace testing -``` - - -> To obtain a `TestInfo` object for the currently running test, call -`current_test_info()` on the `UnitTest` singleton object: - -``` -// Gets information about the currently running test. -// Do NOT delete the returned object - it's managed by the UnitTest class. -const ::testing::TestInfo* const test_info = - ::testing::UnitTest::GetInstance()->current_test_info(); -printf("We are in test %s of test case %s.\n", - test_info->name(), test_info->test_case_name()); -``` - -`current_test_info()` returns a null pointer if no test is running. In -particular, you cannot find the test case name in `TestCaseSetUp()`, -`TestCaseTearDown()` (where you know the test case name implicitly), or -functions called from them. - -_Availability:_ Linux, Windows, Mac. - -# Extending Google Test by Handling Test Events # - -Google Test provides an event listener API to let you receive -notifications about the progress of a test program and test -failures. The events you can listen to include the start and end of -the test program, a test case, or a test method, among others. You may -use this API to augment or replace the standard console output, -replace the XML output, or provide a completely different form of -output, such as a GUI or a database. You can also use test events as -checkpoints to implement a resource leak checker, for example. - -_Availability:_ Linux, Windows, Mac; since v1.4.0. - -## Defining Event Listeners ## - -To define a event listener, you subclass either -[testing::TestEventListener](../include/gtest/gtest.h#L855) -or [testing::EmptyTestEventListener](../include/gtest/gtest.h#L905). -The former is an (abstract) interface, where each pure virtual method
-can be overridden to handle a test event (For example, when a test -starts, the `OnTestStart()` method will be called.). The latter provides -an empty implementation of all methods in the interface, such that a -subclass only needs to override the methods it cares about. - -When an event is fired, its context is passed to the handler function -as an argument. The following argument types are used: - * [UnitTest](../include/gtest/gtest.h#L1007) reflects the state of the entire test program, - * [TestCase](../include/gtest/gtest.h#L689) has information about a test case, which can contain one or more tests, - * [TestInfo](../include/gtest/gtest.h#L599) contains the state of a test, and - * [TestPartResult](../include/gtest/gtest-test-part.h#L42) represents the result of a test assertion. - -An event handler function can examine the argument it receives to find -out interesting information about the event and the test program's -state. Here's an example: - -``` - class MinimalistPrinter : public ::testing::EmptyTestEventListener { - // Called before a test starts. - virtual void OnTestStart(const ::testing::TestInfo& test_info) { - printf("*** Test %s.%s starting.\n", - test_info.test_case_name(), test_info.name()); - } - - // Called after a failed assertion or a SUCCESS(). - virtual void OnTestPartResult( - const ::testing::TestPartResult& test_part_result) { - printf("%s in %s:%d\n%s\n", - test_part_result.failed() ? "*** Failure" : "Success", - test_part_result.file_name(), - test_part_result.line_number(), - test_part_result.summary()); - } - - // Called after a test ends. - virtual void OnTestEnd(const ::testing::TestInfo& test_info) { - printf("*** Test %s.%s ending.\n", - test_info.test_case_name(), test_info.name()); - } - }; -``` - -## Using Event Listeners ## - -To use the event listener you have defined, add an instance of it to -the Google Test event listener list (represented by class -[TestEventListeners](../include/gtest/gtest.h#L929) -- note the "s" at the end of the name) in your -`main()` function, before calling `RUN_ALL_TESTS()`: -``` -int main(int argc, char** argv) { - ::testing::InitGoogleTest(&argc, argv); - // Gets hold of the event listener list. - ::testing::TestEventListeners& listeners = - ::testing::UnitTest::GetInstance()->listeners(); - // Adds a listener to the end. Google Test takes the ownership. - listeners.Append(new MinimalistPrinter); - return RUN_ALL_TESTS(); -} -``` - -There's only one problem: the default test result printer is still in -effect, so its output will mingle with the output from your minimalist -printer. To suppress the default printer, just release it from the -event listener list and delete it. You can do so by adding one line: -``` - ... - delete listeners.Release(listeners.default_result_printer()); - listeners.Append(new MinimalistPrinter); - return RUN_ALL_TESTS(); -``` - -Now, sit back and enjoy a completely different output from your -tests. For more details, you can read this -[sample](../samples/sample9_unittest.cc). - -You may append more than one listener to the list. When an `On*Start()` -or `OnTestPartResult()` event is fired, the listeners will receive it in -the order they appear in the list (since new listeners are added to -the end of the list, the default text printer and the default XML -generator will receive the event first). An `On*End()` event will be -received by the listeners in the _reverse_ order. This allows output by -listeners added later to be framed by output from listeners added -earlier. - -## Generating Failures in Listeners ## - -You may use failure-raising macros (`EXPECT_*()`, `ASSERT_*()`, -`FAIL()`, etc) when processing an event. There are some restrictions: - - 1. You cannot generate any failure in `OnTestPartResult()` (otherwise it will cause `OnTestPartResult()` to be called recursively). - 1. A listener that handles `OnTestPartResult()` is not allowed to generate any failure. - -When you add listeners to the listener list, you should put listeners -that handle `OnTestPartResult()` _before_ listeners that can generate -failures. This ensures that failures generated by the latter are -attributed to the right test by the former. - -We have a sample of failure-raising listener -[here](../samples/sample10_unittest.cc). - -# Running Test Programs: Advanced Options # - -Google Test test programs are ordinary executables. Once built, you can run -them directly and affect their behavior via the following environment variables -and/or command line flags. For the flags to work, your programs must call -`::testing::InitGoogleTest()` before calling `RUN_ALL_TESTS()`. - -To see a list of supported flags and their usage, please run your test -program with the `--help` flag. You can also use `-h`, `-?`, or `/?` -for short. This feature is added in version 1.3.0. - -If an option is specified both by an environment variable and by a -flag, the latter takes precedence. Most of the options can also be -set/read in code: to access the value of command line flag -`--gtest_foo`, write `::testing::GTEST_FLAG(foo)`. A common pattern is -to set the value of a flag before calling `::testing::InitGoogleTest()` -to change the default value of the flag: -``` -int main(int argc, char** argv) { - // Disables elapsed time by default. - ::testing::GTEST_FLAG(print_time) = false; - - // This allows the user to override the flag on the command line. - ::testing::InitGoogleTest(&argc, argv); - - return RUN_ALL_TESTS(); -} -``` - -## Selecting Tests ## - -This section shows various options for choosing which tests to run. - -### Listing Test Names ### - -Sometimes it is necessary to list the available tests in a program before -running them so that a filter may be applied if needed. Including the flag -`--gtest_list_tests` overrides all other flags and lists tests in the following -format: -``` -TestCase1. - TestName1 - TestName2 -TestCase2. - TestName -``` - -None of the tests listed are actually run if the flag is provided. There is no -corresponding environment variable for this flag. - -_Availability:_ Linux, Windows, Mac. - -### Running a Subset of the Tests ### - -By default, a Google Test program runs all tests the user has defined. -Sometimes, you want to run only a subset of the tests (e.g. for debugging or -quickly verifying a change). If you set the `GTEST_FILTER` environment variable -or the `--gtest_filter` flag to a filter string, Google Test will only run the -tests whose full names (in the form of `TestCaseName.TestName`) match the -filter. - -The format of a filter is a '`:`'-separated list of wildcard patterns (called -the positive patterns) optionally followed by a '`-`' and another -'`:`'-separated pattern list (called the negative patterns). A test matches the -filter if and only if it matches any of the positive patterns but does not -match any of the negative patterns. - -A pattern may contain `'*'` (matches any string) or `'?'` (matches any single -character). For convenience, the filter `'*-NegativePatterns'` can be also -written as `'-NegativePatterns'`. - -For example: - - * `./foo_test` Has no flag, and thus runs all its tests. - * `./foo_test --gtest_filter=*` Also runs everything, due to the single match-everything `*` value. - * `./foo_test --gtest_filter=FooTest.*` Runs everything in test case `FooTest`. - * `./foo_test --gtest_filter=*Null*:*Constructor*` Runs any test whose full name contains either `"Null"` or `"Constructor"`. - * `./foo_test --gtest_filter=-*DeathTest.*` Runs all non-death tests. - * `./foo_test --gtest_filter=FooTest.*-FooTest.Bar` Runs everything in test case `FooTest` except `FooTest.Bar`. - -_Availability:_ Linux, Windows, Mac. - -### Temporarily Disabling Tests ### - -If you have a broken test that you cannot fix right away, you can add the -`DISABLED_` prefix to its name. This will exclude it from execution. This is -better than commenting out the code or using `#if 0`, as disabled tests are -still compiled (and thus won't rot). - -If you need to disable all tests in a test case, you can either add `DISABLED_` -to the front of the name of each test, or alternatively add it to the front of -the test case name. - -For example, the following tests won't be run by Google Test, even though they -will still be compiled: - -``` -// Tests that Foo does Abc. -TEST(FooTest, DISABLED_DoesAbc) { ... } - -class DISABLED_BarTest : public ::testing::Test { ... }; - -// Tests that Bar does Xyz. -TEST_F(DISABLED_BarTest, DoesXyz) { ... } -``` - -_Note:_ This feature should only be used for temporary pain-relief. You still -have to fix the disabled tests at a later date. As a reminder, Google Test will -print a banner warning you if a test program contains any disabled tests. - -_Tip:_ You can easily count the number of disabled tests you have -using `grep`. This number can be used as a metric for improving your -test quality. - -_Availability:_ Linux, Windows, Mac. - -### Temporarily Enabling Disabled Tests ### - -To include [disabled tests](#temporarily-disabling-tests) in test -execution, just invoke the test program with the -`--gtest_also_run_disabled_tests` flag or set the -`GTEST_ALSO_RUN_DISABLED_TESTS` environment variable to a value other -than `0`. You can combine this with the -[--gtest\_filter](#running-a-subset-of-the-tests) flag to further select -which disabled tests to run. - -_Availability:_ Linux, Windows, Mac; since version 1.3.0. - -## Repeating the Tests ## - -Once in a while you'll run into a test whose result is hit-or-miss. Perhaps it -will fail only 1% of the time, making it rather hard to reproduce the bug under -a debugger. This can be a major source of frustration. - -The `--gtest_repeat` flag allows you to repeat all (or selected) test methods -in a program many times. Hopefully, a flaky test will eventually fail and give -you a chance to debug. Here's how to use it: - -| `$ foo_test --gtest_repeat=1000` | Repeat foo\_test 1000 times and don't stop at failures. | -|:---------------------------------|:--------------------------------------------------------| -| `$ foo_test --gtest_repeat=-1` | A negative count means repeating forever. | -| `$ foo_test --gtest_repeat=1000 --gtest_break_on_failure` | Repeat foo\_test 1000 times, stopping at the first failure. This is especially useful when running under a debugger: when the testfails, it will drop into the debugger and you can then inspect variables and stacks. | -| `$ foo_test --gtest_repeat=1000 --gtest_filter=FooBar` | Repeat the tests whose name matches the filter 1000 times. | - -If your test program contains global set-up/tear-down code registered -using `AddGlobalTestEnvironment()`, it will be repeated in each -iteration as well, as the flakiness may be in it. You can also specify -the repeat count by setting the `GTEST_REPEAT` environment variable. - -_Availability:_ Linux, Windows, Mac. - -## Shuffling the Tests ## - -You can specify the `--gtest_shuffle` flag (or set the `GTEST_SHUFFLE` -environment variable to `1`) to run the tests in a program in a random -order. This helps to reveal bad dependencies between tests. - -By default, Google Test uses a random seed calculated from the current -time. Therefore you'll get a different order every time. The console -output includes the random seed value, such that you can reproduce an -order-related test failure later. To specify the random seed -explicitly, use the `--gtest_random_seed=SEED` flag (or set the -`GTEST_RANDOM_SEED` environment variable), where `SEED` is an integer -between 0 and 99999. The seed value 0 is special: it tells Google Test -to do the default behavior of calculating the seed from the current -time. - -If you combine this with `--gtest_repeat=N`, Google Test will pick a -different random seed and re-shuffle the tests in each iteration. - -_Availability:_ Linux, Windows, Mac; since v1.4.0. - -## Controlling Test Output ## - -This section teaches how to tweak the way test results are reported. - -### Colored Terminal Output ### - -Google Test can use colors in its terminal output to make it easier to spot -the separation between tests, and whether tests passed. - -You can set the GTEST\_COLOR environment variable or set the `--gtest_color` -command line flag to `yes`, `no`, or `auto` (the default) to enable colors, -disable colors, or let Google Test decide. When the value is `auto`, Google -Test will use colors if and only if the output goes to a terminal and (on -non-Windows platforms) the `TERM` environment variable is set to `xterm` or -`xterm-color`. - -_Availability:_ Linux, Windows, Mac. - -### Suppressing the Elapsed Time ### - -By default, Google Test prints the time it takes to run each test. To -suppress that, run the test program with the `--gtest_print_time=0` -command line flag. Setting the `GTEST_PRINT_TIME` environment -variable to `0` has the same effect. - -_Availability:_ Linux, Windows, Mac. (In Google Test 1.3.0 and lower, -the default behavior is that the elapsed time is **not** printed.) - -### Generating an XML Report ### - -Google Test can emit a detailed XML report to a file in addition to its normal -textual output. The report contains the duration of each test, and thus can -help you identify slow tests. - -To generate the XML report, set the `GTEST_OUTPUT` environment variable or the -`--gtest_output` flag to the string `"xml:_path_to_output_file_"`, which will -create the file at the given location. You can also just use the string -`"xml"`, in which case the output can be found in the `test_detail.xml` file in -the current directory. - -If you specify a directory (for example, `"xml:output/directory/"` on Linux or -`"xml:output\directory\"` on Windows), Google Test will create the XML file in -that directory, named after the test executable (e.g. `foo_test.xml` for test -program `foo_test` or `foo_test.exe`). If the file already exists (perhaps left -over from a previous run), Google Test will pick a different name (e.g. -`foo_test_1.xml`) to avoid overwriting it. - -The report uses the format described here. It is based on the -`junitreport` Ant task and can be parsed by popular continuous build -systems like [Hudson](https://hudson.dev.java.net/). Since that format -was originally intended for Java, a little interpretation is required -to make it apply to Google Test tests, as shown here: - -``` - - - - - - - - - -``` - - * The root `` element corresponds to the entire test program. - * `` elements correspond to Google Test test cases. - * `` elements correspond to Google Test test functions. - -For instance, the following program - -``` -TEST(MathTest, Addition) { ... } -TEST(MathTest, Subtraction) { ... } -TEST(LogicTest, NonContradiction) { ... } -``` - -could generate this report: - -``` - - - - - - - - - - - - - - - -``` - -Things to note: - - * The `tests` attribute of a `` or `` element tells how many test functions the Google Test program or test case contains, while the `failures` attribute tells how many of them failed. - * The `time` attribute expresses the duration of the test, test case, or entire test program in milliseconds. - * Each `` element corresponds to a single failed Google Test assertion. - * Some JUnit concepts don't apply to Google Test, yet we have to conform to the DTD. Therefore you'll see some dummy elements and attributes in the report. You can safely ignore these parts. - -_Availability:_ Linux, Windows, Mac. - -## Controlling How Failures Are Reported ## - -### Turning Assertion Failures into Break-Points ### - -When running test programs under a debugger, it's very convenient if the -debugger can catch an assertion failure and automatically drop into interactive -mode. Google Test's _break-on-failure_ mode supports this behavior. - -To enable it, set the `GTEST_BREAK_ON_FAILURE` environment variable to a value -other than `0` . Alternatively, you can use the `--gtest_break_on_failure` -command line flag. - -_Availability:_ Linux, Windows, Mac. - -### Suppressing Pop-ups Caused by Exceptions ### - -On Windows, Google Test may be used with exceptions enabled. Even when -exceptions are disabled, an application can still throw structured exceptions -(SEH's). If a test throws an exception, by default Google Test doesn't try to -catch it. Instead, you'll see a pop-up dialog, at which point you can attach -the process to a debugger and easily find out what went wrong. - -However, if you don't want to see the pop-ups (for example, if you run the -tests in a batch job), set the `GTEST_CATCH_EXCEPTIONS` environment variable to -a non- `0` value, or use the `--gtest_catch_exceptions` flag. Google Test now -catches all test-thrown exceptions and logs them as failures. - -_Availability:_ Windows. `GTEST_CATCH_EXCEPTIONS` and -`--gtest_catch_exceptions` have no effect on Google Test's behavior on Linux or -Mac, even if exceptions are enabled. It is possible to add support for catching -exceptions on these platforms, but it is not implemented yet. - -### Letting Another Testing Framework Drive ### - -If you work on a project that has already been using another testing -framework and is not ready to completely switch to Google Test yet, -you can get much of Google Test's benefit by using its assertions in -your existing tests. Just change your `main()` function to look -like: - -``` -#include - -int main(int argc, char** argv) { - ::testing::GTEST_FLAG(throw_on_failure) = true; - // Important: Google Test must be initialized. - ::testing::InitGoogleTest(&argc, argv); - - ... whatever your existing testing framework requires ... -} -``` - -With that, you can use Google Test assertions in addition to the -native assertions your testing framework provides, for example: - -``` -void TestFooDoesBar() { - Foo foo; - EXPECT_LE(foo.Bar(1), 100); // A Google Test assertion. - CPPUNIT_ASSERT(foo.IsEmpty()); // A native assertion. -} -``` - -If a Google Test assertion fails, it will print an error message and -throw an exception, which will be treated as a failure by your host -testing framework. If you compile your code with exceptions disabled, -a failed Google Test assertion will instead exit your program with a -non-zero code, which will also signal a test failure to your test -runner. - -If you don't write `::testing::GTEST_FLAG(throw_on_failure) = true;` in -your `main()`, you can alternatively enable this feature by specifying -the `--gtest_throw_on_failure` flag on the command-line or setting the -`GTEST_THROW_ON_FAILURE` environment variable to a non-zero value. - -_Availability:_ Linux, Windows, Mac; since v1.3.0. - -## Distributing Test Functions to Multiple Machines ## - -If you have more than one machine you can use to run a test program, -you might want to run the test functions in parallel and get the -result faster. We call this technique _sharding_, where each machine -is called a _shard_. - -Google Test is compatible with test sharding. To take advantage of -this feature, your test runner (not part of Google Test) needs to do -the following: - - 1. Allocate a number of machines (shards) to run the tests. - 1. On each shard, set the `GTEST_TOTAL_SHARDS` environment variable to the total number of shards. It must be the same for all shards. - 1. On each shard, set the `GTEST_SHARD_INDEX` environment variable to the index of the shard. Different shards must be assigned different indices, which must be in the range `[0, GTEST_TOTAL_SHARDS - 1]`. - 1. Run the same test program on all shards. When Google Test sees the above two environment variables, it will select a subset of the test functions to run. Across all shards, each test function in the program will be run exactly once. - 1. Wait for all shards to finish, then collect and report the results. - -Your project may have tests that were written without Google Test and -thus don't understand this protocol. In order for your test runner to -figure out which test supports sharding, it can set the environment -variable `GTEST_SHARD_STATUS_FILE` to a non-existent file path. If a -test program supports sharding, it will create this file to -acknowledge the fact (the actual contents of the file are not -important at this time; although we may stick some useful information -in it in the future.); otherwise it will not create it. - -Here's an example to make it clear. Suppose you have a test program -`foo_test` that contains the following 5 test functions: -``` -TEST(A, V) -TEST(A, W) -TEST(B, X) -TEST(B, Y) -TEST(B, Z) -``` -and you have 3 machines at your disposal. To run the test functions in -parallel, you would set `GTEST_TOTAL_SHARDS` to 3 on all machines, and -set `GTEST_SHARD_INDEX` to 0, 1, and 2 on the machines respectively. -Then you would run the same `foo_test` on each machine. - -Google Test reserves the right to change how the work is distributed -across the shards, but here's one possible scenario: - - * Machine #0 runs `A.V` and `B.X`. - * Machine #1 runs `A.W` and `B.Y`. - * Machine #2 runs `B.Z`. - -_Availability:_ Linux, Windows, Mac; since version 1.3.0. - -# Fusing Google Test Source Files # - -Google Test's implementation consists of ~30 files (excluding its own -tests). Sometimes you may want them to be packaged up in two files (a -`.h` and a `.cc`) instead, such that you can easily copy them to a new -machine and start hacking there. For this we provide an experimental -Python script `fuse_gtest_files.py` in the `scripts/` directory (since release 1.3.0). -Assuming you have Python 2.4 or above installed on your machine, just -go to that directory and run -``` -python fuse_gtest_files.py OUTPUT_DIR -``` - -and you should see an `OUTPUT_DIR` directory being created with files -`gtest/gtest.h` and `gtest/gtest-all.cc` in it. These files contain -everything you need to use Google Test. Just copy them to anywhere -you want and you are ready to write tests. You can use the -[scrpts/test/Makefile](../scripts/test/Makefile) -file as an example on how to compile your tests against them. - -# Where to Go from Here # - -Congratulations! You've now learned more advanced Google Test tools and are -ready to tackle more complex testing tasks. If you want to dive even deeper, you -can read the [FAQ](V1_5_FAQ.md). diff --git a/googletest/docs/V1_5_Documentation.md b/googletest/docs/V1_5_Documentation.md deleted file mode 100644 index 46bba2ec..00000000 --- a/googletest/docs/V1_5_Documentation.md +++ /dev/null @@ -1,12 +0,0 @@ -This page lists all official documentation wiki pages for Google Test **1.5.0** -- **if you use a different version of Google Test, make sure to read the documentation for that version instead.** - - * [Primer](V1_5_Primer.md) -- start here if you are new to Google Test. - * [Samples](Samples.md) -- learn from examples. - * [AdvancedGuide](V1_5_AdvancedGuide.md) -- learn more about Google Test. - * [XcodeGuide](V1_5_XcodeGuide.md) -- how to use Google Test in Xcode on Mac. - * [Frequently-Asked Questions](V1_5_FAQ.md) -- check here before asking a question on the mailing list. - -To contribute code to Google Test, read: - - * DevGuide -- read this _before_ writing your first patch. - * [PumpManual](V1_5_PumpManual.md) -- how we generate some of Google Test's source files. \ No newline at end of file diff --git a/googletest/docs/V1_5_FAQ.md b/googletest/docs/V1_5_FAQ.md deleted file mode 100644 index e870aff0..00000000 --- a/googletest/docs/V1_5_FAQ.md +++ /dev/null @@ -1,886 +0,0 @@ - - -If you cannot find the answer to your question here, and you have read -[Primer](V1_5_Primer.md) and [AdvancedGuide](V1_5_AdvancedGuide.md), send it to -googletestframework@googlegroups.com. - -## Why should I use Google Test instead of my favorite C++ testing framework? ## - -First, let's say clearly that we don't want to get into the debate of -which C++ testing framework is **the best**. There exist many fine -frameworks for writing C++ tests, and we have tremendous respect for -the developers and users of them. We don't think there is (or will -be) a single best framework - you have to pick the right tool for the -particular task you are tackling. - -We created Google Test because we couldn't find the right combination -of features and conveniences in an existing framework to satisfy _our_ -needs. The following is a list of things that _we_ like about Google -Test. We don't claim them to be unique to Google Test - rather, the -combination of them makes Google Test the choice for us. We hope this -list can help you decide whether it is for you too. - - * Google Test is designed to be portable. It works where many STL types (e.g. `std::string` and `std::vector`) don't compile. It doesn't require exceptions or RTTI. As a result, it runs on Linux, Mac OS X, Windows and several embedded operating systems. - * Nonfatal assertions (`EXPECT_*`) have proven to be great time savers, as they allow a test to report multiple failures in a single edit-compile-test cycle. - * It's easy to write assertions that generate informative messages: you just use the stream syntax to append any additional information, e.g. `ASSERT_EQ(5, Foo(i)) << " where i = " << i;`. It doesn't require a new set of macros or special functions. - * Google Test automatically detects your tests and doesn't require you to enumerate them in order to run them. - * No framework can anticipate all your needs, so Google Test provides `EXPECT_PRED*` to make it easy to extend your assertion vocabulary. For a nicer syntax, you can define your own assertion macros trivially in terms of `EXPECT_PRED*`. - * Death tests are pretty handy for ensuring that your asserts in production code are triggered by the right conditions. - * `SCOPED_TRACE` helps you understand the context of an assertion failure when it comes from inside a sub-routine or loop. - * You can decide which tests to run using name patterns. This saves time when you want to quickly reproduce a test failure. - -## How do I generate 64-bit binaries on Windows (using Visual Studio 2008)? ## - -(Answered by Trevor Robinson) - -Load the supplied Visual Studio solution file, either `msvc\gtest-md.sln` or -`msvc\gtest.sln`. Go through the migration wizard to migrate the -solution and project files to Visual Studio 2008. Select -`Configuration Manager...` from the `Build` menu. Select `` from -the `Active solution platform` dropdown. Select `x64` from the new -platform dropdown, leave `Copy settings from` set to `Win32` and -`Create new project platforms` checked, then click `OK`. You now have -`Win32` and `x64` platform configurations, selectable from the -`Standard` toolbar, which allow you to toggle between building 32-bit or -64-bit binaries (or both at once using Batch Build). - -In order to prevent build output files from overwriting one another, -you'll need to change the `Intermediate Directory` settings for the -newly created platform configuration across all the projects. To do -this, multi-select (e.g. using shift-click) all projects (but not the -solution) in the `Solution Explorer`. Right-click one of them and -select `Properties`. In the left pane, select `Configuration Properties`, -and from the `Configuration` dropdown, select `All Configurations`. -Make sure the selected platform is `x64`. For the -`Intermediate Directory` setting, change the value from -`$(PlatformName)\$(ConfigurationName)` to -`$(OutDir)\$(ProjectName)`. Click `OK` and then build the -solution. When the build is complete, the 64-bit binaries will be in -the `msvc\x64\Debug` directory. - -## Can I use Google Test on MinGW? ## - -We haven't tested this ourselves, but Per Abrahamsen reported that he -was able to compile and install Google Test successfully when using -MinGW from Cygwin. You'll need to configure it with: - -`PATH/TO/configure CC="gcc -mno-cygwin" CXX="g++ -mno-cygwin"` - -You should be able to replace the `-mno-cygwin` option with direct links -to the real MinGW binaries, but we haven't tried that. - -Caveats: - - * There are many warnings when compiling. - * `make check` will produce some errors as not all tests for Google Test itself are compatible with MinGW. - -We also have reports on successful cross compilation of Google Test MinGW binaries on Linux using [these instructions](http://wiki.wxwidgets.org/Cross-Compiling_Under_Linux#Cross-compiling_under_Linux_for_MS_Windows) on the WxWidgets site. - -Please contact `googletestframework@googlegroups.com` if you are -interested in improving the support for MinGW. - -## Why does Google Test support EXPECT\_EQ(NULL, ptr) and ASSERT\_EQ(NULL, ptr) but not EXPECT\_NE(NULL, ptr) and ASSERT\_NE(NULL, ptr)? ## - -Due to some peculiarity of C++, it requires some non-trivial template -meta programming tricks to support using `NULL` as an argument of the -`EXPECT_XX()` and `ASSERT_XX()` macros. Therefore we only do it where -it's most needed (otherwise we make the implementation of Google Test -harder to maintain and more error-prone than necessary). - -The `EXPECT_EQ()` macro takes the _expected_ value as its first -argument and the _actual_ value as the second. It's reasonable that -someone wants to write `EXPECT_EQ(NULL, some_expression)`, and this -indeed was requested several times. Therefore we implemented it. - -The need for `EXPECT_NE(NULL, ptr)` isn't nearly as strong. When the -assertion fails, you already know that `ptr` must be `NULL`, so it -doesn't add any information to print ptr in this case. That means -`EXPECT_TRUE(ptr ! NULL)` works just as well. - -If we were to support `EXPECT_NE(NULL, ptr)`, for consistency we'll -have to support `EXPECT_NE(ptr, NULL)` as well, as unlike `EXPECT_EQ`, -we don't have a convention on the order of the two arguments for -`EXPECT_NE`. This means using the template meta programming tricks -twice in the implementation, making it even harder to understand and -maintain. We believe the benefit doesn't justify the cost. - -Finally, with the growth of Google Mock's [matcher](../../CookBook.md#using-matchers-in-google-test-assertions) library, we are -encouraging people to use the unified `EXPECT_THAT(value, matcher)` -syntax more often in tests. One significant advantage of the matcher -approach is that matchers can be easily combined to form new matchers, -while the `EXPECT_NE`, etc, macros cannot be easily -combined. Therefore we want to invest more in the matchers than in the -`EXPECT_XX()` macros. - -## Does Google Test support running tests in parallel? ## - -Test runners tend to be tightly coupled with the build/test -environment, and Google Test doesn't try to solve the problem of -running tests in parallel. Instead, we tried to make Google Test work -nicely with test runners. For example, Google Test's XML report -contains the time spent on each test, and its `gtest_list_tests` and -`gtest_filter` flags can be used for splitting the execution of test -methods into multiple processes. These functionalities can help the -test runner run the tests in parallel. - -## Why don't Google Test run the tests in different threads to speed things up? ## - -It's difficult to write thread-safe code. Most tests are not written -with thread-safety in mind, and thus may not work correctly in a -multi-threaded setting. - -If you think about it, it's already hard to make your code work when -you know what other threads are doing. It's much harder, and -sometimes even impossible, to make your code work when you don't know -what other threads are doing (remember that test methods can be added, -deleted, or modified after your test was written). If you want to run -the tests in parallel, you'd better run them in different processes. - -## Why aren't Google Test assertions implemented using exceptions? ## - -Our original motivation was to be able to use Google Test in projects -that disable exceptions. Later we realized some additional benefits -of this approach: - - 1. Throwing in a destructor is undefined behavior in C++. Not using exceptions means Google Test's assertions are safe to use in destructors. - 1. The `EXPECT_*` family of macros will continue even after a failure, allowing multiple failures in a `TEST` to be reported in a single run. This is a popular feature, as in C++ the edit-compile-test cycle is usually quite long and being able to fixing more than one thing at a time is a blessing. - 1. If assertions are implemented using exceptions, a test may falsely ignore a failure if it's caught by user code: -``` -try { ... ASSERT_TRUE(...) ... } -catch (...) { ... } -``` -The above code will pass even if the `ASSERT_TRUE` throws. While it's unlikely for someone to write this in a test, it's possible to run into this pattern when you write assertions in callbacks that are called by the code under test. - -The downside of not using exceptions is that `ASSERT_*` (implemented -using `return`) will only abort the current function, not the current -`TEST`. - -## Why do we use two different macros for tests with and without fixtures? ## - -Unfortunately, C++'s macro system doesn't allow us to use the same -macro for both cases. One possibility is to provide only one macro -for tests with fixtures, and require the user to define an empty -fixture sometimes: - -``` -class FooTest : public ::testing::Test {}; - -TEST_F(FooTest, DoesThis) { ... } -``` -or -``` -typedef ::testing::Test FooTest; - -TEST_F(FooTest, DoesThat) { ... } -``` - -Yet, many people think this is one line too many. :-) Our goal was to -make it really easy to write tests, so we tried to make simple tests -trivial to create. That means using a separate macro for such tests. - -We think neither approach is ideal, yet either of them is reasonable. -In the end, it probably doesn't matter much either way. - -## Why don't we use structs as test fixtures? ## - -We like to use structs only when representing passive data. This -distinction between structs and classes is good for documenting the -intent of the code's author. Since test fixtures have logic like -`SetUp()` and `TearDown()`, they are better defined as classes. - -## Why are death tests implemented as assertions instead of using a test runner? ## - -Our goal was to make death tests as convenient for a user as C++ -possibly allows. In particular: - - * The runner-style requires to split the information into two pieces: the definition of the death test itself, and the specification for the runner on how to run the death test and what to expect. The death test would be written in C++, while the runner spec may or may not be. A user needs to carefully keep the two in sync. `ASSERT_DEATH(statement, expected_message)` specifies all necessary information in one place, in one language, without boilerplate code. It is very declarative. - * `ASSERT_DEATH` has a similar syntax and error-reporting semantics as other Google Test assertions, and thus is easy to learn. - * `ASSERT_DEATH` can be mixed with other assertions and other logic at your will. You are not limited to one death test per test method. For example, you can write something like: -``` - if (FooCondition()) { - ASSERT_DEATH(Bar(), "blah"); - } else { - ASSERT_EQ(5, Bar()); - } -``` -If you prefer one death test per test method, you can write your tests in that style too, but we don't want to impose that on the users. The fewer artificial limitations the better. - * `ASSERT_DEATH` can reference local variables in the current function, and you can decide how many death tests you want based on run-time information. For example, -``` - const int count = GetCount(); // Only known at run time. - for (int i = 1; i <= count; i++) { - ASSERT_DEATH({ - double* buffer = new double[i]; - ... initializes buffer ... - Foo(buffer, i) - }, "blah blah"); - } -``` -The runner-based approach tends to be more static and less flexible, or requires more user effort to get this kind of flexibility. - -Another interesting thing about `ASSERT_DEATH` is that it calls `fork()` -to create a child process to run the death test. This is lightening -fast, as `fork()` uses copy-on-write pages and incurs almost zero -overhead, and the child process starts from the user-supplied -statement directly, skipping all global and local initialization and -any code leading to the given statement. If you launch the child -process from scratch, it can take seconds just to load everything and -start running if the test links to many libraries dynamically. - -## My death test modifies some state, but the change seems lost after the death test finishes. Why? ## - -Death tests (`EXPECT_DEATH`, etc) are executed in a sub-process s.t. the -expected crash won't kill the test program (i.e. the parent process). As a -result, any in-memory side effects they incur are observable in their -respective sub-processes, but not in the parent process. You can think of them -as running in a parallel universe, more or less. - -## The compiler complains about "undefined references" to some static const member variables, but I did define them in the class body. What's wrong? ## - -If your class has a static data member: - -``` -// foo.h -class Foo { - ... - static const int kBar = 100; -}; -``` - -You also need to define it _outside_ of the class body in `foo.cc`: - -``` -const int Foo::kBar; // No initializer here. -``` - -Otherwise your code is **invalid C++**, and may break in unexpected ways. In -particular, using it in Google Test comparison assertions (`EXPECT_EQ`, etc) -will generate an "undefined reference" linker error. - -## I have an interface that has several implementations. Can I write a set of tests once and repeat them over all the implementations? ## - -Google Test doesn't yet have good support for this kind of tests, or -data-driven tests in general. We hope to be able to make improvements in this -area soon. - -## Can I derive a test fixture from another? ## - -Yes. - -Each test fixture has a corresponding and same named test case. This means only -one test case can use a particular fixture. Sometimes, however, multiple test -cases may want to use the same or slightly different fixtures. For example, you -may want to make sure that all of a GUI library's test cases don't leak -important system resources like fonts and brushes. - -In Google Test, you share a fixture among test cases by putting the shared -logic in a base test fixture, then deriving from that base a separate fixture -for each test case that wants to use this common logic. You then use `TEST_F()` -to write tests using each derived fixture. - -Typically, your code looks like this: - -``` -// Defines a base test fixture. -class BaseTest : public ::testing::Test { - protected: - ... -}; - -// Derives a fixture FooTest from BaseTest. -class FooTest : public BaseTest { - protected: - virtual void SetUp() { - BaseTest::SetUp(); // Sets up the base fixture first. - ... additional set-up work ... - } - virtual void TearDown() { - ... clean-up work for FooTest ... - BaseTest::TearDown(); // Remember to tear down the base fixture - // after cleaning up FooTest! - } - ... functions and variables for FooTest ... -}; - -// Tests that use the fixture FooTest. -TEST_F(FooTest, Bar) { ... } -TEST_F(FooTest, Baz) { ... } - -... additional fixtures derived from BaseTest ... -``` - -If necessary, you can continue to derive test fixtures from a derived fixture. -Google Test has no limit on how deep the hierarchy can be. - -For a complete example using derived test fixtures, see -`samples/sample5_unittest.cc`. - -## My compiler complains "void value not ignored as it ought to be." What does this mean? ## - -You're probably using an `ASSERT_*()` in a function that doesn't return `void`. -`ASSERT_*()` can only be used in `void` functions. - -## My death test hangs (or seg-faults). How do I fix it? ## - -In Google Test, death tests are run in a child process and the way they work is -delicate. To write death tests you really need to understand how they work. -Please make sure you have read this. - -In particular, death tests don't like having multiple threads in the parent -process. So the first thing you can try is to eliminate creating threads -outside of `EXPECT_DEATH()`. - -Sometimes this is impossible as some library you must use may be creating -threads before `main()` is even reached. In this case, you can try to minimize -the chance of conflicts by either moving as many activities as possible inside -`EXPECT_DEATH()` (in the extreme case, you want to move everything inside), or -leaving as few things as possible in it. Also, you can try to set the death -test style to `"threadsafe"`, which is safer but slower, and see if it helps. - -If you go with thread-safe death tests, remember that they rerun the test -program from the beginning in the child process. Therefore make sure your -program can run side-by-side with itself and is deterministic. - -In the end, this boils down to good concurrent programming. You have to make -sure that there is no race conditions or dead locks in your program. No silver -bullet - sorry! - -## Should I use the constructor/destructor of the test fixture or the set-up/tear-down function? ## - -The first thing to remember is that Google Test does not reuse the -same test fixture object across multiple tests. For each `TEST_F`, -Google Test will create a fresh test fixture object, _immediately_ -call `SetUp()`, run the test, call `TearDown()`, and then -_immediately_ delete the test fixture object. Therefore, there is no -need to write a `SetUp()` or `TearDown()` function if the constructor -or destructor already does the job. - -You may still want to use `SetUp()/TearDown()` in the following cases: - * If the tear-down operation could throw an exception, you must use `TearDown()` as opposed to the destructor, as throwing in a destructor leads to undefined behavior and usually will kill your program right away. Note that many standard libraries (like STL) may throw when exceptions are enabled in the compiler. Therefore you should prefer `TearDown()` if you want to write portable tests that work with or without exceptions. - * The Google Test team is considering making the assertion macros throw on platforms where exceptions are enabled (e.g. Windows, Mac OS, and Linux client-side), which will eliminate the need for the user to propagate failures from a subroutine to its caller. Therefore, you shouldn't use Google Test assertions in a destructor if your code could run on such a platform. - * In a constructor or destructor, you cannot make a virtual function call on this object. (You can call a method declared as virtual, but it will be statically bound.) Therefore, if you need to call a method that will be overriden in a derived class, you have to use `SetUp()/TearDown()`. - -## The compiler complains "no matching function to call" when I use ASSERT\_PREDn. How do I fix it? ## - -If the predicate function you use in `ASSERT_PRED*` or `EXPECT_PRED*` is -overloaded or a template, the compiler will have trouble figuring out which -overloaded version it should use. `ASSERT_PRED_FORMAT*` and -`EXPECT_PRED_FORMAT*` don't have this problem. - -If you see this error, you might want to switch to -`(ASSERT|EXPECT)_PRED_FORMAT*`, which will also give you a better failure -message. If, however, that is not an option, you can resolve the problem by -explicitly telling the compiler which version to pick. - -For example, suppose you have - -``` -bool IsPositive(int n) { - return n > 0; -} -bool IsPositive(double x) { - return x > 0; -} -``` - -you will get a compiler error if you write - -``` -EXPECT_PRED1(IsPositive, 5); -``` - -However, this will work: - -``` -EXPECT_PRED1(*static_cast*(IsPositive), 5); -``` - -(The stuff inside the angled brackets for the `static_cast` operator is the -type of the function pointer for the `int`-version of `IsPositive()`.) - -As another example, when you have a template function - -``` -template -bool IsNegative(T x) { - return x < 0; -} -``` - -you can use it in a predicate assertion like this: - -``` -ASSERT_PRED1(IsNegative**, -5); -``` - -Things are more interesting if your template has more than one parameters. The -following won't compile: - -``` -ASSERT_PRED2(*GreaterThan*, 5, 0); -``` - - -as the C++ pre-processor thinks you are giving `ASSERT_PRED2` 4 arguments, -which is one more than expected. The workaround is to wrap the predicate -function in parentheses: - -``` -ASSERT_PRED2(*(GreaterThan)*, 5, 0); -``` - - -## My compiler complains about "ignoring return value" when I call RUN\_ALL\_TESTS(). Why? ## - -Some people had been ignoring the return value of `RUN_ALL_TESTS()`. That is, -instead of - -``` -return RUN_ALL_TESTS(); -``` - -they write - -``` -RUN_ALL_TESTS(); -``` - -This is wrong and dangerous. A test runner needs to see the return value of -`RUN_ALL_TESTS()` in order to determine if a test has passed. If your `main()` -function ignores it, your test will be considered successful even if it has a -Google Test assertion failure. Very bad. - -To help the users avoid this dangerous bug, the implementation of -`RUN_ALL_TESTS()` causes gcc to raise this warning, when the return value is -ignored. If you see this warning, the fix is simple: just make sure its value -is used as the return value of `main()`. - -## My compiler complains that a constructor (or destructor) cannot return a value. What's going on? ## - -Due to a peculiarity of C++, in order to support the syntax for streaming -messages to an `ASSERT_*`, e.g. - -``` -ASSERT_EQ(1, Foo()) << "blah blah" << foo; -``` - -we had to give up using `ASSERT*` and `FAIL*` (but not `EXPECT*` and -`ADD_FAILURE*`) in constructors and destructors. The workaround is to move the -content of your constructor/destructor to a private void member function, or -switch to `EXPECT_*()` if that works. This section in the user's guide explains -it. - -## My set-up function is not called. Why? ## - -C++ is case-sensitive. It should be spelled as `SetUp()`. Did you -spell it as `Setup()`? - -Similarly, sometimes people spell `SetUpTestCase()` as `SetupTestCase()` and -wonder why it's never called. - -## How do I jump to the line of a failure in Emacs directly? ## - -Google Test's failure message format is understood by Emacs and many other -IDEs, like acme and XCode. If a Google Test message is in a compilation buffer -in Emacs, then it's clickable. You can now hit `enter` on a message to jump to -the corresponding source code, or use `C-x `` to jump to the next failure. - -## I have several test cases which share the same test fixture logic, do I have to define a new test fixture class for each of them? This seems pretty tedious. ## - -You don't have to. Instead of - -``` -class FooTest : public BaseTest {}; - -TEST_F(FooTest, Abc) { ... } -TEST_F(FooTest, Def) { ... } - -class BarTest : public BaseTest {}; - -TEST_F(BarTest, Abc) { ... } -TEST_F(BarTest, Def) { ... } -``` - -you can simply `typedef` the test fixtures: -``` -typedef BaseTest FooTest; - -TEST_F(FooTest, Abc) { ... } -TEST_F(FooTest, Def) { ... } - -typedef BaseTest BarTest; - -TEST_F(BarTest, Abc) { ... } -TEST_F(BarTest, Def) { ... } -``` - -## The Google Test output is buried in a whole bunch of log messages. What do I do? ## - -The Google Test output is meant to be a concise and human-friendly report. If -your test generates textual output itself, it will mix with the Google Test -output, making it hard to read. However, there is an easy solution to this -problem. - -Since most log messages go to stderr, we decided to let Google Test output go -to stdout. This way, you can easily separate the two using redirection. For -example: -``` -./my_test > googletest_output.txt -``` - -## Why should I prefer test fixtures over global variables? ## - -There are several good reasons: - 1. It's likely your test needs to change the states of its global variables. This makes it difficult to keep side effects from escaping one test and contaminating others, making debugging difficult. By using fixtures, each test has a fresh set of variables that's different (but with the same names). Thus, tests are kept independent of each other. - 1. Global variables pollute the global namespace. - 1. Test fixtures can be reused via subclassing, which cannot be done easily with global variables. This is useful if many test cases have something in common. - -## How do I test private class members without writing FRIEND\_TEST()s? ## - -You should try to write testable code, which means classes should be easily -tested from their public interface. One way to achieve this is the Pimpl idiom: -you move all private members of a class into a helper class, and make all -members of the helper class public. - -You have several other options that don't require using `FRIEND_TEST`: - * Write the tests as members of the fixture class: -``` -class Foo { - friend class FooTest; - ... -}; - -class FooTest : public ::testing::Test { - protected: - ... - void Test1() {...} // This accesses private members of class Foo. - void Test2() {...} // So does this one. -}; - -TEST_F(FooTest, Test1) { - Test1(); -} - -TEST_F(FooTest, Test2) { - Test2(); -} -``` - * In the fixture class, write accessors for the tested class' private members, then use the accessors in your tests: -``` -class Foo { - friend class FooTest; - ... -}; - -class FooTest : public ::testing::Test { - protected: - ... - T1 get_private_member1(Foo* obj) { - return obj->private_member1_; - } -}; - -TEST_F(FooTest, Test1) { - ... - get_private_member1(x) - ... -} -``` - * If the methods are declared **protected**, you can change their access level in a test-only subclass: -``` -class YourClass { - ... - protected: // protected access for testability. - int DoSomethingReturningInt(); - ... -}; - -// in the your_class_test.cc file: -class TestableYourClass : public YourClass { - ... - public: using YourClass::DoSomethingReturningInt; // changes access rights - ... -}; - -TEST_F(YourClassTest, DoSomethingTest) { - TestableYourClass obj; - assertEquals(expected_value, obj.DoSomethingReturningInt()); -} -``` - -## How do I test private class static members without writing FRIEND\_TEST()s? ## - -We find private static methods clutter the header file. They are -implementation details and ideally should be kept out of a .h. So often I make -them free functions instead. - -Instead of: -``` -// foo.h -class Foo { - ... - private: - static bool Func(int n); -}; - -// foo.cc -bool Foo::Func(int n) { ... } - -// foo_test.cc -EXPECT_TRUE(Foo::Func(12345)); -``` - -You probably should better write: -``` -// foo.h -class Foo { - ... -}; - -// foo.cc -namespace internal { - bool Func(int n) { ... } -} - -// foo_test.cc -namespace internal { - bool Func(int n); -} - -EXPECT_TRUE(internal::Func(12345)); -``` - -## I would like to run a test several times with different parameters. Do I need to write several similar copies of it? ## - -No. You can use a feature called [value-parameterized tests](V1_5_AdvancedGuide.md#Value_Parameterized_Tests) which -lets you repeat your tests with different parameters, without defining it more than once. - -## How do I test a file that defines main()? ## - -To test a `foo.cc` file, you need to compile and link it into your unit test -program. However, when the file contains a definition for the `main()` -function, it will clash with the `main()` of your unit test, and will result in -a build error. - -The right solution is to split it into three files: - 1. `foo.h` which contains the declarations, - 1. `foo.cc` which contains the definitions except `main()`, and - 1. `foo_main.cc` which contains nothing but the definition of `main()`. - -Then `foo.cc` can be easily tested. - -If you are adding tests to an existing file and don't want an intrusive change -like this, there is a hack: just include the entire `foo.cc` file in your unit -test. For example: -``` -// File foo_unittest.cc - -// The headers section -... - -// Renames main() in foo.cc to make room for the unit test main() -#define main FooMain - -#include "a/b/foo.cc" - -// The tests start here. -... -``` - - -However, please remember this is a hack and should only be used as the last -resort. - -## What can the statement argument in ASSERT\_DEATH() be? ## - -`ASSERT_DEATH(_statement_, _regex_)` (or any death assertion macro) can be used -wherever `_statement_` is valid. So basically `_statement_` can be any C++ -statement that makes sense in the current context. In particular, it can -reference global and/or local variables, and can be: - * a simple function call (often the case), - * a complex expression, or - * a compound statement. - -> Some examples are shown here: - -``` -// A death test can be a simple function call. -TEST(MyDeathTest, FunctionCall) { - ASSERT_DEATH(Xyz(5), "Xyz failed"); -} - -// Or a complex expression that references variables and functions. -TEST(MyDeathTest, ComplexExpression) { - const bool c = Condition(); - ASSERT_DEATH((c ? Func1(0) : object2.Method("test")), - "(Func1|Method) failed"); -} - -// Death assertions can be used any where in a function. In -// particular, they can be inside a loop. -TEST(MyDeathTest, InsideLoop) { - // Verifies that Foo(0), Foo(1), ..., and Foo(4) all die. - for (int i = 0; i < 5; i++) { - EXPECT_DEATH_M(Foo(i), "Foo has \\d+ errors", - ::testing::Message() << "where i is " << i); - } -} - -// A death assertion can contain a compound statement. -TEST(MyDeathTest, CompoundStatement) { - // Verifies that at lease one of Bar(0), Bar(1), ..., and - // Bar(4) dies. - ASSERT_DEATH({ - for (int i = 0; i < 5; i++) { - Bar(i); - } - }, - "Bar has \\d+ errors");} -``` - -`googletest_unittest.cc` contains more examples if you are interested. - -## What syntax does the regular expression in ASSERT\_DEATH use? ## - -On POSIX systems, Google Test uses the POSIX Extended regular -expression syntax -(http://en.wikipedia.org/wiki/Regular_expression#POSIX_Extended_Regular_Expressions). On -Windows, it uses a limited variant of regular expression syntax. For -more details, see the [regular expression syntax](V1_5_AdvancedGuide.md#Regular_Expression_Syntax). - -## I have a fixture class Foo, but TEST\_F(Foo, Bar) gives me error "no matching function for call to Foo::Foo()". Why? ## - -Google Test needs to be able to create objects of your test fixture class, so -it must have a default constructor. Normally the compiler will define one for -you. However, there are cases where you have to define your own: - * If you explicitly declare a non-default constructor for class `Foo`, then you need to define a default constructor, even if it would be empty. - * If `Foo` has a const non-static data member, then you have to define the default constructor _and_ initialize the const member in the initializer list of the constructor. (Early versions of `gcc` doesn't force you to initialize the const member. It's a bug that has been fixed in `gcc 4`.) - -## Why does ASSERT\_DEATH complain about previous threads that were already joined? ## - -With the Linux pthread library, there is no turning back once you cross the -line from single thread to multiple threads. The first time you create a -thread, a manager thread is created in addition, so you get 3, not 2, threads. -Later when the thread you create joins the main thread, the thread count -decrements by 1, but the manager thread will never be killed, so you still have -2 threads, which means you cannot safely run a death test. - -The new NPTL thread library doesn't suffer from this problem, as it doesn't -create a manager thread. However, if you don't control which machine your test -runs on, you shouldn't depend on this. - -## Why does Google Test require the entire test case, instead of individual tests, to be named FOODeathTest when it uses ASSERT\_DEATH? ## - -Google Test does not interleave tests from different test cases. That is, it -runs all tests in one test case first, and then runs all tests in the next test -case, and so on. Google Test does this because it needs to set up a test case -before the first test in it is run, and tear it down afterwords. Splitting up -the test case would require multiple set-up and tear-down processes, which is -inefficient and makes the semantics unclean. - -If we were to determine the order of tests based on test name instead of test -case name, then we would have a problem with the following situation: - -``` -TEST_F(FooTest, AbcDeathTest) { ... } -TEST_F(FooTest, Uvw) { ... } - -TEST_F(BarTest, DefDeathTest) { ... } -TEST_F(BarTest, Xyz) { ... } -``` - -Since `FooTest.AbcDeathTest` needs to run before `BarTest.Xyz`, and we don't -interleave tests from different test cases, we need to run all tests in the -`FooTest` case before running any test in the `BarTest` case. This contradicts -with the requirement to run `BarTest.DefDeathTest` before `FooTest.Uvw`. - -## But I don't like calling my entire test case FOODeathTest when it contains both death tests and non-death tests. What do I do? ## - -You don't have to, but if you like, you may split up the test case into -`FooTest` and `FooDeathTest`, where the names make it clear that they are -related: - -``` -class FooTest : public ::testing::Test { ... }; - -TEST_F(FooTest, Abc) { ... } -TEST_F(FooTest, Def) { ... } - -typedef FooTest FooDeathTest; - -TEST_F(FooDeathTest, Uvw) { ... EXPECT_DEATH(...) ... } -TEST_F(FooDeathTest, Xyz) { ... ASSERT_DEATH(...) ... } -``` - -## The compiler complains about "no match for 'operator<<'" when I use an assertion. What gives? ## - -If you use a user-defined type `FooType` in an assertion, you must make sure -there is an `std::ostream& operator<<(std::ostream&, const FooType&)` function -defined such that we can print a value of `FooType`. - -In addition, if `FooType` is declared in a name space, the `<<` operator also -needs to be defined in the _same_ name space. - -## How do I suppress the memory leak messages on Windows? ## - -Since the statically initialized Google Test singleton requires allocations on -the heap, the Visual C++ memory leak detector will report memory leaks at the -end of the program run. The easiest way to avoid this is to use the -`_CrtMemCheckpoint` and `_CrtMemDumpAllObjectsSince` calls to not report any -statically initialized heap objects. See MSDN for more details and additional -heap check/debug routines. - -## I am building my project with Google Test in Visual Studio and all I'm getting is a bunch of linker errors (or warnings). Help! ## - -You may get a number of the following linker error or warnings if you -attempt to link your test project with the Google Test library when -your project and the are not built using the same compiler settings. - - * LNK2005: symbol already defined in object - * LNK4217: locally defined symbol 'symbol' imported in function 'function' - * LNK4049: locally defined symbol 'symbol' imported - -The Google Test project (gtest.vcproj) has the Runtime Library option -set to /MT (use multi-threaded static libraries, /MTd for debug). If -your project uses something else, for example /MD (use multi-threaded -DLLs, /MDd for debug), you need to change the setting in the Google -Test project to match your project's. - -To update this setting open the project properties in the Visual -Studio IDE then select the branch Configuration Properties | C/C++ | -Code Generation and change the option "Runtime Library". You may also try -using gtest-md.vcproj instead of gtest.vcproj. - -## I put my tests in a library and Google Test doesn't run them. What's happening? ## -Have you read a -[warning](V1_5_Primer.md#important-note-for-visual-c-users) on -the Google Test Primer page? - -## I want to use Google Test with Visual Studio but don't know where to start. ## -Many people are in your position and one of the posted his solution to -our mailing list. Here is his link: -http://hassanjamilahmad.blogspot.com/2009/07/gtest-starters-help.html. - -## My question is not covered in your FAQ! ## - -If you cannot find the answer to your question in this FAQ, there are -some other resources you can use: - - 1. read other [wiki pages](http://code.google.com/p/googletest/w/list), - 1. search the mailing list [archive](http://groups.google.com/group/googletestframework/topics), - 1. ask it on [googletestframework@googlegroups.com](mailto:googletestframework@googlegroups.com) and someone will answer it (to prevent spam, we require you to join the [discussion group](http://groups.google.com/group/googletestframework) before you can post.). - -Please note that creating an issue in the -[issue tracker](http://code.google.com/p/googletest/issues/list) is _not_ -a good way to get your answer, as it is monitored infrequently by a -very small number of people. - -When asking a question, it's helpful to provide as much of the -following information as possible (people cannot help you if there's -not enough information in your question): - - * the version (or the revision number if you check out from SVN directly) of Google Test you use (Google Test is under active development, so it's possible that your problem has been solved in a later version), - * your operating system, - * the name and version of your compiler, - * the complete command line flags you give to your compiler, - * the complete compiler error messages (if the question is about compilation), - * the _actual_ code (ideally, a minimal but complete program) that has the problem you encounter. diff --git a/googletest/docs/V1_5_Primer.md b/googletest/docs/V1_5_Primer.md deleted file mode 100644 index 6960d2ce..00000000 --- a/googletest/docs/V1_5_Primer.md +++ /dev/null @@ -1,497 +0,0 @@ - - -# Introduction: Why Google C++ Testing Framework? # - -_Google C++ Testing Framework_ helps you write better C++ tests. - -No matter whether you work on Linux, Windows, or a Mac, if you write C++ code, -Google Test can help you. - -So what makes a good test, and how does Google C++ Testing Framework fit in? We believe: - 1. Tests should be _independent_ and _repeatable_. It's a pain to debug a test that succeeds or fails as a result of other tests. Google C++ Testing Framework isolates the tests by running each of them on a different object. When a test fails, Google C++ Testing Framework allows you to run it in isolation for quick debugging. - 1. Tests should be well _organized_ and reflect the structure of the tested code. Google C++ Testing Framework groups related tests into test cases that can share data and subroutines. This common pattern is easy to recognize and makes tests easy to maintain. Such consistency is especially helpful when people switch projects and start to work on a new code base. - 1. Tests should be _portable_ and _reusable_. The open-source community has a lot of code that is platform-neutral, its tests should also be platform-neutral. Google C++ Testing Framework works on different OSes, with different compilers (gcc, MSVC, and others), with or without exceptions, so Google C++ Testing Framework tests can easily work with a variety of configurations. (Note that the current release only contains build scripts for Linux - we are actively working on scripts for other platforms.) - 1. When tests fail, they should provide as much _information_ about the problem as possible. Google C++ Testing Framework doesn't stop at the first test failure. Instead, it only stops the current test and continues with the next. You can also set up tests that report non-fatal failures after which the current test continues. Thus, you can detect and fix multiple bugs in a single run-edit-compile cycle. - 1. The testing framework should liberate test writers from housekeeping chores and let them focus on the test _content_. Google C++ Testing Framework automatically keeps track of all tests defined, and doesn't require the user to enumerate them in order to run them. - 1. Tests should be _fast_. With Google C++ Testing Framework, you can reuse shared resources across tests and pay for the set-up/tear-down only once, without making tests depend on each other. - -Since Google C++ Testing Framework is based on the popular xUnit -architecture, you'll feel right at home if you've used JUnit or PyUnit before. -If not, it will take you about 10 minutes to learn the basics and get started. -So let's go! - -_Note:_ We sometimes refer to Google C++ Testing Framework informally -as _Google Test_. - -# Setting up a New Test Project # - -To write a test program using Google Test, you need to compile Google -Test into a library and link your test with it. We provide build -files for some popular build systems (`msvc/` for Visual Studio, -`xcode/` for Mac Xcode, `make/` for GNU make, `codegear/` for Borland -C++ Builder, and the autotools script in the -Google Test root directory). If your build system is not on this -list, you can take a look at `make/Makefile` to learn how Google Test -should be compiled (basically you want to compile `src/gtest-all.cc` -with `GTEST_ROOT` and `GTEST_ROOT/include` in the header search path, -where `GTEST_ROOT` is the Google Test root directory). - -Once you are able to compile the Google Test library, you should -create a project or build target for your test program. Make sure you -have `GTEST_ROOT/include` in the header search path so that the -compiler can find `` when compiling your test. Set up -your test project to link with the Google Test library (for example, -in Visual Studio, this is done by adding a dependency on -`gtest.vcproj`). - -If you still have questions, take a look at how Google Test's own -tests are built and use them as examples. - -# Basic Concepts # - -When using Google Test, you start by writing _assertions_, which are statements -that check whether a condition is true. An assertion's result can be _success_, -_nonfatal failure_, or _fatal failure_. If a fatal failure occurs, it aborts -the current function; otherwise the program continues normally. - -_Tests_ use assertions to verify the tested code's behavior. If a test crashes -or has a failed assertion, then it _fails_; otherwise it _succeeds_. - -A _test case_ contains one or many tests. You should group your tests into test -cases that reflect the structure of the tested code. When multiple tests in a -test case need to share common objects and subroutines, you can put them into a -_test fixture_ class. - -A _test program_ can contain multiple test cases. - -We'll now explain how to write a test program, starting at the individual -assertion level and building up to tests and test cases. - -# Assertions # - -Google Test assertions are macros that resemble function calls. You test a -class or function by making assertions about its behavior. When an assertion -fails, Google Test prints the assertion's source file and line number location, -along with a failure message. You may also supply a custom failure message -which will be appended to Google Test's message. - -The assertions come in pairs that test the same thing but have different -effects on the current function. `ASSERT_*` versions generate fatal failures -when they fail, and **abort the current function**. `EXPECT_*` versions generate -nonfatal failures, which don't abort the current function. Usually `EXPECT_*` -are preferred, as they allow more than one failures to be reported in a test. -However, you should use `ASSERT_*` if it doesn't make sense to continue when -the assertion in question fails. - -Since a failed `ASSERT_*` returns from the current function immediately, -possibly skipping clean-up code that comes after it, it may cause a space leak. -Depending on the nature of the leak, it may or may not be worth fixing - so -keep this in mind if you get a heap checker error in addition to assertion -errors. - -To provide a custom failure message, simply stream it into the macro using the -`<<` operator, or a sequence of such operators. An example: -``` -ASSERT_EQ(x.size(), y.size()) << "Vectors x and y are of unequal length"; - -for (int i = 0; i < x.size(); ++i) { - EXPECT_EQ(x[i], y[i]) << "Vectors x and y differ at index " << i; -} -``` - -Anything that can be streamed to an `ostream` can be streamed to an assertion -macro--in particular, C strings and `string` objects. If a wide string -(`wchar_t*`, `TCHAR*` in `UNICODE` mode on Windows, or `std::wstring`) is -streamed to an assertion, it will be translated to UTF-8 when printed. - -## Basic Assertions ## - -These assertions do basic true/false condition testing. -| **Fatal assertion** | **Nonfatal assertion** | **Verifies** | -|:--------------------|:-----------------------|:-------------| -| `ASSERT_TRUE(`_condition_`)`; | `EXPECT_TRUE(`_condition_`)`; | _condition_ is true | -| `ASSERT_FALSE(`_condition_`)`; | `EXPECT_FALSE(`_condition_`)`; | _condition_ is false | - -Remember, when they fail, `ASSERT_*` yields a fatal failure and -returns from the current function, while `EXPECT_*` yields a nonfatal -failure, allowing the function to continue running. In either case, an -assertion failure means its containing test fails. - -_Availability_: Linux, Windows, Mac. - -## Binary Comparison ## - -This section describes assertions that compare two values. - -| **Fatal assertion** | **Nonfatal assertion** | **Verifies** | -|:--------------------|:-----------------------|:-------------| -|`ASSERT_EQ(`_expected_`, `_actual_`);`|`EXPECT_EQ(`_expected_`, `_actual_`);`| _expected_ `==` _actual_ | -|`ASSERT_NE(`_val1_`, `_val2_`);` |`EXPECT_NE(`_val1_`, `_val2_`);` | _val1_ `!=` _val2_ | -|`ASSERT_LT(`_val1_`, `_val2_`);` |`EXPECT_LT(`_val1_`, `_val2_`);` | _val1_ `<` _val2_ | -|`ASSERT_LE(`_val1_`, `_val2_`);` |`EXPECT_LE(`_val1_`, `_val2_`);` | _val1_ `<=` _val2_ | -|`ASSERT_GT(`_val1_`, `_val2_`);` |`EXPECT_GT(`_val1_`, `_val2_`);` | _val1_ `>` _val2_ | -|`ASSERT_GE(`_val1_`, `_val2_`);` |`EXPECT_GE(`_val1_`, `_val2_`);` | _val1_ `>=` _val2_ | - -In the event of a failure, Google Test prints both _val1_ and _val2_ -. In `ASSERT_EQ*` and `EXPECT_EQ*` (and all other equality assertions -we'll introduce later), you should put the expression you want to test -in the position of _actual_, and put its expected value in _expected_, -as Google Test's failure messages are optimized for this convention. - -Value arguments must be comparable by the assertion's comparison operator or -you'll get a compiler error. Values must also support the `<<` operator for -streaming to an `ostream`. All built-in types support this. - -These assertions can work with a user-defined type, but only if you define the -corresponding comparison operator (e.g. `==`, `<`, etc). If the corresponding -operator is defined, prefer using the `ASSERT_*()` macros because they will -print out not only the result of the comparison, but the two operands as well. - -Arguments are always evaluated exactly once. Therefore, it's OK for the -arguments to have side effects. However, as with any ordinary C/C++ function, -the arguments' evaluation order is undefined (i.e. the compiler is free to -choose any order) and your code should not depend on any particular argument -evaluation order. - -`ASSERT_EQ()` does pointer equality on pointers. If used on two C strings, it -tests if they are in the same memory location, not if they have the same value. -Therefore, if you want to compare C strings (e.g. `const char*`) by value, use -`ASSERT_STREQ()` , which will be described later on. In particular, to assert -that a C string is `NULL`, use `ASSERT_STREQ(NULL, c_string)` . However, to -compare two `string` objects, you should use `ASSERT_EQ`. - -Macros in this section work with both narrow and wide string objects (`string` -and `wstring`). - -_Availability_: Linux, Windows, Mac. - -## String Comparison ## - -The assertions in this group compare two **C strings**. If you want to compare -two `string` objects, use `EXPECT_EQ`, `EXPECT_NE`, and etc instead. - -| **Fatal assertion** | **Nonfatal assertion** | **Verifies** | -|:--------------------|:-----------------------|:-------------| -| `ASSERT_STREQ(`_expected\_str_`, `_actual\_str_`);` | `EXPECT_STREQ(`_expected\_str_`, `_actual\_str_`);` | the two C strings have the same content | -| `ASSERT_STRNE(`_str1_`, `_str2_`);` | `EXPECT_STRNE(`_str1_`, `_str2_`);` | the two C strings have different content | -| `ASSERT_STRCASEEQ(`_expected\_str_`, `_actual\_str_`);`| `EXPECT_STRCASEEQ(`_expected\_str_`, `_actual\_str_`);` | the two C strings have the same content, ignoring case | -| `ASSERT_STRCASENE(`_str1_`, `_str2_`);`| `EXPECT_STRCASENE(`_str1_`, `_str2_`);` | the two C strings have different content, ignoring case | - -Note that "CASE" in an assertion name means that case is ignored. - -`*STREQ*` and `*STRNE*` also accept wide C strings (`wchar_t*`). If a -comparison of two wide strings fails, their values will be printed as UTF-8 -narrow strings. - -A `NULL` pointer and an empty string are considered _different_. - -_Availability_: Linux, Windows, Mac. - -See also: For more string comparison tricks (substring, prefix, suffix, and -regular expression matching, for example), see the [AdvancedGuide Advanced -Google Test Guide]. - -# Simple Tests # - -To create a test: - 1. Use the `TEST()` macro to define and name a test function, These are ordinary C++ functions that don't return a value. - 1. In this function, along with any valid C++ statements you want to include, use the various Google Test assertions to check values. - 1. The test's result is determined by the assertions; if any assertion in the test fails (either fatally or non-fatally), or if the test crashes, the entire test fails. Otherwise, it succeeds. - -``` -TEST(test_case_name, test_name) { - ... test body ... -} -``` - - -`TEST()` arguments go from general to specific. The _first_ argument is the -name of the test case, and the _second_ argument is the test's name within the -test case. Remember that a test case can contain any number of individual -tests. A test's _full name_ consists of its containing test case and its -individual name. Tests from different test cases can have the same individual -name. - -For example, let's take a simple integer function: -``` -int Factorial(int n); // Returns the factorial of n -``` - -A test case for this function might look like: -``` -// Tests factorial of 0. -TEST(FactorialTest, HandlesZeroInput) { - EXPECT_EQ(1, Factorial(0)); -} - -// Tests factorial of positive numbers. -TEST(FactorialTest, HandlesPositiveInput) { - EXPECT_EQ(1, Factorial(1)); - EXPECT_EQ(2, Factorial(2)); - EXPECT_EQ(6, Factorial(3)); - EXPECT_EQ(40320, Factorial(8)); -} -``` - -Google Test groups the test results by test cases, so logically-related tests -should be in the same test case; in other words, the first argument to their -`TEST()` should be the same. In the above example, we have two tests, -`HandlesZeroInput` and `HandlesPositiveInput`, that belong to the same test -case `FactorialTest`. - -_Availability_: Linux, Windows, Mac. - -# Test Fixtures: Using the Same Data Configuration for Multiple Tests # - -If you find yourself writing two or more tests that operate on similar data, -you can use a _test fixture_. It allows you to reuse the same configuration of -objects for several different tests. - -To create a fixture, just: - 1. Derive a class from `::testing::Test` . Start its body with `protected:` or `public:` as we'll want to access fixture members from sub-classes. - 1. Inside the class, declare any objects you plan to use. - 1. If necessary, write a default constructor or `SetUp()` function to prepare the objects for each test. A common mistake is to spell `SetUp()` as `Setup()` with a small `u` - don't let that happen to you. - 1. If necessary, write a destructor or `TearDown()` function to release any resources you allocated in `SetUp()` . To learn when you should use the constructor/destructor and when you should use `SetUp()/TearDown()`, read this [FAQ entry](V1_5_FAQ.md#should-i-use-the-constructordestructor-of-the-test-fixture-or-the-set-uptear-down-function). - 1. If needed, define subroutines for your tests to share. - -When using a fixture, use `TEST_F()` instead of `TEST()` as it allows you to -access objects and subroutines in the test fixture: -``` -TEST_F(test_case_name, test_name) { - ... test body ... -} -``` - -Like `TEST()`, the first argument is the test case name, but for `TEST_F()` -this must be the name of the test fixture class. You've probably guessed: `_F` -is for fixture. - -Unfortunately, the C++ macro system does not allow us to create a single macro -that can handle both types of tests. Using the wrong macro causes a compiler -error. - -Also, you must first define a test fixture class before using it in a -`TEST_F()`, or you'll get the compiler error "`virtual outside class -declaration`". - -For each test defined with `TEST_F()`, Google Test will: - 1. Create a _fresh_ test fixture at runtime - 1. Immediately initialize it via `SetUp()` , - 1. Run the test - 1. Clean up by calling `TearDown()` - 1. Delete the test fixture. Note that different tests in the same test case have different test fixture objects, and Google Test always deletes a test fixture before it creates the next one. Google Test does not reuse the same test fixture for multiple tests. Any changes one test makes to the fixture do not affect other tests. - -As an example, let's write tests for a FIFO queue class named `Queue`, which -has the following interface: -``` -template // E is the element type. -class Queue { - public: - Queue(); - void Enqueue(const E& element); - E* Dequeue(); // Returns NULL if the queue is empty. - size_t size() const; - ... -}; -``` - -First, define a fixture class. By convention, you should give it the name -`FooTest` where `Foo` is the class being tested. -``` -class QueueTest : public ::testing::Test { - protected: - virtual void SetUp() { - q1_.Enqueue(1); - q2_.Enqueue(2); - q2_.Enqueue(3); - } - - // virtual void TearDown() {} - - Queue q0_; - Queue q1_; - Queue q2_; -}; -``` - -In this case, `TearDown()` is not needed since we don't have to clean up after -each test, other than what's already done by the destructor. - -Now we'll write tests using `TEST_F()` and this fixture. -``` -TEST_F(QueueTest, IsEmptyInitially) { - EXPECT_EQ(0, q0_.size()); -} - -TEST_F(QueueTest, DequeueWorks) { - int* n = q0_.Dequeue(); - EXPECT_EQ(NULL, n); - - n = q1_.Dequeue(); - ASSERT_TRUE(n != NULL); - EXPECT_EQ(1, *n); - EXPECT_EQ(0, q1_.size()); - delete n; - - n = q2_.Dequeue(); - ASSERT_TRUE(n != NULL); - EXPECT_EQ(2, *n); - EXPECT_EQ(1, q2_.size()); - delete n; -} -``` - -The above uses both `ASSERT_*` and `EXPECT_*` assertions. The rule of thumb is -to use `EXPECT_*` when you want the test to continue to reveal more errors -after the assertion failure, and use `ASSERT_*` when continuing after failure -doesn't make sense. For example, the second assertion in the `Dequeue` test is -`ASSERT_TRUE(n != NULL)`, as we need to dereference the pointer `n` later, -which would lead to a segfault when `n` is `NULL`. - -When these tests run, the following happens: - 1. Google Test constructs a `QueueTest` object (let's call it `t1` ). - 1. `t1.SetUp()` initializes `t1` . - 1. The first test ( `IsEmptyInitially` ) runs on `t1` . - 1. `t1.TearDown()` cleans up after the test finishes. - 1. `t1` is destructed. - 1. The above steps are repeated on another `QueueTest` object, this time running the `DequeueWorks` test. - -_Availability_: Linux, Windows, Mac. - -_Note_: Google Test automatically saves all _Google Test_ flags when a test -object is constructed, and restores them when it is destructed. - -# Invoking the Tests # - -`TEST()` and `TEST_F()` implicitly register their tests with Google Test. So, unlike with many other C++ testing frameworks, you don't have to re-list all your defined tests in order to run them. - -After defining your tests, you can run them with `RUN_ALL_TESTS()` , which returns `0` if all the tests are successful, or `1` otherwise. Note that `RUN_ALL_TESTS()` runs _all tests_ in your link unit -- they can be from different test cases, or even different source files. - -When invoked, the `RUN_ALL_TESTS()` macro: - 1. Saves the state of all Google Test flags. - 1. Creates a test fixture object for the first test. - 1. Initializes it via `SetUp()`. - 1. Runs the test on the fixture object. - 1. Cleans up the fixture via `TearDown()`. - 1. Deletes the fixture. - 1. Restores the state of all Google Test flags. - 1. Repeats the above steps for the next test, until all tests have run. - -In addition, if the text fixture's constructor generates a fatal failure in -step 2, there is no point for step 3 - 5 and they are thus skipped. Similarly, -if step 3 generates a fatal failure, step 4 will be skipped. - -_Important_: You must not ignore the return value of `RUN_ALL_TESTS()`, or `gcc` -will give you a compiler error. The rationale for this design is that the -automated testing service determines whether a test has passed based on its -exit code, not on its stdout/stderr output; thus your `main()` function must -return the value of `RUN_ALL_TESTS()`. - -Also, you should call `RUN_ALL_TESTS()` only **once**. Calling it more than once -conflicts with some advanced Google Test features (e.g. thread-safe death -tests) and thus is not supported. - -_Availability_: Linux, Windows, Mac. - -# Writing the main() Function # - -You can start from this boilerplate: -``` -#include "this/package/foo.h" -#include - -namespace { - -// The fixture for testing class Foo. -class FooTest : public ::testing::Test { - protected: - // You can remove any or all of the following functions if its body - // is empty. - - FooTest() { - // You can do set-up work for each test here. - } - - virtual ~FooTest() { - // You can do clean-up work that doesn't throw exceptions here. - } - - // If the constructor and destructor are not enough for setting up - // and cleaning up each test, you can define the following methods: - - virtual void SetUp() { - // Code here will be called immediately after the constructor (right - // before each test). - } - - virtual void TearDown() { - // Code here will be called immediately after each test (right - // before the destructor). - } - - // Objects declared here can be used by all tests in the test case for Foo. -}; - -// Tests that the Foo::Bar() method does Abc. -TEST_F(FooTest, MethodBarDoesAbc) { - const string input_filepath = "this/package/testdata/myinputfile.dat"; - const string output_filepath = "this/package/testdata/myoutputfile.dat"; - Foo f; - EXPECT_EQ(0, f.Bar(input_filepath, output_filepath)); -} - -// Tests that Foo does Xyz. -TEST_F(FooTest, DoesXyz) { - // Exercises the Xyz feature of Foo. -} - -} // namespace - -int main(int argc, char **argv) { - ::testing::InitGoogleTest(&argc, argv); - return RUN_ALL_TESTS(); -} -``` - -The `::testing::InitGoogleTest()` function parses the command line for Google -Test flags, and removes all recognized flags. This allows the user to control a -test program's behavior via various flags, which we'll cover in [AdvancedGuide](V1_5_AdvancedGuide.md). -You must call this function before calling `RUN_ALL_TESTS()`, or the flags -won't be properly initialized. - -On Windows, `InitGoogleTest()` also works with wide strings, so it can be used -in programs compiled in `UNICODE` mode as well. - -But maybe you think that writing all those main() functions is too much work? We agree with you completely and that's why Google Test provides a basic implementation of main(). If it fits your needs, then just link your test with gtest\_main library and you are good to go. - -## Important note for Visual C++ users ## -If you put your tests into a library and your `main()` function is in a different library or in your .exe file, those tests will not run. The reason is a [bug](https://connect.microsoft.com/feedback/viewfeedback.aspx?FeedbackID=244410&siteid=210) in Visual C++. When you define your tests, Google Test creates certain static objects to register them. These objects are not referenced from elsewhere but their constructors are still supposed to run. When Visual C++ linker sees that nothing in the library is referenced from other places it throws the library out. You have to reference your library with tests from your main program to keep the linker from discarding it. Here is how to do it. Somewhere in your library code declare a function: -``` -__declspec(dllexport) int PullInMyLibrary() { return 0; } -``` -If you put your tests in a static library (not DLL) then `__declspec(dllexport)` is not required. Now, in your main program, write a code that invokes that function: -``` -int PullInMyLibrary(); -static int dummy = PullInMyLibrary(); -``` -This will keep your tests referenced and will make them register themselves at startup. - -In addition, if you define your tests in a static library, add `/OPT:NOREF` to your main program linker options. If you use MSVC++ IDE, go to your .exe project properties/Configuration Properties/Linker/Optimization and set References setting to `Keep Unreferenced Data (/OPT:NOREF)`. This will keep Visual C++ linker from discarding individual symbols generated by your tests from the final executable. - -There is one more pitfall, though. If you use Google Test as a static library (that's how it is defined in gtest.vcproj) your tests must also reside in a static library. If you have to have them in a DLL, you _must_ change Google Test to build into a DLL as well. Otherwise your tests will not run correctly or will not run at all. The general conclusion here is: make your life easier - do not write your tests in libraries! - -# Where to Go from Here # - -Congratulations! You've learned the Google Test basics. You can start writing -and running Google Test tests, read some [samples](Samples.md), or continue with -[AdvancedGuide](V1_5_AdvancedGuide.md), which describes many more useful Google Test features. - -# Known Limitations # - -Google Test is designed to be thread-safe. The implementation is -thread-safe on systems where the `pthreads` library is available. It -is currently _unsafe_ to use Google Test assertions from two threads -concurrently on other systems (e.g. Windows). In most tests this is -not an issue as usually the assertions are done in the main thread. If -you want to help, you can volunteer to implement the necessary -synchronization primitives in `gtest-port.h` for your platform. diff --git a/googletest/docs/V1_5_PumpManual.md b/googletest/docs/V1_5_PumpManual.md deleted file mode 100644 index 15710789..00000000 --- a/googletest/docs/V1_5_PumpManual.md +++ /dev/null @@ -1,177 +0,0 @@ - - -Pump is Useful for Meta Programming. - -# The Problem # - -Template and macro libraries often need to define many classes, -functions, or macros that vary only (or almost only) in the number of -arguments they take. It's a lot of repetitive, mechanical, and -error-prone work. - -Variadic templates and variadic macros can alleviate the problem. -However, while both are being considered by the C++ committee, neither -is in the standard yet or widely supported by compilers. Thus they -are often not a good choice, especially when your code needs to be -portable. And their capabilities are still limited. - -As a result, authors of such libraries often have to write scripts to -generate their implementation. However, our experience is that it's -tedious to write such scripts, which tend to reflect the structure of -the generated code poorly and are often hard to read and edit. For -example, a small change needed in the generated code may require some -non-intuitive, non-trivial changes in the script. This is especially -painful when experimenting with the code. - -# Our Solution # - -Pump (for Pump is Useful for Meta Programming, Pretty Useful for Meta -Programming, or Practical Utility for Meta Programming, whichever you -prefer) is a simple meta-programming tool for C++. The idea is that a -programmer writes a `foo.pump` file which contains C++ code plus meta -code that manipulates the C++ code. The meta code can handle -iterations over a range, nested iterations, local meta variable -definitions, simple arithmetic, and conditional expressions. You can -view it as a small Domain-Specific Language. The meta language is -designed to be non-intrusive (s.t. it won't confuse Emacs' C++ mode, -for example) and concise, making Pump code intuitive and easy to -maintain. - -## Highlights ## - - * The implementation is in a single Python script and thus ultra portable: no build or installation is needed and it works cross platforms. - * Pump tries to be smart with respect to [Google's style guide](http://code.google.com/p/google-styleguide/): it breaks long lines (easy to have when they are generated) at acceptable places to fit within 80 columns and indent the continuation lines correctly. - * The format is human-readable and more concise than XML. - * The format works relatively well with Emacs' C++ mode. - -## Examples ## - -The following Pump code (where meta keywords start with `$`, `[[` and `]]` are meta brackets, and `$$` starts a meta comment that ends with the line): - -``` -$var n = 3 $$ Defines a meta variable n. -$range i 0..n $$ Declares the range of meta iterator i (inclusive). -$for i [[ - $$ Meta loop. -// Foo$i does blah for $i-ary predicates. -$range j 1..i -template -class Foo$i { -$if i == 0 [[ - blah a; -]] $elif i <= 2 [[ - blah b; -]] $else [[ - blah c; -]] -}; - -]] -``` - -will be translated by the Pump compiler to: - -``` -// Foo0 does blah for 0-ary predicates. -template -class Foo0 { - blah a; -}; - -// Foo1 does blah for 1-ary predicates. -template -class Foo1 { - blah b; -}; - -// Foo2 does blah for 2-ary predicates. -template -class Foo2 { - blah b; -}; - -// Foo3 does blah for 3-ary predicates. -template -class Foo3 { - blah c; -}; -``` - -In another example, - -``` -$range i 1..n -Func($for i + [[a$i]]); -$$ The text between i and [[ is the separator between iterations. -``` - -will generate one of the following lines (without the comments), depending on the value of `n`: - -``` -Func(); // If n is 0. -Func(a1); // If n is 1. -Func(a1 + a2); // If n is 2. -Func(a1 + a2 + a3); // If n is 3. -// And so on... -``` - -## Constructs ## - -We support the following meta programming constructs: - -| `$var id = exp` | Defines a named constant value. `$id` is valid util the end of the current meta lexical block. | -|:----------------|:-----------------------------------------------------------------------------------------------| -| $range id exp..exp | Sets the range of an iteration variable, which can be reused in multiple loops later. | -| $for id sep [[code ](.md)] | Iteration. The range of `id` must have been defined earlier. `$id` is valid in `code`. | -| `$($)` | Generates a single `$` character. | -| `$id` | Value of the named constant or iteration variable. | -| `$(exp)` | Value of the expression. | -| `$if exp [[ code ]] else_branch` | Conditional. | -| `[[ code ]]` | Meta lexical block. | -| `cpp_code` | Raw C++ code. | -| `$$ comment` | Meta comment. | - -**Note:** To give the user some freedom in formatting the Pump source -code, Pump ignores a new-line character if it's right after `$for foo` -or next to `[[` or `]]`. Without this rule you'll often be forced to write -very long lines to get the desired output. Therefore sometimes you may -need to insert an extra new-line in such places for a new-line to show -up in your output. - -## Grammar ## - -``` -code ::= atomic_code* -atomic_code ::= $var id = exp - | $var id = [[ code ]] - | $range id exp..exp - | $for id sep [[ code ]] - | $($) - | $id - | $(exp) - | $if exp [[ code ]] else_branch - | [[ code ]] - | cpp_code -sep ::= cpp_code | empty_string -else_branch ::= $else [[ code ]] - | $elif exp [[ code ]] else_branch - | empty_string -exp ::= simple_expression_in_Python_syntax -``` - -## Code ## - -You can find the source code of Pump in [scripts/pump.py](http://code.google.com/p/googletest/source/browse/trunk/scripts/pump.py). It is still -very unpolished and lacks automated tests, although it has been -successfully used many times. If you find a chance to use it in your -project, please let us know what you think! We also welcome help on -improving Pump. - -## Real Examples ## - -You can find real-world applications of Pump in [Google Test](http://www.google.com/codesearch?q=file%3A\.pump%24+package%3Ahttp%3A%2F%2Fgoogletest\.googlecode\.com) and [Google Mock](http://www.google.com/codesearch?q=file%3A\.pump%24+package%3Ahttp%3A%2F%2Fgooglemock\.googlecode\.com). The source file `foo.h.pump` generates `foo.h`. - -## Tips ## - - * If a meta variable is followed by a letter or digit, you can separate them using `[[]]`, which inserts an empty string. For example `Foo$j[[]]Helper` generate `Foo1Helper` when `j` is 1. - * To avoid extra-long Pump source lines, you can break a line anywhere you want by inserting `[[]]` followed by a new line. Since any new-line character next to `[[` or `]]` is ignored, the generated code won't contain this new line. \ No newline at end of file diff --git a/googletest/docs/V1_5_XcodeGuide.md b/googletest/docs/V1_5_XcodeGuide.md deleted file mode 100644 index bf24bf51..00000000 --- a/googletest/docs/V1_5_XcodeGuide.md +++ /dev/null @@ -1,93 +0,0 @@ - - -This guide will explain how to use the Google Testing Framework in your Xcode projects on Mac OS X. This tutorial begins by quickly explaining what to do for experienced users. After the quick start, the guide goes provides additional explanation about each step. - -# Quick Start # - -Here is the quick guide for using Google Test in your Xcode project. - - 1. Download the source from the [website](http://code.google.com/p/googletest) using this command: `svn checkout http://googletest.googlecode.com/svn/trunk/ googletest-read-only` - 1. Open up the `gtest.xcodeproj` in the `googletest-read-only/xcode/` directory and build the gtest.framework. - 1. Create a new "Shell Tool" target in your Xcode project called something like "UnitTests" - 1. Add the gtest.framework to your project and add it to the "Link Binary with Libraries" build phase of "UnitTests" - 1. Add your unit test source code to the "Compile Sources" build phase of "UnitTests" - 1. Edit the "UnitTests" executable and add an environment variable named "DYLD\_FRAMEWORK\_PATH" with a value equal to the path to the framework containing the gtest.framework relative to the compiled executable. - 1. Build and Go - -The following sections further explain each of the steps listed above in depth, describing in more detail how to complete it including some variations. - -# Get the Source # - -Currently, the gtest.framework discussed here isn't available in a tagged release of Google Test, it is only available in the trunk. As explained at the Google Test [site](http://code.google.com/p/googletest/source/checkout">svn), you can get the code from anonymous SVN with this command: - -``` -svn checkout http://googletest.googlecode.com/svn/trunk/ googletest-read-only -``` - -Alternatively, if you are working with Subversion in your own code base, you can add Google Test as an external dependency to your own Subversion repository. By following this approach, everyone that checks out your svn repository will also receive a copy of Google Test (a specific version, if you wish) without having to check it out explicitly. This makes the set up of your project simpler and reduces the copied code in the repository. - -To use `svn:externals`, decide where you would like to have the external source reside. You might choose to put the external source inside the trunk, because you want it to be part of the branch when you make a release. However, keeping it outside the trunk in a version-tagged directory called something like `third-party/googletest/1.0.1`, is another option. Once the location is established, use `svn propedit svn:externals _directory_` to set the svn:externals property on a directory in your repository. This directory won't contain the code, but be its versioned parent directory. - -The command `svn propedit` will bring up your Subversion editor, making editing the long, (potentially multi-line) property simpler. This same method can be used to check out a tagged branch, by using the appropriate URL (e.g. `http://googletest.googlecode.com/svn/tags/release-1.0.1`). Additionally, the svn:externals property allows the specification of a particular revision of the trunk with the `-r_##_` option (e.g. `externals/src/googletest -r60 http://googletest.googlecode.com/svn/trunk`). - -Here is an example of using the svn:externals properties on a trunk (read via `svn propget`) of a project. This value checks out a copy of Google Test into the `trunk/externals/src/googletest/` directory. - -``` -[Computer:svn] user$ svn propget svn:externals trunk -externals/src/googletest http://googletest.googlecode.com/svn/trunk -``` - -# Add the Framework to Your Project # - -The next step is to build and add the gtest.framework to your own project. This guide describes two common ways below. - - * **Option 1** --- The simplest way to add Google Test to your own project, is to open gtest.xcodeproj (found in the xcode/ directory of the Google Test trunk) and build the framework manually. Then, add the built framework into your project using the "Add->Existing Framework..." from the context menu or "Project->Add..." from the main menu. The gtest.framework is relocatable and contains the headers and object code that you'll need to make tests. This method requires rebuilding every time you upgrade Google Test in your project. - * **Option 2** --- If you are going to be living off the trunk of Google Test, incorporating its latest features into your unit tests (or are a Google Test developer yourself). You'll want to rebuild the framework every time the source updates. to do this, you'll need to add the gtest.xcodeproj file, not the framework itself, to your own Xcode project. Then, from the build products that are revealed by the project's disclosure triangle, you can find the gtest.framework, which can be added to your targets (discussed below). - -# Make a Test Target # - -To start writing tests, make a new "Shell Tool" target. This target template is available under BSD, Cocoa, or Carbon. Add your unit test source code to the "Compile Sources" build phase of the target. - -Next, you'll want to add gtest.framework in two different ways, depending upon which option you chose above. - - * **Option 1** --- During compilation, Xcode will need to know that you are linking against the gtest.framework. Add the gtest.framework to the "Link Binary with Libraries" build phase of your test target. This will include the Google Test headers in your header search path, and will tell the linker where to find the library. - * **Option 2** --- If your working out of the trunk, you'll also want to add gtest.framework to your "Link Binary with Libraries" build phase of your test target. In addition, you'll want to add the gtest.framework as a dependency to your unit test target. This way, Xcode will make sure that gtest.framework is up to date, every time your build your target. Finally, if you don't share build directories with Google Test, you'll have to copy the gtest.framework into your own build products directory using a "Run Script" build phase. - -# Set Up the Executable Run Environment # - -Since the unit test executable is a shell tool, it doesn't have a bundle with a `Contents/Frameworks` directory, in which to place gtest.framework. Instead, the dynamic linker must be told at runtime to search for the framework in another location. This can be accomplished by setting the "DYLD\_FRAMEWORK\_PATH" environment variable in the "Edit Active Executable ..." Arguments tab, under "Variables to be set in the environment:". The path for this value is the path (relative or absolute) of the directory containing the gtest.framework. - -If you haven't set up the DYLD\_FRAMEWORK\_PATH, correctly, you might get a message like this: - -``` -[Session started at 2008-08-15 06:23:57 -0600.] - dyld: Library not loaded: @loader_path/../Frameworks/gtest.framework/Versions/A/gtest - Referenced from: /Users/username/Documents/Sandbox/gtestSample/build/Debug/WidgetFrameworkTest - Reason: image not found -``` - -To correct this problem, got to the directory containing the executable named in "Referenced from:" value in the error message above. Then, with the terminal in this location, find the relative path to the directory containing the gtest.framework. That is the value you'll need to set as the DYLD\_FRAMEWORK\_PATH. - -# Build and Go # - -Now, when you click "Build and Go", the test will be executed. Dumping out something like this: - -``` -[Session started at 2008-08-06 06:36:13 -0600.] -[==========] Running 2 tests from 1 test case. -[----------] Global test environment set-up. -[----------] 2 tests from WidgetInitializerTest -[ RUN ] WidgetInitializerTest.TestConstructor -[ OK ] WidgetInitializerTest.TestConstructor -[ RUN ] WidgetInitializerTest.TestConversion -[ OK ] WidgetInitializerTest.TestConversion -[----------] Global test environment tear-down -[==========] 2 tests from 1 test case ran. -[ PASSED ] 2 tests. - -The Debugger has exited with status 0. -``` - -# Summary # - -Unit testing is a valuable way to ensure your data model stays valid even during rapid development or refactoring. The Google Testing Framework is a great unit testing framework for C and C++ which integrates well with an Xcode development environment. \ No newline at end of file diff --git a/googletest/docs/V1_6_AdvancedGuide.md b/googletest/docs/V1_6_AdvancedGuide.md deleted file mode 100644 index 78864b16..00000000 --- a/googletest/docs/V1_6_AdvancedGuide.md +++ /dev/null @@ -1,2178 +0,0 @@ - - -Now that you have read [Primer](V1_6_Primer.md) and learned how to write tests -using Google Test, it's time to learn some new tricks. This document -will show you more assertions as well as how to construct complex -failure messages, propagate fatal failures, reuse and speed up your -test fixtures, and use various flags with your tests. - -# More Assertions # - -This section covers some less frequently used, but still significant, -assertions. - -## Explicit Success and Failure ## - -These three assertions do not actually test a value or expression. Instead, -they generate a success or failure directly. Like the macros that actually -perform a test, you may stream a custom failure message into the them. - -| `SUCCEED();` | -|:-------------| - -Generates a success. This does NOT make the overall test succeed. A test is -considered successful only if none of its assertions fail during its execution. - -Note: `SUCCEED()` is purely documentary and currently doesn't generate any -user-visible output. However, we may add `SUCCEED()` messages to Google Test's -output in the future. - -| `FAIL();` | `ADD_FAILURE();` | `ADD_FAILURE_AT("`_file\_path_`", `_line\_number_`);` | -|:-----------|:-----------------|:------------------------------------------------------| - -`FAIL()` generates a fatal failure, while `ADD_FAILURE()` and `ADD_FAILURE_AT()` generate a nonfatal -failure. These are useful when control flow, rather than a Boolean expression, -deteremines the test's success or failure. For example, you might want to write -something like: - -``` -switch(expression) { - case 1: ... some checks ... - case 2: ... some other checks - ... - default: FAIL() << "We shouldn't get here."; -} -``` - -_Availability_: Linux, Windows, Mac. - -## Exception Assertions ## - -These are for verifying that a piece of code throws (or does not -throw) an exception of the given type: - -| **Fatal assertion** | **Nonfatal assertion** | **Verifies** | -|:--------------------|:-----------------------|:-------------| -| `ASSERT_THROW(`_statement_, _exception\_type_`);` | `EXPECT_THROW(`_statement_, _exception\_type_`);` | _statement_ throws an exception of the given type | -| `ASSERT_ANY_THROW(`_statement_`);` | `EXPECT_ANY_THROW(`_statement_`);` | _statement_ throws an exception of any type | -| `ASSERT_NO_THROW(`_statement_`);` | `EXPECT_NO_THROW(`_statement_`);` | _statement_ doesn't throw any exception | - -Examples: - -``` -ASSERT_THROW(Foo(5), bar_exception); - -EXPECT_NO_THROW({ - int n = 5; - Bar(&n); -}); -``` - -_Availability_: Linux, Windows, Mac; since version 1.1.0. - -## Predicate Assertions for Better Error Messages ## - -Even though Google Test has a rich set of assertions, they can never be -complete, as it's impossible (nor a good idea) to anticipate all the scenarios -a user might run into. Therefore, sometimes a user has to use `EXPECT_TRUE()` -to check a complex expression, for lack of a better macro. This has the problem -of not showing you the values of the parts of the expression, making it hard to -understand what went wrong. As a workaround, some users choose to construct the -failure message by themselves, streaming it into `EXPECT_TRUE()`. However, this -is awkward especially when the expression has side-effects or is expensive to -evaluate. - -Google Test gives you three different options to solve this problem: - -### Using an Existing Boolean Function ### - -If you already have a function or a functor that returns `bool` (or a type -that can be implicitly converted to `bool`), you can use it in a _predicate -assertion_ to get the function arguments printed for free: - -| **Fatal assertion** | **Nonfatal assertion** | **Verifies** | -|:--------------------|:-----------------------|:-------------| -| `ASSERT_PRED1(`_pred1, val1_`);` | `EXPECT_PRED1(`_pred1, val1_`);` | _pred1(val1)_ returns true | -| `ASSERT_PRED2(`_pred2, val1, val2_`);` | `EXPECT_PRED2(`_pred2, val1, val2_`);` | _pred2(val1, val2)_ returns true | -| ... | ... | ... | - -In the above, _predn_ is an _n_-ary predicate function or functor, where -_val1_, _val2_, ..., and _valn_ are its arguments. The assertion succeeds -if the predicate returns `true` when applied to the given arguments, and fails -otherwise. When the assertion fails, it prints the value of each argument. In -either case, the arguments are evaluated exactly once. - -Here's an example. Given - -``` -// Returns true iff m and n have no common divisors except 1. -bool MutuallyPrime(int m, int n) { ... } -const int a = 3; -const int b = 4; -const int c = 10; -``` - -the assertion `EXPECT_PRED2(MutuallyPrime, a, b);` will succeed, while the -assertion `EXPECT_PRED2(MutuallyPrime, b, c);` will fail with the message - -
-!MutuallyPrime(b, c) is false, where

-b is 4

-c is 10

-
- -**Notes:** - - 1. If you see a compiler error "no matching function to call" when using `ASSERT_PRED*` or `EXPECT_PRED*`, please see [this](v1_6_FAQ.md#ithe-compiler-complains-about-undefined-references-to-some-static-const-member-variables-but-i-did-define-them-in-the-class-body-whats-wrong) for how to resolve it. - 1. Currently we only provide predicate assertions of arity <= 5. If you need a higher-arity assertion, let us know. - -_Availability_: Linux, Windows, Mac - -### Using a Function That Returns an AssertionResult ### - -While `EXPECT_PRED*()` and friends are handy for a quick job, the -syntax is not satisfactory: you have to use different macros for -different arities, and it feels more like Lisp than C++. The -`::testing::AssertionResult` class solves this problem. - -An `AssertionResult` object represents the result of an assertion -(whether it's a success or a failure, and an associated message). You -can create an `AssertionResult` using one of these factory -functions: - -``` -namespace testing { - -// Returns an AssertionResult object to indicate that an assertion has -// succeeded. -AssertionResult AssertionSuccess(); - -// Returns an AssertionResult object to indicate that an assertion has -// failed. -AssertionResult AssertionFailure(); - -} -``` - -You can then use the `<<` operator to stream messages to the -`AssertionResult` object. - -To provide more readable messages in Boolean assertions -(e.g. `EXPECT_TRUE()`), write a predicate function that returns -`AssertionResult` instead of `bool`. For example, if you define -`IsEven()` as: - -``` -::testing::AssertionResult IsEven(int n) { - if ((n % 2) == 0) - return ::testing::AssertionSuccess(); - else - return ::testing::AssertionFailure() << n << " is odd"; -} -``` - -instead of: - -``` -bool IsEven(int n) { - return (n % 2) == 0; -} -``` - -the failed assertion `EXPECT_TRUE(IsEven(Fib(4)))` will print: - -
-Value of: !IsEven(Fib(4))

-Actual: false (*3 is odd*)

-Expected: true

-
- -instead of a more opaque - -
-Value of: !IsEven(Fib(4))

-Actual: false

-Expected: true

-
- -If you want informative messages in `EXPECT_FALSE` and `ASSERT_FALSE` -as well, and are fine with making the predicate slower in the success -case, you can supply a success message: - -``` -::testing::AssertionResult IsEven(int n) { - if ((n % 2) == 0) - return ::testing::AssertionSuccess() << n << " is even"; - else - return ::testing::AssertionFailure() << n << " is odd"; -} -``` - -Then the statement `EXPECT_FALSE(IsEven(Fib(6)))` will print - -
-Value of: !IsEven(Fib(6))

-Actual: true (8 is even)

-Expected: false

-
- -_Availability_: Linux, Windows, Mac; since version 1.4.1. - -### Using a Predicate-Formatter ### - -If you find the default message generated by `(ASSERT|EXPECT)_PRED*` and -`(ASSERT|EXPECT)_(TRUE|FALSE)` unsatisfactory, or some arguments to your -predicate do not support streaming to `ostream`, you can instead use the -following _predicate-formatter assertions_ to _fully_ customize how the -message is formatted: - -| **Fatal assertion** | **Nonfatal assertion** | **Verifies** | -|:--------------------|:-----------------------|:-------------| -| `ASSERT_PRED_FORMAT1(`_pred\_format1, val1_`);` | `EXPECT_PRED_FORMAT1(`_pred\_format1, val1_`); | _pred\_format1(val1)_ is successful | -| `ASSERT_PRED_FORMAT2(`_pred\_format2, val1, val2_`);` | `EXPECT_PRED_FORMAT2(`_pred\_format2, val1, val2_`);` | _pred\_format2(val1, val2)_ is successful | -| `...` | `...` | `...` | - -The difference between this and the previous two groups of macros is that instead of -a predicate, `(ASSERT|EXPECT)_PRED_FORMAT*` take a _predicate-formatter_ -(_pred\_formatn_), which is a function or functor with the signature: - -`::testing::AssertionResult PredicateFormattern(const char* `_expr1_`, const char* `_expr2_`, ... const char* `_exprn_`, T1 `_val1_`, T2 `_val2_`, ... Tn `_valn_`);` - -where _val1_, _val2_, ..., and _valn_ are the values of the predicate -arguments, and _expr1_, _expr2_, ..., and _exprn_ are the corresponding -expressions as they appear in the source code. The types `T1`, `T2`, ..., and -`Tn` can be either value types or reference types. For example, if an -argument has type `Foo`, you can declare it as either `Foo` or `const Foo&`, -whichever is appropriate. - -A predicate-formatter returns a `::testing::AssertionResult` object to indicate -whether the assertion has succeeded or not. The only way to create such an -object is to call one of these factory functions: - -As an example, let's improve the failure message in the previous example, which uses `EXPECT_PRED2()`: - -``` -// Returns the smallest prime common divisor of m and n, -// or 1 when m and n are mutually prime. -int SmallestPrimeCommonDivisor(int m, int n) { ... } - -// A predicate-formatter for asserting that two integers are mutually prime. -::testing::AssertionResult AssertMutuallyPrime(const char* m_expr, - const char* n_expr, - int m, - int n) { - if (MutuallyPrime(m, n)) - return ::testing::AssertionSuccess(); - - return ::testing::AssertionFailure() - << m_expr << " and " << n_expr << " (" << m << " and " << n - << ") are not mutually prime, " << "as they have a common divisor " - << SmallestPrimeCommonDivisor(m, n); -} -``` - -With this predicate-formatter, we can use - -``` -EXPECT_PRED_FORMAT2(AssertMutuallyPrime, b, c); -``` - -to generate the message - -
-b and c (4 and 10) are not mutually prime, as they have a common divisor 2.

-
- -As you may have realized, many of the assertions we introduced earlier are -special cases of `(EXPECT|ASSERT)_PRED_FORMAT*`. In fact, most of them are -indeed defined using `(EXPECT|ASSERT)_PRED_FORMAT*`. - -_Availability_: Linux, Windows, Mac. - - -## Floating-Point Comparison ## - -Comparing floating-point numbers is tricky. Due to round-off errors, it is -very unlikely that two floating-points will match exactly. Therefore, -`ASSERT_EQ` 's naive comparison usually doesn't work. And since floating-points -can have a wide value range, no single fixed error bound works. It's better to -compare by a fixed relative error bound, except for values close to 0 due to -the loss of precision there. - -In general, for floating-point comparison to make sense, the user needs to -carefully choose the error bound. If they don't want or care to, comparing in -terms of Units in the Last Place (ULPs) is a good default, and Google Test -provides assertions to do this. Full details about ULPs are quite long; if you -want to learn more, see -[this article on float comparison](http://www.cygnus-software.com/papers/comparingfloats/comparingfloats.htm). - -### Floating-Point Macros ### - -| **Fatal assertion** | **Nonfatal assertion** | **Verifies** | -|:--------------------|:-----------------------|:-------------| -| `ASSERT_FLOAT_EQ(`_expected, actual_`);` | `EXPECT_FLOAT_EQ(`_expected, actual_`);` | the two `float` values are almost equal | -| `ASSERT_DOUBLE_EQ(`_expected, actual_`);` | `EXPECT_DOUBLE_EQ(`_expected, actual_`);` | the two `double` values are almost equal | - -By "almost equal", we mean the two values are within 4 ULP's from each -other. - -The following assertions allow you to choose the acceptable error bound: - -| **Fatal assertion** | **Nonfatal assertion** | **Verifies** | -|:--------------------|:-----------------------|:-------------| -| `ASSERT_NEAR(`_val1, val2, abs\_error_`);` | `EXPECT_NEAR`_(val1, val2, abs\_error_`);` | the difference between _val1_ and _val2_ doesn't exceed the given absolute error | - -_Availability_: Linux, Windows, Mac. - -### Floating-Point Predicate-Format Functions ### - -Some floating-point operations are useful, but not that often used. In order -to avoid an explosion of new macros, we provide them as predicate-format -functions that can be used in predicate assertion macros (e.g. -`EXPECT_PRED_FORMAT2`, etc). - -``` -EXPECT_PRED_FORMAT2(::testing::FloatLE, val1, val2); -EXPECT_PRED_FORMAT2(::testing::DoubleLE, val1, val2); -``` - -Verifies that _val1_ is less than, or almost equal to, _val2_. You can -replace `EXPECT_PRED_FORMAT2` in the above table with `ASSERT_PRED_FORMAT2`. - -_Availability_: Linux, Windows, Mac. - -## Windows HRESULT assertions ## - -These assertions test for `HRESULT` success or failure. - -| **Fatal assertion** | **Nonfatal assertion** | **Verifies** | -|:--------------------|:-----------------------|:-------------| -| `ASSERT_HRESULT_SUCCEEDED(`_expression_`);` | `EXPECT_HRESULT_SUCCEEDED(`_expression_`);` | _expression_ is a success `HRESULT` | -| `ASSERT_HRESULT_FAILED(`_expression_`);` | `EXPECT_HRESULT_FAILED(`_expression_`);` | _expression_ is a failure `HRESULT` | - -The generated output contains the human-readable error message -associated with the `HRESULT` code returned by _expression_. - -You might use them like this: - -``` -CComPtr shell; -ASSERT_HRESULT_SUCCEEDED(shell.CoCreateInstance(L"Shell.Application")); -CComVariant empty; -ASSERT_HRESULT_SUCCEEDED(shell->ShellExecute(CComBSTR(url), empty, empty, empty, empty)); -``` - -_Availability_: Windows. - -## Type Assertions ## - -You can call the function -``` -::testing::StaticAssertTypeEq(); -``` -to assert that types `T1` and `T2` are the same. The function does -nothing if the assertion is satisfied. If the types are different, -the function call will fail to compile, and the compiler error message -will likely (depending on the compiler) show you the actual values of -`T1` and `T2`. This is mainly useful inside template code. - -_Caveat:_ When used inside a member function of a class template or a -function template, `StaticAssertTypeEq()` is effective _only if_ -the function is instantiated. For example, given: -``` -template class Foo { - public: - void Bar() { ::testing::StaticAssertTypeEq(); } -}; -``` -the code: -``` -void Test1() { Foo foo; } -``` -will _not_ generate a compiler error, as `Foo::Bar()` is never -actually instantiated. Instead, you need: -``` -void Test2() { Foo foo; foo.Bar(); } -``` -to cause a compiler error. - -_Availability:_ Linux, Windows, Mac; since version 1.3.0. - -## Assertion Placement ## - -You can use assertions in any C++ function. In particular, it doesn't -have to be a method of the test fixture class. The one constraint is -that assertions that generate a fatal failure (`FAIL*` and `ASSERT_*`) -can only be used in void-returning functions. This is a consequence of -Google Test not using exceptions. By placing it in a non-void function -you'll get a confusing compile error like -`"error: void value not ignored as it ought to be"`. - -If you need to use assertions in a function that returns non-void, one option -is to make the function return the value in an out parameter instead. For -example, you can rewrite `T2 Foo(T1 x)` to `void Foo(T1 x, T2* result)`. You -need to make sure that `*result` contains some sensible value even when the -function returns prematurely. As the function now returns `void`, you can use -any assertion inside of it. - -If changing the function's type is not an option, you should just use -assertions that generate non-fatal failures, such as `ADD_FAILURE*` and -`EXPECT_*`. - -_Note_: Constructors and destructors are not considered void-returning -functions, according to the C++ language specification, and so you may not use -fatal assertions in them. You'll get a compilation error if you try. A simple -workaround is to transfer the entire body of the constructor or destructor to a -private void-returning method. However, you should be aware that a fatal -assertion failure in a constructor does not terminate the current test, as your -intuition might suggest; it merely returns from the constructor early, possibly -leaving your object in a partially-constructed state. Likewise, a fatal -assertion failure in a destructor may leave your object in a -partially-destructed state. Use assertions carefully in these situations! - -# Teaching Google Test How to Print Your Values # - -When a test assertion such as `EXPECT_EQ` fails, Google Test prints the -argument values to help you debug. It does this using a -user-extensible value printer. - -This printer knows how to print built-in C++ types, native arrays, STL -containers, and any type that supports the `<<` operator. For other -types, it prints the raw bytes in the value and hopes that you the -user can figure it out. - -As mentioned earlier, the printer is _extensible_. That means -you can teach it to do a better job at printing your particular type -than to dump the bytes. To do that, define `<<` for your type: - -``` -#include - -namespace foo { - -class Bar { ... }; // We want Google Test to be able to print instances of this. - -// It's important that the << operator is defined in the SAME -// namespace that defines Bar. C++'s look-up rules rely on that. -::std::ostream& operator<<(::std::ostream& os, const Bar& bar) { - return os << bar.DebugString(); // whatever needed to print bar to os -} - -} // namespace foo -``` - -Sometimes, this might not be an option: your team may consider it bad -style to have a `<<` operator for `Bar`, or `Bar` may already have a -`<<` operator that doesn't do what you want (and you cannot change -it). If so, you can instead define a `PrintTo()` function like this: - -``` -#include - -namespace foo { - -class Bar { ... }; - -// It's important that PrintTo() is defined in the SAME -// namespace that defines Bar. C++'s look-up rules rely on that. -void PrintTo(const Bar& bar, ::std::ostream* os) { - *os << bar.DebugString(); // whatever needed to print bar to os -} - -} // namespace foo -``` - -If you have defined both `<<` and `PrintTo()`, the latter will be used -when Google Test is concerned. This allows you to customize how the value -appears in Google Test's output without affecting code that relies on the -behavior of its `<<` operator. - -If you want to print a value `x` using Google Test's value printer -yourself, just call `::testing::PrintToString(`_x_`)`, which -returns an `std::string`: - -``` -vector > bar_ints = GetBarIntVector(); - -EXPECT_TRUE(IsCorrectBarIntVector(bar_ints)) - << "bar_ints = " << ::testing::PrintToString(bar_ints); -``` - -# Death Tests # - -In many applications, there are assertions that can cause application failure -if a condition is not met. These sanity checks, which ensure that the program -is in a known good state, are there to fail at the earliest possible time after -some program state is corrupted. If the assertion checks the wrong condition, -then the program may proceed in an erroneous state, which could lead to memory -corruption, security holes, or worse. Hence it is vitally important to test -that such assertion statements work as expected. - -Since these precondition checks cause the processes to die, we call such tests -_death tests_. More generally, any test that checks that a program terminates -(except by throwing an exception) in an expected fashion is also a death test. - -Note that if a piece of code throws an exception, we don't consider it "death" -for the purpose of death tests, as the caller of the code could catch the exception -and avoid the crash. If you want to verify exceptions thrown by your code, -see [Exception Assertions](#exception-assertions). - -If you want to test `EXPECT_*()/ASSERT_*()` failures in your test code, see [Catching Failures](#catching-failures). - -## How to Write a Death Test ## - -Google Test has the following macros to support death tests: - -| **Fatal assertion** | **Nonfatal assertion** | **Verifies** | -|:--------------------|:-----------------------|:-------------| -| `ASSERT_DEATH(`_statement, regex_`); | `EXPECT_DEATH(`_statement, regex_`); | _statement_ crashes with the given error | -| `ASSERT_DEATH_IF_SUPPORTED(`_statement, regex_`); | `EXPECT_DEATH_IF_SUPPORTED(`_statement, regex_`); | if death tests are supported, verifies that _statement_ crashes with the given error; otherwise verifies nothing | -| `ASSERT_EXIT(`_statement, predicate, regex_`); | `EXPECT_EXIT(`_statement, predicate, regex_`); |_statement_ exits with the given error and its exit code matches _predicate_ | - -where _statement_ is a statement that is expected to cause the process to -die, _predicate_ is a function or function object that evaluates an integer -exit status, and _regex_ is a regular expression that the stderr output of -_statement_ is expected to match. Note that _statement_ can be _any valid -statement_ (including _compound statement_) and doesn't have to be an -expression. - -As usual, the `ASSERT` variants abort the current test function, while the -`EXPECT` variants do not. - -**Note:** We use the word "crash" here to mean that the process -terminates with a _non-zero_ exit status code. There are two -possibilities: either the process has called `exit()` or `_exit()` -with a non-zero value, or it may be killed by a signal. - -This means that if _statement_ terminates the process with a 0 exit -code, it is _not_ considered a crash by `EXPECT_DEATH`. Use -`EXPECT_EXIT` instead if this is the case, or if you want to restrict -the exit code more precisely. - -A predicate here must accept an `int` and return a `bool`. The death test -succeeds only if the predicate returns `true`. Google Test defines a few -predicates that handle the most common cases: - -``` -::testing::ExitedWithCode(exit_code) -``` - -This expression is `true` if the program exited normally with the given exit -code. - -``` -::testing::KilledBySignal(signal_number) // Not available on Windows. -``` - -This expression is `true` if the program was killed by the given signal. - -The `*_DEATH` macros are convenient wrappers for `*_EXIT` that use a predicate -that verifies the process' exit code is non-zero. - -Note that a death test only cares about three things: - - 1. does _statement_ abort or exit the process? - 1. (in the case of `ASSERT_EXIT` and `EXPECT_EXIT`) does the exit status satisfy _predicate_? Or (in the case of `ASSERT_DEATH` and `EXPECT_DEATH`) is the exit status non-zero? And - 1. does the stderr output match _regex_? - -In particular, if _statement_ generates an `ASSERT_*` or `EXPECT_*` failure, it will **not** cause the death test to fail, as Google Test assertions don't abort the process. - -To write a death test, simply use one of the above macros inside your test -function. For example, - -``` -TEST(My*DeathTest*, Foo) { - // This death test uses a compound statement. - ASSERT_DEATH({ int n = 5; Foo(&n); }, "Error on line .* of Foo()"); -} -TEST(MyDeathTest, NormalExit) { - EXPECT_EXIT(NormalExit(), ::testing::ExitedWithCode(0), "Success"); -} -TEST(MyDeathTest, KillMyself) { - EXPECT_EXIT(KillMyself(), ::testing::KilledBySignal(SIGKILL), "Sending myself unblockable signal"); -} -``` - -verifies that: - - * calling `Foo(5)` causes the process to die with the given error message, - * calling `NormalExit()` causes the process to print `"Success"` to stderr and exit with exit code 0, and - * calling `KillMyself()` kills the process with signal `SIGKILL`. - -The test function body may contain other assertions and statements as well, if -necessary. - -_Important:_ We strongly recommend you to follow the convention of naming your -test case (not test) `*DeathTest` when it contains a death test, as -demonstrated in the above example. The `Death Tests And Threads` section below -explains why. - -If a test fixture class is shared by normal tests and death tests, you -can use typedef to introduce an alias for the fixture class and avoid -duplicating its code: -``` -class FooTest : public ::testing::Test { ... }; - -typedef FooTest FooDeathTest; - -TEST_F(FooTest, DoesThis) { - // normal test -} - -TEST_F(FooDeathTest, DoesThat) { - // death test -} -``` - -_Availability:_ Linux, Windows (requires MSVC 8.0 or above), Cygwin, and Mac (the latter three are supported since v1.3.0). `(ASSERT|EXPECT)_DEATH_IF_SUPPORTED` are new in v1.4.0. - -## Regular Expression Syntax ## - -On POSIX systems (e.g. Linux, Cygwin, and Mac), Google Test uses the -[POSIX extended regular expression](http://www.opengroup.org/onlinepubs/009695399/basedefs/xbd_chap09.html#tag_09_04) -syntax in death tests. To learn about this syntax, you may want to read this [Wikipedia entry](http://en.wikipedia.org/wiki/Regular_expression#POSIX_Extended_Regular_Expressions). - -On Windows, Google Test uses its own simple regular expression -implementation. It lacks many features you can find in POSIX extended -regular expressions. For example, we don't support union (`"x|y"`), -grouping (`"(xy)"`), brackets (`"[xy]"`), and repetition count -(`"x{5,7}"`), among others. Below is what we do support (`A` denotes a -literal character, period (`.`), or a single `\\` escape sequence; `x` -and `y` denote regular expressions.): - -| `c` | matches any literal character `c` | -|:----|:----------------------------------| -| `\\d` | matches any decimal digit | -| `\\D` | matches any character that's not a decimal digit | -| `\\f` | matches `\f` | -| `\\n` | matches `\n` | -| `\\r` | matches `\r` | -| `\\s` | matches any ASCII whitespace, including `\n` | -| `\\S` | matches any character that's not a whitespace | -| `\\t` | matches `\t` | -| `\\v` | matches `\v` | -| `\\w` | matches any letter, `_`, or decimal digit | -| `\\W` | matches any character that `\\w` doesn't match | -| `\\c` | matches any literal character `c`, which must be a punctuation | -| `.` | matches any single character except `\n` | -| `A?` | matches 0 or 1 occurrences of `A` | -| `A*` | matches 0 or many occurrences of `A` | -| `A+` | matches 1 or many occurrences of `A` | -| `^` | matches the beginning of a string (not that of each line) | -| `$` | matches the end of a string (not that of each line) | -| `xy` | matches `x` followed by `y` | - -To help you determine which capability is available on your system, -Google Test defines macro `GTEST_USES_POSIX_RE=1` when it uses POSIX -extended regular expressions, or `GTEST_USES_SIMPLE_RE=1` when it uses -the simple version. If you want your death tests to work in both -cases, you can either `#if` on these macros or use the more limited -syntax only. - -## How It Works ## - -Under the hood, `ASSERT_EXIT()` spawns a new process and executes the -death test statement in that process. The details of of how precisely -that happens depend on the platform and the variable -`::testing::GTEST_FLAG(death_test_style)` (which is initialized from the -command-line flag `--gtest_death_test_style`). - - * On POSIX systems, `fork()` (or `clone()` on Linux) is used to spawn the child, after which: - * If the variable's value is `"fast"`, the death test statement is immediately executed. - * If the variable's value is `"threadsafe"`, the child process re-executes the unit test binary just as it was originally invoked, but with some extra flags to cause just the single death test under consideration to be run. - * On Windows, the child is spawned using the `CreateProcess()` API, and re-executes the binary to cause just the single death test under consideration to be run - much like the `threadsafe` mode on POSIX. - -Other values for the variable are illegal and will cause the death test to -fail. Currently, the flag's default value is `"fast"`. However, we reserve the -right to change it in the future. Therefore, your tests should not depend on -this. - -In either case, the parent process waits for the child process to complete, and checks that - - 1. the child's exit status satisfies the predicate, and - 1. the child's stderr matches the regular expression. - -If the death test statement runs to completion without dying, the child -process will nonetheless terminate, and the assertion fails. - -## Death Tests And Threads ## - -The reason for the two death test styles has to do with thread safety. Due to -well-known problems with forking in the presence of threads, death tests should -be run in a single-threaded context. Sometimes, however, it isn't feasible to -arrange that kind of environment. For example, statically-initialized modules -may start threads before main is ever reached. Once threads have been created, -it may be difficult or impossible to clean them up. - -Google Test has three features intended to raise awareness of threading issues. - - 1. A warning is emitted if multiple threads are running when a death test is encountered. - 1. Test cases with a name ending in "DeathTest" are run before all other tests. - 1. It uses `clone()` instead of `fork()` to spawn the child process on Linux (`clone()` is not available on Cygwin and Mac), as `fork()` is more likely to cause the child to hang when the parent process has multiple threads. - -It's perfectly fine to create threads inside a death test statement; they are -executed in a separate process and cannot affect the parent. - -## Death Test Styles ## - -The "threadsafe" death test style was introduced in order to help mitigate the -risks of testing in a possibly multithreaded environment. It trades increased -test execution time (potentially dramatically so) for improved thread safety. -We suggest using the faster, default "fast" style unless your test has specific -problems with it. - -You can choose a particular style of death tests by setting the flag -programmatically: - -``` -::testing::FLAGS_gtest_death_test_style = "threadsafe"; -``` - -You can do this in `main()` to set the style for all death tests in the -binary, or in individual tests. Recall that flags are saved before running each -test and restored afterwards, so you need not do that yourself. For example: - -``` -TEST(MyDeathTest, TestOne) { - ::testing::FLAGS_gtest_death_test_style = "threadsafe"; - // This test is run in the "threadsafe" style: - ASSERT_DEATH(ThisShouldDie(), ""); -} - -TEST(MyDeathTest, TestTwo) { - // This test is run in the "fast" style: - ASSERT_DEATH(ThisShouldDie(), ""); -} - -int main(int argc, char** argv) { - ::testing::InitGoogleTest(&argc, argv); - ::testing::FLAGS_gtest_death_test_style = "fast"; - return RUN_ALL_TESTS(); -} -``` - -## Caveats ## - -The _statement_ argument of `ASSERT_EXIT()` can be any valid C++ statement. -If it leaves the current function via a `return` statement or by throwing an exception, -the death test is considered to have failed. Some Google Test macros may return -from the current function (e.g. `ASSERT_TRUE()`), so be sure to avoid them in _statement_. - -Since _statement_ runs in the child process, any in-memory side effect (e.g. -modifying a variable, releasing memory, etc) it causes will _not_ be observable -in the parent process. In particular, if you release memory in a death test, -your program will fail the heap check as the parent process will never see the -memory reclaimed. To solve this problem, you can - - 1. try not to free memory in a death test; - 1. free the memory again in the parent process; or - 1. do not use the heap checker in your program. - -Due to an implementation detail, you cannot place multiple death test -assertions on the same line; otherwise, compilation will fail with an unobvious -error message. - -Despite the improved thread safety afforded by the "threadsafe" style of death -test, thread problems such as deadlock are still possible in the presence of -handlers registered with `pthread_atfork(3)`. - -# Using Assertions in Sub-routines # - -## Adding Traces to Assertions ## - -If a test sub-routine is called from several places, when an assertion -inside it fails, it can be hard to tell which invocation of the -sub-routine the failure is from. You can alleviate this problem using -extra logging or custom failure messages, but that usually clutters up -your tests. A better solution is to use the `SCOPED_TRACE` macro: - -| `SCOPED_TRACE(`_message_`);` | -|:-----------------------------| - -where _message_ can be anything streamable to `std::ostream`. This -macro will cause the current file name, line number, and the given -message to be added in every failure message. The effect will be -undone when the control leaves the current lexical scope. - -For example, - -``` -10: void Sub1(int n) { -11: EXPECT_EQ(1, Bar(n)); -12: EXPECT_EQ(2, Bar(n + 1)); -13: } -14: -15: TEST(FooTest, Bar) { -16: { -17: SCOPED_TRACE("A"); // This trace point will be included in -18: // every failure in this scope. -19: Sub1(1); -20: } -21: // Now it won't. -22: Sub1(9); -23: } -``` - -could result in messages like these: - -``` -path/to/foo_test.cc:11: Failure -Value of: Bar(n) -Expected: 1 - Actual: 2 - Trace: -path/to/foo_test.cc:17: A - -path/to/foo_test.cc:12: Failure -Value of: Bar(n + 1) -Expected: 2 - Actual: 3 -``` - -Without the trace, it would've been difficult to know which invocation -of `Sub1()` the two failures come from respectively. (You could add an -extra message to each assertion in `Sub1()` to indicate the value of -`n`, but that's tedious.) - -Some tips on using `SCOPED_TRACE`: - - 1. With a suitable message, it's often enough to use `SCOPED_TRACE` at the beginning of a sub-routine, instead of at each call site. - 1. When calling sub-routines inside a loop, make the loop iterator part of the message in `SCOPED_TRACE` such that you can know which iteration the failure is from. - 1. Sometimes the line number of the trace point is enough for identifying the particular invocation of a sub-routine. In this case, you don't have to choose a unique message for `SCOPED_TRACE`. You can simply use `""`. - 1. You can use `SCOPED_TRACE` in an inner scope when there is one in the outer scope. In this case, all active trace points will be included in the failure messages, in reverse order they are encountered. - 1. The trace dump is clickable in Emacs' compilation buffer - hit return on a line number and you'll be taken to that line in the source file! - -_Availability:_ Linux, Windows, Mac. - -## Propagating Fatal Failures ## - -A common pitfall when using `ASSERT_*` and `FAIL*` is not understanding that -when they fail they only abort the _current function_, not the entire test. For -example, the following test will segfault: -``` -void Subroutine() { - // Generates a fatal failure and aborts the current function. - ASSERT_EQ(1, 2); - // The following won't be executed. - ... -} - -TEST(FooTest, Bar) { - Subroutine(); - // The intended behavior is for the fatal failure - // in Subroutine() to abort the entire test. - // The actual behavior: the function goes on after Subroutine() returns. - int* p = NULL; - *p = 3; // Segfault! -} -``` - -Since we don't use exceptions, it is technically impossible to -implement the intended behavior here. To alleviate this, Google Test -provides two solutions. You could use either the -`(ASSERT|EXPECT)_NO_FATAL_FAILURE` assertions or the -`HasFatalFailure()` function. They are described in the following two -subsections. - -### Asserting on Subroutines ### - -As shown above, if your test calls a subroutine that has an `ASSERT_*` -failure in it, the test will continue after the subroutine -returns. This may not be what you want. - -Often people want fatal failures to propagate like exceptions. For -that Google Test offers the following macros: - -| **Fatal assertion** | **Nonfatal assertion** | **Verifies** | -|:--------------------|:-----------------------|:-------------| -| `ASSERT_NO_FATAL_FAILURE(`_statement_`);` | `EXPECT_NO_FATAL_FAILURE(`_statement_`);` | _statement_ doesn't generate any new fatal failures in the current thread. | - -Only failures in the thread that executes the assertion are checked to -determine the result of this type of assertions. If _statement_ -creates new threads, failures in these threads are ignored. - -Examples: - -``` -ASSERT_NO_FATAL_FAILURE(Foo()); - -int i; -EXPECT_NO_FATAL_FAILURE({ - i = Bar(); -}); -``` - -_Availability:_ Linux, Windows, Mac. Assertions from multiple threads -are currently not supported. - -### Checking for Failures in the Current Test ### - -`HasFatalFailure()` in the `::testing::Test` class returns `true` if an -assertion in the current test has suffered a fatal failure. This -allows functions to catch fatal failures in a sub-routine and return -early. - -``` -class Test { - public: - ... - static bool HasFatalFailure(); -}; -``` - -The typical usage, which basically simulates the behavior of a thrown -exception, is: - -``` -TEST(FooTest, Bar) { - Subroutine(); - // Aborts if Subroutine() had a fatal failure. - if (HasFatalFailure()) - return; - // The following won't be executed. - ... -} -``` - -If `HasFatalFailure()` is used outside of `TEST()` , `TEST_F()` , or a test -fixture, you must add the `::testing::Test::` prefix, as in: - -``` -if (::testing::Test::HasFatalFailure()) - return; -``` - -Similarly, `HasNonfatalFailure()` returns `true` if the current test -has at least one non-fatal failure, and `HasFailure()` returns `true` -if the current test has at least one failure of either kind. - -_Availability:_ Linux, Windows, Mac. `HasNonfatalFailure()` and -`HasFailure()` are available since version 1.4.0. - -# Logging Additional Information # - -In your test code, you can call `RecordProperty("key", value)` to log -additional information, where `value` can be either a C string or a 32-bit -integer. The _last_ value recorded for a key will be emitted to the XML output -if you specify one. For example, the test - -``` -TEST_F(WidgetUsageTest, MinAndMaxWidgets) { - RecordProperty("MaximumWidgets", ComputeMaxUsage()); - RecordProperty("MinimumWidgets", ComputeMinUsage()); -} -``` - -will output XML like this: - -``` -... - -... -``` - -_Note_: - * `RecordProperty()` is a static member of the `Test` class. Therefore it needs to be prefixed with `::testing::Test::` if used outside of the `TEST` body and the test fixture class. - * `key` must be a valid XML attribute name, and cannot conflict with the ones already used by Google Test (`name`, `status`, `time`, and `classname`). - -_Availability_: Linux, Windows, Mac. - -# Sharing Resources Between Tests in the Same Test Case # - - - -Google Test creates a new test fixture object for each test in order to make -tests independent and easier to debug. However, sometimes tests use resources -that are expensive to set up, making the one-copy-per-test model prohibitively -expensive. - -If the tests don't change the resource, there's no harm in them sharing a -single resource copy. So, in addition to per-test set-up/tear-down, Google Test -also supports per-test-case set-up/tear-down. To use it: - - 1. In your test fixture class (say `FooTest` ), define as `static` some member variables to hold the shared resources. - 1. In the same test fixture class, define a `static void SetUpTestCase()` function (remember not to spell it as **`SetupTestCase`** with a small `u`!) to set up the shared resources and a `static void TearDownTestCase()` function to tear them down. - -That's it! Google Test automatically calls `SetUpTestCase()` before running the -_first test_ in the `FooTest` test case (i.e. before creating the first -`FooTest` object), and calls `TearDownTestCase()` after running the _last test_ -in it (i.e. after deleting the last `FooTest` object). In between, the tests -can use the shared resources. - -Remember that the test order is undefined, so your code can't depend on a test -preceding or following another. Also, the tests must either not modify the -state of any shared resource, or, if they do modify the state, they must -restore the state to its original value before passing control to the next -test. - -Here's an example of per-test-case set-up and tear-down: -``` -class FooTest : public ::testing::Test { - protected: - // Per-test-case set-up. - // Called before the first test in this test case. - // Can be omitted if not needed. - static void SetUpTestCase() { - shared_resource_ = new ...; - } - - // Per-test-case tear-down. - // Called after the last test in this test case. - // Can be omitted if not needed. - static void TearDownTestCase() { - delete shared_resource_; - shared_resource_ = NULL; - } - - // You can define per-test set-up and tear-down logic as usual. - virtual void SetUp() { ... } - virtual void TearDown() { ... } - - // Some expensive resource shared by all tests. - static T* shared_resource_; -}; - -T* FooTest::shared_resource_ = NULL; - -TEST_F(FooTest, Test1) { - ... you can refer to shared_resource here ... -} -TEST_F(FooTest, Test2) { - ... you can refer to shared_resource here ... -} -``` - -_Availability:_ Linux, Windows, Mac. - -# Global Set-Up and Tear-Down # - -Just as you can do set-up and tear-down at the test level and the test case -level, you can also do it at the test program level. Here's how. - -First, you subclass the `::testing::Environment` class to define a test -environment, which knows how to set-up and tear-down: - -``` -class Environment { - public: - virtual ~Environment() {} - // Override this to define how to set up the environment. - virtual void SetUp() {} - // Override this to define how to tear down the environment. - virtual void TearDown() {} -}; -``` - -Then, you register an instance of your environment class with Google Test by -calling the `::testing::AddGlobalTestEnvironment()` function: - -``` -Environment* AddGlobalTestEnvironment(Environment* env); -``` - -Now, when `RUN_ALL_TESTS()` is called, it first calls the `SetUp()` method of -the environment object, then runs the tests if there was no fatal failures, and -finally calls `TearDown()` of the environment object. - -It's OK to register multiple environment objects. In this case, their `SetUp()` -will be called in the order they are registered, and their `TearDown()` will be -called in the reverse order. - -Note that Google Test takes ownership of the registered environment objects. -Therefore **do not delete them** by yourself. - -You should call `AddGlobalTestEnvironment()` before `RUN_ALL_TESTS()` is -called, probably in `main()`. If you use `gtest_main`, you need to call -this before `main()` starts for it to take effect. One way to do this is to -define a global variable like this: - -``` -::testing::Environment* const foo_env = ::testing::AddGlobalTestEnvironment(new FooEnvironment); -``` - -However, we strongly recommend you to write your own `main()` and call -`AddGlobalTestEnvironment()` there, as relying on initialization of global -variables makes the code harder to read and may cause problems when you -register multiple environments from different translation units and the -environments have dependencies among them (remember that the compiler doesn't -guarantee the order in which global variables from different translation units -are initialized). - -_Availability:_ Linux, Windows, Mac. - - -# Value Parameterized Tests # - -_Value-parameterized tests_ allow you to test your code with different -parameters without writing multiple copies of the same test. - -Suppose you write a test for your code and then realize that your code is affected by a presence of a Boolean command line flag. - -``` -TEST(MyCodeTest, TestFoo) { - // A code to test foo(). -} -``` - -Usually people factor their test code into a function with a Boolean parameter in such situations. The function sets the flag, then executes the testing code. - -``` -void TestFooHelper(bool flag_value) { - flag = flag_value; - // A code to test foo(). -} - -TEST(MyCodeTest, TestFooo) { - TestFooHelper(false); - TestFooHelper(true); -} -``` - -But this setup has serious drawbacks. First, when a test assertion fails in your tests, it becomes unclear what value of the parameter caused it to fail. You can stream a clarifying message into your `EXPECT`/`ASSERT` statements, but it you'll have to do it with all of them. Second, you have to add one such helper function per test. What if you have ten tests? Twenty? A hundred? - -Value-parameterized tests will let you write your test only once and then easily instantiate and run it with an arbitrary number of parameter values. - -Here are some other situations when value-parameterized tests come handy: - - * You want to test different implementations of an OO interface. - * You want to test your code over various inputs (a.k.a. data-driven testing). This feature is easy to abuse, so please exercise your good sense when doing it! - -## How to Write Value-Parameterized Tests ## - -To write value-parameterized tests, first you should define a fixture -class. It must be derived from both `::testing::Test` and -`::testing::WithParamInterface` (the latter is a pure interface), -where `T` is the type of your parameter values. For convenience, you -can just derive the fixture class from `::testing::TestWithParam`, -which itself is derived from both `::testing::Test` and -`::testing::WithParamInterface`. `T` can be any copyable type. If -it's a raw pointer, you are responsible for managing the lifespan of -the pointed values. - -``` -class FooTest : public ::testing::TestWithParam { - // You can implement all the usual fixture class members here. - // To access the test parameter, call GetParam() from class - // TestWithParam. -}; - -// Or, when you want to add parameters to a pre-existing fixture class: -class BaseTest : public ::testing::Test { - ... -}; -class BarTest : public BaseTest, - public ::testing::WithParamInterface { - ... -}; -``` - -Then, use the `TEST_P` macro to define as many test patterns using -this fixture as you want. The `_P` suffix is for "parameterized" or -"pattern", whichever you prefer to think. - -``` -TEST_P(FooTest, DoesBlah) { - // Inside a test, access the test parameter with the GetParam() method - // of the TestWithParam class: - EXPECT_TRUE(foo.Blah(GetParam())); - ... -} - -TEST_P(FooTest, HasBlahBlah) { - ... -} -``` - -Finally, you can use `INSTANTIATE_TEST_CASE_P` to instantiate the test -case with any set of parameters you want. Google Test defines a number of -functions for generating test parameters. They return what we call -(surprise!) _parameter generators_. Here is a summary of them, -which are all in the `testing` namespace: - -| `Range(begin, end[, step])` | Yields values `{begin, begin+step, begin+step+step, ...}`. The values do not include `end`. `step` defaults to 1. | -|:----------------------------|:------------------------------------------------------------------------------------------------------------------| -| `Values(v1, v2, ..., vN)` | Yields values `{v1, v2, ..., vN}`. | -| `ValuesIn(container)` and `ValuesIn(begin, end)` | Yields values from a C-style array, an STL-style container, or an iterator range `[begin, end)`. `container`, `begin`, and `end` can be expressions whose values are determined at run time. | -| `Bool()` | Yields sequence `{false, true}`. | -| `Combine(g1, g2, ..., gN)` | Yields all combinations (the Cartesian product for the math savvy) of the values generated by the `N` generators. This is only available if your system provides the `` header. If you are sure your system does, and Google Test disagrees, you can override it by defining `GTEST_HAS_TR1_TUPLE=1`. See comments in [include/gtest/internal/gtest-port.h](../include/gtest/internal/gtest-port.h) for more information. | - -For more details, see the comments at the definitions of these functions in the [source code](../include/gtest/gtest-param-test.h). - -The following statement will instantiate tests from the `FooTest` test case -each with parameter values `"meeny"`, `"miny"`, and `"moe"`. - -``` -INSTANTIATE_TEST_CASE_P(InstantiationName, - FooTest, - ::testing::Values("meeny", "miny", "moe")); -``` - -To distinguish different instances of the pattern (yes, you can -instantiate it more than once), the first argument to -`INSTANTIATE_TEST_CASE_P` is a prefix that will be added to the actual -test case name. Remember to pick unique prefixes for different -instantiations. The tests from the instantiation above will have these -names: - - * `InstantiationName/FooTest.DoesBlah/0` for `"meeny"` - * `InstantiationName/FooTest.DoesBlah/1` for `"miny"` - * `InstantiationName/FooTest.DoesBlah/2` for `"moe"` - * `InstantiationName/FooTest.HasBlahBlah/0` for `"meeny"` - * `InstantiationName/FooTest.HasBlahBlah/1` for `"miny"` - * `InstantiationName/FooTest.HasBlahBlah/2` for `"moe"` - -You can use these names in [--gtest\-filter](#running-a-subset-of-the-tests). - -This statement will instantiate all tests from `FooTest` again, each -with parameter values `"cat"` and `"dog"`: - -``` -const char* pets[] = {"cat", "dog"}; -INSTANTIATE_TEST_CASE_P(AnotherInstantiationName, FooTest, - ::testing::ValuesIn(pets)); -``` - -The tests from the instantiation above will have these names: - - * `AnotherInstantiationName/FooTest.DoesBlah/0` for `"cat"` - * `AnotherInstantiationName/FooTest.DoesBlah/1` for `"dog"` - * `AnotherInstantiationName/FooTest.HasBlahBlah/0` for `"cat"` - * `AnotherInstantiationName/FooTest.HasBlahBlah/1` for `"dog"` - -Please note that `INSTANTIATE_TEST_CASE_P` will instantiate _all_ -tests in the given test case, whether their definitions come before or -_after_ the `INSTANTIATE_TEST_CASE_P` statement. - -You can see -[these](../samples/sample7_unittest.cc) -[files](../samples/sample8_unittest.cc) for more examples. - -_Availability_: Linux, Windows (requires MSVC 8.0 or above), Mac; since version 1.2.0. - -## Creating Value-Parameterized Abstract Tests ## - -In the above, we define and instantiate `FooTest` in the same source -file. Sometimes you may want to define value-parameterized tests in a -library and let other people instantiate them later. This pattern is -known as abstract tests. As an example of its application, when you -are designing an interface you can write a standard suite of abstract -tests (perhaps using a factory function as the test parameter) that -all implementations of the interface are expected to pass. When -someone implements the interface, he can instantiate your suite to get -all the interface-conformance tests for free. - -To define abstract tests, you should organize your code like this: - - 1. Put the definition of the parameterized test fixture class (e.g. `FooTest`) in a header file, say `foo_param_test.h`. Think of this as _declaring_ your abstract tests. - 1. Put the `TEST_P` definitions in `foo_param_test.cc`, which includes `foo_param_test.h`. Think of this as _implementing_ your abstract tests. - -Once they are defined, you can instantiate them by including -`foo_param_test.h`, invoking `INSTANTIATE_TEST_CASE_P()`, and linking -with `foo_param_test.cc`. You can instantiate the same abstract test -case multiple times, possibly in different source files. - -# Typed Tests # - -Suppose you have multiple implementations of the same interface and -want to make sure that all of them satisfy some common requirements. -Or, you may have defined several types that are supposed to conform to -the same "concept" and you want to verify it. In both cases, you want -the same test logic repeated for different types. - -While you can write one `TEST` or `TEST_F` for each type you want to -test (and you may even factor the test logic into a function template -that you invoke from the `TEST`), it's tedious and doesn't scale: -if you want _m_ tests over _n_ types, you'll end up writing _m\*n_ -`TEST`s. - -_Typed tests_ allow you to repeat the same test logic over a list of -types. You only need to write the test logic once, although you must -know the type list when writing typed tests. Here's how you do it: - -First, define a fixture class template. It should be parameterized -by a type. Remember to derive it from `::testing::Test`: - -``` -template -class FooTest : public ::testing::Test { - public: - ... - typedef std::list List; - static T shared_; - T value_; -}; -``` - -Next, associate a list of types with the test case, which will be -repeated for each type in the list: - -``` -typedef ::testing::Types MyTypes; -TYPED_TEST_CASE(FooTest, MyTypes); -``` - -The `typedef` is necessary for the `TYPED_TEST_CASE` macro to parse -correctly. Otherwise the compiler will think that each comma in the -type list introduces a new macro argument. - -Then, use `TYPED_TEST()` instead of `TEST_F()` to define a typed test -for this test case. You can repeat this as many times as you want: - -``` -TYPED_TEST(FooTest, DoesBlah) { - // Inside a test, refer to the special name TypeParam to get the type - // parameter. Since we are inside a derived class template, C++ requires - // us to visit the members of FooTest via 'this'. - TypeParam n = this->value_; - - // To visit static members of the fixture, add the 'TestFixture::' - // prefix. - n += TestFixture::shared_; - - // To refer to typedefs in the fixture, add the 'typename TestFixture::' - // prefix. The 'typename' is required to satisfy the compiler. - typename TestFixture::List values; - values.push_back(n); - ... -} - -TYPED_TEST(FooTest, HasPropertyA) { ... } -``` - -You can see `samples/sample6_unittest.cc` for a complete example. - -_Availability:_ Linux, Windows (requires MSVC 8.0 or above), Mac; -since version 1.1.0. - -# Type-Parameterized Tests # - -_Type-parameterized tests_ are like typed tests, except that they -don't require you to know the list of types ahead of time. Instead, -you can define the test logic first and instantiate it with different -type lists later. You can even instantiate it more than once in the -same program. - -If you are designing an interface or concept, you can define a suite -of type-parameterized tests to verify properties that any valid -implementation of the interface/concept should have. Then, the author -of each implementation can just instantiate the test suite with his -type to verify that it conforms to the requirements, without having to -write similar tests repeatedly. Here's an example: - -First, define a fixture class template, as we did with typed tests: - -``` -template -class FooTest : public ::testing::Test { - ... -}; -``` - -Next, declare that you will define a type-parameterized test case: - -``` -TYPED_TEST_CASE_P(FooTest); -``` - -The `_P` suffix is for "parameterized" or "pattern", whichever you -prefer to think. - -Then, use `TYPED_TEST_P()` to define a type-parameterized test. You -can repeat this as many times as you want: - -``` -TYPED_TEST_P(FooTest, DoesBlah) { - // Inside a test, refer to TypeParam to get the type parameter. - TypeParam n = 0; - ... -} - -TYPED_TEST_P(FooTest, HasPropertyA) { ... } -``` - -Now the tricky part: you need to register all test patterns using the -`REGISTER_TYPED_TEST_CASE_P` macro before you can instantiate them. -The first argument of the macro is the test case name; the rest are -the names of the tests in this test case: - -``` -REGISTER_TYPED_TEST_CASE_P(FooTest, - DoesBlah, HasPropertyA); -``` - -Finally, you are free to instantiate the pattern with the types you -want. If you put the above code in a header file, you can `#include` -it in multiple C++ source files and instantiate it multiple times. - -``` -typedef ::testing::Types MyTypes; -INSTANTIATE_TYPED_TEST_CASE_P(My, FooTest, MyTypes); -``` - -To distinguish different instances of the pattern, the first argument -to the `INSTANTIATE_TYPED_TEST_CASE_P` macro is a prefix that will be -added to the actual test case name. Remember to pick unique prefixes -for different instances. - -In the special case where the type list contains only one type, you -can write that type directly without `::testing::Types<...>`, like this: - -``` -INSTANTIATE_TYPED_TEST_CASE_P(My, FooTest, int); -``` - -You can see `samples/sample6_unittest.cc` for a complete example. - -_Availability:_ Linux, Windows (requires MSVC 8.0 or above), Mac; -since version 1.1.0. - -# Testing Private Code # - -If you change your software's internal implementation, your tests should not -break as long as the change is not observable by users. Therefore, per the -_black-box testing principle_, most of the time you should test your code -through its public interfaces. - -If you still find yourself needing to test internal implementation code, -consider if there's a better design that wouldn't require you to do so. If you -absolutely have to test non-public interface code though, you can. There are -two cases to consider: - - * Static functions (_not_ the same as static member functions!) or unnamed namespaces, and - * Private or protected class members - -## Static Functions ## - -Both static functions and definitions/declarations in an unnamed namespace are -only visible within the same translation unit. To test them, you can `#include` -the entire `.cc` file being tested in your `*_test.cc` file. (`#include`ing `.cc` -files is not a good way to reuse code - you should not do this in production -code!) - -However, a better approach is to move the private code into the -`foo::internal` namespace, where `foo` is the namespace your project normally -uses, and put the private declarations in a `*-internal.h` file. Your -production `.cc` files and your tests are allowed to include this internal -header, but your clients are not. This way, you can fully test your internal -implementation without leaking it to your clients. - -## Private Class Members ## - -Private class members are only accessible from within the class or by friends. -To access a class' private members, you can declare your test fixture as a -friend to the class and define accessors in your fixture. Tests using the -fixture can then access the private members of your production class via the -accessors in the fixture. Note that even though your fixture is a friend to -your production class, your tests are not automatically friends to it, as they -are technically defined in sub-classes of the fixture. - -Another way to test private members is to refactor them into an implementation -class, which is then declared in a `*-internal.h` file. Your clients aren't -allowed to include this header but your tests can. Such is called the Pimpl -(Private Implementation) idiom. - -Or, you can declare an individual test as a friend of your class by adding this -line in the class body: - -``` -FRIEND_TEST(TestCaseName, TestName); -``` - -For example, -``` -// foo.h -#include "gtest/gtest_prod.h" - -// Defines FRIEND_TEST. -class Foo { - ... - private: - FRIEND_TEST(FooTest, BarReturnsZeroOnNull); - int Bar(void* x); -}; - -// foo_test.cc -... -TEST(FooTest, BarReturnsZeroOnNull) { - Foo foo; - EXPECT_EQ(0, foo.Bar(NULL)); - // Uses Foo's private member Bar(). -} -``` - -Pay special attention when your class is defined in a namespace, as you should -define your test fixtures and tests in the same namespace if you want them to -be friends of your class. For example, if the code to be tested looks like: - -``` -namespace my_namespace { - -class Foo { - friend class FooTest; - FRIEND_TEST(FooTest, Bar); - FRIEND_TEST(FooTest, Baz); - ... - definition of the class Foo - ... -}; - -} // namespace my_namespace -``` - -Your test code should be something like: - -``` -namespace my_namespace { -class FooTest : public ::testing::Test { - protected: - ... -}; - -TEST_F(FooTest, Bar) { ... } -TEST_F(FooTest, Baz) { ... } - -} // namespace my_namespace -``` - -# Catching Failures # - -If you are building a testing utility on top of Google Test, you'll -want to test your utility. What framework would you use to test it? -Google Test, of course. - -The challenge is to verify that your testing utility reports failures -correctly. In frameworks that report a failure by throwing an -exception, you could catch the exception and assert on it. But Google -Test doesn't use exceptions, so how do we test that a piece of code -generates an expected failure? - -`"gtest/gtest-spi.h"` contains some constructs to do this. After -`#include`ing this header, you can use - -| `EXPECT_FATAL_FAILURE(`_statement, substring_`);` | -|:--------------------------------------------------| - -to assert that _statement_ generates a fatal (e.g. `ASSERT_*`) failure -whose message contains the given _substring_, or use - -| `EXPECT_NONFATAL_FAILURE(`_statement, substring_`);` | -|:-----------------------------------------------------| - -if you are expecting a non-fatal (e.g. `EXPECT_*`) failure. - -For technical reasons, there are some caveats: - - 1. You cannot stream a failure message to either macro. - 1. _statement_ in `EXPECT_FATAL_FAILURE()` cannot reference local non-static variables or non-static members of `this` object. - 1. _statement_ in `EXPECT_FATAL_FAILURE()` cannot return a value. - -_Note:_ Google Test is designed with threads in mind. Once the -synchronization primitives in `"gtest/internal/gtest-port.h"` have -been implemented, Google Test will become thread-safe, meaning that -you can then use assertions in multiple threads concurrently. Before - -that, however, Google Test only supports single-threaded usage. Once -thread-safe, `EXPECT_FATAL_FAILURE()` and `EXPECT_NONFATAL_FAILURE()` -will capture failures in the current thread only. If _statement_ -creates new threads, failures in these threads will be ignored. If -you want to capture failures from all threads instead, you should use -the following macros: - -| `EXPECT_FATAL_FAILURE_ON_ALL_THREADS(`_statement, substring_`);` | -|:-----------------------------------------------------------------| -| `EXPECT_NONFATAL_FAILURE_ON_ALL_THREADS(`_statement, substring_`);` | - -# Getting the Current Test's Name # - -Sometimes a function may need to know the name of the currently running test. -For example, you may be using the `SetUp()` method of your test fixture to set -the golden file name based on which test is running. The `::testing::TestInfo` -class has this information: - -``` -namespace testing { - -class TestInfo { - public: - // Returns the test case name and the test name, respectively. - // - // Do NOT delete or free the return value - it's managed by the - // TestInfo class. - const char* test_case_name() const; - const char* name() const; -}; - -} // namespace testing -``` - - -> To obtain a `TestInfo` object for the currently running test, call -`current_test_info()` on the `UnitTest` singleton object: - -``` -// Gets information about the currently running test. -// Do NOT delete the returned object - it's managed by the UnitTest class. -const ::testing::TestInfo* const test_info = - ::testing::UnitTest::GetInstance()->current_test_info(); -printf("We are in test %s of test case %s.\n", - test_info->name(), test_info->test_case_name()); -``` - -`current_test_info()` returns a null pointer if no test is running. In -particular, you cannot find the test case name in `TestCaseSetUp()`, -`TestCaseTearDown()` (where you know the test case name implicitly), or -functions called from them. - -_Availability:_ Linux, Windows, Mac. - -# Extending Google Test by Handling Test Events # - -Google Test provides an event listener API to let you receive -notifications about the progress of a test program and test -failures. The events you can listen to include the start and end of -the test program, a test case, or a test method, among others. You may -use this API to augment or replace the standard console output, -replace the XML output, or provide a completely different form of -output, such as a GUI or a database. You can also use test events as -checkpoints to implement a resource leak checker, for example. - -_Availability:_ Linux, Windows, Mac; since v1.4.0. - -## Defining Event Listeners ## - -To define a event listener, you subclass either -[testing::TestEventListener](../include/gtest/gtest.h#L855) -or [testing::EmptyTestEventListener](../include/gtest/gtest.h#L905). -The former is an (abstract) interface, where each pure virtual method
-can be overridden to handle a test event (For example, when a test -starts, the `OnTestStart()` method will be called.). The latter provides -an empty implementation of all methods in the interface, such that a -subclass only needs to override the methods it cares about. - -When an event is fired, its context is passed to the handler function -as an argument. The following argument types are used: - * [UnitTest](../include/gtest/gtest.h#L1007) reflects the state of the entire test program, - * [TestCase](../include/gtest/gtest.h#L689) has information about a test case, which can contain one or more tests, - * [TestInfo](../include/gtest/gtest.h#L599) contains the state of a test, and - * [TestPartResult](../include/gtest/gtest-test-part.h#L42) represents the result of a test assertion. - -An event handler function can examine the argument it receives to find -out interesting information about the event and the test program's -state. Here's an example: - -``` - class MinimalistPrinter : public ::testing::EmptyTestEventListener { - // Called before a test starts. - virtual void OnTestStart(const ::testing::TestInfo& test_info) { - printf("*** Test %s.%s starting.\n", - test_info.test_case_name(), test_info.name()); - } - - // Called after a failed assertion or a SUCCEED() invocation. - virtual void OnTestPartResult( - const ::testing::TestPartResult& test_part_result) { - printf("%s in %s:%d\n%s\n", - test_part_result.failed() ? "*** Failure" : "Success", - test_part_result.file_name(), - test_part_result.line_number(), - test_part_result.summary()); - } - - // Called after a test ends. - virtual void OnTestEnd(const ::testing::TestInfo& test_info) { - printf("*** Test %s.%s ending.\n", - test_info.test_case_name(), test_info.name()); - } - }; -``` - -## Using Event Listeners ## - -To use the event listener you have defined, add an instance of it to -the Google Test event listener list (represented by class -[TestEventListeners](../include/gtest/gtest.h#L929) -- note the "s" at the end of the name) in your -`main()` function, before calling `RUN_ALL_TESTS()`: -``` -int main(int argc, char** argv) { - ::testing::InitGoogleTest(&argc, argv); - // Gets hold of the event listener list. - ::testing::TestEventListeners& listeners = - ::testing::UnitTest::GetInstance()->listeners(); - // Adds a listener to the end. Google Test takes the ownership. - listeners.Append(new MinimalistPrinter); - return RUN_ALL_TESTS(); -} -``` - -There's only one problem: the default test result printer is still in -effect, so its output will mingle with the output from your minimalist -printer. To suppress the default printer, just release it from the -event listener list and delete it. You can do so by adding one line: -``` - ... - delete listeners.Release(listeners.default_result_printer()); - listeners.Append(new MinimalistPrinter); - return RUN_ALL_TESTS(); -``` - -Now, sit back and enjoy a completely different output from your -tests. For more details, you can read this -[sample](../samples/sample9_unittest.cc). - -You may append more than one listener to the list. When an `On*Start()` -or `OnTestPartResult()` event is fired, the listeners will receive it in -the order they appear in the list (since new listeners are added to -the end of the list, the default text printer and the default XML -generator will receive the event first). An `On*End()` event will be -received by the listeners in the _reverse_ order. This allows output by -listeners added later to be framed by output from listeners added -earlier. - -## Generating Failures in Listeners ## - -You may use failure-raising macros (`EXPECT_*()`, `ASSERT_*()`, -`FAIL()`, etc) when processing an event. There are some restrictions: - - 1. You cannot generate any failure in `OnTestPartResult()` (otherwise it will cause `OnTestPartResult()` to be called recursively). - 1. A listener that handles `OnTestPartResult()` is not allowed to generate any failure. - -When you add listeners to the listener list, you should put listeners -that handle `OnTestPartResult()` _before_ listeners that can generate -failures. This ensures that failures generated by the latter are -attributed to the right test by the former. - -We have a sample of failure-raising listener -[here](../samples/sample10_unittest.cc). - -# Running Test Programs: Advanced Options # - -Google Test test programs are ordinary executables. Once built, you can run -them directly and affect their behavior via the following environment variables -and/or command line flags. For the flags to work, your programs must call -`::testing::InitGoogleTest()` before calling `RUN_ALL_TESTS()`. - -To see a list of supported flags and their usage, please run your test -program with the `--help` flag. You can also use `-h`, `-?`, or `/?` -for short. This feature is added in version 1.3.0. - -If an option is specified both by an environment variable and by a -flag, the latter takes precedence. Most of the options can also be -set/read in code: to access the value of command line flag -`--gtest_foo`, write `::testing::GTEST_FLAG(foo)`. A common pattern is -to set the value of a flag before calling `::testing::InitGoogleTest()` -to change the default value of the flag: -``` -int main(int argc, char** argv) { - // Disables elapsed time by default. - ::testing::GTEST_FLAG(print_time) = false; - - // This allows the user to override the flag on the command line. - ::testing::InitGoogleTest(&argc, argv); - - return RUN_ALL_TESTS(); -} -``` - -## Selecting Tests ## - -This section shows various options for choosing which tests to run. - -### Listing Test Names ### - -Sometimes it is necessary to list the available tests in a program before -running them so that a filter may be applied if needed. Including the flag -`--gtest_list_tests` overrides all other flags and lists tests in the following -format: -``` -TestCase1. - TestName1 - TestName2 -TestCase2. - TestName -``` - -None of the tests listed are actually run if the flag is provided. There is no -corresponding environment variable for this flag. - -_Availability:_ Linux, Windows, Mac. - -### Running a Subset of the Tests ### - -By default, a Google Test program runs all tests the user has defined. -Sometimes, you want to run only a subset of the tests (e.g. for debugging or -quickly verifying a change). If you set the `GTEST_FILTER` environment variable -or the `--gtest_filter` flag to a filter string, Google Test will only run the -tests whose full names (in the form of `TestCaseName.TestName`) match the -filter. - -The format of a filter is a '`:`'-separated list of wildcard patterns (called -the positive patterns) optionally followed by a '`-`' and another -'`:`'-separated pattern list (called the negative patterns). A test matches the -filter if and only if it matches any of the positive patterns but does not -match any of the negative patterns. - -A pattern may contain `'*'` (matches any string) or `'?'` (matches any single -character). For convenience, the filter `'*-NegativePatterns'` can be also -written as `'-NegativePatterns'`. - -For example: - - * `./foo_test` Has no flag, and thus runs all its tests. - * `./foo_test --gtest_filter=*` Also runs everything, due to the single match-everything `*` value. - * `./foo_test --gtest_filter=FooTest.*` Runs everything in test case `FooTest`. - * `./foo_test --gtest_filter=*Null*:*Constructor*` Runs any test whose full name contains either `"Null"` or `"Constructor"`. - * `./foo_test --gtest_filter=-*DeathTest.*` Runs all non-death tests. - * `./foo_test --gtest_filter=FooTest.*-FooTest.Bar` Runs everything in test case `FooTest` except `FooTest.Bar`. - -_Availability:_ Linux, Windows, Mac. - -### Temporarily Disabling Tests ### - -If you have a broken test that you cannot fix right away, you can add the -`DISABLED_` prefix to its name. This will exclude it from execution. This is -better than commenting out the code or using `#if 0`, as disabled tests are -still compiled (and thus won't rot). - -If you need to disable all tests in a test case, you can either add `DISABLED_` -to the front of the name of each test, or alternatively add it to the front of -the test case name. - -For example, the following tests won't be run by Google Test, even though they -will still be compiled: - -``` -// Tests that Foo does Abc. -TEST(FooTest, DISABLED_DoesAbc) { ... } - -class DISABLED_BarTest : public ::testing::Test { ... }; - -// Tests that Bar does Xyz. -TEST_F(DISABLED_BarTest, DoesXyz) { ... } -``` - -_Note:_ This feature should only be used for temporary pain-relief. You still -have to fix the disabled tests at a later date. As a reminder, Google Test will -print a banner warning you if a test program contains any disabled tests. - -_Tip:_ You can easily count the number of disabled tests you have -using `grep`. This number can be used as a metric for improving your -test quality. - -_Availability:_ Linux, Windows, Mac. - -### Temporarily Enabling Disabled Tests ### - -To include [disabled tests](#temporarily-disabling-tests) in test -execution, just invoke the test program with the -`--gtest_also_run_disabled_tests` flag or set the -`GTEST_ALSO_RUN_DISABLED_TESTS` environment variable to a value other -than `0`. You can combine this with the -[--gtest\-filter](#running-a-subset-of-the_tests) flag to further select -which disabled tests to run. - -_Availability:_ Linux, Windows, Mac; since version 1.3.0. - -## Repeating the Tests ## - -Once in a while you'll run into a test whose result is hit-or-miss. Perhaps it -will fail only 1% of the time, making it rather hard to reproduce the bug under -a debugger. This can be a major source of frustration. - -The `--gtest_repeat` flag allows you to repeat all (or selected) test methods -in a program many times. Hopefully, a flaky test will eventually fail and give -you a chance to debug. Here's how to use it: - -| `$ foo_test --gtest_repeat=1000` | Repeat foo\_test 1000 times and don't stop at failures. | -|:---------------------------------|:--------------------------------------------------------| -| `$ foo_test --gtest_repeat=-1` | A negative count means repeating forever. | -| `$ foo_test --gtest_repeat=1000 --gtest_break_on_failure` | Repeat foo\_test 1000 times, stopping at the first failure. This is especially useful when running under a debugger: when the testfails, it will drop into the debugger and you can then inspect variables and stacks. | -| `$ foo_test --gtest_repeat=1000 --gtest_filter=FooBar` | Repeat the tests whose name matches the filter 1000 times. | - -If your test program contains global set-up/tear-down code registered -using `AddGlobalTestEnvironment()`, it will be repeated in each -iteration as well, as the flakiness may be in it. You can also specify -the repeat count by setting the `GTEST_REPEAT` environment variable. - -_Availability:_ Linux, Windows, Mac. - -## Shuffling the Tests ## - -You can specify the `--gtest_shuffle` flag (or set the `GTEST_SHUFFLE` -environment variable to `1`) to run the tests in a program in a random -order. This helps to reveal bad dependencies between tests. - -By default, Google Test uses a random seed calculated from the current -time. Therefore you'll get a different order every time. The console -output includes the random seed value, such that you can reproduce an -order-related test failure later. To specify the random seed -explicitly, use the `--gtest_random_seed=SEED` flag (or set the -`GTEST_RANDOM_SEED` environment variable), where `SEED` is an integer -between 0 and 99999. The seed value 0 is special: it tells Google Test -to do the default behavior of calculating the seed from the current -time. - -If you combine this with `--gtest_repeat=N`, Google Test will pick a -different random seed and re-shuffle the tests in each iteration. - -_Availability:_ Linux, Windows, Mac; since v1.4.0. - -## Controlling Test Output ## - -This section teaches how to tweak the way test results are reported. - -### Colored Terminal Output ### - -Google Test can use colors in its terminal output to make it easier to spot -the separation between tests, and whether tests passed. - -You can set the GTEST\_COLOR environment variable or set the `--gtest_color` -command line flag to `yes`, `no`, or `auto` (the default) to enable colors, -disable colors, or let Google Test decide. When the value is `auto`, Google -Test will use colors if and only if the output goes to a terminal and (on -non-Windows platforms) the `TERM` environment variable is set to `xterm` or -`xterm-color`. - -_Availability:_ Linux, Windows, Mac. - -### Suppressing the Elapsed Time ### - -By default, Google Test prints the time it takes to run each test. To -suppress that, run the test program with the `--gtest_print_time=0` -command line flag. Setting the `GTEST_PRINT_TIME` environment -variable to `0` has the same effect. - -_Availability:_ Linux, Windows, Mac. (In Google Test 1.3.0 and lower, -the default behavior is that the elapsed time is **not** printed.) - -### Generating an XML Report ### - -Google Test can emit a detailed XML report to a file in addition to its normal -textual output. The report contains the duration of each test, and thus can -help you identify slow tests. - -To generate the XML report, set the `GTEST_OUTPUT` environment variable or the -`--gtest_output` flag to the string `"xml:_path_to_output_file_"`, which will -create the file at the given location. You can also just use the string -`"xml"`, in which case the output can be found in the `test_detail.xml` file in -the current directory. - -If you specify a directory (for example, `"xml:output/directory/"` on Linux or -`"xml:output\directory\"` on Windows), Google Test will create the XML file in -that directory, named after the test executable (e.g. `foo_test.xml` for test -program `foo_test` or `foo_test.exe`). If the file already exists (perhaps left -over from a previous run), Google Test will pick a different name (e.g. -`foo_test_1.xml`) to avoid overwriting it. - -The report uses the format described here. It is based on the -`junitreport` Ant task and can be parsed by popular continuous build -systems like [Hudson](https://hudson.dev.java.net/). Since that format -was originally intended for Java, a little interpretation is required -to make it apply to Google Test tests, as shown here: - -``` - - - - - - - - - -``` - - * The root `` element corresponds to the entire test program. - * `` elements correspond to Google Test test cases. - * `` elements correspond to Google Test test functions. - -For instance, the following program - -``` -TEST(MathTest, Addition) { ... } -TEST(MathTest, Subtraction) { ... } -TEST(LogicTest, NonContradiction) { ... } -``` - -could generate this report: - -``` - - - - - - - - - - - - - - - -``` - -Things to note: - - * The `tests` attribute of a `` or `` element tells how many test functions the Google Test program or test case contains, while the `failures` attribute tells how many of them failed. - * The `time` attribute expresses the duration of the test, test case, or entire test program in milliseconds. - * Each `` element corresponds to a single failed Google Test assertion. - * Some JUnit concepts don't apply to Google Test, yet we have to conform to the DTD. Therefore you'll see some dummy elements and attributes in the report. You can safely ignore these parts. - -_Availability:_ Linux, Windows, Mac. - -## Controlling How Failures Are Reported ## - -### Turning Assertion Failures into Break-Points ### - -When running test programs under a debugger, it's very convenient if the -debugger can catch an assertion failure and automatically drop into interactive -mode. Google Test's _break-on-failure_ mode supports this behavior. - -To enable it, set the `GTEST_BREAK_ON_FAILURE` environment variable to a value -other than `0` . Alternatively, you can use the `--gtest_break_on_failure` -command line flag. - -_Availability:_ Linux, Windows, Mac. - -### Disabling Catching Test-Thrown Exceptions ### - -Google Test can be used either with or without exceptions enabled. If -a test throws a C++ exception or (on Windows) a structured exception -(SEH), by default Google Test catches it, reports it as a test -failure, and continues with the next test method. This maximizes the -coverage of a test run. Also, on Windows an uncaught exception will -cause a pop-up window, so catching the exceptions allows you to run -the tests automatically. - -When debugging the test failures, however, you may instead want the -exceptions to be handled by the debugger, such that you can examine -the call stack when an exception is thrown. To achieve that, set the -`GTEST_CATCH_EXCEPTIONS` environment variable to `0`, or use the -`--gtest_catch_exceptions=0` flag when running the tests. - -**Availability**: Linux, Windows, Mac. - -### Letting Another Testing Framework Drive ### - -If you work on a project that has already been using another testing -framework and is not ready to completely switch to Google Test yet, -you can get much of Google Test's benefit by using its assertions in -your existing tests. Just change your `main()` function to look -like: - -``` -#include "gtest/gtest.h" - -int main(int argc, char** argv) { - ::testing::GTEST_FLAG(throw_on_failure) = true; - // Important: Google Test must be initialized. - ::testing::InitGoogleTest(&argc, argv); - - ... whatever your existing testing framework requires ... -} -``` - -With that, you can use Google Test assertions in addition to the -native assertions your testing framework provides, for example: - -``` -void TestFooDoesBar() { - Foo foo; - EXPECT_LE(foo.Bar(1), 100); // A Google Test assertion. - CPPUNIT_ASSERT(foo.IsEmpty()); // A native assertion. -} -``` - -If a Google Test assertion fails, it will print an error message and -throw an exception, which will be treated as a failure by your host -testing framework. If you compile your code with exceptions disabled, -a failed Google Test assertion will instead exit your program with a -non-zero code, which will also signal a test failure to your test -runner. - -If you don't write `::testing::GTEST_FLAG(throw_on_failure) = true;` in -your `main()`, you can alternatively enable this feature by specifying -the `--gtest_throw_on_failure` flag on the command-line or setting the -`GTEST_THROW_ON_FAILURE` environment variable to a non-zero value. - -_Availability:_ Linux, Windows, Mac; since v1.3.0. - -## Distributing Test Functions to Multiple Machines ## - -If you have more than one machine you can use to run a test program, -you might want to run the test functions in parallel and get the -result faster. We call this technique _sharding_, where each machine -is called a _shard_. - -Google Test is compatible with test sharding. To take advantage of -this feature, your test runner (not part of Google Test) needs to do -the following: - - 1. Allocate a number of machines (shards) to run the tests. - 1. On each shard, set the `GTEST_TOTAL_SHARDS` environment variable to the total number of shards. It must be the same for all shards. - 1. On each shard, set the `GTEST_SHARD_INDEX` environment variable to the index of the shard. Different shards must be assigned different indices, which must be in the range `[0, GTEST_TOTAL_SHARDS - 1]`. - 1. Run the same test program on all shards. When Google Test sees the above two environment variables, it will select a subset of the test functions to run. Across all shards, each test function in the program will be run exactly once. - 1. Wait for all shards to finish, then collect and report the results. - -Your project may have tests that were written without Google Test and -thus don't understand this protocol. In order for your test runner to -figure out which test supports sharding, it can set the environment -variable `GTEST_SHARD_STATUS_FILE` to a non-existent file path. If a -test program supports sharding, it will create this file to -acknowledge the fact (the actual contents of the file are not -important at this time; although we may stick some useful information -in it in the future.); otherwise it will not create it. - -Here's an example to make it clear. Suppose you have a test program -`foo_test` that contains the following 5 test functions: -``` -TEST(A, V) -TEST(A, W) -TEST(B, X) -TEST(B, Y) -TEST(B, Z) -``` -and you have 3 machines at your disposal. To run the test functions in -parallel, you would set `GTEST_TOTAL_SHARDS` to 3 on all machines, and -set `GTEST_SHARD_INDEX` to 0, 1, and 2 on the machines respectively. -Then you would run the same `foo_test` on each machine. - -Google Test reserves the right to change how the work is distributed -across the shards, but here's one possible scenario: - - * Machine #0 runs `A.V` and `B.X`. - * Machine #1 runs `A.W` and `B.Y`. - * Machine #2 runs `B.Z`. - -_Availability:_ Linux, Windows, Mac; since version 1.3.0. - -# Fusing Google Test Source Files # - -Google Test's implementation consists of ~30 files (excluding its own -tests). Sometimes you may want them to be packaged up in two files (a -`.h` and a `.cc`) instead, such that you can easily copy them to a new -machine and start hacking there. For this we provide an experimental -Python script `fuse_gtest_files.py` in the `scripts/` directory (since release 1.3.0). -Assuming you have Python 2.4 or above installed on your machine, just -go to that directory and run -``` -python fuse_gtest_files.py OUTPUT_DIR -``` - -and you should see an `OUTPUT_DIR` directory being created with files -`gtest/gtest.h` and `gtest/gtest-all.cc` in it. These files contain -everything you need to use Google Test. Just copy them to anywhere -you want and you are ready to write tests. You can use the -[scripts/test/Makefile](../scripts/test/Makefile) -file as an example on how to compile your tests against them. - -# Where to Go from Here # - -Congratulations! You've now learned more advanced Google Test tools and are -ready to tackle more complex testing tasks. If you want to dive even deeper, you -can read the [Frequently-Asked Questions](V1_6_FAQ.md). diff --git a/googletest/docs/V1_6_Documentation.md b/googletest/docs/V1_6_Documentation.md deleted file mode 100644 index ca924660..00000000 --- a/googletest/docs/V1_6_Documentation.md +++ /dev/null @@ -1,14 +0,0 @@ -This page lists all documentation wiki pages for Google Test **1.6** --- **if you use a released version of Google Test, please read the -documentation for that specific version instead.** - - * [Primer](V1_6_Primer.md) -- start here if you are new to Google Test. - * [Samples](V1_6_Samples.md) -- learn from examples. - * [AdvancedGuide](V1_6_AdvancedGuide.md) -- learn more about Google Test. - * [XcodeGuide](V1_6_XcodeGuide.md) -- how to use Google Test in Xcode on Mac. - * [Frequently-Asked Questions](V1_6_FAQ.md) -- check here before asking a question on the mailing list. - -To contribute code to Google Test, read: - - * [DevGuide](DevGuide.md) -- read this _before_ writing your first patch. - * [PumpManual](V1_6_PumpManual.md) -- how we generate some of Google Test's source files. \ No newline at end of file diff --git a/googletest/docs/V1_6_FAQ.md b/googletest/docs/V1_6_FAQ.md deleted file mode 100644 index 2b7f7840..00000000 --- a/googletest/docs/V1_6_FAQ.md +++ /dev/null @@ -1,1038 +0,0 @@ - - -If you cannot find the answer to your question here, and you have read -[Primer](V1_6_Primer.md) and [AdvancedGuide](V1_6_AdvancedGuide.md), send it to -googletestframework@googlegroups.com. - -## Why should I use Google Test instead of my favorite C++ testing framework? ## - -First, let us say clearly that we don't want to get into the debate of -which C++ testing framework is **the best**. There exist many fine -frameworks for writing C++ tests, and we have tremendous respect for -the developers and users of them. We don't think there is (or will -be) a single best framework - you have to pick the right tool for the -particular task you are tackling. - -We created Google Test because we couldn't find the right combination -of features and conveniences in an existing framework to satisfy _our_ -needs. The following is a list of things that _we_ like about Google -Test. We don't claim them to be unique to Google Test - rather, the -combination of them makes Google Test the choice for us. We hope this -list can help you decide whether it is for you too. - - * Google Test is designed to be portable: it doesn't require exceptions or RTTI; it works around various bugs in various compilers and environments; etc. As a result, it works on Linux, Mac OS X, Windows and several embedded operating systems. - * Nonfatal assertions (`EXPECT_*`) have proven to be great time savers, as they allow a test to report multiple failures in a single edit-compile-test cycle. - * It's easy to write assertions that generate informative messages: you just use the stream syntax to append any additional information, e.g. `ASSERT_EQ(5, Foo(i)) << " where i = " << i;`. It doesn't require a new set of macros or special functions. - * Google Test automatically detects your tests and doesn't require you to enumerate them in order to run them. - * Death tests are pretty handy for ensuring that your asserts in production code are triggered by the right conditions. - * `SCOPED_TRACE` helps you understand the context of an assertion failure when it comes from inside a sub-routine or loop. - * You can decide which tests to run using name patterns. This saves time when you want to quickly reproduce a test failure. - * Google Test can generate XML test result reports that can be parsed by popular continuous build system like Hudson. - * Simple things are easy in Google Test, while hard things are possible: in addition to advanced features like [global test environments](V1_6_AdvancedGuide.md#Global_Set-Up_and_Tear-Down) and tests parameterized by [values](V1_6_AdvancedGuide.md#value-parameterized-tests) or [types](V1_6_AdvancedGuide.md#typed-tests), Google Test supports various ways for the user to extend the framework -- if Google Test doesn't do something out of the box, chances are that a user can implement the feature using Google Test's public API, without changing Google Test itself. In particular, you can: - * expand your testing vocabulary by defining [custom predicates](V1_6_AdvancedGuide.md#predicate-assertions-for-better-error-messages), - * teach Google Test how to [print your types](V1_6_AdvancedGuide.md#teaching-google-test-how-to-print-your-values), - * define your own testing macros or utilities and verify them using Google Test's [Service Provider Interface](V1_6_AdvancedGuide.md#catching-failures), and - * reflect on the test cases or change the test output format by intercepting the [test events](V1_6_AdvancedGuide.md#extending-google-test-by-handling-test-events). - -## I'm getting warnings when compiling Google Test. Would you fix them? ## - -We strive to minimize compiler warnings Google Test generates. Before releasing a new version, we test to make sure that it doesn't generate warnings when compiled using its CMake script on Windows, Linux, and Mac OS. - -Unfortunately, this doesn't mean you are guaranteed to see no warnings when compiling Google Test in your environment: - - * You may be using a different compiler as we use, or a different version of the same compiler. We cannot possibly test for all compilers. - * You may be compiling on a different platform as we do. - * Your project may be using different compiler flags as we do. - -It is not always possible to make Google Test warning-free for everyone. Or, it may not be desirable if the warning is rarely enabled and fixing the violations makes the code more complex. - -If you see warnings when compiling Google Test, we suggest that you use the `-isystem` flag (assuming your are using GCC) to mark Google Test headers as system headers. That'll suppress warnings from Google Test headers. - -## Why should not test case names and test names contain underscore? ## - -Underscore (`_`) is special, as C++ reserves the following to be used by -the compiler and the standard library: - - 1. any identifier that starts with an `_` followed by an upper-case letter, and - 1. any identifier that containers two consecutive underscores (i.e. `__`) _anywhere_ in its name. - -User code is _prohibited_ from using such identifiers. - -Now let's look at what this means for `TEST` and `TEST_F`. - -Currently `TEST(TestCaseName, TestName)` generates a class named -`TestCaseName_TestName_Test`. What happens if `TestCaseName` or `TestName` -contains `_`? - - 1. If `TestCaseName` starts with an `_` followed by an upper-case letter (say, `_Foo`), we end up with `_Foo_TestName_Test`, which is reserved and thus invalid. - 1. If `TestCaseName` ends with an `_` (say, `Foo_`), we get `Foo__TestName_Test`, which is invalid. - 1. If `TestName` starts with an `_` (say, `_Bar`), we get `TestCaseName__Bar_Test`, which is invalid. - 1. If `TestName` ends with an `_` (say, `Bar_`), we get `TestCaseName_Bar__Test`, which is invalid. - -So clearly `TestCaseName` and `TestName` cannot start or end with `_` -(Actually, `TestCaseName` can start with `_` -- as long as the `_` isn't -followed by an upper-case letter. But that's getting complicated. So -for simplicity we just say that it cannot start with `_`.). - -It may seem fine for `TestCaseName` and `TestName` to contain `_` in the -middle. However, consider this: -``` -TEST(Time, Flies_Like_An_Arrow) { ... } -TEST(Time_Flies, Like_An_Arrow) { ... } -``` - -Now, the two `TEST`s will both generate the same class -(`Time_Files_Like_An_Arrow_Test`). That's not good. - -So for simplicity, we just ask the users to avoid `_` in `TestCaseName` -and `TestName`. The rule is more constraining than necessary, but it's -simple and easy to remember. It also gives Google Test some wiggle -room in case its implementation needs to change in the future. - -If you violate the rule, there may not be immediately consequences, -but your test may (just may) break with a new compiler (or a new -version of the compiler you are using) or with a new version of Google -Test. Therefore it's best to follow the rule. - -## Why is it not recommended to install a pre-compiled copy of Google Test (for example, into /usr/local)? ## - -In the early days, we said that you could install -compiled Google Test libraries on `*`nix systems using `make install`. -Then every user of your machine can write tests without -recompiling Google Test. - -This seemed like a good idea, but it has a -got-cha: every user needs to compile his tests using the _same_ compiler -flags used to compile the installed Google Test libraries; otherwise -he may run into undefined behaviors (i.e. the tests can behave -strangely and may even crash for no obvious reasons). - -Why? Because C++ has this thing called the One-Definition Rule: if -two C++ source files contain different definitions of the same -class/function/variable, and you link them together, you violate the -rule. The linker may or may not catch the error (in many cases it's -not required by the C++ standard to catch the violation). If it -doesn't, you get strange run-time behaviors that are unexpected and -hard to debug. - -If you compile Google Test and your test code using different compiler -flags, they may see different definitions of the same -class/function/variable (e.g. due to the use of `#if` in Google Test). -Therefore, for your sanity, we recommend to avoid installing pre-compiled -Google Test libraries. Instead, each project should compile -Google Test itself such that it can be sure that the same flags are -used for both Google Test and the tests. - -## How do I generate 64-bit binaries on Windows (using Visual Studio 2008)? ## - -(Answered by Trevor Robinson) - -Load the supplied Visual Studio solution file, either `msvc\gtest-md.sln` or -`msvc\gtest.sln`. Go through the migration wizard to migrate the -solution and project files to Visual Studio 2008. Select -`Configuration Manager...` from the `Build` menu. Select `` from -the `Active solution platform` dropdown. Select `x64` from the new -platform dropdown, leave `Copy settings from` set to `Win32` and -`Create new project platforms` checked, then click `OK`. You now have -`Win32` and `x64` platform configurations, selectable from the -`Standard` toolbar, which allow you to toggle between building 32-bit or -64-bit binaries (or both at once using Batch Build). - -In order to prevent build output files from overwriting one another, -you'll need to change the `Intermediate Directory` settings for the -newly created platform configuration across all the projects. To do -this, multi-select (e.g. using shift-click) all projects (but not the -solution) in the `Solution Explorer`. Right-click one of them and -select `Properties`. In the left pane, select `Configuration Properties`, -and from the `Configuration` dropdown, select `All Configurations`. -Make sure the selected platform is `x64`. For the -`Intermediate Directory` setting, change the value from -`$(PlatformName)\$(ConfigurationName)` to -`$(OutDir)\$(ProjectName)`. Click `OK` and then build the -solution. When the build is complete, the 64-bit binaries will be in -the `msvc\x64\Debug` directory. - -## Can I use Google Test on MinGW? ## - -We haven't tested this ourselves, but Per Abrahamsen reported that he -was able to compile and install Google Test successfully when using -MinGW from Cygwin. You'll need to configure it with: - -`PATH/TO/configure CC="gcc -mno-cygwin" CXX="g++ -mno-cygwin"` - -You should be able to replace the `-mno-cygwin` option with direct links -to the real MinGW binaries, but we haven't tried that. - -Caveats: - - * There are many warnings when compiling. - * `make check` will produce some errors as not all tests for Google Test itself are compatible with MinGW. - -We also have reports on successful cross compilation of Google Test -MinGW binaries on Linux using -[these instructions](http://wiki.wxwidgets.org/Cross-Compiling_Under_Linux#Cross-compiling_under_Linux_for_MS_Windows) -on the WxWidgets site. - -Please contact `googletestframework@googlegroups.com` if you are -interested in improving the support for MinGW. - -## Why does Google Test support EXPECT\_EQ(NULL, ptr) and ASSERT\_EQ(NULL, ptr) but not EXPECT\_NE(NULL, ptr) and ASSERT\_NE(NULL, ptr)? ## - -Due to some peculiarity of C++, it requires some non-trivial template -meta programming tricks to support using `NULL` as an argument of the -`EXPECT_XX()` and `ASSERT_XX()` macros. Therefore we only do it where -it's most needed (otherwise we make the implementation of Google Test -harder to maintain and more error-prone than necessary). - -The `EXPECT_EQ()` macro takes the _expected_ value as its first -argument and the _actual_ value as the second. It's reasonable that -someone wants to write `EXPECT_EQ(NULL, some_expression)`, and this -indeed was requested several times. Therefore we implemented it. - -The need for `EXPECT_NE(NULL, ptr)` isn't nearly as strong. When the -assertion fails, you already know that `ptr` must be `NULL`, so it -doesn't add any information to print ptr in this case. That means -`EXPECT_TRUE(ptr ! NULL)` works just as well. - -If we were to support `EXPECT_NE(NULL, ptr)`, for consistency we'll -have to support `EXPECT_NE(ptr, NULL)` as well, as unlike `EXPECT_EQ`, -we don't have a convention on the order of the two arguments for -`EXPECT_NE`. This means using the template meta programming tricks -twice in the implementation, making it even harder to understand and -maintain. We believe the benefit doesn't justify the cost. - -Finally, with the growth of Google Mock's [matcher](../../CookBook.md#using-matchers-in-google-test-assertions) library, we are -encouraging people to use the unified `EXPECT_THAT(value, matcher)` -syntax more often in tests. One significant advantage of the matcher -approach is that matchers can be easily combined to form new matchers, -while the `EXPECT_NE`, etc, macros cannot be easily -combined. Therefore we want to invest more in the matchers than in the -`EXPECT_XX()` macros. - -## Does Google Test support running tests in parallel? ## - -Test runners tend to be tightly coupled with the build/test -environment, and Google Test doesn't try to solve the problem of -running tests in parallel. Instead, we tried to make Google Test work -nicely with test runners. For example, Google Test's XML report -contains the time spent on each test, and its `gtest_list_tests` and -`gtest_filter` flags can be used for splitting the execution of test -methods into multiple processes. These functionalities can help the -test runner run the tests in parallel. - -## Why don't Google Test run the tests in different threads to speed things up? ## - -It's difficult to write thread-safe code. Most tests are not written -with thread-safety in mind, and thus may not work correctly in a -multi-threaded setting. - -If you think about it, it's already hard to make your code work when -you know what other threads are doing. It's much harder, and -sometimes even impossible, to make your code work when you don't know -what other threads are doing (remember that test methods can be added, -deleted, or modified after your test was written). If you want to run -the tests in parallel, you'd better run them in different processes. - -## Why aren't Google Test assertions implemented using exceptions? ## - -Our original motivation was to be able to use Google Test in projects -that disable exceptions. Later we realized some additional benefits -of this approach: - - 1. Throwing in a destructor is undefined behavior in C++. Not using exceptions means Google Test's assertions are safe to use in destructors. - 1. The `EXPECT_*` family of macros will continue even after a failure, allowing multiple failures in a `TEST` to be reported in a single run. This is a popular feature, as in C++ the edit-compile-test cycle is usually quite long and being able to fixing more than one thing at a time is a blessing. - 1. If assertions are implemented using exceptions, a test may falsely ignore a failure if it's caught by user code: -``` -try { ... ASSERT_TRUE(...) ... } -catch (...) { ... } -``` -The above code will pass even if the `ASSERT_TRUE` throws. While it's unlikely for someone to write this in a test, it's possible to run into this pattern when you write assertions in callbacks that are called by the code under test. - -The downside of not using exceptions is that `ASSERT_*` (implemented -using `return`) will only abort the current function, not the current -`TEST`. - -## Why do we use two different macros for tests with and without fixtures? ## - -Unfortunately, C++'s macro system doesn't allow us to use the same -macro for both cases. One possibility is to provide only one macro -for tests with fixtures, and require the user to define an empty -fixture sometimes: - -``` -class FooTest : public ::testing::Test {}; - -TEST_F(FooTest, DoesThis) { ... } -``` -or -``` -typedef ::testing::Test FooTest; - -TEST_F(FooTest, DoesThat) { ... } -``` - -Yet, many people think this is one line too many. :-) Our goal was to -make it really easy to write tests, so we tried to make simple tests -trivial to create. That means using a separate macro for such tests. - -We think neither approach is ideal, yet either of them is reasonable. -In the end, it probably doesn't matter much either way. - -## Why don't we use structs as test fixtures? ## - -We like to use structs only when representing passive data. This -distinction between structs and classes is good for documenting the -intent of the code's author. Since test fixtures have logic like -`SetUp()` and `TearDown()`, they are better defined as classes. - -## Why are death tests implemented as assertions instead of using a test runner? ## - -Our goal was to make death tests as convenient for a user as C++ -possibly allows. In particular: - - * The runner-style requires to split the information into two pieces: the definition of the death test itself, and the specification for the runner on how to run the death test and what to expect. The death test would be written in C++, while the runner spec may or may not be. A user needs to carefully keep the two in sync. `ASSERT_DEATH(statement, expected_message)` specifies all necessary information in one place, in one language, without boilerplate code. It is very declarative. - * `ASSERT_DEATH` has a similar syntax and error-reporting semantics as other Google Test assertions, and thus is easy to learn. - * `ASSERT_DEATH` can be mixed with other assertions and other logic at your will. You are not limited to one death test per test method. For example, you can write something like: -``` - if (FooCondition()) { - ASSERT_DEATH(Bar(), "blah"); - } else { - ASSERT_EQ(5, Bar()); - } -``` -If you prefer one death test per test method, you can write your tests in that style too, but we don't want to impose that on the users. The fewer artificial limitations the better. - * `ASSERT_DEATH` can reference local variables in the current function, and you can decide how many death tests you want based on run-time information. For example, -``` - const int count = GetCount(); // Only known at run time. - for (int i = 1; i <= count; i++) { - ASSERT_DEATH({ - double* buffer = new double[i]; - ... initializes buffer ... - Foo(buffer, i) - }, "blah blah"); - } -``` -The runner-based approach tends to be more static and less flexible, or requires more user effort to get this kind of flexibility. - -Another interesting thing about `ASSERT_DEATH` is that it calls `fork()` -to create a child process to run the death test. This is lightening -fast, as `fork()` uses copy-on-write pages and incurs almost zero -overhead, and the child process starts from the user-supplied -statement directly, skipping all global and local initialization and -any code leading to the given statement. If you launch the child -process from scratch, it can take seconds just to load everything and -start running if the test links to many libraries dynamically. - -## My death test modifies some state, but the change seems lost after the death test finishes. Why? ## - -Death tests (`EXPECT_DEATH`, etc) are executed in a sub-process s.t. the -expected crash won't kill the test program (i.e. the parent process). As a -result, any in-memory side effects they incur are observable in their -respective sub-processes, but not in the parent process. You can think of them -as running in a parallel universe, more or less. - -## The compiler complains about "undefined references" to some static const member variables, but I did define them in the class body. What's wrong? ## - -If your class has a static data member: - -``` -// foo.h -class Foo { - ... - static const int kBar = 100; -}; -``` - -You also need to define it _outside_ of the class body in `foo.cc`: - -``` -const int Foo::kBar; // No initializer here. -``` - -Otherwise your code is **invalid C++**, and may break in unexpected ways. In -particular, using it in Google Test comparison assertions (`EXPECT_EQ`, etc) -will generate an "undefined reference" linker error. - -## I have an interface that has several implementations. Can I write a set of tests once and repeat them over all the implementations? ## - -Google Test doesn't yet have good support for this kind of tests, or -data-driven tests in general. We hope to be able to make improvements in this -area soon. - -## Can I derive a test fixture from another? ## - -Yes. - -Each test fixture has a corresponding and same named test case. This means only -one test case can use a particular fixture. Sometimes, however, multiple test -cases may want to use the same or slightly different fixtures. For example, you -may want to make sure that all of a GUI library's test cases don't leak -important system resources like fonts and brushes. - -In Google Test, you share a fixture among test cases by putting the shared -logic in a base test fixture, then deriving from that base a separate fixture -for each test case that wants to use this common logic. You then use `TEST_F()` -to write tests using each derived fixture. - -Typically, your code looks like this: - -``` -// Defines a base test fixture. -class BaseTest : public ::testing::Test { - protected: - ... -}; - -// Derives a fixture FooTest from BaseTest. -class FooTest : public BaseTest { - protected: - virtual void SetUp() { - BaseTest::SetUp(); // Sets up the base fixture first. - ... additional set-up work ... - } - virtual void TearDown() { - ... clean-up work for FooTest ... - BaseTest::TearDown(); // Remember to tear down the base fixture - // after cleaning up FooTest! - } - ... functions and variables for FooTest ... -}; - -// Tests that use the fixture FooTest. -TEST_F(FooTest, Bar) { ... } -TEST_F(FooTest, Baz) { ... } - -... additional fixtures derived from BaseTest ... -``` - -If necessary, you can continue to derive test fixtures from a derived fixture. -Google Test has no limit on how deep the hierarchy can be. - -For a complete example using derived test fixtures, see -[sample5](../samples/sample5_unittest.cc). - -## My compiler complains "void value not ignored as it ought to be." What does this mean? ## - -You're probably using an `ASSERT_*()` in a function that doesn't return `void`. -`ASSERT_*()` can only be used in `void` functions. - -## My death test hangs (or seg-faults). How do I fix it? ## - -In Google Test, death tests are run in a child process and the way they work is -delicate. To write death tests you really need to understand how they work. -Please make sure you have read this. - -In particular, death tests don't like having multiple threads in the parent -process. So the first thing you can try is to eliminate creating threads -outside of `EXPECT_DEATH()`. - -Sometimes this is impossible as some library you must use may be creating -threads before `main()` is even reached. In this case, you can try to minimize -the chance of conflicts by either moving as many activities as possible inside -`EXPECT_DEATH()` (in the extreme case, you want to move everything inside), or -leaving as few things as possible in it. Also, you can try to set the death -test style to `"threadsafe"`, which is safer but slower, and see if it helps. - -If you go with thread-safe death tests, remember that they rerun the test -program from the beginning in the child process. Therefore make sure your -program can run side-by-side with itself and is deterministic. - -In the end, this boils down to good concurrent programming. You have to make -sure that there is no race conditions or dead locks in your program. No silver -bullet - sorry! - -## Should I use the constructor/destructor of the test fixture or the set-up/tear-down function? ## - -The first thing to remember is that Google Test does not reuse the -same test fixture object across multiple tests. For each `TEST_F`, -Google Test will create a fresh test fixture object, _immediately_ -call `SetUp()`, run the test, call `TearDown()`, and then -_immediately_ delete the test fixture object. Therefore, there is no -need to write a `SetUp()` or `TearDown()` function if the constructor -or destructor already does the job. - -You may still want to use `SetUp()/TearDown()` in the following cases: - * If the tear-down operation could throw an exception, you must use `TearDown()` as opposed to the destructor, as throwing in a destructor leads to undefined behavior and usually will kill your program right away. Note that many standard libraries (like STL) may throw when exceptions are enabled in the compiler. Therefore you should prefer `TearDown()` if you want to write portable tests that work with or without exceptions. - * The Google Test team is considering making the assertion macros throw on platforms where exceptions are enabled (e.g. Windows, Mac OS, and Linux client-side), which will eliminate the need for the user to propagate failures from a subroutine to its caller. Therefore, you shouldn't use Google Test assertions in a destructor if your code could run on such a platform. - * In a constructor or destructor, you cannot make a virtual function call on this object. (You can call a method declared as virtual, but it will be statically bound.) Therefore, if you need to call a method that will be overriden in a derived class, you have to use `SetUp()/TearDown()`. - -## The compiler complains "no matching function to call" when I use ASSERT\_PREDn. How do I fix it? ## - -If the predicate function you use in `ASSERT_PRED*` or `EXPECT_PRED*` is -overloaded or a template, the compiler will have trouble figuring out which -overloaded version it should use. `ASSERT_PRED_FORMAT*` and -`EXPECT_PRED_FORMAT*` don't have this problem. - -If you see this error, you might want to switch to -`(ASSERT|EXPECT)_PRED_FORMAT*`, which will also give you a better failure -message. If, however, that is not an option, you can resolve the problem by -explicitly telling the compiler which version to pick. - -For example, suppose you have - -``` -bool IsPositive(int n) { - return n > 0; -} -bool IsPositive(double x) { - return x > 0; -} -``` - -you will get a compiler error if you write - -``` -EXPECT_PRED1(IsPositive, 5); -``` - -However, this will work: - -``` -EXPECT_PRED1(*static_cast*(IsPositive), 5); -``` - -(The stuff inside the angled brackets for the `static_cast` operator is the -type of the function pointer for the `int`-version of `IsPositive()`.) - -As another example, when you have a template function - -``` -template -bool IsNegative(T x) { - return x < 0; -} -``` - -you can use it in a predicate assertion like this: - -``` -ASSERT_PRED1(IsNegative**, -5); -``` - -Things are more interesting if your template has more than one parameters. The -following won't compile: - -``` -ASSERT_PRED2(*GreaterThan*, 5, 0); -``` - - -as the C++ pre-processor thinks you are giving `ASSERT_PRED2` 4 arguments, -which is one more than expected. The workaround is to wrap the predicate -function in parentheses: - -``` -ASSERT_PRED2(*(GreaterThan)*, 5, 0); -``` - - -## My compiler complains about "ignoring return value" when I call RUN\_ALL\_TESTS(). Why? ## - -Some people had been ignoring the return value of `RUN_ALL_TESTS()`. That is, -instead of - -``` -return RUN_ALL_TESTS(); -``` - -they write - -``` -RUN_ALL_TESTS(); -``` - -This is wrong and dangerous. A test runner needs to see the return value of -`RUN_ALL_TESTS()` in order to determine if a test has passed. If your `main()` -function ignores it, your test will be considered successful even if it has a -Google Test assertion failure. Very bad. - -To help the users avoid this dangerous bug, the implementation of -`RUN_ALL_TESTS()` causes gcc to raise this warning, when the return value is -ignored. If you see this warning, the fix is simple: just make sure its value -is used as the return value of `main()`. - -## My compiler complains that a constructor (or destructor) cannot return a value. What's going on? ## - -Due to a peculiarity of C++, in order to support the syntax for streaming -messages to an `ASSERT_*`, e.g. - -``` -ASSERT_EQ(1, Foo()) << "blah blah" << foo; -``` - -we had to give up using `ASSERT*` and `FAIL*` (but not `EXPECT*` and -`ADD_FAILURE*`) in constructors and destructors. The workaround is to move the -content of your constructor/destructor to a private void member function, or -switch to `EXPECT_*()` if that works. This section in the user's guide explains -it. - -## My set-up function is not called. Why? ## - -C++ is case-sensitive. It should be spelled as `SetUp()`. Did you -spell it as `Setup()`? - -Similarly, sometimes people spell `SetUpTestCase()` as `SetupTestCase()` and -wonder why it's never called. - -## How do I jump to the line of a failure in Emacs directly? ## - -Google Test's failure message format is understood by Emacs and many other -IDEs, like acme and XCode. If a Google Test message is in a compilation buffer -in Emacs, then it's clickable. You can now hit `enter` on a message to jump to -the corresponding source code, or use `C-x `` to jump to the next failure. - -## I have several test cases which share the same test fixture logic, do I have to define a new test fixture class for each of them? This seems pretty tedious. ## - -You don't have to. Instead of - -``` -class FooTest : public BaseTest {}; - -TEST_F(FooTest, Abc) { ... } -TEST_F(FooTest, Def) { ... } - -class BarTest : public BaseTest {}; - -TEST_F(BarTest, Abc) { ... } -TEST_F(BarTest, Def) { ... } -``` - -you can simply `typedef` the test fixtures: -``` -typedef BaseTest FooTest; - -TEST_F(FooTest, Abc) { ... } -TEST_F(FooTest, Def) { ... } - -typedef BaseTest BarTest; - -TEST_F(BarTest, Abc) { ... } -TEST_F(BarTest, Def) { ... } -``` - -## The Google Test output is buried in a whole bunch of log messages. What do I do? ## - -The Google Test output is meant to be a concise and human-friendly report. If -your test generates textual output itself, it will mix with the Google Test -output, making it hard to read. However, there is an easy solution to this -problem. - -Since most log messages go to stderr, we decided to let Google Test output go -to stdout. This way, you can easily separate the two using redirection. For -example: -``` -./my_test > googletest_output.txt -``` - -## Why should I prefer test fixtures over global variables? ## - -There are several good reasons: - 1. It's likely your test needs to change the states of its global variables. This makes it difficult to keep side effects from escaping one test and contaminating others, making debugging difficult. By using fixtures, each test has a fresh set of variables that's different (but with the same names). Thus, tests are kept independent of each other. - 1. Global variables pollute the global namespace. - 1. Test fixtures can be reused via subclassing, which cannot be done easily with global variables. This is useful if many test cases have something in common. - -## How do I test private class members without writing FRIEND\_TEST()s? ## - -You should try to write testable code, which means classes should be easily -tested from their public interface. One way to achieve this is the Pimpl idiom: -you move all private members of a class into a helper class, and make all -members of the helper class public. - -You have several other options that don't require using `FRIEND_TEST`: - * Write the tests as members of the fixture class: -``` -class Foo { - friend class FooTest; - ... -}; - -class FooTest : public ::testing::Test { - protected: - ... - void Test1() {...} // This accesses private members of class Foo. - void Test2() {...} // So does this one. -}; - -TEST_F(FooTest, Test1) { - Test1(); -} - -TEST_F(FooTest, Test2) { - Test2(); -} -``` - * In the fixture class, write accessors for the tested class' private members, then use the accessors in your tests: -``` -class Foo { - friend class FooTest; - ... -}; - -class FooTest : public ::testing::Test { - protected: - ... - T1 get_private_member1(Foo* obj) { - return obj->private_member1_; - } -}; - -TEST_F(FooTest, Test1) { - ... - get_private_member1(x) - ... -} -``` - * If the methods are declared **protected**, you can change their access level in a test-only subclass: -``` -class YourClass { - ... - protected: // protected access for testability. - int DoSomethingReturningInt(); - ... -}; - -// in the your_class_test.cc file: -class TestableYourClass : public YourClass { - ... - public: using YourClass::DoSomethingReturningInt; // changes access rights - ... -}; - -TEST_F(YourClassTest, DoSomethingTest) { - TestableYourClass obj; - assertEquals(expected_value, obj.DoSomethingReturningInt()); -} -``` - -## How do I test private class static members without writing FRIEND\_TEST()s? ## - -We find private static methods clutter the header file. They are -implementation details and ideally should be kept out of a .h. So often I make -them free functions instead. - -Instead of: -``` -// foo.h -class Foo { - ... - private: - static bool Func(int n); -}; - -// foo.cc -bool Foo::Func(int n) { ... } - -// foo_test.cc -EXPECT_TRUE(Foo::Func(12345)); -``` - -You probably should better write: -``` -// foo.h -class Foo { - ... -}; - -// foo.cc -namespace internal { - bool Func(int n) { ... } -} - -// foo_test.cc -namespace internal { - bool Func(int n); -} - -EXPECT_TRUE(internal::Func(12345)); -``` - -## I would like to run a test several times with different parameters. Do I need to write several similar copies of it? ## - -No. You can use a feature called [value-parameterized tests](V1_6_AdvancedGuide.md#Value_Parameterized_Tests) which -lets you repeat your tests with different parameters, without defining it more than once. - -## How do I test a file that defines main()? ## - -To test a `foo.cc` file, you need to compile and link it into your unit test -program. However, when the file contains a definition for the `main()` -function, it will clash with the `main()` of your unit test, and will result in -a build error. - -The right solution is to split it into three files: - 1. `foo.h` which contains the declarations, - 1. `foo.cc` which contains the definitions except `main()`, and - 1. `foo_main.cc` which contains nothing but the definition of `main()`. - -Then `foo.cc` can be easily tested. - -If you are adding tests to an existing file and don't want an intrusive change -like this, there is a hack: just include the entire `foo.cc` file in your unit -test. For example: -``` -// File foo_unittest.cc - -// The headers section -... - -// Renames main() in foo.cc to make room for the unit test main() -#define main FooMain - -#include "a/b/foo.cc" - -// The tests start here. -... -``` - - -However, please remember this is a hack and should only be used as the last -resort. - -## What can the statement argument in ASSERT\_DEATH() be? ## - -`ASSERT_DEATH(_statement_, _regex_)` (or any death assertion macro) can be used -wherever `_statement_` is valid. So basically `_statement_` can be any C++ -statement that makes sense in the current context. In particular, it can -reference global and/or local variables, and can be: - * a simple function call (often the case), - * a complex expression, or - * a compound statement. - -> Some examples are shown here: - -``` -// A death test can be a simple function call. -TEST(MyDeathTest, FunctionCall) { - ASSERT_DEATH(Xyz(5), "Xyz failed"); -} - -// Or a complex expression that references variables and functions. -TEST(MyDeathTest, ComplexExpression) { - const bool c = Condition(); - ASSERT_DEATH((c ? Func1(0) : object2.Method("test")), - "(Func1|Method) failed"); -} - -// Death assertions can be used any where in a function. In -// particular, they can be inside a loop. -TEST(MyDeathTest, InsideLoop) { - // Verifies that Foo(0), Foo(1), ..., and Foo(4) all die. - for (int i = 0; i < 5; i++) { - EXPECT_DEATH_M(Foo(i), "Foo has \\d+ errors", - ::testing::Message() << "where i is " << i); - } -} - -// A death assertion can contain a compound statement. -TEST(MyDeathTest, CompoundStatement) { - // Verifies that at lease one of Bar(0), Bar(1), ..., and - // Bar(4) dies. - ASSERT_DEATH({ - for (int i = 0; i < 5; i++) { - Bar(i); - } - }, - "Bar has \\d+ errors");} -``` - -`googletest_unittest.cc` contains more examples if you are interested. - -## What syntax does the regular expression in ASSERT\_DEATH use? ## - -On POSIX systems, Google Test uses the POSIX Extended regular -expression syntax -(http://en.wikipedia.org/wiki/Regular_expression#POSIX_Extended_Regular_Expressions). -On Windows, it uses a limited variant of regular expression -syntax. For more details, see the -[regular expression syntax](V1_6_AdvancedGuide.md#Regular_Expression_Syntax). - -## I have a fixture class Foo, but TEST\_F(Foo, Bar) gives me error "no matching function for call to Foo::Foo()". Why? ## - -Google Test needs to be able to create objects of your test fixture class, so -it must have a default constructor. Normally the compiler will define one for -you. However, there are cases where you have to define your own: - * If you explicitly declare a non-default constructor for class `Foo`, then you need to define a default constructor, even if it would be empty. - * If `Foo` has a const non-static data member, then you have to define the default constructor _and_ initialize the const member in the initializer list of the constructor. (Early versions of `gcc` doesn't force you to initialize the const member. It's a bug that has been fixed in `gcc 4`.) - -## Why does ASSERT\_DEATH complain about previous threads that were already joined? ## - -With the Linux pthread library, there is no turning back once you cross the -line from single thread to multiple threads. The first time you create a -thread, a manager thread is created in addition, so you get 3, not 2, threads. -Later when the thread you create joins the main thread, the thread count -decrements by 1, but the manager thread will never be killed, so you still have -2 threads, which means you cannot safely run a death test. - -The new NPTL thread library doesn't suffer from this problem, as it doesn't -create a manager thread. However, if you don't control which machine your test -runs on, you shouldn't depend on this. - -## Why does Google Test require the entire test case, instead of individual tests, to be named FOODeathTest when it uses ASSERT\_DEATH? ## - -Google Test does not interleave tests from different test cases. That is, it -runs all tests in one test case first, and then runs all tests in the next test -case, and so on. Google Test does this because it needs to set up a test case -before the first test in it is run, and tear it down afterwords. Splitting up -the test case would require multiple set-up and tear-down processes, which is -inefficient and makes the semantics unclean. - -If we were to determine the order of tests based on test name instead of test -case name, then we would have a problem with the following situation: - -``` -TEST_F(FooTest, AbcDeathTest) { ... } -TEST_F(FooTest, Uvw) { ... } - -TEST_F(BarTest, DefDeathTest) { ... } -TEST_F(BarTest, Xyz) { ... } -``` - -Since `FooTest.AbcDeathTest` needs to run before `BarTest.Xyz`, and we don't -interleave tests from different test cases, we need to run all tests in the -`FooTest` case before running any test in the `BarTest` case. This contradicts -with the requirement to run `BarTest.DefDeathTest` before `FooTest.Uvw`. - -## But I don't like calling my entire test case FOODeathTest when it contains both death tests and non-death tests. What do I do? ## - -You don't have to, but if you like, you may split up the test case into -`FooTest` and `FooDeathTest`, where the names make it clear that they are -related: - -``` -class FooTest : public ::testing::Test { ... }; - -TEST_F(FooTest, Abc) { ... } -TEST_F(FooTest, Def) { ... } - -typedef FooTest FooDeathTest; - -TEST_F(FooDeathTest, Uvw) { ... EXPECT_DEATH(...) ... } -TEST_F(FooDeathTest, Xyz) { ... ASSERT_DEATH(...) ... } -``` - -## The compiler complains about "no match for 'operator<<'" when I use an assertion. What gives? ## - -If you use a user-defined type `FooType` in an assertion, you must make sure -there is an `std::ostream& operator<<(std::ostream&, const FooType&)` function -defined such that we can print a value of `FooType`. - -In addition, if `FooType` is declared in a name space, the `<<` operator also -needs to be defined in the _same_ name space. - -## How do I suppress the memory leak messages on Windows? ## - -Since the statically initialized Google Test singleton requires allocations on -the heap, the Visual C++ memory leak detector will report memory leaks at the -end of the program run. The easiest way to avoid this is to use the -`_CrtMemCheckpoint` and `_CrtMemDumpAllObjectsSince` calls to not report any -statically initialized heap objects. See MSDN for more details and additional -heap check/debug routines. - -## I am building my project with Google Test in Visual Studio and all I'm getting is a bunch of linker errors (or warnings). Help! ## - -You may get a number of the following linker error or warnings if you -attempt to link your test project with the Google Test library when -your project and the are not built using the same compiler settings. - - * LNK2005: symbol already defined in object - * LNK4217: locally defined symbol 'symbol' imported in function 'function' - * LNK4049: locally defined symbol 'symbol' imported - -The Google Test project (gtest.vcproj) has the Runtime Library option -set to /MT (use multi-threaded static libraries, /MTd for debug). If -your project uses something else, for example /MD (use multi-threaded -DLLs, /MDd for debug), you need to change the setting in the Google -Test project to match your project's. - -To update this setting open the project properties in the Visual -Studio IDE then select the branch Configuration Properties | C/C++ | -Code Generation and change the option "Runtime Library". You may also try -using gtest-md.vcproj instead of gtest.vcproj. - -## I put my tests in a library and Google Test doesn't run them. What's happening? ## -Have you read a -[warning](V1_6_Primer.md#important-note-for-visual-c-users) on -the Google Test Primer page? - -## I want to use Google Test with Visual Studio but don't know where to start. ## -Many people are in your position and one of the posted his solution to -our mailing list. Here is his link: -http://hassanjamilahmad.blogspot.com/2009/07/gtest-starters-help.html. - -## I am seeing compile errors mentioning std::type\_traits when I try to use Google Test on Solaris. ## -Google Test uses parts of the standard C++ library that SunStudio does not support. -Our users reported success using alternative implementations. Try running the build after runing this commad: - -`export CC=cc CXX=CC CXXFLAGS='-library=stlport4'` - -## How can my code detect if it is running in a test? ## - -If you write code that sniffs whether it's running in a test and does -different things accordingly, you are leaking test-only logic into -production code and there is no easy way to ensure that the test-only -code paths aren't run by mistake in production. Such cleverness also -leads to -[Heisenbugs](http://en.wikipedia.org/wiki/Unusual_software_bug#Heisenbug). -Therefore we strongly advise against the practice, and Google Test doesn't -provide a way to do it. - -In general, the recommended way to cause the code to behave -differently under test is [dependency injection](http://jamesshore.com/Blog/Dependency-Injection-Demystified.html). -You can inject different functionality from the test and from the -production code. Since your production code doesn't link in the -for-test logic at all, there is no danger in accidentally running it. - -However, if you _really_, _really_, _really_ have no choice, and if -you follow the rule of ending your test program names with `_test`, -you can use the _horrible_ hack of sniffing your executable name -(`argv[0]` in `main()`) to know whether the code is under test. - -## Google Test defines a macro that clashes with one defined by another library. How do I deal with that? ## - -In C++, macros don't obey namespaces. Therefore two libraries that -both define a macro of the same name will clash if you `#include` both -definitions. In case a Google Test macro clashes with another -library, you can force Google Test to rename its macro to avoid the -conflict. - -Specifically, if both Google Test and some other code define macro -`FOO`, you can add -``` - -DGTEST_DONT_DEFINE_FOO=1 -``` -to the compiler flags to tell Google Test to change the macro's name -from `FOO` to `GTEST_FOO`. For example, with `-DGTEST_DONT_DEFINE_TEST=1`, you'll need to write -``` - GTEST_TEST(SomeTest, DoesThis) { ... } -``` -instead of -``` - TEST(SomeTest, DoesThis) { ... } -``` -in order to define a test. - -Currently, the following `TEST`, `FAIL`, `SUCCEED`, and the basic comparison assertion macros can have alternative names. You can see the full list of covered macros [here](http://www.google.com/codesearch?q=if+!GTEST_DONT_DEFINE_\w%2B+package:http://googletest\.googlecode\.com+file:/include/gtest/gtest.h). More information can be found in the "Avoiding Macro Name Clashes" section of the README file. - -## My question is not covered in your FAQ! ## - -If you cannot find the answer to your question in this FAQ, there are -some other resources you can use: - - 1. read other [wiki pages](http://code.google.com/p/googletest/w/list), - 1. search the mailing list [archive](http://groups.google.com/group/googletestframework/topics), - 1. ask it on [googletestframework@googlegroups.com](mailto:googletestframework@googlegroups.com) and someone will answer it (to prevent spam, we require you to join the [discussion group](http://groups.google.com/group/googletestframework) before you can post.). - -Please note that creating an issue in the -[issue tracker](http://code.google.com/p/googletest/issues/list) is _not_ -a good way to get your answer, as it is monitored infrequently by a -very small number of people. - -When asking a question, it's helpful to provide as much of the -following information as possible (people cannot help you if there's -not enough information in your question): - - * the version (or the revision number if you check out from SVN directly) of Google Test you use (Google Test is under active development, so it's possible that your problem has been solved in a later version), - * your operating system, - * the name and version of your compiler, - * the complete command line flags you give to your compiler, - * the complete compiler error messages (if the question is about compilation), - * the _actual_ code (ideally, a minimal but complete program) that has the problem you encounter. diff --git a/googletest/docs/V1_6_Primer.md b/googletest/docs/V1_6_Primer.md deleted file mode 100644 index 8d840ef4..00000000 --- a/googletest/docs/V1_6_Primer.md +++ /dev/null @@ -1,501 +0,0 @@ - - -# Introduction: Why Google C++ Testing Framework? # - -_Google C++ Testing Framework_ helps you write better C++ tests. - -No matter whether you work on Linux, Windows, or a Mac, if you write C++ code, -Google Test can help you. - -So what makes a good test, and how does Google C++ Testing Framework fit in? We believe: - 1. Tests should be _independent_ and _repeatable_. It's a pain to debug a test that succeeds or fails as a result of other tests. Google C++ Testing Framework isolates the tests by running each of them on a different object. When a test fails, Google C++ Testing Framework allows you to run it in isolation for quick debugging. - 1. Tests should be well _organized_ and reflect the structure of the tested code. Google C++ Testing Framework groups related tests into test cases that can share data and subroutines. This common pattern is easy to recognize and makes tests easy to maintain. Such consistency is especially helpful when people switch projects and start to work on a new code base. - 1. Tests should be _portable_ and _reusable_. The open-source community has a lot of code that is platform-neutral, its tests should also be platform-neutral. Google C++ Testing Framework works on different OSes, with different compilers (gcc, MSVC, and others), with or without exceptions, so Google C++ Testing Framework tests can easily work with a variety of configurations. (Note that the current release only contains build scripts for Linux - we are actively working on scripts for other platforms.) - 1. When tests fail, they should provide as much _information_ about the problem as possible. Google C++ Testing Framework doesn't stop at the first test failure. Instead, it only stops the current test and continues with the next. You can also set up tests that report non-fatal failures after which the current test continues. Thus, you can detect and fix multiple bugs in a single run-edit-compile cycle. - 1. The testing framework should liberate test writers from housekeeping chores and let them focus on the test _content_. Google C++ Testing Framework automatically keeps track of all tests defined, and doesn't require the user to enumerate them in order to run them. - 1. Tests should be _fast_. With Google C++ Testing Framework, you can reuse shared resources across tests and pay for the set-up/tear-down only once, without making tests depend on each other. - -Since Google C++ Testing Framework is based on the popular xUnit -architecture, you'll feel right at home if you've used JUnit or PyUnit before. -If not, it will take you about 10 minutes to learn the basics and get started. -So let's go! - -_Note:_ We sometimes refer to Google C++ Testing Framework informally -as _Google Test_. - -# Setting up a New Test Project # - -To write a test program using Google Test, you need to compile Google -Test into a library and link your test with it. We provide build -files for some popular build systems: `msvc/` for Visual Studio, -`xcode/` for Mac Xcode, `make/` for GNU make, `codegear/` for Borland -C++ Builder, and the autotools script (deprecated) and -`CMakeLists.txt` for CMake (recommended) in the Google Test root -directory. If your build system is not on this list, you can take a -look at `make/Makefile` to learn how Google Test should be compiled -(basically you want to compile `src/gtest-all.cc` with `GTEST_ROOT` -and `GTEST_ROOT/include` in the header search path, where `GTEST_ROOT` -is the Google Test root directory). - -Once you are able to compile the Google Test library, you should -create a project or build target for your test program. Make sure you -have `GTEST_ROOT/include` in the header search path so that the -compiler can find `"gtest/gtest.h"` when compiling your test. Set up -your test project to link with the Google Test library (for example, -in Visual Studio, this is done by adding a dependency on -`gtest.vcproj`). - -If you still have questions, take a look at how Google Test's own -tests are built and use them as examples. - -# Basic Concepts # - -When using Google Test, you start by writing _assertions_, which are statements -that check whether a condition is true. An assertion's result can be _success_, -_nonfatal failure_, or _fatal failure_. If a fatal failure occurs, it aborts -the current function; otherwise the program continues normally. - -_Tests_ use assertions to verify the tested code's behavior. If a test crashes -or has a failed assertion, then it _fails_; otherwise it _succeeds_. - -A _test case_ contains one or many tests. You should group your tests into test -cases that reflect the structure of the tested code. When multiple tests in a -test case need to share common objects and subroutines, you can put them into a -_test fixture_ class. - -A _test program_ can contain multiple test cases. - -We'll now explain how to write a test program, starting at the individual -assertion level and building up to tests and test cases. - -# Assertions # - -Google Test assertions are macros that resemble function calls. You test a -class or function by making assertions about its behavior. When an assertion -fails, Google Test prints the assertion's source file and line number location, -along with a failure message. You may also supply a custom failure message -which will be appended to Google Test's message. - -The assertions come in pairs that test the same thing but have different -effects on the current function. `ASSERT_*` versions generate fatal failures -when they fail, and **abort the current function**. `EXPECT_*` versions generate -nonfatal failures, which don't abort the current function. Usually `EXPECT_*` -are preferred, as they allow more than one failures to be reported in a test. -However, you should use `ASSERT_*` if it doesn't make sense to continue when -the assertion in question fails. - -Since a failed `ASSERT_*` returns from the current function immediately, -possibly skipping clean-up code that comes after it, it may cause a space leak. -Depending on the nature of the leak, it may or may not be worth fixing - so -keep this in mind if you get a heap checker error in addition to assertion -errors. - -To provide a custom failure message, simply stream it into the macro using the -`<<` operator, or a sequence of such operators. An example: -``` -ASSERT_EQ(x.size(), y.size()) << "Vectors x and y are of unequal length"; - -for (int i = 0; i < x.size(); ++i) { - EXPECT_EQ(x[i], y[i]) << "Vectors x and y differ at index " << i; -} -``` - -Anything that can be streamed to an `ostream` can be streamed to an assertion -macro--in particular, C strings and `string` objects. If a wide string -(`wchar_t*`, `TCHAR*` in `UNICODE` mode on Windows, or `std::wstring`) is -streamed to an assertion, it will be translated to UTF-8 when printed. - -## Basic Assertions ## - -These assertions do basic true/false condition testing. -| **Fatal assertion** | **Nonfatal assertion** | **Verifies** | -|:--------------------|:-----------------------|:-------------| -| `ASSERT_TRUE(`_condition_`)`; | `EXPECT_TRUE(`_condition_`)`; | _condition_ is true | -| `ASSERT_FALSE(`_condition_`)`; | `EXPECT_FALSE(`_condition_`)`; | _condition_ is false | - -Remember, when they fail, `ASSERT_*` yields a fatal failure and -returns from the current function, while `EXPECT_*` yields a nonfatal -failure, allowing the function to continue running. In either case, an -assertion failure means its containing test fails. - -_Availability_: Linux, Windows, Mac. - -## Binary Comparison ## - -This section describes assertions that compare two values. - -| **Fatal assertion** | **Nonfatal assertion** | **Verifies** | -|:--------------------|:-----------------------|:-------------| -|`ASSERT_EQ(`_expected_`, `_actual_`);`|`EXPECT_EQ(`_expected_`, `_actual_`);`| _expected_ `==` _actual_ | -|`ASSERT_NE(`_val1_`, `_val2_`);` |`EXPECT_NE(`_val1_`, `_val2_`);` | _val1_ `!=` _val2_ | -|`ASSERT_LT(`_val1_`, `_val2_`);` |`EXPECT_LT(`_val1_`, `_val2_`);` | _val1_ `<` _val2_ | -|`ASSERT_LE(`_val1_`, `_val2_`);` |`EXPECT_LE(`_val1_`, `_val2_`);` | _val1_ `<=` _val2_ | -|`ASSERT_GT(`_val1_`, `_val2_`);` |`EXPECT_GT(`_val1_`, `_val2_`);` | _val1_ `>` _val2_ | -|`ASSERT_GE(`_val1_`, `_val2_`);` |`EXPECT_GE(`_val1_`, `_val2_`);` | _val1_ `>=` _val2_ | - -In the event of a failure, Google Test prints both _val1_ and _val2_ -. In `ASSERT_EQ*` and `EXPECT_EQ*` (and all other equality assertions -we'll introduce later), you should put the expression you want to test -in the position of _actual_, and put its expected value in _expected_, -as Google Test's failure messages are optimized for this convention. - -Value arguments must be comparable by the assertion's comparison -operator or you'll get a compiler error. We used to require the -arguments to support the `<<` operator for streaming to an `ostream`, -but it's no longer necessary since v1.6.0 (if `<<` is supported, it -will be called to print the arguments when the assertion fails; -otherwise Google Test will attempt to print them in the best way it -can. For more details and how to customize the printing of the -arguments, see this Google Mock [recipe](../../googlemock/docs/CookBook.md#teaching-google-mock-how-to-print-your-values).). - -These assertions can work with a user-defined type, but only if you define the -corresponding comparison operator (e.g. `==`, `<`, etc). If the corresponding -operator is defined, prefer using the `ASSERT_*()` macros because they will -print out not only the result of the comparison, but the two operands as well. - -Arguments are always evaluated exactly once. Therefore, it's OK for the -arguments to have side effects. However, as with any ordinary C/C++ function, -the arguments' evaluation order is undefined (i.e. the compiler is free to -choose any order) and your code should not depend on any particular argument -evaluation order. - -`ASSERT_EQ()` does pointer equality on pointers. If used on two C strings, it -tests if they are in the same memory location, not if they have the same value. -Therefore, if you want to compare C strings (e.g. `const char*`) by value, use -`ASSERT_STREQ()` , which will be described later on. In particular, to assert -that a C string is `NULL`, use `ASSERT_STREQ(NULL, c_string)` . However, to -compare two `string` objects, you should use `ASSERT_EQ`. - -Macros in this section work with both narrow and wide string objects (`string` -and `wstring`). - -_Availability_: Linux, Windows, Mac. - -## String Comparison ## - -The assertions in this group compare two **C strings**. If you want to compare -two `string` objects, use `EXPECT_EQ`, `EXPECT_NE`, and etc instead. - -| **Fatal assertion** | **Nonfatal assertion** | **Verifies** | -|:--------------------|:-----------------------|:-------------| -| `ASSERT_STREQ(`_expected\_str_`, `_actual\_str_`);` | `EXPECT_STREQ(`_expected\_str_`, `_actual\_str_`);` | the two C strings have the same content | -| `ASSERT_STRNE(`_str1_`, `_str2_`);` | `EXPECT_STRNE(`_str1_`, `_str2_`);` | the two C strings have different content | -| `ASSERT_STRCASEEQ(`_expected\_str_`, `_actual\_str_`);`| `EXPECT_STRCASEEQ(`_expected\_str_`, `_actual\_str_`);` | the two C strings have the same content, ignoring case | -| `ASSERT_STRCASENE(`_str1_`, `_str2_`);`| `EXPECT_STRCASENE(`_str1_`, `_str2_`);` | the two C strings have different content, ignoring case | - -Note that "CASE" in an assertion name means that case is ignored. - -`*STREQ*` and `*STRNE*` also accept wide C strings (`wchar_t*`). If a -comparison of two wide strings fails, their values will be printed as UTF-8 -narrow strings. - -A `NULL` pointer and an empty string are considered _different_. - -_Availability_: Linux, Windows, Mac. - -See also: For more string comparison tricks (substring, prefix, suffix, and -regular expression matching, for example), see the [Advanced Google Test Guide](V1_6_AdvancedGuide.md). - -# Simple Tests # - -To create a test: - 1. Use the `TEST()` macro to define and name a test function, These are ordinary C++ functions that don't return a value. - 1. In this function, along with any valid C++ statements you want to include, use the various Google Test assertions to check values. - 1. The test's result is determined by the assertions; if any assertion in the test fails (either fatally or non-fatally), or if the test crashes, the entire test fails. Otherwise, it succeeds. - -``` -TEST(test_case_name, test_name) { - ... test body ... -} -``` - - -`TEST()` arguments go from general to specific. The _first_ argument is the -name of the test case, and the _second_ argument is the test's name within the -test case. Both names must be valid C++ identifiers, and they should not contain underscore (`_`). A test's _full name_ consists of its containing test case and its -individual name. Tests from different test cases can have the same individual -name. - -For example, let's take a simple integer function: -``` -int Factorial(int n); // Returns the factorial of n -``` - -A test case for this function might look like: -``` -// Tests factorial of 0. -TEST(FactorialTest, HandlesZeroInput) { - EXPECT_EQ(1, Factorial(0)); -} - -// Tests factorial of positive numbers. -TEST(FactorialTest, HandlesPositiveInput) { - EXPECT_EQ(1, Factorial(1)); - EXPECT_EQ(2, Factorial(2)); - EXPECT_EQ(6, Factorial(3)); - EXPECT_EQ(40320, Factorial(8)); -} -``` - -Google Test groups the test results by test cases, so logically-related tests -should be in the same test case; in other words, the first argument to their -`TEST()` should be the same. In the above example, we have two tests, -`HandlesZeroInput` and `HandlesPositiveInput`, that belong to the same test -case `FactorialTest`. - -_Availability_: Linux, Windows, Mac. - -# Test Fixtures: Using the Same Data Configuration for Multiple Tests # - -If you find yourself writing two or more tests that operate on similar data, -you can use a _test fixture_. It allows you to reuse the same configuration of -objects for several different tests. - -To create a fixture, just: - 1. Derive a class from `::testing::Test` . Start its body with `protected:` or `public:` as we'll want to access fixture members from sub-classes. - 1. Inside the class, declare any objects you plan to use. - 1. If necessary, write a default constructor or `SetUp()` function to prepare the objects for each test. A common mistake is to spell `SetUp()` as `Setup()` with a small `u` - don't let that happen to you. - 1. If necessary, write a destructor or `TearDown()` function to release any resources you allocated in `SetUp()` . To learn when you should use the constructor/destructor and when you should use `SetUp()/TearDown()`, read this [FAQ entry](V1_6_FAQ.md#should-i-use-the-constructordestructor-of-the-test-fixture-or-the-set-uptear-down-function). - 1. If needed, define subroutines for your tests to share. - -When using a fixture, use `TEST_F()` instead of `TEST()` as it allows you to -access objects and subroutines in the test fixture: -``` -TEST_F(test_case_name, test_name) { - ... test body ... -} -``` - -Like `TEST()`, the first argument is the test case name, but for `TEST_F()` -this must be the name of the test fixture class. You've probably guessed: `_F` -is for fixture. - -Unfortunately, the C++ macro system does not allow us to create a single macro -that can handle both types of tests. Using the wrong macro causes a compiler -error. - -Also, you must first define a test fixture class before using it in a -`TEST_F()`, or you'll get the compiler error "`virtual outside class -declaration`". - -For each test defined with `TEST_F()`, Google Test will: - 1. Create a _fresh_ test fixture at runtime - 1. Immediately initialize it via `SetUp()` , - 1. Run the test - 1. Clean up by calling `TearDown()` - 1. Delete the test fixture. Note that different tests in the same test case have different test fixture objects, and Google Test always deletes a test fixture before it creates the next one. Google Test does not reuse the same test fixture for multiple tests. Any changes one test makes to the fixture do not affect other tests. - -As an example, let's write tests for a FIFO queue class named `Queue`, which -has the following interface: -``` -template // E is the element type. -class Queue { - public: - Queue(); - void Enqueue(const E& element); - E* Dequeue(); // Returns NULL if the queue is empty. - size_t size() const; - ... -}; -``` - -First, define a fixture class. By convention, you should give it the name -`FooTest` where `Foo` is the class being tested. -``` -class QueueTest : public ::testing::Test { - protected: - virtual void SetUp() { - q1_.Enqueue(1); - q2_.Enqueue(2); - q2_.Enqueue(3); - } - - // virtual void TearDown() {} - - Queue q0_; - Queue q1_; - Queue q2_; -}; -``` - -In this case, `TearDown()` is not needed since we don't have to clean up after -each test, other than what's already done by the destructor. - -Now we'll write tests using `TEST_F()` and this fixture. -``` -TEST_F(QueueTest, IsEmptyInitially) { - EXPECT_EQ(0, q0_.size()); -} - -TEST_F(QueueTest, DequeueWorks) { - int* n = q0_.Dequeue(); - EXPECT_EQ(NULL, n); - - n = q1_.Dequeue(); - ASSERT_TRUE(n != NULL); - EXPECT_EQ(1, *n); - EXPECT_EQ(0, q1_.size()); - delete n; - - n = q2_.Dequeue(); - ASSERT_TRUE(n != NULL); - EXPECT_EQ(2, *n); - EXPECT_EQ(1, q2_.size()); - delete n; -} -``` - -The above uses both `ASSERT_*` and `EXPECT_*` assertions. The rule of thumb is -to use `EXPECT_*` when you want the test to continue to reveal more errors -after the assertion failure, and use `ASSERT_*` when continuing after failure -doesn't make sense. For example, the second assertion in the `Dequeue` test is -`ASSERT_TRUE(n != NULL)`, as we need to dereference the pointer `n` later, -which would lead to a segfault when `n` is `NULL`. - -When these tests run, the following happens: - 1. Google Test constructs a `QueueTest` object (let's call it `t1` ). - 1. `t1.SetUp()` initializes `t1` . - 1. The first test ( `IsEmptyInitially` ) runs on `t1` . - 1. `t1.TearDown()` cleans up after the test finishes. - 1. `t1` is destructed. - 1. The above steps are repeated on another `QueueTest` object, this time running the `DequeueWorks` test. - -_Availability_: Linux, Windows, Mac. - -_Note_: Google Test automatically saves all _Google Test_ flags when a test -object is constructed, and restores them when it is destructed. - -# Invoking the Tests # - -`TEST()` and `TEST_F()` implicitly register their tests with Google Test. So, unlike with many other C++ testing frameworks, you don't have to re-list all your defined tests in order to run them. - -After defining your tests, you can run them with `RUN_ALL_TESTS()` , which returns `0` if all the tests are successful, or `1` otherwise. Note that `RUN_ALL_TESTS()` runs _all tests_ in your link unit -- they can be from different test cases, or even different source files. - -When invoked, the `RUN_ALL_TESTS()` macro: - 1. Saves the state of all Google Test flags. - 1. Creates a test fixture object for the first test. - 1. Initializes it via `SetUp()`. - 1. Runs the test on the fixture object. - 1. Cleans up the fixture via `TearDown()`. - 1. Deletes the fixture. - 1. Restores the state of all Google Test flags. - 1. Repeats the above steps for the next test, until all tests have run. - -In addition, if the text fixture's constructor generates a fatal failure in -step 2, there is no point for step 3 - 5 and they are thus skipped. Similarly, -if step 3 generates a fatal failure, step 4 will be skipped. - -_Important_: You must not ignore the return value of `RUN_ALL_TESTS()`, or `gcc` -will give you a compiler error. The rationale for this design is that the -automated testing service determines whether a test has passed based on its -exit code, not on its stdout/stderr output; thus your `main()` function must -return the value of `RUN_ALL_TESTS()`. - -Also, you should call `RUN_ALL_TESTS()` only **once**. Calling it more than once -conflicts with some advanced Google Test features (e.g. thread-safe death -tests) and thus is not supported. - -_Availability_: Linux, Windows, Mac. - -# Writing the main() Function # - -You can start from this boilerplate: -``` -#include "this/package/foo.h" -#include "gtest/gtest.h" - -namespace { - -// The fixture for testing class Foo. -class FooTest : public ::testing::Test { - protected: - // You can remove any or all of the following functions if its body - // is empty. - - FooTest() { - // You can do set-up work for each test here. - } - - virtual ~FooTest() { - // You can do clean-up work that doesn't throw exceptions here. - } - - // If the constructor and destructor are not enough for setting up - // and cleaning up each test, you can define the following methods: - - virtual void SetUp() { - // Code here will be called immediately after the constructor (right - // before each test). - } - - virtual void TearDown() { - // Code here will be called immediately after each test (right - // before the destructor). - } - - // Objects declared here can be used by all tests in the test case for Foo. -}; - -// Tests that the Foo::Bar() method does Abc. -TEST_F(FooTest, MethodBarDoesAbc) { - const string input_filepath = "this/package/testdata/myinputfile.dat"; - const string output_filepath = "this/package/testdata/myoutputfile.dat"; - Foo f; - EXPECT_EQ(0, f.Bar(input_filepath, output_filepath)); -} - -// Tests that Foo does Xyz. -TEST_F(FooTest, DoesXyz) { - // Exercises the Xyz feature of Foo. -} - -} // namespace - -int main(int argc, char **argv) { - ::testing::InitGoogleTest(&argc, argv); - return RUN_ALL_TESTS(); -} -``` - -The `::testing::InitGoogleTest()` function parses the command line for Google -Test flags, and removes all recognized flags. This allows the user to control a -test program's behavior via various flags, which we'll cover in [AdvancedGuide](V1_6_AdvancedGuide.md). -You must call this function before calling `RUN_ALL_TESTS()`, or the flags -won't be properly initialized. - -On Windows, `InitGoogleTest()` also works with wide strings, so it can be used -in programs compiled in `UNICODE` mode as well. - -But maybe you think that writing all those main() functions is too much work? We agree with you completely and that's why Google Test provides a basic implementation of main(). If it fits your needs, then just link your test with gtest\_main library and you are good to go. - -## Important note for Visual C++ users ## -If you put your tests into a library and your `main()` function is in a different library or in your .exe file, those tests will not run. The reason is a [bug](https://connect.microsoft.com/feedback/viewfeedback.aspx?FeedbackID=244410&siteid=210) in Visual C++. When you define your tests, Google Test creates certain static objects to register them. These objects are not referenced from elsewhere but their constructors are still supposed to run. When Visual C++ linker sees that nothing in the library is referenced from other places it throws the library out. You have to reference your library with tests from your main program to keep the linker from discarding it. Here is how to do it. Somewhere in your library code declare a function: -``` -__declspec(dllexport) int PullInMyLibrary() { return 0; } -``` -If you put your tests in a static library (not DLL) then `__declspec(dllexport)` is not required. Now, in your main program, write a code that invokes that function: -``` -int PullInMyLibrary(); -static int dummy = PullInMyLibrary(); -``` -This will keep your tests referenced and will make them register themselves at startup. - -In addition, if you define your tests in a static library, add `/OPT:NOREF` to your main program linker options. If you use MSVC++ IDE, go to your .exe project properties/Configuration Properties/Linker/Optimization and set References setting to `Keep Unreferenced Data (/OPT:NOREF)`. This will keep Visual C++ linker from discarding individual symbols generated by your tests from the final executable. - -There is one more pitfall, though. If you use Google Test as a static library (that's how it is defined in gtest.vcproj) your tests must also reside in a static library. If you have to have them in a DLL, you _must_ change Google Test to build into a DLL as well. Otherwise your tests will not run correctly or will not run at all. The general conclusion here is: make your life easier - do not write your tests in libraries! - -# Where to Go from Here # - -Congratulations! You've learned the Google Test basics. You can start writing -and running Google Test tests, read some [samples](V1_6_Samples.md), or continue with -[AdvancedGuide](V1_6_AdvancedGuide.md), which describes many more useful Google Test features. - -# Known Limitations # - -Google Test is designed to be thread-safe. The implementation is -thread-safe on systems where the `pthreads` library is available. It -is currently _unsafe_ to use Google Test assertions from two threads -concurrently on other systems (e.g. Windows). In most tests this is -not an issue as usually the assertions are done in the main thread. If -you want to help, you can volunteer to implement the necessary -synchronization primitives in `gtest-port.h` for your platform. diff --git a/googletest/docs/V1_6_PumpManual.md b/googletest/docs/V1_6_PumpManual.md deleted file mode 100644 index 8184f153..00000000 --- a/googletest/docs/V1_6_PumpManual.md +++ /dev/null @@ -1,177 +0,0 @@ - - -Pump is Useful for Meta Programming. - -# The Problem # - -Template and macro libraries often need to define many classes, -functions, or macros that vary only (or almost only) in the number of -arguments they take. It's a lot of repetitive, mechanical, and -error-prone work. - -Variadic templates and variadic macros can alleviate the problem. -However, while both are being considered by the C++ committee, neither -is in the standard yet or widely supported by compilers. Thus they -are often not a good choice, especially when your code needs to be -portable. And their capabilities are still limited. - -As a result, authors of such libraries often have to write scripts to -generate their implementation. However, our experience is that it's -tedious to write such scripts, which tend to reflect the structure of -the generated code poorly and are often hard to read and edit. For -example, a small change needed in the generated code may require some -non-intuitive, non-trivial changes in the script. This is especially -painful when experimenting with the code. - -# Our Solution # - -Pump (for Pump is Useful for Meta Programming, Pretty Useful for Meta -Programming, or Practical Utility for Meta Programming, whichever you -prefer) is a simple meta-programming tool for C++. The idea is that a -programmer writes a `foo.pump` file which contains C++ code plus meta -code that manipulates the C++ code. The meta code can handle -iterations over a range, nested iterations, local meta variable -definitions, simple arithmetic, and conditional expressions. You can -view it as a small Domain-Specific Language. The meta language is -designed to be non-intrusive (s.t. it won't confuse Emacs' C++ mode, -for example) and concise, making Pump code intuitive and easy to -maintain. - -## Highlights ## - - * The implementation is in a single Python script and thus ultra portable: no build or installation is needed and it works cross platforms. - * Pump tries to be smart with respect to [Google's style guide](http://code.google.com/p/google-styleguide/): it breaks long lines (easy to have when they are generated) at acceptable places to fit within 80 columns and indent the continuation lines correctly. - * The format is human-readable and more concise than XML. - * The format works relatively well with Emacs' C++ mode. - -## Examples ## - -The following Pump code (where meta keywords start with `$`, `[[` and `]]` are meta brackets, and `$$` starts a meta comment that ends with the line): - -``` -$var n = 3 $$ Defines a meta variable n. -$range i 0..n $$ Declares the range of meta iterator i (inclusive). -$for i [[ - $$ Meta loop. -// Foo$i does blah for $i-ary predicates. -$range j 1..i -template -class Foo$i { -$if i == 0 [[ - blah a; -]] $elif i <= 2 [[ - blah b; -]] $else [[ - blah c; -]] -}; - -]] -``` - -will be translated by the Pump compiler to: - -``` -// Foo0 does blah for 0-ary predicates. -template -class Foo0 { - blah a; -}; - -// Foo1 does blah for 1-ary predicates. -template -class Foo1 { - blah b; -}; - -// Foo2 does blah for 2-ary predicates. -template -class Foo2 { - blah b; -}; - -// Foo3 does blah for 3-ary predicates. -template -class Foo3 { - blah c; -}; -``` - -In another example, - -``` -$range i 1..n -Func($for i + [[a$i]]); -$$ The text between i and [[ is the separator between iterations. -``` - -will generate one of the following lines (without the comments), depending on the value of `n`: - -``` -Func(); // If n is 0. -Func(a1); // If n is 1. -Func(a1 + a2); // If n is 2. -Func(a1 + a2 + a3); // If n is 3. -// And so on... -``` - -## Constructs ## - -We support the following meta programming constructs: - -| `$var id = exp` | Defines a named constant value. `$id` is valid util the end of the current meta lexical block. | -|:----------------|:-----------------------------------------------------------------------------------------------| -| `$range id exp..exp` | Sets the range of an iteration variable, which can be reused in multiple loops later. | -| `$for id sep [[ code ]]` | Iteration. The range of `id` must have been defined earlier. `$id` is valid in `code`. | -| `$($)` | Generates a single `$` character. | -| `$id` | Value of the named constant or iteration variable. | -| `$(exp)` | Value of the expression. | -| `$if exp [[ code ]] else_branch` | Conditional. | -| `[[ code ]]` | Meta lexical block. | -| `cpp_code` | Raw C++ code. | -| `$$ comment` | Meta comment. | - -**Note:** To give the user some freedom in formatting the Pump source -code, Pump ignores a new-line character if it's right after `$for foo` -or next to `[[` or `]]`. Without this rule you'll often be forced to write -very long lines to get the desired output. Therefore sometimes you may -need to insert an extra new-line in such places for a new-line to show -up in your output. - -## Grammar ## - -``` -code ::= atomic_code* -atomic_code ::= $var id = exp - | $var id = [[ code ]] - | $range id exp..exp - | $for id sep [[ code ]] - | $($) - | $id - | $(exp) - | $if exp [[ code ]] else_branch - | [[ code ]] - | cpp_code -sep ::= cpp_code | empty_string -else_branch ::= $else [[ code ]] - | $elif exp [[ code ]] else_branch - | empty_string -exp ::= simple_expression_in_Python_syntax -``` - -## Code ## - -You can find the source code of Pump in [scripts/pump.py](../scripts/pump.py). It is still -very unpolished and lacks automated tests, although it has been -successfully used many times. If you find a chance to use it in your -project, please let us know what you think! We also welcome help on -improving Pump. - -## Real Examples ## - -You can find real-world applications of Pump in [Google Test](http://www.google.com/codesearch?q=file%3A\.pump%24+package%3Ahttp%3A%2F%2Fgoogletest\.googlecode\.com) and [Google Mock](http://www.google.com/codesearch?q=file%3A\.pump%24+package%3Ahttp%3A%2F%2Fgooglemock\.googlecode\.com). The source file `foo.h.pump` generates `foo.h`. - -## Tips ## - - * If a meta variable is followed by a letter or digit, you can separate them using `[[]]`, which inserts an empty string. For example `Foo$j[[]]Helper` generate `Foo1Helper` when `j` is 1. - * To avoid extra-long Pump source lines, you can break a line anywhere you want by inserting `[[]]` followed by a new line. Since any new-line character next to `[[` or `]]` is ignored, the generated code won't contain this new line. diff --git a/googletest/docs/V1_6_Samples.md b/googletest/docs/V1_6_Samples.md deleted file mode 100644 index f21d2005..00000000 --- a/googletest/docs/V1_6_Samples.md +++ /dev/null @@ -1,14 +0,0 @@ -If you're like us, you'd like to look at some Google Test sample code. The -[samples folder](../samples) has a number of well-commented samples showing how to use a -variety of Google Test features. - - * [Sample #1](../samples/sample1_unittest.cc) shows the basic steps of using Google Test to test C++ functions. - * [Sample #2](../samples/sample2_unittest.cc) shows a more complex unit test for a class with multiple member functions. - * [Sample #3](../samples/sample3_unittest.cc) uses a test fixture. - * [Sample #4](../samples/sample4_unittest.cc) is another basic example of using Google Test. - * [Sample #5](../samples/sample5_unittest.cc) teaches how to reuse a test fixture in multiple test cases by deriving sub-fixtures from it. - * [Sample #6](../samples/sample6_unittest.cc) demonstrates type-parameterized tests. - * [Sample #7](../samples/sample7_unittest.cc) teaches the basics of value-parameterized tests. - * [Sample #8](../samples/sample8_unittest.cc) shows using `Combine()` in value-parameterized tests. - * [Sample #9](../samples/sample9_unittest.cc) shows use of the listener API to modify Google Test's console output and the use of its reflection API to inspect test results. - * [Sample #10](../samples/sample10_unittest.cc) shows use of the listener API to implement a primitive memory leak checker. diff --git a/googletest/docs/V1_6_XcodeGuide.md b/googletest/docs/V1_6_XcodeGuide.md deleted file mode 100644 index bf24bf51..00000000 --- a/googletest/docs/V1_6_XcodeGuide.md +++ /dev/null @@ -1,93 +0,0 @@ - - -This guide will explain how to use the Google Testing Framework in your Xcode projects on Mac OS X. This tutorial begins by quickly explaining what to do for experienced users. After the quick start, the guide goes provides additional explanation about each step. - -# Quick Start # - -Here is the quick guide for using Google Test in your Xcode project. - - 1. Download the source from the [website](http://code.google.com/p/googletest) using this command: `svn checkout http://googletest.googlecode.com/svn/trunk/ googletest-read-only` - 1. Open up the `gtest.xcodeproj` in the `googletest-read-only/xcode/` directory and build the gtest.framework. - 1. Create a new "Shell Tool" target in your Xcode project called something like "UnitTests" - 1. Add the gtest.framework to your project and add it to the "Link Binary with Libraries" build phase of "UnitTests" - 1. Add your unit test source code to the "Compile Sources" build phase of "UnitTests" - 1. Edit the "UnitTests" executable and add an environment variable named "DYLD\_FRAMEWORK\_PATH" with a value equal to the path to the framework containing the gtest.framework relative to the compiled executable. - 1. Build and Go - -The following sections further explain each of the steps listed above in depth, describing in more detail how to complete it including some variations. - -# Get the Source # - -Currently, the gtest.framework discussed here isn't available in a tagged release of Google Test, it is only available in the trunk. As explained at the Google Test [site](http://code.google.com/p/googletest/source/checkout">svn), you can get the code from anonymous SVN with this command: - -``` -svn checkout http://googletest.googlecode.com/svn/trunk/ googletest-read-only -``` - -Alternatively, if you are working with Subversion in your own code base, you can add Google Test as an external dependency to your own Subversion repository. By following this approach, everyone that checks out your svn repository will also receive a copy of Google Test (a specific version, if you wish) without having to check it out explicitly. This makes the set up of your project simpler and reduces the copied code in the repository. - -To use `svn:externals`, decide where you would like to have the external source reside. You might choose to put the external source inside the trunk, because you want it to be part of the branch when you make a release. However, keeping it outside the trunk in a version-tagged directory called something like `third-party/googletest/1.0.1`, is another option. Once the location is established, use `svn propedit svn:externals _directory_` to set the svn:externals property on a directory in your repository. This directory won't contain the code, but be its versioned parent directory. - -The command `svn propedit` will bring up your Subversion editor, making editing the long, (potentially multi-line) property simpler. This same method can be used to check out a tagged branch, by using the appropriate URL (e.g. `http://googletest.googlecode.com/svn/tags/release-1.0.1`). Additionally, the svn:externals property allows the specification of a particular revision of the trunk with the `-r_##_` option (e.g. `externals/src/googletest -r60 http://googletest.googlecode.com/svn/trunk`). - -Here is an example of using the svn:externals properties on a trunk (read via `svn propget`) of a project. This value checks out a copy of Google Test into the `trunk/externals/src/googletest/` directory. - -``` -[Computer:svn] user$ svn propget svn:externals trunk -externals/src/googletest http://googletest.googlecode.com/svn/trunk -``` - -# Add the Framework to Your Project # - -The next step is to build and add the gtest.framework to your own project. This guide describes two common ways below. - - * **Option 1** --- The simplest way to add Google Test to your own project, is to open gtest.xcodeproj (found in the xcode/ directory of the Google Test trunk) and build the framework manually. Then, add the built framework into your project using the "Add->Existing Framework..." from the context menu or "Project->Add..." from the main menu. The gtest.framework is relocatable and contains the headers and object code that you'll need to make tests. This method requires rebuilding every time you upgrade Google Test in your project. - * **Option 2** --- If you are going to be living off the trunk of Google Test, incorporating its latest features into your unit tests (or are a Google Test developer yourself). You'll want to rebuild the framework every time the source updates. to do this, you'll need to add the gtest.xcodeproj file, not the framework itself, to your own Xcode project. Then, from the build products that are revealed by the project's disclosure triangle, you can find the gtest.framework, which can be added to your targets (discussed below). - -# Make a Test Target # - -To start writing tests, make a new "Shell Tool" target. This target template is available under BSD, Cocoa, or Carbon. Add your unit test source code to the "Compile Sources" build phase of the target. - -Next, you'll want to add gtest.framework in two different ways, depending upon which option you chose above. - - * **Option 1** --- During compilation, Xcode will need to know that you are linking against the gtest.framework. Add the gtest.framework to the "Link Binary with Libraries" build phase of your test target. This will include the Google Test headers in your header search path, and will tell the linker where to find the library. - * **Option 2** --- If your working out of the trunk, you'll also want to add gtest.framework to your "Link Binary with Libraries" build phase of your test target. In addition, you'll want to add the gtest.framework as a dependency to your unit test target. This way, Xcode will make sure that gtest.framework is up to date, every time your build your target. Finally, if you don't share build directories with Google Test, you'll have to copy the gtest.framework into your own build products directory using a "Run Script" build phase. - -# Set Up the Executable Run Environment # - -Since the unit test executable is a shell tool, it doesn't have a bundle with a `Contents/Frameworks` directory, in which to place gtest.framework. Instead, the dynamic linker must be told at runtime to search for the framework in another location. This can be accomplished by setting the "DYLD\_FRAMEWORK\_PATH" environment variable in the "Edit Active Executable ..." Arguments tab, under "Variables to be set in the environment:". The path for this value is the path (relative or absolute) of the directory containing the gtest.framework. - -If you haven't set up the DYLD\_FRAMEWORK\_PATH, correctly, you might get a message like this: - -``` -[Session started at 2008-08-15 06:23:57 -0600.] - dyld: Library not loaded: @loader_path/../Frameworks/gtest.framework/Versions/A/gtest - Referenced from: /Users/username/Documents/Sandbox/gtestSample/build/Debug/WidgetFrameworkTest - Reason: image not found -``` - -To correct this problem, got to the directory containing the executable named in "Referenced from:" value in the error message above. Then, with the terminal in this location, find the relative path to the directory containing the gtest.framework. That is the value you'll need to set as the DYLD\_FRAMEWORK\_PATH. - -# Build and Go # - -Now, when you click "Build and Go", the test will be executed. Dumping out something like this: - -``` -[Session started at 2008-08-06 06:36:13 -0600.] -[==========] Running 2 tests from 1 test case. -[----------] Global test environment set-up. -[----------] 2 tests from WidgetInitializerTest -[ RUN ] WidgetInitializerTest.TestConstructor -[ OK ] WidgetInitializerTest.TestConstructor -[ RUN ] WidgetInitializerTest.TestConversion -[ OK ] WidgetInitializerTest.TestConversion -[----------] Global test environment tear-down -[==========] 2 tests from 1 test case ran. -[ PASSED ] 2 tests. - -The Debugger has exited with status 0. -``` - -# Summary # - -Unit testing is a valuable way to ensure your data model stays valid even during rapid development or refactoring. The Google Testing Framework is a great unit testing framework for C and C++ which integrates well with an Xcode development environment. \ No newline at end of file diff --git a/googletest/docs/V1_7_AdvancedGuide.md b/googletest/docs/V1_7_AdvancedGuide.md deleted file mode 100644 index dd4af8f3..00000000 --- a/googletest/docs/V1_7_AdvancedGuide.md +++ /dev/null @@ -1,2181 +0,0 @@ - - -Now that you have read [Primer](V1_7_Primer.md) and learned how to write tests -using Google Test, it's time to learn some new tricks. This document -will show you more assertions as well as how to construct complex -failure messages, propagate fatal failures, reuse and speed up your -test fixtures, and use various flags with your tests. - -# More Assertions # - -This section covers some less frequently used, but still significant, -assertions. - -## Explicit Success and Failure ## - -These three assertions do not actually test a value or expression. Instead, -they generate a success or failure directly. Like the macros that actually -perform a test, you may stream a custom failure message into the them. - -| `SUCCEED();` | -|:-------------| - -Generates a success. This does NOT make the overall test succeed. A test is -considered successful only if none of its assertions fail during its execution. - -Note: `SUCCEED()` is purely documentary and currently doesn't generate any -user-visible output. However, we may add `SUCCEED()` messages to Google Test's -output in the future. - -| `FAIL();` | `ADD_FAILURE();` | `ADD_FAILURE_AT("`_file\_path_`", `_line\_number_`);` | -|:-----------|:-----------------|:------------------------------------------------------| - -`FAIL()` generates a fatal failure, while `ADD_FAILURE()` and `ADD_FAILURE_AT()` generate a nonfatal -failure. These are useful when control flow, rather than a Boolean expression, -deteremines the test's success or failure. For example, you might want to write -something like: - -``` -switch(expression) { - case 1: ... some checks ... - case 2: ... some other checks - ... - default: FAIL() << "We shouldn't get here."; -} -``` - -_Availability_: Linux, Windows, Mac. - -## Exception Assertions ## - -These are for verifying that a piece of code throws (or does not -throw) an exception of the given type: - -| **Fatal assertion** | **Nonfatal assertion** | **Verifies** | -|:--------------------|:-----------------------|:-------------| -| `ASSERT_THROW(`_statement_, _exception\_type_`);` | `EXPECT_THROW(`_statement_, _exception\_type_`);` | _statement_ throws an exception of the given type | -| `ASSERT_ANY_THROW(`_statement_`);` | `EXPECT_ANY_THROW(`_statement_`);` | _statement_ throws an exception of any type | -| `ASSERT_NO_THROW(`_statement_`);` | `EXPECT_NO_THROW(`_statement_`);` | _statement_ doesn't throw any exception | - -Examples: - -``` -ASSERT_THROW(Foo(5), bar_exception); - -EXPECT_NO_THROW({ - int n = 5; - Bar(&n); -}); -``` - -_Availability_: Linux, Windows, Mac; since version 1.1.0. - -## Predicate Assertions for Better Error Messages ## - -Even though Google Test has a rich set of assertions, they can never be -complete, as it's impossible (nor a good idea) to anticipate all the scenarios -a user might run into. Therefore, sometimes a user has to use `EXPECT_TRUE()` -to check a complex expression, for lack of a better macro. This has the problem -of not showing you the values of the parts of the expression, making it hard to -understand what went wrong. As a workaround, some users choose to construct the -failure message by themselves, streaming it into `EXPECT_TRUE()`. However, this -is awkward especially when the expression has side-effects or is expensive to -evaluate. - -Google Test gives you three different options to solve this problem: - -### Using an Existing Boolean Function ### - -If you already have a function or a functor that returns `bool` (or a type -that can be implicitly converted to `bool`), you can use it in a _predicate -assertion_ to get the function arguments printed for free: - -| **Fatal assertion** | **Nonfatal assertion** | **Verifies** | -|:--------------------|:-----------------------|:-------------| -| `ASSERT_PRED1(`_pred1, val1_`);` | `EXPECT_PRED1(`_pred1, val1_`);` | _pred1(val1)_ returns true | -| `ASSERT_PRED2(`_pred2, val1, val2_`);` | `EXPECT_PRED2(`_pred2, val1, val2_`);` | _pred2(val1, val2)_ returns true | -| ... | ... | ... | - -In the above, _predn_ is an _n_-ary predicate function or functor, where -_val1_, _val2_, ..., and _valn_ are its arguments. The assertion succeeds -if the predicate returns `true` when applied to the given arguments, and fails -otherwise. When the assertion fails, it prints the value of each argument. In -either case, the arguments are evaluated exactly once. - -Here's an example. Given - -``` -// Returns true iff m and n have no common divisors except 1. -bool MutuallyPrime(int m, int n) { ... } -const int a = 3; -const int b = 4; -const int c = 10; -``` - -the assertion `EXPECT_PRED2(MutuallyPrime, a, b);` will succeed, while the -assertion `EXPECT_PRED2(MutuallyPrime, b, c);` will fail with the message - -
-!MutuallyPrime(b, c) is false, where

-b is 4

-c is 10

-
- -**Notes:** - - 1. If you see a compiler error "no matching function to call" when using `ASSERT_PRED*` or `EXPECT_PRED*`, please see [this](V1_7_FAQ.md#the-compiler-complains-about-undefined-references-to-some-static-const-member-variables-but-i-did-define-them-in-the-class-body-whats-wrong) for how to resolve it. - 1. Currently we only provide predicate assertions of arity <= 5. If you need a higher-arity assertion, let us know. - -_Availability_: Linux, Windows, Mac - -### Using a Function That Returns an AssertionResult ### - -While `EXPECT_PRED*()` and friends are handy for a quick job, the -syntax is not satisfactory: you have to use different macros for -different arities, and it feels more like Lisp than C++. The -`::testing::AssertionResult` class solves this problem. - -An `AssertionResult` object represents the result of an assertion -(whether it's a success or a failure, and an associated message). You -can create an `AssertionResult` using one of these factory -functions: - -``` -namespace testing { - -// Returns an AssertionResult object to indicate that an assertion has -// succeeded. -AssertionResult AssertionSuccess(); - -// Returns an AssertionResult object to indicate that an assertion has -// failed. -AssertionResult AssertionFailure(); - -} -``` - -You can then use the `<<` operator to stream messages to the -`AssertionResult` object. - -To provide more readable messages in Boolean assertions -(e.g. `EXPECT_TRUE()`), write a predicate function that returns -`AssertionResult` instead of `bool`. For example, if you define -`IsEven()` as: - -``` -::testing::AssertionResult IsEven(int n) { - if ((n % 2) == 0) - return ::testing::AssertionSuccess(); - else - return ::testing::AssertionFailure() << n << " is odd"; -} -``` - -instead of: - -``` -bool IsEven(int n) { - return (n % 2) == 0; -} -``` - -the failed assertion `EXPECT_TRUE(IsEven(Fib(4)))` will print: - -
-Value of: IsEven(Fib(4))

-Actual: false (*3 is odd*)

-Expected: true

-
- -instead of a more opaque - -
-Value of: IsEven(Fib(4))

-Actual: false

-Expected: true

-
- -If you want informative messages in `EXPECT_FALSE` and `ASSERT_FALSE` -as well, and are fine with making the predicate slower in the success -case, you can supply a success message: - -``` -::testing::AssertionResult IsEven(int n) { - if ((n % 2) == 0) - return ::testing::AssertionSuccess() << n << " is even"; - else - return ::testing::AssertionFailure() << n << " is odd"; -} -``` - -Then the statement `EXPECT_FALSE(IsEven(Fib(6)))` will print - -
-Value of: IsEven(Fib(6))

-Actual: true (8 is even)

-Expected: false

-
- -_Availability_: Linux, Windows, Mac; since version 1.4.1. - -### Using a Predicate-Formatter ### - -If you find the default message generated by `(ASSERT|EXPECT)_PRED*` and -`(ASSERT|EXPECT)_(TRUE|FALSE)` unsatisfactory, or some arguments to your -predicate do not support streaming to `ostream`, you can instead use the -following _predicate-formatter assertions_ to _fully_ customize how the -message is formatted: - -| **Fatal assertion** | **Nonfatal assertion** | **Verifies** | -|:--------------------|:-----------------------|:-------------| -| `ASSERT_PRED_FORMAT1(`_pred\_format1, val1_`);` | `EXPECT_PRED_FORMAT1(`_pred\_format1, val1_`); | _pred\_format1(val1)_ is successful | -| `ASSERT_PRED_FORMAT2(`_pred\_format2, val1, val2_`);` | `EXPECT_PRED_FORMAT2(`_pred\_format2, val1, val2_`);` | _pred\_format2(val1, val2)_ is successful | -| `...` | `...` | `...` | - -The difference between this and the previous two groups of macros is that instead of -a predicate, `(ASSERT|EXPECT)_PRED_FORMAT*` take a _predicate-formatter_ -(_pred\_formatn_), which is a function or functor with the signature: - -`::testing::AssertionResult PredicateFormattern(const char* `_expr1_`, const char* `_expr2_`, ... const char* `_exprn_`, T1 `_val1_`, T2 `_val2_`, ... Tn `_valn_`);` - -where _val1_, _val2_, ..., and _valn_ are the values of the predicate -arguments, and _expr1_, _expr2_, ..., and _exprn_ are the corresponding -expressions as they appear in the source code. The types `T1`, `T2`, ..., and -`Tn` can be either value types or reference types. For example, if an -argument has type `Foo`, you can declare it as either `Foo` or `const Foo&`, -whichever is appropriate. - -A predicate-formatter returns a `::testing::AssertionResult` object to indicate -whether the assertion has succeeded or not. The only way to create such an -object is to call one of these factory functions: - -As an example, let's improve the failure message in the previous example, which uses `EXPECT_PRED2()`: - -``` -// Returns the smallest prime common divisor of m and n, -// or 1 when m and n are mutually prime. -int SmallestPrimeCommonDivisor(int m, int n) { ... } - -// A predicate-formatter for asserting that two integers are mutually prime. -::testing::AssertionResult AssertMutuallyPrime(const char* m_expr, - const char* n_expr, - int m, - int n) { - if (MutuallyPrime(m, n)) - return ::testing::AssertionSuccess(); - - return ::testing::AssertionFailure() - << m_expr << " and " << n_expr << " (" << m << " and " << n - << ") are not mutually prime, " << "as they have a common divisor " - << SmallestPrimeCommonDivisor(m, n); -} -``` - -With this predicate-formatter, we can use - -``` -EXPECT_PRED_FORMAT2(AssertMutuallyPrime, b, c); -``` - -to generate the message - -
-b and c (4 and 10) are not mutually prime, as they have a common divisor 2.

-
- -As you may have realized, many of the assertions we introduced earlier are -special cases of `(EXPECT|ASSERT)_PRED_FORMAT*`. In fact, most of them are -indeed defined using `(EXPECT|ASSERT)_PRED_FORMAT*`. - -_Availability_: Linux, Windows, Mac. - - -## Floating-Point Comparison ## - -Comparing floating-point numbers is tricky. Due to round-off errors, it is -very unlikely that two floating-points will match exactly. Therefore, -`ASSERT_EQ` 's naive comparison usually doesn't work. And since floating-points -can have a wide value range, no single fixed error bound works. It's better to -compare by a fixed relative error bound, except for values close to 0 due to -the loss of precision there. - -In general, for floating-point comparison to make sense, the user needs to -carefully choose the error bound. If they don't want or care to, comparing in -terms of Units in the Last Place (ULPs) is a good default, and Google Test -provides assertions to do this. Full details about ULPs are quite long; if you -want to learn more, see -[this article on float comparison](http://www.cygnus-software.com/papers/comparingfloats/comparingfloats.htm). - -### Floating-Point Macros ### - -| **Fatal assertion** | **Nonfatal assertion** | **Verifies** | -|:--------------------|:-----------------------|:-------------| -| `ASSERT_FLOAT_EQ(`_expected, actual_`);` | `EXPECT_FLOAT_EQ(`_expected, actual_`);` | the two `float` values are almost equal | -| `ASSERT_DOUBLE_EQ(`_expected, actual_`);` | `EXPECT_DOUBLE_EQ(`_expected, actual_`);` | the two `double` values are almost equal | - -By "almost equal", we mean the two values are within 4 ULP's from each -other. - -The following assertions allow you to choose the acceptable error bound: - -| **Fatal assertion** | **Nonfatal assertion** | **Verifies** | -|:--------------------|:-----------------------|:-------------| -| `ASSERT_NEAR(`_val1, val2, abs\_error_`);` | `EXPECT_NEAR`_(val1, val2, abs\_error_`);` | the difference between _val1_ and _val2_ doesn't exceed the given absolute error | - -_Availability_: Linux, Windows, Mac. - -### Floating-Point Predicate-Format Functions ### - -Some floating-point operations are useful, but not that often used. In order -to avoid an explosion of new macros, we provide them as predicate-format -functions that can be used in predicate assertion macros (e.g. -`EXPECT_PRED_FORMAT2`, etc). - -``` -EXPECT_PRED_FORMAT2(::testing::FloatLE, val1, val2); -EXPECT_PRED_FORMAT2(::testing::DoubleLE, val1, val2); -``` - -Verifies that _val1_ is less than, or almost equal to, _val2_. You can -replace `EXPECT_PRED_FORMAT2` in the above table with `ASSERT_PRED_FORMAT2`. - -_Availability_: Linux, Windows, Mac. - -## Windows HRESULT assertions ## - -These assertions test for `HRESULT` success or failure. - -| **Fatal assertion** | **Nonfatal assertion** | **Verifies** | -|:--------------------|:-----------------------|:-------------| -| `ASSERT_HRESULT_SUCCEEDED(`_expression_`);` | `EXPECT_HRESULT_SUCCEEDED(`_expression_`);` | _expression_ is a success `HRESULT` | -| `ASSERT_HRESULT_FAILED(`_expression_`);` | `EXPECT_HRESULT_FAILED(`_expression_`);` | _expression_ is a failure `HRESULT` | - -The generated output contains the human-readable error message -associated with the `HRESULT` code returned by _expression_. - -You might use them like this: - -``` -CComPtr shell; -ASSERT_HRESULT_SUCCEEDED(shell.CoCreateInstance(L"Shell.Application")); -CComVariant empty; -ASSERT_HRESULT_SUCCEEDED(shell->ShellExecute(CComBSTR(url), empty, empty, empty, empty)); -``` - -_Availability_: Windows. - -## Type Assertions ## - -You can call the function -``` -::testing::StaticAssertTypeEq(); -``` -to assert that types `T1` and `T2` are the same. The function does -nothing if the assertion is satisfied. If the types are different, -the function call will fail to compile, and the compiler error message -will likely (depending on the compiler) show you the actual values of -`T1` and `T2`. This is mainly useful inside template code. - -_Caveat:_ When used inside a member function of a class template or a -function template, `StaticAssertTypeEq()` is effective _only if_ -the function is instantiated. For example, given: -``` -template class Foo { - public: - void Bar() { ::testing::StaticAssertTypeEq(); } -}; -``` -the code: -``` -void Test1() { Foo foo; } -``` -will _not_ generate a compiler error, as `Foo::Bar()` is never -actually instantiated. Instead, you need: -``` -void Test2() { Foo foo; foo.Bar(); } -``` -to cause a compiler error. - -_Availability:_ Linux, Windows, Mac; since version 1.3.0. - -## Assertion Placement ## - -You can use assertions in any C++ function. In particular, it doesn't -have to be a method of the test fixture class. The one constraint is -that assertions that generate a fatal failure (`FAIL*` and `ASSERT_*`) -can only be used in void-returning functions. This is a consequence of -Google Test not using exceptions. By placing it in a non-void function -you'll get a confusing compile error like -`"error: void value not ignored as it ought to be"`. - -If you need to use assertions in a function that returns non-void, one option -is to make the function return the value in an out parameter instead. For -example, you can rewrite `T2 Foo(T1 x)` to `void Foo(T1 x, T2* result)`. You -need to make sure that `*result` contains some sensible value even when the -function returns prematurely. As the function now returns `void`, you can use -any assertion inside of it. - -If changing the function's type is not an option, you should just use -assertions that generate non-fatal failures, such as `ADD_FAILURE*` and -`EXPECT_*`. - -_Note_: Constructors and destructors are not considered void-returning -functions, according to the C++ language specification, and so you may not use -fatal assertions in them. You'll get a compilation error if you try. A simple -workaround is to transfer the entire body of the constructor or destructor to a -private void-returning method. However, you should be aware that a fatal -assertion failure in a constructor does not terminate the current test, as your -intuition might suggest; it merely returns from the constructor early, possibly -leaving your object in a partially-constructed state. Likewise, a fatal -assertion failure in a destructor may leave your object in a -partially-destructed state. Use assertions carefully in these situations! - -# Teaching Google Test How to Print Your Values # - -When a test assertion such as `EXPECT_EQ` fails, Google Test prints the -argument values to help you debug. It does this using a -user-extensible value printer. - -This printer knows how to print built-in C++ types, native arrays, STL -containers, and any type that supports the `<<` operator. For other -types, it prints the raw bytes in the value and hopes that you the -user can figure it out. - -As mentioned earlier, the printer is _extensible_. That means -you can teach it to do a better job at printing your particular type -than to dump the bytes. To do that, define `<<` for your type: - -``` -#include - -namespace foo { - -class Bar { ... }; // We want Google Test to be able to print instances of this. - -// It's important that the << operator is defined in the SAME -// namespace that defines Bar. C++'s look-up rules rely on that. -::std::ostream& operator<<(::std::ostream& os, const Bar& bar) { - return os << bar.DebugString(); // whatever needed to print bar to os -} - -} // namespace foo -``` - -Sometimes, this might not be an option: your team may consider it bad -style to have a `<<` operator for `Bar`, or `Bar` may already have a -`<<` operator that doesn't do what you want (and you cannot change -it). If so, you can instead define a `PrintTo()` function like this: - -``` -#include - -namespace foo { - -class Bar { ... }; - -// It's important that PrintTo() is defined in the SAME -// namespace that defines Bar. C++'s look-up rules rely on that. -void PrintTo(const Bar& bar, ::std::ostream* os) { - *os << bar.DebugString(); // whatever needed to print bar to os -} - -} // namespace foo -``` - -If you have defined both `<<` and `PrintTo()`, the latter will be used -when Google Test is concerned. This allows you to customize how the value -appears in Google Test's output without affecting code that relies on the -behavior of its `<<` operator. - -If you want to print a value `x` using Google Test's value printer -yourself, just call `::testing::PrintToString(`_x_`)`, which -returns an `std::string`: - -``` -vector > bar_ints = GetBarIntVector(); - -EXPECT_TRUE(IsCorrectBarIntVector(bar_ints)) - << "bar_ints = " << ::testing::PrintToString(bar_ints); -``` - -# Death Tests # - -In many applications, there are assertions that can cause application failure -if a condition is not met. These sanity checks, which ensure that the program -is in a known good state, are there to fail at the earliest possible time after -some program state is corrupted. If the assertion checks the wrong condition, -then the program may proceed in an erroneous state, which could lead to memory -corruption, security holes, or worse. Hence it is vitally important to test -that such assertion statements work as expected. - -Since these precondition checks cause the processes to die, we call such tests -_death tests_. More generally, any test that checks that a program terminates -(except by throwing an exception) in an expected fashion is also a death test. - -Note that if a piece of code throws an exception, we don't consider it "death" -for the purpose of death tests, as the caller of the code could catch the exception -and avoid the crash. If you want to verify exceptions thrown by your code, -see [Exception Assertions](#exception-assertions). - -If you want to test `EXPECT_*()/ASSERT_*()` failures in your test code, see [Catching Failures](#catching-failures). - -## How to Write a Death Test ## - -Google Test has the following macros to support death tests: - -| **Fatal assertion** | **Nonfatal assertion** | **Verifies** | -|:--------------------|:-----------------------|:-------------| -| `ASSERT_DEATH(`_statement, regex_`); | `EXPECT_DEATH(`_statement, regex_`); | _statement_ crashes with the given error | -| `ASSERT_DEATH_IF_SUPPORTED(`_statement, regex_`); | `EXPECT_DEATH_IF_SUPPORTED(`_statement, regex_`); | if death tests are supported, verifies that _statement_ crashes with the given error; otherwise verifies nothing | -| `ASSERT_EXIT(`_statement, predicate, regex_`); | `EXPECT_EXIT(`_statement, predicate, regex_`); |_statement_ exits with the given error and its exit code matches _predicate_ | - -where _statement_ is a statement that is expected to cause the process to -die, _predicate_ is a function or function object that evaluates an integer -exit status, and _regex_ is a regular expression that the stderr output of -_statement_ is expected to match. Note that _statement_ can be _any valid -statement_ (including _compound statement_) and doesn't have to be an -expression. - -As usual, the `ASSERT` variants abort the current test function, while the -`EXPECT` variants do not. - -**Note:** We use the word "crash" here to mean that the process -terminates with a _non-zero_ exit status code. There are two -possibilities: either the process has called `exit()` or `_exit()` -with a non-zero value, or it may be killed by a signal. - -This means that if _statement_ terminates the process with a 0 exit -code, it is _not_ considered a crash by `EXPECT_DEATH`. Use -`EXPECT_EXIT` instead if this is the case, or if you want to restrict -the exit code more precisely. - -A predicate here must accept an `int` and return a `bool`. The death test -succeeds only if the predicate returns `true`. Google Test defines a few -predicates that handle the most common cases: - -``` -::testing::ExitedWithCode(exit_code) -``` - -This expression is `true` if the program exited normally with the given exit -code. - -``` -::testing::KilledBySignal(signal_number) // Not available on Windows. -``` - -This expression is `true` if the program was killed by the given signal. - -The `*_DEATH` macros are convenient wrappers for `*_EXIT` that use a predicate -that verifies the process' exit code is non-zero. - -Note that a death test only cares about three things: - - 1. does _statement_ abort or exit the process? - 1. (in the case of `ASSERT_EXIT` and `EXPECT_EXIT`) does the exit status satisfy _predicate_? Or (in the case of `ASSERT_DEATH` and `EXPECT_DEATH`) is the exit status non-zero? And - 1. does the stderr output match _regex_? - -In particular, if _statement_ generates an `ASSERT_*` or `EXPECT_*` failure, it will **not** cause the death test to fail, as Google Test assertions don't abort the process. - -To write a death test, simply use one of the above macros inside your test -function. For example, - -``` -TEST(MyDeathTest, Foo) { - // This death test uses a compound statement. - ASSERT_DEATH({ int n = 5; Foo(&n); }, "Error on line .* of Foo()"); -} -TEST(MyDeathTest, NormalExit) { - EXPECT_EXIT(NormalExit(), ::testing::ExitedWithCode(0), "Success"); -} -TEST(MyDeathTest, KillMyself) { - EXPECT_EXIT(KillMyself(), ::testing::KilledBySignal(SIGKILL), "Sending myself unblockable signal"); -} -``` - -verifies that: - - * calling `Foo(5)` causes the process to die with the given error message, - * calling `NormalExit()` causes the process to print `"Success"` to stderr and exit with exit code 0, and - * calling `KillMyself()` kills the process with signal `SIGKILL`. - -The test function body may contain other assertions and statements as well, if -necessary. - -_Important:_ We strongly recommend you to follow the convention of naming your -test case (not test) `*DeathTest` when it contains a death test, as -demonstrated in the above example. The `Death Tests And Threads` section below -explains why. - -If a test fixture class is shared by normal tests and death tests, you -can use typedef to introduce an alias for the fixture class and avoid -duplicating its code: -``` -class FooTest : public ::testing::Test { ... }; - -typedef FooTest FooDeathTest; - -TEST_F(FooTest, DoesThis) { - // normal test -} - -TEST_F(FooDeathTest, DoesThat) { - // death test -} -``` - -_Availability:_ Linux, Windows (requires MSVC 8.0 or above), Cygwin, and Mac (the latter three are supported since v1.3.0). `(ASSERT|EXPECT)_DEATH_IF_SUPPORTED` are new in v1.4.0. - -## Regular Expression Syntax ## - -On POSIX systems (e.g. Linux, Cygwin, and Mac), Google Test uses the -[POSIX extended regular expression](http://www.opengroup.org/onlinepubs/009695399/basedefs/xbd_chap09.html#tag_09_04) -syntax in death tests. To learn about this syntax, you may want to read this [Wikipedia entry](http://en.wikipedia.org/wiki/Regular_expression#POSIX_Extended_Regular_Expressions). - -On Windows, Google Test uses its own simple regular expression -implementation. It lacks many features you can find in POSIX extended -regular expressions. For example, we don't support union (`"x|y"`), -grouping (`"(xy)"`), brackets (`"[xy]"`), and repetition count -(`"x{5,7}"`), among others. Below is what we do support (Letter `A` denotes a -literal character, period (`.`), or a single `\\` escape sequence; `x` -and `y` denote regular expressions.): - -| `c` | matches any literal character `c` | -|:----|:----------------------------------| -| `\\d` | matches any decimal digit | -| `\\D` | matches any character that's not a decimal digit | -| `\\f` | matches `\f` | -| `\\n` | matches `\n` | -| `\\r` | matches `\r` | -| `\\s` | matches any ASCII whitespace, including `\n` | -| `\\S` | matches any character that's not a whitespace | -| `\\t` | matches `\t` | -| `\\v` | matches `\v` | -| `\\w` | matches any letter, `_`, or decimal digit | -| `\\W` | matches any character that `\\w` doesn't match | -| `\\c` | matches any literal character `c`, which must be a punctuation | -| `\\.` | matches the `.` character | -| `.` | matches any single character except `\n` | -| `A?` | matches 0 or 1 occurrences of `A` | -| `A*` | matches 0 or many occurrences of `A` | -| `A+` | matches 1 or many occurrences of `A` | -| `^` | matches the beginning of a string (not that of each line) | -| `$` | matches the end of a string (not that of each line) | -| `xy` | matches `x` followed by `y` | - -To help you determine which capability is available on your system, -Google Test defines macro `GTEST_USES_POSIX_RE=1` when it uses POSIX -extended regular expressions, or `GTEST_USES_SIMPLE_RE=1` when it uses -the simple version. If you want your death tests to work in both -cases, you can either `#if` on these macros or use the more limited -syntax only. - -## How It Works ## - -Under the hood, `ASSERT_EXIT()` spawns a new process and executes the -death test statement in that process. The details of of how precisely -that happens depend on the platform and the variable -`::testing::GTEST_FLAG(death_test_style)` (which is initialized from the -command-line flag `--gtest_death_test_style`). - - * On POSIX systems, `fork()` (or `clone()` on Linux) is used to spawn the child, after which: - * If the variable's value is `"fast"`, the death test statement is immediately executed. - * If the variable's value is `"threadsafe"`, the child process re-executes the unit test binary just as it was originally invoked, but with some extra flags to cause just the single death test under consideration to be run. - * On Windows, the child is spawned using the `CreateProcess()` API, and re-executes the binary to cause just the single death test under consideration to be run - much like the `threadsafe` mode on POSIX. - -Other values for the variable are illegal and will cause the death test to -fail. Currently, the flag's default value is `"fast"`. However, we reserve the -right to change it in the future. Therefore, your tests should not depend on -this. - -In either case, the parent process waits for the child process to complete, and checks that - - 1. the child's exit status satisfies the predicate, and - 1. the child's stderr matches the regular expression. - -If the death test statement runs to completion without dying, the child -process will nonetheless terminate, and the assertion fails. - -## Death Tests And Threads ## - -The reason for the two death test styles has to do with thread safety. Due to -well-known problems with forking in the presence of threads, death tests should -be run in a single-threaded context. Sometimes, however, it isn't feasible to -arrange that kind of environment. For example, statically-initialized modules -may start threads before main is ever reached. Once threads have been created, -it may be difficult or impossible to clean them up. - -Google Test has three features intended to raise awareness of threading issues. - - 1. A warning is emitted if multiple threads are running when a death test is encountered. - 1. Test cases with a name ending in "DeathTest" are run before all other tests. - 1. It uses `clone()` instead of `fork()` to spawn the child process on Linux (`clone()` is not available on Cygwin and Mac), as `fork()` is more likely to cause the child to hang when the parent process has multiple threads. - -It's perfectly fine to create threads inside a death test statement; they are -executed in a separate process and cannot affect the parent. - -## Death Test Styles ## - -The "threadsafe" death test style was introduced in order to help mitigate the -risks of testing in a possibly multithreaded environment. It trades increased -test execution time (potentially dramatically so) for improved thread safety. -We suggest using the faster, default "fast" style unless your test has specific -problems with it. - -You can choose a particular style of death tests by setting the flag -programmatically: - -``` -::testing::FLAGS_gtest_death_test_style = "threadsafe"; -``` - -You can do this in `main()` to set the style for all death tests in the -binary, or in individual tests. Recall that flags are saved before running each -test and restored afterwards, so you need not do that yourself. For example: - -``` -TEST(MyDeathTest, TestOne) { - ::testing::FLAGS_gtest_death_test_style = "threadsafe"; - // This test is run in the "threadsafe" style: - ASSERT_DEATH(ThisShouldDie(), ""); -} - -TEST(MyDeathTest, TestTwo) { - // This test is run in the "fast" style: - ASSERT_DEATH(ThisShouldDie(), ""); -} - -int main(int argc, char** argv) { - ::testing::InitGoogleTest(&argc, argv); - ::testing::FLAGS_gtest_death_test_style = "fast"; - return RUN_ALL_TESTS(); -} -``` - -## Caveats ## - -The _statement_ argument of `ASSERT_EXIT()` can be any valid C++ statement. -If it leaves the current function via a `return` statement or by throwing an exception, -the death test is considered to have failed. Some Google Test macros may return -from the current function (e.g. `ASSERT_TRUE()`), so be sure to avoid them in _statement_. - -Since _statement_ runs in the child process, any in-memory side effect (e.g. -modifying a variable, releasing memory, etc) it causes will _not_ be observable -in the parent process. In particular, if you release memory in a death test, -your program will fail the heap check as the parent process will never see the -memory reclaimed. To solve this problem, you can - - 1. try not to free memory in a death test; - 1. free the memory again in the parent process; or - 1. do not use the heap checker in your program. - -Due to an implementation detail, you cannot place multiple death test -assertions on the same line; otherwise, compilation will fail with an unobvious -error message. - -Despite the improved thread safety afforded by the "threadsafe" style of death -test, thread problems such as deadlock are still possible in the presence of -handlers registered with `pthread_atfork(3)`. - -# Using Assertions in Sub-routines # - -## Adding Traces to Assertions ## - -If a test sub-routine is called from several places, when an assertion -inside it fails, it can be hard to tell which invocation of the -sub-routine the failure is from. You can alleviate this problem using -extra logging or custom failure messages, but that usually clutters up -your tests. A better solution is to use the `SCOPED_TRACE` macro: - -| `SCOPED_TRACE(`_message_`);` | -|:-----------------------------| - -where _message_ can be anything streamable to `std::ostream`. This -macro will cause the current file name, line number, and the given -message to be added in every failure message. The effect will be -undone when the control leaves the current lexical scope. - -For example, - -``` -10: void Sub1(int n) { -11: EXPECT_EQ(1, Bar(n)); -12: EXPECT_EQ(2, Bar(n + 1)); -13: } -14: -15: TEST(FooTest, Bar) { -16: { -17: SCOPED_TRACE("A"); // This trace point will be included in -18: // every failure in this scope. -19: Sub1(1); -20: } -21: // Now it won't. -22: Sub1(9); -23: } -``` - -could result in messages like these: - -``` -path/to/foo_test.cc:11: Failure -Value of: Bar(n) -Expected: 1 - Actual: 2 - Trace: -path/to/foo_test.cc:17: A - -path/to/foo_test.cc:12: Failure -Value of: Bar(n + 1) -Expected: 2 - Actual: 3 -``` - -Without the trace, it would've been difficult to know which invocation -of `Sub1()` the two failures come from respectively. (You could add an -extra message to each assertion in `Sub1()` to indicate the value of -`n`, but that's tedious.) - -Some tips on using `SCOPED_TRACE`: - - 1. With a suitable message, it's often enough to use `SCOPED_TRACE` at the beginning of a sub-routine, instead of at each call site. - 1. When calling sub-routines inside a loop, make the loop iterator part of the message in `SCOPED_TRACE` such that you can know which iteration the failure is from. - 1. Sometimes the line number of the trace point is enough for identifying the particular invocation of a sub-routine. In this case, you don't have to choose a unique message for `SCOPED_TRACE`. You can simply use `""`. - 1. You can use `SCOPED_TRACE` in an inner scope when there is one in the outer scope. In this case, all active trace points will be included in the failure messages, in reverse order they are encountered. - 1. The trace dump is clickable in Emacs' compilation buffer - hit return on a line number and you'll be taken to that line in the source file! - -_Availability:_ Linux, Windows, Mac. - -## Propagating Fatal Failures ## - -A common pitfall when using `ASSERT_*` and `FAIL*` is not understanding that -when they fail they only abort the _current function_, not the entire test. For -example, the following test will segfault: -``` -void Subroutine() { - // Generates a fatal failure and aborts the current function. - ASSERT_EQ(1, 2); - // The following won't be executed. - ... -} - -TEST(FooTest, Bar) { - Subroutine(); - // The intended behavior is for the fatal failure - // in Subroutine() to abort the entire test. - // The actual behavior: the function goes on after Subroutine() returns. - int* p = NULL; - *p = 3; // Segfault! -} -``` - -Since we don't use exceptions, it is technically impossible to -implement the intended behavior here. To alleviate this, Google Test -provides two solutions. You could use either the -`(ASSERT|EXPECT)_NO_FATAL_FAILURE` assertions or the -`HasFatalFailure()` function. They are described in the following two -subsections. - -### Asserting on Subroutines ### - -As shown above, if your test calls a subroutine that has an `ASSERT_*` -failure in it, the test will continue after the subroutine -returns. This may not be what you want. - -Often people want fatal failures to propagate like exceptions. For -that Google Test offers the following macros: - -| **Fatal assertion** | **Nonfatal assertion** | **Verifies** | -|:--------------------|:-----------------------|:-------------| -| `ASSERT_NO_FATAL_FAILURE(`_statement_`);` | `EXPECT_NO_FATAL_FAILURE(`_statement_`);` | _statement_ doesn't generate any new fatal failures in the current thread. | - -Only failures in the thread that executes the assertion are checked to -determine the result of this type of assertions. If _statement_ -creates new threads, failures in these threads are ignored. - -Examples: - -``` -ASSERT_NO_FATAL_FAILURE(Foo()); - -int i; -EXPECT_NO_FATAL_FAILURE({ - i = Bar(); -}); -``` - -_Availability:_ Linux, Windows, Mac. Assertions from multiple threads -are currently not supported. - -### Checking for Failures in the Current Test ### - -`HasFatalFailure()` in the `::testing::Test` class returns `true` if an -assertion in the current test has suffered a fatal failure. This -allows functions to catch fatal failures in a sub-routine and return -early. - -``` -class Test { - public: - ... - static bool HasFatalFailure(); -}; -``` - -The typical usage, which basically simulates the behavior of a thrown -exception, is: - -``` -TEST(FooTest, Bar) { - Subroutine(); - // Aborts if Subroutine() had a fatal failure. - if (HasFatalFailure()) - return; - // The following won't be executed. - ... -} -``` - -If `HasFatalFailure()` is used outside of `TEST()` , `TEST_F()` , or a test -fixture, you must add the `::testing::Test::` prefix, as in: - -``` -if (::testing::Test::HasFatalFailure()) - return; -``` - -Similarly, `HasNonfatalFailure()` returns `true` if the current test -has at least one non-fatal failure, and `HasFailure()` returns `true` -if the current test has at least one failure of either kind. - -_Availability:_ Linux, Windows, Mac. `HasNonfatalFailure()` and -`HasFailure()` are available since version 1.4.0. - -# Logging Additional Information # - -In your test code, you can call `RecordProperty("key", value)` to log -additional information, where `value` can be either a string or an `int`. The _last_ value recorded for a key will be emitted to the XML output -if you specify one. For example, the test - -``` -TEST_F(WidgetUsageTest, MinAndMaxWidgets) { - RecordProperty("MaximumWidgets", ComputeMaxUsage()); - RecordProperty("MinimumWidgets", ComputeMinUsage()); -} -``` - -will output XML like this: - -``` -... - -... -``` - -_Note_: - * `RecordProperty()` is a static member of the `Test` class. Therefore it needs to be prefixed with `::testing::Test::` if used outside of the `TEST` body and the test fixture class. - * `key` must be a valid XML attribute name, and cannot conflict with the ones already used by Google Test (`name`, `status`, `time`, `classname`, `type_param`, and `value_param`). - * Calling `RecordProperty()` outside of the lifespan of a test is allowed. If it's called outside of a test but between a test case's `SetUpTestCase()` and `TearDownTestCase()` methods, it will be attributed to the XML element for the test case. If it's called outside of all test cases (e.g. in a test environment), it will be attributed to the top-level XML element. - -_Availability_: Linux, Windows, Mac. - -# Sharing Resources Between Tests in the Same Test Case # - - - -Google Test creates a new test fixture object for each test in order to make -tests independent and easier to debug. However, sometimes tests use resources -that are expensive to set up, making the one-copy-per-test model prohibitively -expensive. - -If the tests don't change the resource, there's no harm in them sharing a -single resource copy. So, in addition to per-test set-up/tear-down, Google Test -also supports per-test-case set-up/tear-down. To use it: - - 1. In your test fixture class (say `FooTest` ), define as `static` some member variables to hold the shared resources. - 1. In the same test fixture class, define a `static void SetUpTestCase()` function (remember not to spell it as **`SetupTestCase`** with a small `u`!) to set up the shared resources and a `static void TearDownTestCase()` function to tear them down. - -That's it! Google Test automatically calls `SetUpTestCase()` before running the -_first test_ in the `FooTest` test case (i.e. before creating the first -`FooTest` object), and calls `TearDownTestCase()` after running the _last test_ -in it (i.e. after deleting the last `FooTest` object). In between, the tests -can use the shared resources. - -Remember that the test order is undefined, so your code can't depend on a test -preceding or following another. Also, the tests must either not modify the -state of any shared resource, or, if they do modify the state, they must -restore the state to its original value before passing control to the next -test. - -Here's an example of per-test-case set-up and tear-down: -``` -class FooTest : public ::testing::Test { - protected: - // Per-test-case set-up. - // Called before the first test in this test case. - // Can be omitted if not needed. - static void SetUpTestCase() { - shared_resource_ = new ...; - } - - // Per-test-case tear-down. - // Called after the last test in this test case. - // Can be omitted if not needed. - static void TearDownTestCase() { - delete shared_resource_; - shared_resource_ = NULL; - } - - // You can define per-test set-up and tear-down logic as usual. - virtual void SetUp() { ... } - virtual void TearDown() { ... } - - // Some expensive resource shared by all tests. - static T* shared_resource_; -}; - -T* FooTest::shared_resource_ = NULL; - -TEST_F(FooTest, Test1) { - ... you can refer to shared_resource here ... -} -TEST_F(FooTest, Test2) { - ... you can refer to shared_resource here ... -} -``` - -_Availability:_ Linux, Windows, Mac. - -# Global Set-Up and Tear-Down # - -Just as you can do set-up and tear-down at the test level and the test case -level, you can also do it at the test program level. Here's how. - -First, you subclass the `::testing::Environment` class to define a test -environment, which knows how to set-up and tear-down: - -``` -class Environment { - public: - virtual ~Environment() {} - // Override this to define how to set up the environment. - virtual void SetUp() {} - // Override this to define how to tear down the environment. - virtual void TearDown() {} -}; -``` - -Then, you register an instance of your environment class with Google Test by -calling the `::testing::AddGlobalTestEnvironment()` function: - -``` -Environment* AddGlobalTestEnvironment(Environment* env); -``` - -Now, when `RUN_ALL_TESTS()` is called, it first calls the `SetUp()` method of -the environment object, then runs the tests if there was no fatal failures, and -finally calls `TearDown()` of the environment object. - -It's OK to register multiple environment objects. In this case, their `SetUp()` -will be called in the order they are registered, and their `TearDown()` will be -called in the reverse order. - -Note that Google Test takes ownership of the registered environment objects. -Therefore **do not delete them** by yourself. - -You should call `AddGlobalTestEnvironment()` before `RUN_ALL_TESTS()` is -called, probably in `main()`. If you use `gtest_main`, you need to call -this before `main()` starts for it to take effect. One way to do this is to -define a global variable like this: - -``` -::testing::Environment* const foo_env = ::testing::AddGlobalTestEnvironment(new FooEnvironment); -``` - -However, we strongly recommend you to write your own `main()` and call -`AddGlobalTestEnvironment()` there, as relying on initialization of global -variables makes the code harder to read and may cause problems when you -register multiple environments from different translation units and the -environments have dependencies among them (remember that the compiler doesn't -guarantee the order in which global variables from different translation units -are initialized). - -_Availability:_ Linux, Windows, Mac. - - -# Value Parameterized Tests # - -_Value-parameterized tests_ allow you to test your code with different -parameters without writing multiple copies of the same test. - -Suppose you write a test for your code and then realize that your code is affected by a presence of a Boolean command line flag. - -``` -TEST(MyCodeTest, TestFoo) { - // A code to test foo(). -} -``` - -Usually people factor their test code into a function with a Boolean parameter in such situations. The function sets the flag, then executes the testing code. - -``` -void TestFooHelper(bool flag_value) { - flag = flag_value; - // A code to test foo(). -} - -TEST(MyCodeTest, TestFoo) { - TestFooHelper(false); - TestFooHelper(true); -} -``` - -But this setup has serious drawbacks. First, when a test assertion fails in your tests, it becomes unclear what value of the parameter caused it to fail. You can stream a clarifying message into your `EXPECT`/`ASSERT` statements, but it you'll have to do it with all of them. Second, you have to add one such helper function per test. What if you have ten tests? Twenty? A hundred? - -Value-parameterized tests will let you write your test only once and then easily instantiate and run it with an arbitrary number of parameter values. - -Here are some other situations when value-parameterized tests come handy: - - * You want to test different implementations of an OO interface. - * You want to test your code over various inputs (a.k.a. data-driven testing). This feature is easy to abuse, so please exercise your good sense when doing it! - -## How to Write Value-Parameterized Tests ## - -To write value-parameterized tests, first you should define a fixture -class. It must be derived from both `::testing::Test` and -`::testing::WithParamInterface` (the latter is a pure interface), -where `T` is the type of your parameter values. For convenience, you -can just derive the fixture class from `::testing::TestWithParam`, -which itself is derived from both `::testing::Test` and -`::testing::WithParamInterface`. `T` can be any copyable type. If -it's a raw pointer, you are responsible for managing the lifespan of -the pointed values. - -``` -class FooTest : public ::testing::TestWithParam { - // You can implement all the usual fixture class members here. - // To access the test parameter, call GetParam() from class - // TestWithParam. -}; - -// Or, when you want to add parameters to a pre-existing fixture class: -class BaseTest : public ::testing::Test { - ... -}; -class BarTest : public BaseTest, - public ::testing::WithParamInterface { - ... -}; -``` - -Then, use the `TEST_P` macro to define as many test patterns using -this fixture as you want. The `_P` suffix is for "parameterized" or -"pattern", whichever you prefer to think. - -``` -TEST_P(FooTest, DoesBlah) { - // Inside a test, access the test parameter with the GetParam() method - // of the TestWithParam class: - EXPECT_TRUE(foo.Blah(GetParam())); - ... -} - -TEST_P(FooTest, HasBlahBlah) { - ... -} -``` - -Finally, you can use `INSTANTIATE_TEST_CASE_P` to instantiate the test -case with any set of parameters you want. Google Test defines a number of -functions for generating test parameters. They return what we call -(surprise!) _parameter generators_. Here is a summary of them, -which are all in the `testing` namespace: - -| `Range(begin, end[, step])` | Yields values `{begin, begin+step, begin+step+step, ...}`. The values do not include `end`. `step` defaults to 1. | -|:----------------------------|:------------------------------------------------------------------------------------------------------------------| -| `Values(v1, v2, ..., vN)` | Yields values `{v1, v2, ..., vN}`. | -| `ValuesIn(container)` and `ValuesIn(begin, end)` | Yields values from a C-style array, an STL-style container, or an iterator range `[begin, end)`. `container`, `begin`, and `end` can be expressions whose values are determined at run time. | -| `Bool()` | Yields sequence `{false, true}`. | -| `Combine(g1, g2, ..., gN)` | Yields all combinations (the Cartesian product for the math savvy) of the values generated by the `N` generators. This is only available if your system provides the `` header. If you are sure your system does, and Google Test disagrees, you can override it by defining `GTEST_HAS_TR1_TUPLE=1`. See comments in [include/gtest/internal/gtest-port.h](../include/gtest/internal/gtest-port.h) for more information. | - -For more details, see the comments at the definitions of these functions in the [source code](../include/gtest/gtest-param-test.h). - -The following statement will instantiate tests from the `FooTest` test case -each with parameter values `"meeny"`, `"miny"`, and `"moe"`. - -``` -INSTANTIATE_TEST_CASE_P(InstantiationName, - FooTest, - ::testing::Values("meeny", "miny", "moe")); -``` - -To distinguish different instances of the pattern (yes, you can -instantiate it more than once), the first argument to -`INSTANTIATE_TEST_CASE_P` is a prefix that will be added to the actual -test case name. Remember to pick unique prefixes for different -instantiations. The tests from the instantiation above will have these -names: - - * `InstantiationName/FooTest.DoesBlah/0` for `"meeny"` - * `InstantiationName/FooTest.DoesBlah/1` for `"miny"` - * `InstantiationName/FooTest.DoesBlah/2` for `"moe"` - * `InstantiationName/FooTest.HasBlahBlah/0` for `"meeny"` - * `InstantiationName/FooTest.HasBlahBlah/1` for `"miny"` - * `InstantiationName/FooTest.HasBlahBlah/2` for `"moe"` - -You can use these names in [--gtest\_filter](#running-a-subset-of-the-tests). - -This statement will instantiate all tests from `FooTest` again, each -with parameter values `"cat"` and `"dog"`: - -``` -const char* pets[] = {"cat", "dog"}; -INSTANTIATE_TEST_CASE_P(AnotherInstantiationName, FooTest, - ::testing::ValuesIn(pets)); -``` - -The tests from the instantiation above will have these names: - - * `AnotherInstantiationName/FooTest.DoesBlah/0` for `"cat"` - * `AnotherInstantiationName/FooTest.DoesBlah/1` for `"dog"` - * `AnotherInstantiationName/FooTest.HasBlahBlah/0` for `"cat"` - * `AnotherInstantiationName/FooTest.HasBlahBlah/1` for `"dog"` - -Please note that `INSTANTIATE_TEST_CASE_P` will instantiate _all_ -tests in the given test case, whether their definitions come before or -_after_ the `INSTANTIATE_TEST_CASE_P` statement. - -You can see -[these](../samples/sample7_unittest.cc) -[files](../samples/sample8_unittest.cc) for more examples. - -_Availability_: Linux, Windows (requires MSVC 8.0 or above), Mac; since version 1.2.0. - -## Creating Value-Parameterized Abstract Tests ## - -In the above, we define and instantiate `FooTest` in the same source -file. Sometimes you may want to define value-parameterized tests in a -library and let other people instantiate them later. This pattern is -known as abstract tests. As an example of its application, when you -are designing an interface you can write a standard suite of abstract -tests (perhaps using a factory function as the test parameter) that -all implementations of the interface are expected to pass. When -someone implements the interface, he can instantiate your suite to get -all the interface-conformance tests for free. - -To define abstract tests, you should organize your code like this: - - 1. Put the definition of the parameterized test fixture class (e.g. `FooTest`) in a header file, say `foo_param_test.h`. Think of this as _declaring_ your abstract tests. - 1. Put the `TEST_P` definitions in `foo_param_test.cc`, which includes `foo_param_test.h`. Think of this as _implementing_ your abstract tests. - -Once they are defined, you can instantiate them by including -`foo_param_test.h`, invoking `INSTANTIATE_TEST_CASE_P()`, and linking -with `foo_param_test.cc`. You can instantiate the same abstract test -case multiple times, possibly in different source files. - -# Typed Tests # - -Suppose you have multiple implementations of the same interface and -want to make sure that all of them satisfy some common requirements. -Or, you may have defined several types that are supposed to conform to -the same "concept" and you want to verify it. In both cases, you want -the same test logic repeated for different types. - -While you can write one `TEST` or `TEST_F` for each type you want to -test (and you may even factor the test logic into a function template -that you invoke from the `TEST`), it's tedious and doesn't scale: -if you want _m_ tests over _n_ types, you'll end up writing _m\*n_ -`TEST`s. - -_Typed tests_ allow you to repeat the same test logic over a list of -types. You only need to write the test logic once, although you must -know the type list when writing typed tests. Here's how you do it: - -First, define a fixture class template. It should be parameterized -by a type. Remember to derive it from `::testing::Test`: - -``` -template -class FooTest : public ::testing::Test { - public: - ... - typedef std::list List; - static T shared_; - T value_; -}; -``` - -Next, associate a list of types with the test case, which will be -repeated for each type in the list: - -``` -typedef ::testing::Types MyTypes; -TYPED_TEST_CASE(FooTest, MyTypes); -``` - -The `typedef` is necessary for the `TYPED_TEST_CASE` macro to parse -correctly. Otherwise the compiler will think that each comma in the -type list introduces a new macro argument. - -Then, use `TYPED_TEST()` instead of `TEST_F()` to define a typed test -for this test case. You can repeat this as many times as you want: - -``` -TYPED_TEST(FooTest, DoesBlah) { - // Inside a test, refer to the special name TypeParam to get the type - // parameter. Since we are inside a derived class template, C++ requires - // us to visit the members of FooTest via 'this'. - TypeParam n = this->value_; - - // To visit static members of the fixture, add the 'TestFixture::' - // prefix. - n += TestFixture::shared_; - - // To refer to typedefs in the fixture, add the 'typename TestFixture::' - // prefix. The 'typename' is required to satisfy the compiler. - typename TestFixture::List values; - values.push_back(n); - ... -} - -TYPED_TEST(FooTest, HasPropertyA) { ... } -``` - -You can see `samples/sample6_unittest.cc` for a complete example. - -_Availability:_ Linux, Windows (requires MSVC 8.0 or above), Mac; -since version 1.1.0. - -# Type-Parameterized Tests # - -_Type-parameterized tests_ are like typed tests, except that they -don't require you to know the list of types ahead of time. Instead, -you can define the test logic first and instantiate it with different -type lists later. You can even instantiate it more than once in the -same program. - -If you are designing an interface or concept, you can define a suite -of type-parameterized tests to verify properties that any valid -implementation of the interface/concept should have. Then, the author -of each implementation can just instantiate the test suite with his -type to verify that it conforms to the requirements, without having to -write similar tests repeatedly. Here's an example: - -First, define a fixture class template, as we did with typed tests: - -``` -template -class FooTest : public ::testing::Test { - ... -}; -``` - -Next, declare that you will define a type-parameterized test case: - -``` -TYPED_TEST_CASE_P(FooTest); -``` - -The `_P` suffix is for "parameterized" or "pattern", whichever you -prefer to think. - -Then, use `TYPED_TEST_P()` to define a type-parameterized test. You -can repeat this as many times as you want: - -``` -TYPED_TEST_P(FooTest, DoesBlah) { - // Inside a test, refer to TypeParam to get the type parameter. - TypeParam n = 0; - ... -} - -TYPED_TEST_P(FooTest, HasPropertyA) { ... } -``` - -Now the tricky part: you need to register all test patterns using the -`REGISTER_TYPED_TEST_CASE_P` macro before you can instantiate them. -The first argument of the macro is the test case name; the rest are -the names of the tests in this test case: - -``` -REGISTER_TYPED_TEST_CASE_P(FooTest, - DoesBlah, HasPropertyA); -``` - -Finally, you are free to instantiate the pattern with the types you -want. If you put the above code in a header file, you can `#include` -it in multiple C++ source files and instantiate it multiple times. - -``` -typedef ::testing::Types MyTypes; -INSTANTIATE_TYPED_TEST_CASE_P(My, FooTest, MyTypes); -``` - -To distinguish different instances of the pattern, the first argument -to the `INSTANTIATE_TYPED_TEST_CASE_P` macro is a prefix that will be -added to the actual test case name. Remember to pick unique prefixes -for different instances. - -In the special case where the type list contains only one type, you -can write that type directly without `::testing::Types<...>`, like this: - -``` -INSTANTIATE_TYPED_TEST_CASE_P(My, FooTest, int); -``` - -You can see `samples/sample6_unittest.cc` for a complete example. - -_Availability:_ Linux, Windows (requires MSVC 8.0 or above), Mac; -since version 1.1.0. - -# Testing Private Code # - -If you change your software's internal implementation, your tests should not -break as long as the change is not observable by users. Therefore, per the -_black-box testing principle_, most of the time you should test your code -through its public interfaces. - -If you still find yourself needing to test internal implementation code, -consider if there's a better design that wouldn't require you to do so. If you -absolutely have to test non-public interface code though, you can. There are -two cases to consider: - - * Static functions (_not_ the same as static member functions!) or unnamed namespaces, and - * Private or protected class members - -## Static Functions ## - -Both static functions and definitions/declarations in an unnamed namespace are -only visible within the same translation unit. To test them, you can `#include` -the entire `.cc` file being tested in your `*_test.cc` file. (`#include`ing `.cc` -files is not a good way to reuse code - you should not do this in production -code!) - -However, a better approach is to move the private code into the -`foo::internal` namespace, where `foo` is the namespace your project normally -uses, and put the private declarations in a `*-internal.h` file. Your -production `.cc` files and your tests are allowed to include this internal -header, but your clients are not. This way, you can fully test your internal -implementation without leaking it to your clients. - -## Private Class Members ## - -Private class members are only accessible from within the class or by friends. -To access a class' private members, you can declare your test fixture as a -friend to the class and define accessors in your fixture. Tests using the -fixture can then access the private members of your production class via the -accessors in the fixture. Note that even though your fixture is a friend to -your production class, your tests are not automatically friends to it, as they -are technically defined in sub-classes of the fixture. - -Another way to test private members is to refactor them into an implementation -class, which is then declared in a `*-internal.h` file. Your clients aren't -allowed to include this header but your tests can. Such is called the Pimpl -(Private Implementation) idiom. - -Or, you can declare an individual test as a friend of your class by adding this -line in the class body: - -``` -FRIEND_TEST(TestCaseName, TestName); -``` - -For example, -``` -// foo.h -#include "gtest/gtest_prod.h" - -// Defines FRIEND_TEST. -class Foo { - ... - private: - FRIEND_TEST(FooTest, BarReturnsZeroOnNull); - int Bar(void* x); -}; - -// foo_test.cc -... -TEST(FooTest, BarReturnsZeroOnNull) { - Foo foo; - EXPECT_EQ(0, foo.Bar(NULL)); - // Uses Foo's private member Bar(). -} -``` - -Pay special attention when your class is defined in a namespace, as you should -define your test fixtures and tests in the same namespace if you want them to -be friends of your class. For example, if the code to be tested looks like: - -``` -namespace my_namespace { - -class Foo { - friend class FooTest; - FRIEND_TEST(FooTest, Bar); - FRIEND_TEST(FooTest, Baz); - ... - definition of the class Foo - ... -}; - -} // namespace my_namespace -``` - -Your test code should be something like: - -``` -namespace my_namespace { -class FooTest : public ::testing::Test { - protected: - ... -}; - -TEST_F(FooTest, Bar) { ... } -TEST_F(FooTest, Baz) { ... } - -} // namespace my_namespace -``` - -# Catching Failures # - -If you are building a testing utility on top of Google Test, you'll -want to test your utility. What framework would you use to test it? -Google Test, of course. - -The challenge is to verify that your testing utility reports failures -correctly. In frameworks that report a failure by throwing an -exception, you could catch the exception and assert on it. But Google -Test doesn't use exceptions, so how do we test that a piece of code -generates an expected failure? - -`"gtest/gtest-spi.h"` contains some constructs to do this. After -`#include`ing this header, you can use - -| `EXPECT_FATAL_FAILURE(`_statement, substring_`);` | -|:--------------------------------------------------| - -to assert that _statement_ generates a fatal (e.g. `ASSERT_*`) failure -whose message contains the given _substring_, or use - -| `EXPECT_NONFATAL_FAILURE(`_statement, substring_`);` | -|:-----------------------------------------------------| - -if you are expecting a non-fatal (e.g. `EXPECT_*`) failure. - -For technical reasons, there are some caveats: - - 1. You cannot stream a failure message to either macro. - 1. _statement_ in `EXPECT_FATAL_FAILURE()` cannot reference local non-static variables or non-static members of `this` object. - 1. _statement_ in `EXPECT_FATAL_FAILURE()` cannot return a value. - -_Note:_ Google Test is designed with threads in mind. Once the -synchronization primitives in `"gtest/internal/gtest-port.h"` have -been implemented, Google Test will become thread-safe, meaning that -you can then use assertions in multiple threads concurrently. Before - -that, however, Google Test only supports single-threaded usage. Once -thread-safe, `EXPECT_FATAL_FAILURE()` and `EXPECT_NONFATAL_FAILURE()` -will capture failures in the current thread only. If _statement_ -creates new threads, failures in these threads will be ignored. If -you want to capture failures from all threads instead, you should use -the following macros: - -| `EXPECT_FATAL_FAILURE_ON_ALL_THREADS(`_statement, substring_`);` | -|:-----------------------------------------------------------------| -| `EXPECT_NONFATAL_FAILURE_ON_ALL_THREADS(`_statement, substring_`);` | - -# Getting the Current Test's Name # - -Sometimes a function may need to know the name of the currently running test. -For example, you may be using the `SetUp()` method of your test fixture to set -the golden file name based on which test is running. The `::testing::TestInfo` -class has this information: - -``` -namespace testing { - -class TestInfo { - public: - // Returns the test case name and the test name, respectively. - // - // Do NOT delete or free the return value - it's managed by the - // TestInfo class. - const char* test_case_name() const; - const char* name() const; -}; - -} // namespace testing -``` - - -> To obtain a `TestInfo` object for the currently running test, call -`current_test_info()` on the `UnitTest` singleton object: - -``` -// Gets information about the currently running test. -// Do NOT delete the returned object - it's managed by the UnitTest class. -const ::testing::TestInfo* const test_info = - ::testing::UnitTest::GetInstance()->current_test_info(); -printf("We are in test %s of test case %s.\n", - test_info->name(), test_info->test_case_name()); -``` - -`current_test_info()` returns a null pointer if no test is running. In -particular, you cannot find the test case name in `TestCaseSetUp()`, -`TestCaseTearDown()` (where you know the test case name implicitly), or -functions called from them. - -_Availability:_ Linux, Windows, Mac. - -# Extending Google Test by Handling Test Events # - -Google Test provides an event listener API to let you receive -notifications about the progress of a test program and test -failures. The events you can listen to include the start and end of -the test program, a test case, or a test method, among others. You may -use this API to augment or replace the standard console output, -replace the XML output, or provide a completely different form of -output, such as a GUI or a database. You can also use test events as -checkpoints to implement a resource leak checker, for example. - -_Availability:_ Linux, Windows, Mac; since v1.4.0. - -## Defining Event Listeners ## - -To define a event listener, you subclass either -[testing::TestEventListener](../include/gtest/gtest.h#L855) -or [testing::EmptyTestEventListener](../include/gtest/gtest.h#L905). -The former is an (abstract) interface, where each pure virtual method
-can be overridden to handle a test event (For example, when a test -starts, the `OnTestStart()` method will be called.). The latter provides -an empty implementation of all methods in the interface, such that a -subclass only needs to override the methods it cares about. - -When an event is fired, its context is passed to the handler function -as an argument. The following argument types are used: - * [UnitTest](../include/gtest/gtest.h#L1007) reflects the state of the entire test program, - * [TestCase](../include/gtest/gtest.h#L689) has information about a test case, which can contain one or more tests, - * [TestInfo](../include/gtest/gtest.h#L599) contains the state of a test, and - * [TestPartResult](../include/gtest/gtest-test-part.h#L42) represents the result of a test assertion. - -An event handler function can examine the argument it receives to find -out interesting information about the event and the test program's -state. Here's an example: - -``` - class MinimalistPrinter : public ::testing::EmptyTestEventListener { - // Called before a test starts. - virtual void OnTestStart(const ::testing::TestInfo& test_info) { - printf("*** Test %s.%s starting.\n", - test_info.test_case_name(), test_info.name()); - } - - // Called after a failed assertion or a SUCCEED() invocation. - virtual void OnTestPartResult( - const ::testing::TestPartResult& test_part_result) { - printf("%s in %s:%d\n%s\n", - test_part_result.failed() ? "*** Failure" : "Success", - test_part_result.file_name(), - test_part_result.line_number(), - test_part_result.summary()); - } - - // Called after a test ends. - virtual void OnTestEnd(const ::testing::TestInfo& test_info) { - printf("*** Test %s.%s ending.\n", - test_info.test_case_name(), test_info.name()); - } - }; -``` - -## Using Event Listeners ## - -To use the event listener you have defined, add an instance of it to -the Google Test event listener list (represented by class -[TestEventListeners](../include/gtest/gtest.h#L929) -- note the "s" at the end of the name) in your -`main()` function, before calling `RUN_ALL_TESTS()`: -``` -int main(int argc, char** argv) { - ::testing::InitGoogleTest(&argc, argv); - // Gets hold of the event listener list. - ::testing::TestEventListeners& listeners = - ::testing::UnitTest::GetInstance()->listeners(); - // Adds a listener to the end. Google Test takes the ownership. - listeners.Append(new MinimalistPrinter); - return RUN_ALL_TESTS(); -} -``` - -There's only one problem: the default test result printer is still in -effect, so its output will mingle with the output from your minimalist -printer. To suppress the default printer, just release it from the -event listener list and delete it. You can do so by adding one line: -``` - ... - delete listeners.Release(listeners.default_result_printer()); - listeners.Append(new MinimalistPrinter); - return RUN_ALL_TESTS(); -``` - -Now, sit back and enjoy a completely different output from your -tests. For more details, you can read this -[sample](../samples/sample9_unittest.cc). - -You may append more than one listener to the list. When an `On*Start()` -or `OnTestPartResult()` event is fired, the listeners will receive it in -the order they appear in the list (since new listeners are added to -the end of the list, the default text printer and the default XML -generator will receive the event first). An `On*End()` event will be -received by the listeners in the _reverse_ order. This allows output by -listeners added later to be framed by output from listeners added -earlier. - -## Generating Failures in Listeners ## - -You may use failure-raising macros (`EXPECT_*()`, `ASSERT_*()`, -`FAIL()`, etc) when processing an event. There are some restrictions: - - 1. You cannot generate any failure in `OnTestPartResult()` (otherwise it will cause `OnTestPartResult()` to be called recursively). - 1. A listener that handles `OnTestPartResult()` is not allowed to generate any failure. - -When you add listeners to the listener list, you should put listeners -that handle `OnTestPartResult()` _before_ listeners that can generate -failures. This ensures that failures generated by the latter are -attributed to the right test by the former. - -We have a sample of failure-raising listener -[here](../samples/sample10_unittest.cc). - -# Running Test Programs: Advanced Options # - -Google Test test programs are ordinary executables. Once built, you can run -them directly and affect their behavior via the following environment variables -and/or command line flags. For the flags to work, your programs must call -`::testing::InitGoogleTest()` before calling `RUN_ALL_TESTS()`. - -To see a list of supported flags and their usage, please run your test -program with the `--help` flag. You can also use `-h`, `-?`, or `/?` -for short. This feature is added in version 1.3.0. - -If an option is specified both by an environment variable and by a -flag, the latter takes precedence. Most of the options can also be -set/read in code: to access the value of command line flag -`--gtest_foo`, write `::testing::GTEST_FLAG(foo)`. A common pattern is -to set the value of a flag before calling `::testing::InitGoogleTest()` -to change the default value of the flag: -``` -int main(int argc, char** argv) { - // Disables elapsed time by default. - ::testing::GTEST_FLAG(print_time) = false; - - // This allows the user to override the flag on the command line. - ::testing::InitGoogleTest(&argc, argv); - - return RUN_ALL_TESTS(); -} -``` - -## Selecting Tests ## - -This section shows various options for choosing which tests to run. - -### Listing Test Names ### - -Sometimes it is necessary to list the available tests in a program before -running them so that a filter may be applied if needed. Including the flag -`--gtest_list_tests` overrides all other flags and lists tests in the following -format: -``` -TestCase1. - TestName1 - TestName2 -TestCase2. - TestName -``` - -None of the tests listed are actually run if the flag is provided. There is no -corresponding environment variable for this flag. - -_Availability:_ Linux, Windows, Mac. - -### Running a Subset of the Tests ### - -By default, a Google Test program runs all tests the user has defined. -Sometimes, you want to run only a subset of the tests (e.g. for debugging or -quickly verifying a change). If you set the `GTEST_FILTER` environment variable -or the `--gtest_filter` flag to a filter string, Google Test will only run the -tests whose full names (in the form of `TestCaseName.TestName`) match the -filter. - -The format of a filter is a '`:`'-separated list of wildcard patterns (called -the positive patterns) optionally followed by a '`-`' and another -'`:`'-separated pattern list (called the negative patterns). A test matches the -filter if and only if it matches any of the positive patterns but does not -match any of the negative patterns. - -A pattern may contain `'*'` (matches any string) or `'?'` (matches any single -character). For convenience, the filter `'*-NegativePatterns'` can be also -written as `'-NegativePatterns'`. - -For example: - - * `./foo_test` Has no flag, and thus runs all its tests. - * `./foo_test --gtest_filter=*` Also runs everything, due to the single match-everything `*` value. - * `./foo_test --gtest_filter=FooTest.*` Runs everything in test case `FooTest`. - * `./foo_test --gtest_filter=*Null*:*Constructor*` Runs any test whose full name contains either `"Null"` or `"Constructor"`. - * `./foo_test --gtest_filter=-*DeathTest.*` Runs all non-death tests. - * `./foo_test --gtest_filter=FooTest.*-FooTest.Bar` Runs everything in test case `FooTest` except `FooTest.Bar`. - -_Availability:_ Linux, Windows, Mac. - -### Temporarily Disabling Tests ### - -If you have a broken test that you cannot fix right away, you can add the -`DISABLED_` prefix to its name. This will exclude it from execution. This is -better than commenting out the code or using `#if 0`, as disabled tests are -still compiled (and thus won't rot). - -If you need to disable all tests in a test case, you can either add `DISABLED_` -to the front of the name of each test, or alternatively add it to the front of -the test case name. - -For example, the following tests won't be run by Google Test, even though they -will still be compiled: - -``` -// Tests that Foo does Abc. -TEST(FooTest, DISABLED_DoesAbc) { ... } - -class DISABLED_BarTest : public ::testing::Test { ... }; - -// Tests that Bar does Xyz. -TEST_F(DISABLED_BarTest, DoesXyz) { ... } -``` - -_Note:_ This feature should only be used for temporary pain-relief. You still -have to fix the disabled tests at a later date. As a reminder, Google Test will -print a banner warning you if a test program contains any disabled tests. - -_Tip:_ You can easily count the number of disabled tests you have -using `grep`. This number can be used as a metric for improving your -test quality. - -_Availability:_ Linux, Windows, Mac. - -### Temporarily Enabling Disabled Tests ### - -To include [disabled tests](#temporarily-disabling-tests) in test -execution, just invoke the test program with the -`--gtest_also_run_disabled_tests` flag or set the -`GTEST_ALSO_RUN_DISABLED_TESTS` environment variable to a value other -than `0`. You can combine this with the -[--gtest\_filter](#running-a-subset-of-the-tests) flag to further select -which disabled tests to run. - -_Availability:_ Linux, Windows, Mac; since version 1.3.0. - -## Repeating the Tests ## - -Once in a while you'll run into a test whose result is hit-or-miss. Perhaps it -will fail only 1% of the time, making it rather hard to reproduce the bug under -a debugger. This can be a major source of frustration. - -The `--gtest_repeat` flag allows you to repeat all (or selected) test methods -in a program many times. Hopefully, a flaky test will eventually fail and give -you a chance to debug. Here's how to use it: - -| `$ foo_test --gtest_repeat=1000` | Repeat foo\_test 1000 times and don't stop at failures. | -|:---------------------------------|:--------------------------------------------------------| -| `$ foo_test --gtest_repeat=-1` | A negative count means repeating forever. | -| `$ foo_test --gtest_repeat=1000 --gtest_break_on_failure` | Repeat foo\_test 1000 times, stopping at the first failure. This is especially useful when running under a debugger: when the testfails, it will drop into the debugger and you can then inspect variables and stacks. | -| `$ foo_test --gtest_repeat=1000 --gtest_filter=FooBar` | Repeat the tests whose name matches the filter 1000 times. | - -If your test program contains global set-up/tear-down code registered -using `AddGlobalTestEnvironment()`, it will be repeated in each -iteration as well, as the flakiness may be in it. You can also specify -the repeat count by setting the `GTEST_REPEAT` environment variable. - -_Availability:_ Linux, Windows, Mac. - -## Shuffling the Tests ## - -You can specify the `--gtest_shuffle` flag (or set the `GTEST_SHUFFLE` -environment variable to `1`) to run the tests in a program in a random -order. This helps to reveal bad dependencies between tests. - -By default, Google Test uses a random seed calculated from the current -time. Therefore you'll get a different order every time. The console -output includes the random seed value, such that you can reproduce an -order-related test failure later. To specify the random seed -explicitly, use the `--gtest_random_seed=SEED` flag (or set the -`GTEST_RANDOM_SEED` environment variable), where `SEED` is an integer -between 0 and 99999. The seed value 0 is special: it tells Google Test -to do the default behavior of calculating the seed from the current -time. - -If you combine this with `--gtest_repeat=N`, Google Test will pick a -different random seed and re-shuffle the tests in each iteration. - -_Availability:_ Linux, Windows, Mac; since v1.4.0. - -## Controlling Test Output ## - -This section teaches how to tweak the way test results are reported. - -### Colored Terminal Output ### - -Google Test can use colors in its terminal output to make it easier to spot -the separation between tests, and whether tests passed. - -You can set the GTEST\_COLOR environment variable or set the `--gtest_color` -command line flag to `yes`, `no`, or `auto` (the default) to enable colors, -disable colors, or let Google Test decide. When the value is `auto`, Google -Test will use colors if and only if the output goes to a terminal and (on -non-Windows platforms) the `TERM` environment variable is set to `xterm` or -`xterm-color`. - -_Availability:_ Linux, Windows, Mac. - -### Suppressing the Elapsed Time ### - -By default, Google Test prints the time it takes to run each test. To -suppress that, run the test program with the `--gtest_print_time=0` -command line flag. Setting the `GTEST_PRINT_TIME` environment -variable to `0` has the same effect. - -_Availability:_ Linux, Windows, Mac. (In Google Test 1.3.0 and lower, -the default behavior is that the elapsed time is **not** printed.) - -### Generating an XML Report ### - -Google Test can emit a detailed XML report to a file in addition to its normal -textual output. The report contains the duration of each test, and thus can -help you identify slow tests. - -To generate the XML report, set the `GTEST_OUTPUT` environment variable or the -`--gtest_output` flag to the string `"xml:_path_to_output_file_"`, which will -create the file at the given location. You can also just use the string -`"xml"`, in which case the output can be found in the `test_detail.xml` file in -the current directory. - -If you specify a directory (for example, `"xml:output/directory/"` on Linux or -`"xml:output\directory\"` on Windows), Google Test will create the XML file in -that directory, named after the test executable (e.g. `foo_test.xml` for test -program `foo_test` or `foo_test.exe`). If the file already exists (perhaps left -over from a previous run), Google Test will pick a different name (e.g. -`foo_test_1.xml`) to avoid overwriting it. - -The report uses the format described here. It is based on the -`junitreport` Ant task and can be parsed by popular continuous build -systems like [Jenkins](http://jenkins-ci.org/). Since that format -was originally intended for Java, a little interpretation is required -to make it apply to Google Test tests, as shown here: - -``` - - - - - - - - - -``` - - * The root `` element corresponds to the entire test program. - * `` elements correspond to Google Test test cases. - * `` elements correspond to Google Test test functions. - -For instance, the following program - -``` -TEST(MathTest, Addition) { ... } -TEST(MathTest, Subtraction) { ... } -TEST(LogicTest, NonContradiction) { ... } -``` - -could generate this report: - -``` - - - - - - - - - - - - - - - -``` - -Things to note: - - * The `tests` attribute of a `` or `` element tells how many test functions the Google Test program or test case contains, while the `failures` attribute tells how many of them failed. - * The `time` attribute expresses the duration of the test, test case, or entire test program in milliseconds. - * Each `` element corresponds to a single failed Google Test assertion. - * Some JUnit concepts don't apply to Google Test, yet we have to conform to the DTD. Therefore you'll see some dummy elements and attributes in the report. You can safely ignore these parts. - -_Availability:_ Linux, Windows, Mac. - -## Controlling How Failures Are Reported ## - -### Turning Assertion Failures into Break-Points ### - -When running test programs under a debugger, it's very convenient if the -debugger can catch an assertion failure and automatically drop into interactive -mode. Google Test's _break-on-failure_ mode supports this behavior. - -To enable it, set the `GTEST_BREAK_ON_FAILURE` environment variable to a value -other than `0` . Alternatively, you can use the `--gtest_break_on_failure` -command line flag. - -_Availability:_ Linux, Windows, Mac. - -### Disabling Catching Test-Thrown Exceptions ### - -Google Test can be used either with or without exceptions enabled. If -a test throws a C++ exception or (on Windows) a structured exception -(SEH), by default Google Test catches it, reports it as a test -failure, and continues with the next test method. This maximizes the -coverage of a test run. Also, on Windows an uncaught exception will -cause a pop-up window, so catching the exceptions allows you to run -the tests automatically. - -When debugging the test failures, however, you may instead want the -exceptions to be handled by the debugger, such that you can examine -the call stack when an exception is thrown. To achieve that, set the -`GTEST_CATCH_EXCEPTIONS` environment variable to `0`, or use the -`--gtest_catch_exceptions=0` flag when running the tests. - -**Availability**: Linux, Windows, Mac. - -### Letting Another Testing Framework Drive ### - -If you work on a project that has already been using another testing -framework and is not ready to completely switch to Google Test yet, -you can get much of Google Test's benefit by using its assertions in -your existing tests. Just change your `main()` function to look -like: - -``` -#include "gtest/gtest.h" - -int main(int argc, char** argv) { - ::testing::GTEST_FLAG(throw_on_failure) = true; - // Important: Google Test must be initialized. - ::testing::InitGoogleTest(&argc, argv); - - ... whatever your existing testing framework requires ... -} -``` - -With that, you can use Google Test assertions in addition to the -native assertions your testing framework provides, for example: - -``` -void TestFooDoesBar() { - Foo foo; - EXPECT_LE(foo.Bar(1), 100); // A Google Test assertion. - CPPUNIT_ASSERT(foo.IsEmpty()); // A native assertion. -} -``` - -If a Google Test assertion fails, it will print an error message and -throw an exception, which will be treated as a failure by your host -testing framework. If you compile your code with exceptions disabled, -a failed Google Test assertion will instead exit your program with a -non-zero code, which will also signal a test failure to your test -runner. - -If you don't write `::testing::GTEST_FLAG(throw_on_failure) = true;` in -your `main()`, you can alternatively enable this feature by specifying -the `--gtest_throw_on_failure` flag on the command-line or setting the -`GTEST_THROW_ON_FAILURE` environment variable to a non-zero value. - -Death tests are _not_ supported when other test framework is used to organize tests. - -_Availability:_ Linux, Windows, Mac; since v1.3.0. - -## Distributing Test Functions to Multiple Machines ## - -If you have more than one machine you can use to run a test program, -you might want to run the test functions in parallel and get the -result faster. We call this technique _sharding_, where each machine -is called a _shard_. - -Google Test is compatible with test sharding. To take advantage of -this feature, your test runner (not part of Google Test) needs to do -the following: - - 1. Allocate a number of machines (shards) to run the tests. - 1. On each shard, set the `GTEST_TOTAL_SHARDS` environment variable to the total number of shards. It must be the same for all shards. - 1. On each shard, set the `GTEST_SHARD_INDEX` environment variable to the index of the shard. Different shards must be assigned different indices, which must be in the range `[0, GTEST_TOTAL_SHARDS - 1]`. - 1. Run the same test program on all shards. When Google Test sees the above two environment variables, it will select a subset of the test functions to run. Across all shards, each test function in the program will be run exactly once. - 1. Wait for all shards to finish, then collect and report the results. - -Your project may have tests that were written without Google Test and -thus don't understand this protocol. In order for your test runner to -figure out which test supports sharding, it can set the environment -variable `GTEST_SHARD_STATUS_FILE` to a non-existent file path. If a -test program supports sharding, it will create this file to -acknowledge the fact (the actual contents of the file are not -important at this time; although we may stick some useful information -in it in the future.); otherwise it will not create it. - -Here's an example to make it clear. Suppose you have a test program -`foo_test` that contains the following 5 test functions: -``` -TEST(A, V) -TEST(A, W) -TEST(B, X) -TEST(B, Y) -TEST(B, Z) -``` -and you have 3 machines at your disposal. To run the test functions in -parallel, you would set `GTEST_TOTAL_SHARDS` to 3 on all machines, and -set `GTEST_SHARD_INDEX` to 0, 1, and 2 on the machines respectively. -Then you would run the same `foo_test` on each machine. - -Google Test reserves the right to change how the work is distributed -across the shards, but here's one possible scenario: - - * Machine #0 runs `A.V` and `B.X`. - * Machine #1 runs `A.W` and `B.Y`. - * Machine #2 runs `B.Z`. - -_Availability:_ Linux, Windows, Mac; since version 1.3.0. - -# Fusing Google Test Source Files # - -Google Test's implementation consists of ~30 files (excluding its own -tests). Sometimes you may want them to be packaged up in two files (a -`.h` and a `.cc`) instead, such that you can easily copy them to a new -machine and start hacking there. For this we provide an experimental -Python script `fuse_gtest_files.py` in the `scripts/` directory (since release 1.3.0). -Assuming you have Python 2.4 or above installed on your machine, just -go to that directory and run -``` -python fuse_gtest_files.py OUTPUT_DIR -``` - -and you should see an `OUTPUT_DIR` directory being created with files -`gtest/gtest.h` and `gtest/gtest-all.cc` in it. These files contain -everything you need to use Google Test. Just copy them to anywhere -you want and you are ready to write tests. You can use the -[scripts/test/Makefile](../scripts/test/Makefile) -file as an example on how to compile your tests against them. - -# Where to Go from Here # - -Congratulations! You've now learned more advanced Google Test tools and are -ready to tackle more complex testing tasks. If you want to dive even deeper, you -can read the [Frequently-Asked Questions](V1_7_FAQ.md). diff --git a/googletest/docs/V1_7_Documentation.md b/googletest/docs/V1_7_Documentation.md deleted file mode 100644 index 282697a5..00000000 --- a/googletest/docs/V1_7_Documentation.md +++ /dev/null @@ -1,14 +0,0 @@ -This page lists all documentation wiki pages for Google Test **(the SVN trunk version)** --- **if you use a released version of Google Test, please read the -documentation for that specific version instead.** - - * [Primer](V1_7_Primer.md) -- start here if you are new to Google Test. - * [Samples](V1_7_Samples.md) -- learn from examples. - * [AdvancedGuide](V1_7_AdvancedGuide.md) -- learn more about Google Test. - * [XcodeGuide](V1_7_XcodeGuide.md) -- how to use Google Test in Xcode on Mac. - * [Frequently-Asked Questions](V1_7_FAQ.md) -- check here before asking a question on the mailing list. - -To contribute code to Google Test, read: - - * [DevGuide](DevGuide.md) -- read this _before_ writing your first patch. - * [PumpManual](V1_7_PumpManual.md) -- how we generate some of Google Test's source files. \ No newline at end of file diff --git a/googletest/docs/V1_7_FAQ.md b/googletest/docs/V1_7_FAQ.md deleted file mode 100644 index 3dd914dc..00000000 --- a/googletest/docs/V1_7_FAQ.md +++ /dev/null @@ -1,1082 +0,0 @@ - - -If you cannot find the answer to your question here, and you have read -[Primer](V1_7_Primer.md) and [AdvancedGuide](V1_7_AdvancedGuide.md), send it to -googletestframework@googlegroups.com. - -## Why should I use Google Test instead of my favorite C++ testing framework? ## - -First, let us say clearly that we don't want to get into the debate of -which C++ testing framework is **the best**. There exist many fine -frameworks for writing C++ tests, and we have tremendous respect for -the developers and users of them. We don't think there is (or will -be) a single best framework - you have to pick the right tool for the -particular task you are tackling. - -We created Google Test because we couldn't find the right combination -of features and conveniences in an existing framework to satisfy _our_ -needs. The following is a list of things that _we_ like about Google -Test. We don't claim them to be unique to Google Test - rather, the -combination of them makes Google Test the choice for us. We hope this -list can help you decide whether it is for you too. - - * Google Test is designed to be portable: it doesn't require exceptions or RTTI; it works around various bugs in various compilers and environments; etc. As a result, it works on Linux, Mac OS X, Windows and several embedded operating systems. - * Nonfatal assertions (`EXPECT_*`) have proven to be great time savers, as they allow a test to report multiple failures in a single edit-compile-test cycle. - * It's easy to write assertions that generate informative messages: you just use the stream syntax to append any additional information, e.g. `ASSERT_EQ(5, Foo(i)) << " where i = " << i;`. It doesn't require a new set of macros or special functions. - * Google Test automatically detects your tests and doesn't require you to enumerate them in order to run them. - * Death tests are pretty handy for ensuring that your asserts in production code are triggered by the right conditions. - * `SCOPED_TRACE` helps you understand the context of an assertion failure when it comes from inside a sub-routine or loop. - * You can decide which tests to run using name patterns. This saves time when you want to quickly reproduce a test failure. - * Google Test can generate XML test result reports that can be parsed by popular continuous build system like Hudson. - * Simple things are easy in Google Test, while hard things are possible: in addition to advanced features like [global test environments](V1_7_AdvancedGuide.md#global-set-up-and-tear-down) and tests parameterized by [values](V1_7_AdvancedGuide.md#value-parameterized-tests) or [types](V1_7_AdvancedGuide.md#typed-tests), Google Test supports various ways for the user to extend the framework -- if Google Test doesn't do something out of the box, chances are that a user can implement the feature using Google Test's public API, without changing Google Test itself. In particular, you can: - * expand your testing vocabulary by defining [custom predicates](V1_7_AdvancedGuide.md#predicate-assertions-for-better-error-messages), - * teach Google Test how to [print your types](V1_7_AdvancedGuide.md#teaching-google-test-how-to-print-your-values), - * define your own testing macros or utilities and verify them using Google Test's [Service Provider Interface](V1_7_AdvancedGuide.md#catching-failures), and - * reflect on the test cases or change the test output format by intercepting the [test events](V1_7_AdvancedGuide.md#extending-google-test-by-handling-test-events). - -## I'm getting warnings when compiling Google Test. Would you fix them? ## - -We strive to minimize compiler warnings Google Test generates. Before releasing a new version, we test to make sure that it doesn't generate warnings when compiled using its CMake script on Windows, Linux, and Mac OS. - -Unfortunately, this doesn't mean you are guaranteed to see no warnings when compiling Google Test in your environment: - - * You may be using a different compiler as we use, or a different version of the same compiler. We cannot possibly test for all compilers. - * You may be compiling on a different platform as we do. - * Your project may be using different compiler flags as we do. - -It is not always possible to make Google Test warning-free for everyone. Or, it may not be desirable if the warning is rarely enabled and fixing the violations makes the code more complex. - -If you see warnings when compiling Google Test, we suggest that you use the `-isystem` flag (assuming your are using GCC) to mark Google Test headers as system headers. That'll suppress warnings from Google Test headers. - -## Why should not test case names and test names contain underscore? ## - -Underscore (`_`) is special, as C++ reserves the following to be used by -the compiler and the standard library: - - 1. any identifier that starts with an `_` followed by an upper-case letter, and - 1. any identifier that containers two consecutive underscores (i.e. `__`) _anywhere_ in its name. - -User code is _prohibited_ from using such identifiers. - -Now let's look at what this means for `TEST` and `TEST_F`. - -Currently `TEST(TestCaseName, TestName)` generates a class named -`TestCaseName_TestName_Test`. What happens if `TestCaseName` or `TestName` -contains `_`? - - 1. If `TestCaseName` starts with an `_` followed by an upper-case letter (say, `_Foo`), we end up with `_Foo_TestName_Test`, which is reserved and thus invalid. - 1. If `TestCaseName` ends with an `_` (say, `Foo_`), we get `Foo__TestName_Test`, which is invalid. - 1. If `TestName` starts with an `_` (say, `_Bar`), we get `TestCaseName__Bar_Test`, which is invalid. - 1. If `TestName` ends with an `_` (say, `Bar_`), we get `TestCaseName_Bar__Test`, which is invalid. - -So clearly `TestCaseName` and `TestName` cannot start or end with `_` -(Actually, `TestCaseName` can start with `_` -- as long as the `_` isn't -followed by an upper-case letter. But that's getting complicated. So -for simplicity we just say that it cannot start with `_`.). - -It may seem fine for `TestCaseName` and `TestName` to contain `_` in the -middle. However, consider this: -``` -TEST(Time, Flies_Like_An_Arrow) { ... } -TEST(Time_Flies, Like_An_Arrow) { ... } -``` - -Now, the two `TEST`s will both generate the same class -(`Time_Files_Like_An_Arrow_Test`). That's not good. - -So for simplicity, we just ask the users to avoid `_` in `TestCaseName` -and `TestName`. The rule is more constraining than necessary, but it's -simple and easy to remember. It also gives Google Test some wiggle -room in case its implementation needs to change in the future. - -If you violate the rule, there may not be immediately consequences, -but your test may (just may) break with a new compiler (or a new -version of the compiler you are using) or with a new version of Google -Test. Therefore it's best to follow the rule. - -## Why is it not recommended to install a pre-compiled copy of Google Test (for example, into /usr/local)? ## - -In the early days, we said that you could install -compiled Google Test libraries on `*`nix systems using `make install`. -Then every user of your machine can write tests without -recompiling Google Test. - -This seemed like a good idea, but it has a -got-cha: every user needs to compile his tests using the _same_ compiler -flags used to compile the installed Google Test libraries; otherwise -he may run into undefined behaviors (i.e. the tests can behave -strangely and may even crash for no obvious reasons). - -Why? Because C++ has this thing called the One-Definition Rule: if -two C++ source files contain different definitions of the same -class/function/variable, and you link them together, you violate the -rule. The linker may or may not catch the error (in many cases it's -not required by the C++ standard to catch the violation). If it -doesn't, you get strange run-time behaviors that are unexpected and -hard to debug. - -If you compile Google Test and your test code using different compiler -flags, they may see different definitions of the same -class/function/variable (e.g. due to the use of `#if` in Google Test). -Therefore, for your sanity, we recommend to avoid installing pre-compiled -Google Test libraries. Instead, each project should compile -Google Test itself such that it can be sure that the same flags are -used for both Google Test and the tests. - -## How do I generate 64-bit binaries on Windows (using Visual Studio 2008)? ## - -(Answered by Trevor Robinson) - -Load the supplied Visual Studio solution file, either `msvc\gtest-md.sln` or -`msvc\gtest.sln`. Go through the migration wizard to migrate the -solution and project files to Visual Studio 2008. Select -`Configuration Manager...` from the `Build` menu. Select `` from -the `Active solution platform` dropdown. Select `x64` from the new -platform dropdown, leave `Copy settings from` set to `Win32` and -`Create new project platforms` checked, then click `OK`. You now have -`Win32` and `x64` platform configurations, selectable from the -`Standard` toolbar, which allow you to toggle between building 32-bit or -64-bit binaries (or both at once using Batch Build). - -In order to prevent build output files from overwriting one another, -you'll need to change the `Intermediate Directory` settings for the -newly created platform configuration across all the projects. To do -this, multi-select (e.g. using shift-click) all projects (but not the -solution) in the `Solution Explorer`. Right-click one of them and -select `Properties`. In the left pane, select `Configuration Properties`, -and from the `Configuration` dropdown, select `All Configurations`. -Make sure the selected platform is `x64`. For the -`Intermediate Directory` setting, change the value from -`$(PlatformName)\$(ConfigurationName)` to -`$(OutDir)\$(ProjectName)`. Click `OK` and then build the -solution. When the build is complete, the 64-bit binaries will be in -the `msvc\x64\Debug` directory. - -## Can I use Google Test on MinGW? ## - -We haven't tested this ourselves, but Per Abrahamsen reported that he -was able to compile and install Google Test successfully when using -MinGW from Cygwin. You'll need to configure it with: - -`PATH/TO/configure CC="gcc -mno-cygwin" CXX="g++ -mno-cygwin"` - -You should be able to replace the `-mno-cygwin` option with direct links -to the real MinGW binaries, but we haven't tried that. - -Caveats: - - * There are many warnings when compiling. - * `make check` will produce some errors as not all tests for Google Test itself are compatible with MinGW. - -We also have reports on successful cross compilation of Google Test -MinGW binaries on Linux using -[these instructions](http://wiki.wxwidgets.org/Cross-Compiling_Under_Linux#Cross-compiling_under_Linux_for_MS_Windows) -on the WxWidgets site. - -Please contact `googletestframework@googlegroups.com` if you are -interested in improving the support for MinGW. - -## Why does Google Test support EXPECT\_EQ(NULL, ptr) and ASSERT\_EQ(NULL, ptr) but not EXPECT\_NE(NULL, ptr) and ASSERT\_NE(NULL, ptr)? ## - -Due to some peculiarity of C++, it requires some non-trivial template -meta programming tricks to support using `NULL` as an argument of the -`EXPECT_XX()` and `ASSERT_XX()` macros. Therefore we only do it where -it's most needed (otherwise we make the implementation of Google Test -harder to maintain and more error-prone than necessary). - -The `EXPECT_EQ()` macro takes the _expected_ value as its first -argument and the _actual_ value as the second. It's reasonable that -someone wants to write `EXPECT_EQ(NULL, some_expression)`, and this -indeed was requested several times. Therefore we implemented it. - -The need for `EXPECT_NE(NULL, ptr)` isn't nearly as strong. When the -assertion fails, you already know that `ptr` must be `NULL`, so it -doesn't add any information to print ptr in this case. That means -`EXPECT_TRUE(ptr != NULL)` works just as well. - -If we were to support `EXPECT_NE(NULL, ptr)`, for consistency we'll -have to support `EXPECT_NE(ptr, NULL)` as well, as unlike `EXPECT_EQ`, -we don't have a convention on the order of the two arguments for -`EXPECT_NE`. This means using the template meta programming tricks -twice in the implementation, making it even harder to understand and -maintain. We believe the benefit doesn't justify the cost. - -Finally, with the growth of Google Mock's [matcher](../../CookBook.md#using-matchers-in-google-test-assertions) library, we are -encouraging people to use the unified `EXPECT_THAT(value, matcher)` -syntax more often in tests. One significant advantage of the matcher -approach is that matchers can be easily combined to form new matchers, -while the `EXPECT_NE`, etc, macros cannot be easily -combined. Therefore we want to invest more in the matchers than in the -`EXPECT_XX()` macros. - -## Does Google Test support running tests in parallel? ## - -Test runners tend to be tightly coupled with the build/test -environment, and Google Test doesn't try to solve the problem of -running tests in parallel. Instead, we tried to make Google Test work -nicely with test runners. For example, Google Test's XML report -contains the time spent on each test, and its `gtest_list_tests` and -`gtest_filter` flags can be used for splitting the execution of test -methods into multiple processes. These functionalities can help the -test runner run the tests in parallel. - -## Why don't Google Test run the tests in different threads to speed things up? ## - -It's difficult to write thread-safe code. Most tests are not written -with thread-safety in mind, and thus may not work correctly in a -multi-threaded setting. - -If you think about it, it's already hard to make your code work when -you know what other threads are doing. It's much harder, and -sometimes even impossible, to make your code work when you don't know -what other threads are doing (remember that test methods can be added, -deleted, or modified after your test was written). If you want to run -the tests in parallel, you'd better run them in different processes. - -## Why aren't Google Test assertions implemented using exceptions? ## - -Our original motivation was to be able to use Google Test in projects -that disable exceptions. Later we realized some additional benefits -of this approach: - - 1. Throwing in a destructor is undefined behavior in C++. Not using exceptions means Google Test's assertions are safe to use in destructors. - 1. The `EXPECT_*` family of macros will continue even after a failure, allowing multiple failures in a `TEST` to be reported in a single run. This is a popular feature, as in C++ the edit-compile-test cycle is usually quite long and being able to fixing more than one thing at a time is a blessing. - 1. If assertions are implemented using exceptions, a test may falsely ignore a failure if it's caught by user code: -``` -try { ... ASSERT_TRUE(...) ... } -catch (...) { ... } -``` -The above code will pass even if the `ASSERT_TRUE` throws. While it's unlikely for someone to write this in a test, it's possible to run into this pattern when you write assertions in callbacks that are called by the code under test. - -The downside of not using exceptions is that `ASSERT_*` (implemented -using `return`) will only abort the current function, not the current -`TEST`. - -## Why do we use two different macros for tests with and without fixtures? ## - -Unfortunately, C++'s macro system doesn't allow us to use the same -macro for both cases. One possibility is to provide only one macro -for tests with fixtures, and require the user to define an empty -fixture sometimes: - -``` -class FooTest : public ::testing::Test {}; - -TEST_F(FooTest, DoesThis) { ... } -``` -or -``` -typedef ::testing::Test FooTest; - -TEST_F(FooTest, DoesThat) { ... } -``` - -Yet, many people think this is one line too many. :-) Our goal was to -make it really easy to write tests, so we tried to make simple tests -trivial to create. That means using a separate macro for such tests. - -We think neither approach is ideal, yet either of them is reasonable. -In the end, it probably doesn't matter much either way. - -## Why don't we use structs as test fixtures? ## - -We like to use structs only when representing passive data. This -distinction between structs and classes is good for documenting the -intent of the code's author. Since test fixtures have logic like -`SetUp()` and `TearDown()`, they are better defined as classes. - -## Why are death tests implemented as assertions instead of using a test runner? ## - -Our goal was to make death tests as convenient for a user as C++ -possibly allows. In particular: - - * The runner-style requires to split the information into two pieces: the definition of the death test itself, and the specification for the runner on how to run the death test and what to expect. The death test would be written in C++, while the runner spec may or may not be. A user needs to carefully keep the two in sync. `ASSERT_DEATH(statement, expected_message)` specifies all necessary information in one place, in one language, without boilerplate code. It is very declarative. - * `ASSERT_DEATH` has a similar syntax and error-reporting semantics as other Google Test assertions, and thus is easy to learn. - * `ASSERT_DEATH` can be mixed with other assertions and other logic at your will. You are not limited to one death test per test method. For example, you can write something like: -``` - if (FooCondition()) { - ASSERT_DEATH(Bar(), "blah"); - } else { - ASSERT_EQ(5, Bar()); - } -``` -If you prefer one death test per test method, you can write your tests in that style too, but we don't want to impose that on the users. The fewer artificial limitations the better. - * `ASSERT_DEATH` can reference local variables in the current function, and you can decide how many death tests you want based on run-time information. For example, -``` - const int count = GetCount(); // Only known at run time. - for (int i = 1; i <= count; i++) { - ASSERT_DEATH({ - double* buffer = new double[i]; - ... initializes buffer ... - Foo(buffer, i) - }, "blah blah"); - } -``` -The runner-based approach tends to be more static and less flexible, or requires more user effort to get this kind of flexibility. - -Another interesting thing about `ASSERT_DEATH` is that it calls `fork()` -to create a child process to run the death test. This is lightening -fast, as `fork()` uses copy-on-write pages and incurs almost zero -overhead, and the child process starts from the user-supplied -statement directly, skipping all global and local initialization and -any code leading to the given statement. If you launch the child -process from scratch, it can take seconds just to load everything and -start running if the test links to many libraries dynamically. - -## My death test modifies some state, but the change seems lost after the death test finishes. Why? ## - -Death tests (`EXPECT_DEATH`, etc) are executed in a sub-process s.t. the -expected crash won't kill the test program (i.e. the parent process). As a -result, any in-memory side effects they incur are observable in their -respective sub-processes, but not in the parent process. You can think of them -as running in a parallel universe, more or less. - -## The compiler complains about "undefined references" to some static const member variables, but I did define them in the class body. What's wrong? ## - -If your class has a static data member: - -``` -// foo.h -class Foo { - ... - static const int kBar = 100; -}; -``` - -You also need to define it _outside_ of the class body in `foo.cc`: - -``` -const int Foo::kBar; // No initializer here. -``` - -Otherwise your code is **invalid C++**, and may break in unexpected ways. In -particular, using it in Google Test comparison assertions (`EXPECT_EQ`, etc) -will generate an "undefined reference" linker error. - -## I have an interface that has several implementations. Can I write a set of tests once and repeat them over all the implementations? ## - -Google Test doesn't yet have good support for this kind of tests, or -data-driven tests in general. We hope to be able to make improvements in this -area soon. - -## Can I derive a test fixture from another? ## - -Yes. - -Each test fixture has a corresponding and same named test case. This means only -one test case can use a particular fixture. Sometimes, however, multiple test -cases may want to use the same or slightly different fixtures. For example, you -may want to make sure that all of a GUI library's test cases don't leak -important system resources like fonts and brushes. - -In Google Test, you share a fixture among test cases by putting the shared -logic in a base test fixture, then deriving from that base a separate fixture -for each test case that wants to use this common logic. You then use `TEST_F()` -to write tests using each derived fixture. - -Typically, your code looks like this: - -``` -// Defines a base test fixture. -class BaseTest : public ::testing::Test { - protected: - ... -}; - -// Derives a fixture FooTest from BaseTest. -class FooTest : public BaseTest { - protected: - virtual void SetUp() { - BaseTest::SetUp(); // Sets up the base fixture first. - ... additional set-up work ... - } - virtual void TearDown() { - ... clean-up work for FooTest ... - BaseTest::TearDown(); // Remember to tear down the base fixture - // after cleaning up FooTest! - } - ... functions and variables for FooTest ... -}; - -// Tests that use the fixture FooTest. -TEST_F(FooTest, Bar) { ... } -TEST_F(FooTest, Baz) { ... } - -... additional fixtures derived from BaseTest ... -``` - -If necessary, you can continue to derive test fixtures from a derived fixture. -Google Test has no limit on how deep the hierarchy can be. - -For a complete example using derived test fixtures, see -[sample5](../samples/sample5_unittest.cc). - -## My compiler complains "void value not ignored as it ought to be." What does this mean? ## - -You're probably using an `ASSERT_*()` in a function that doesn't return `void`. -`ASSERT_*()` can only be used in `void` functions. - -## My death test hangs (or seg-faults). How do I fix it? ## - -In Google Test, death tests are run in a child process and the way they work is -delicate. To write death tests you really need to understand how they work. -Please make sure you have read this. - -In particular, death tests don't like having multiple threads in the parent -process. So the first thing you can try is to eliminate creating threads -outside of `EXPECT_DEATH()`. - -Sometimes this is impossible as some library you must use may be creating -threads before `main()` is even reached. In this case, you can try to minimize -the chance of conflicts by either moving as many activities as possible inside -`EXPECT_DEATH()` (in the extreme case, you want to move everything inside), or -leaving as few things as possible in it. Also, you can try to set the death -test style to `"threadsafe"`, which is safer but slower, and see if it helps. - -If you go with thread-safe death tests, remember that they rerun the test -program from the beginning in the child process. Therefore make sure your -program can run side-by-side with itself and is deterministic. - -In the end, this boils down to good concurrent programming. You have to make -sure that there is no race conditions or dead locks in your program. No silver -bullet - sorry! - -## Should I use the constructor/destructor of the test fixture or the set-up/tear-down function? ## - -The first thing to remember is that Google Test does not reuse the -same test fixture object across multiple tests. For each `TEST_F`, -Google Test will create a fresh test fixture object, _immediately_ -call `SetUp()`, run the test, call `TearDown()`, and then -_immediately_ delete the test fixture object. Therefore, there is no -need to write a `SetUp()` or `TearDown()` function if the constructor -or destructor already does the job. - -You may still want to use `SetUp()/TearDown()` in the following cases: - * If the tear-down operation could throw an exception, you must use `TearDown()` as opposed to the destructor, as throwing in a destructor leads to undefined behavior and usually will kill your program right away. Note that many standard libraries (like STL) may throw when exceptions are enabled in the compiler. Therefore you should prefer `TearDown()` if you want to write portable tests that work with or without exceptions. - * The assertion macros throw an exception when flag `--gtest_throw_on_failure` is specified. Therefore, you shouldn't use Google Test assertions in a destructor if you plan to run your tests with this flag. - * In a constructor or destructor, you cannot make a virtual function call on this object. (You can call a method declared as virtual, but it will be statically bound.) Therefore, if you need to call a method that will be overriden in a derived class, you have to use `SetUp()/TearDown()`. - -## The compiler complains "no matching function to call" when I use ASSERT\_PREDn. How do I fix it? ## - -If the predicate function you use in `ASSERT_PRED*` or `EXPECT_PRED*` is -overloaded or a template, the compiler will have trouble figuring out which -overloaded version it should use. `ASSERT_PRED_FORMAT*` and -`EXPECT_PRED_FORMAT*` don't have this problem. - -If you see this error, you might want to switch to -`(ASSERT|EXPECT)_PRED_FORMAT*`, which will also give you a better failure -message. If, however, that is not an option, you can resolve the problem by -explicitly telling the compiler which version to pick. - -For example, suppose you have - -``` -bool IsPositive(int n) { - return n > 0; -} -bool IsPositive(double x) { - return x > 0; -} -``` - -you will get a compiler error if you write - -``` -EXPECT_PRED1(IsPositive, 5); -``` - -However, this will work: - -``` -EXPECT_PRED1(*static_cast*(IsPositive), 5); -``` - -(The stuff inside the angled brackets for the `static_cast` operator is the -type of the function pointer for the `int`-version of `IsPositive()`.) - -As another example, when you have a template function - -``` -template -bool IsNegative(T x) { - return x < 0; -} -``` - -you can use it in a predicate assertion like this: - -``` -ASSERT_PRED1(IsNegative**, -5); -``` - -Things are more interesting if your template has more than one parameters. The -following won't compile: - -``` -ASSERT_PRED2(*GreaterThan*, 5, 0); -``` - - -as the C++ pre-processor thinks you are giving `ASSERT_PRED2` 4 arguments, -which is one more than expected. The workaround is to wrap the predicate -function in parentheses: - -``` -ASSERT_PRED2(*(GreaterThan)*, 5, 0); -``` - - -## My compiler complains about "ignoring return value" when I call RUN\_ALL\_TESTS(). Why? ## - -Some people had been ignoring the return value of `RUN_ALL_TESTS()`. That is, -instead of - -``` -return RUN_ALL_TESTS(); -``` - -they write - -``` -RUN_ALL_TESTS(); -``` - -This is wrong and dangerous. A test runner needs to see the return value of -`RUN_ALL_TESTS()` in order to determine if a test has passed. If your `main()` -function ignores it, your test will be considered successful even if it has a -Google Test assertion failure. Very bad. - -To help the users avoid this dangerous bug, the implementation of -`RUN_ALL_TESTS()` causes gcc to raise this warning, when the return value is -ignored. If you see this warning, the fix is simple: just make sure its value -is used as the return value of `main()`. - -## My compiler complains that a constructor (or destructor) cannot return a value. What's going on? ## - -Due to a peculiarity of C++, in order to support the syntax for streaming -messages to an `ASSERT_*`, e.g. - -``` -ASSERT_EQ(1, Foo()) << "blah blah" << foo; -``` - -we had to give up using `ASSERT*` and `FAIL*` (but not `EXPECT*` and -`ADD_FAILURE*`) in constructors and destructors. The workaround is to move the -content of your constructor/destructor to a private void member function, or -switch to `EXPECT_*()` if that works. This section in the user's guide explains -it. - -## My set-up function is not called. Why? ## - -C++ is case-sensitive. It should be spelled as `SetUp()`. Did you -spell it as `Setup()`? - -Similarly, sometimes people spell `SetUpTestCase()` as `SetupTestCase()` and -wonder why it's never called. - -## How do I jump to the line of a failure in Emacs directly? ## - -Google Test's failure message format is understood by Emacs and many other -IDEs, like acme and XCode. If a Google Test message is in a compilation buffer -in Emacs, then it's clickable. You can now hit `enter` on a message to jump to -the corresponding source code, or use `C-x `` to jump to the next failure. - -## I have several test cases which share the same test fixture logic, do I have to define a new test fixture class for each of them? This seems pretty tedious. ## - -You don't have to. Instead of - -``` -class FooTest : public BaseTest {}; - -TEST_F(FooTest, Abc) { ... } -TEST_F(FooTest, Def) { ... } - -class BarTest : public BaseTest {}; - -TEST_F(BarTest, Abc) { ... } -TEST_F(BarTest, Def) { ... } -``` - -you can simply `typedef` the test fixtures: -``` -typedef BaseTest FooTest; - -TEST_F(FooTest, Abc) { ... } -TEST_F(FooTest, Def) { ... } - -typedef BaseTest BarTest; - -TEST_F(BarTest, Abc) { ... } -TEST_F(BarTest, Def) { ... } -``` - -## The Google Test output is buried in a whole bunch of log messages. What do I do? ## - -The Google Test output is meant to be a concise and human-friendly report. If -your test generates textual output itself, it will mix with the Google Test -output, making it hard to read. However, there is an easy solution to this -problem. - -Since most log messages go to stderr, we decided to let Google Test output go -to stdout. This way, you can easily separate the two using redirection. For -example: -``` -./my_test > googletest_output.txt -``` - -## Why should I prefer test fixtures over global variables? ## - -There are several good reasons: - 1. It's likely your test needs to change the states of its global variables. This makes it difficult to keep side effects from escaping one test and contaminating others, making debugging difficult. By using fixtures, each test has a fresh set of variables that's different (but with the same names). Thus, tests are kept independent of each other. - 1. Global variables pollute the global namespace. - 1. Test fixtures can be reused via subclassing, which cannot be done easily with global variables. This is useful if many test cases have something in common. - -## How do I test private class members without writing FRIEND\_TEST()s? ## - -You should try to write testable code, which means classes should be easily -tested from their public interface. One way to achieve this is the Pimpl idiom: -you move all private members of a class into a helper class, and make all -members of the helper class public. - -You have several other options that don't require using `FRIEND_TEST`: - * Write the tests as members of the fixture class: -``` -class Foo { - friend class FooTest; - ... -}; - -class FooTest : public ::testing::Test { - protected: - ... - void Test1() {...} // This accesses private members of class Foo. - void Test2() {...} // So does this one. -}; - -TEST_F(FooTest, Test1) { - Test1(); -} - -TEST_F(FooTest, Test2) { - Test2(); -} -``` - * In the fixture class, write accessors for the tested class' private members, then use the accessors in your tests: -``` -class Foo { - friend class FooTest; - ... -}; - -class FooTest : public ::testing::Test { - protected: - ... - T1 get_private_member1(Foo* obj) { - return obj->private_member1_; - } -}; - -TEST_F(FooTest, Test1) { - ... - get_private_member1(x) - ... -} -``` - * If the methods are declared **protected**, you can change their access level in a test-only subclass: -``` -class YourClass { - ... - protected: // protected access for testability. - int DoSomethingReturningInt(); - ... -}; - -// in the your_class_test.cc file: -class TestableYourClass : public YourClass { - ... - public: using YourClass::DoSomethingReturningInt; // changes access rights - ... -}; - -TEST_F(YourClassTest, DoSomethingTest) { - TestableYourClass obj; - assertEquals(expected_value, obj.DoSomethingReturningInt()); -} -``` - -## How do I test private class static members without writing FRIEND\_TEST()s? ## - -We find private static methods clutter the header file. They are -implementation details and ideally should be kept out of a .h. So often I make -them free functions instead. - -Instead of: -``` -// foo.h -class Foo { - ... - private: - static bool Func(int n); -}; - -// foo.cc -bool Foo::Func(int n) { ... } - -// foo_test.cc -EXPECT_TRUE(Foo::Func(12345)); -``` - -You probably should better write: -``` -// foo.h -class Foo { - ... -}; - -// foo.cc -namespace internal { - bool Func(int n) { ... } -} - -// foo_test.cc -namespace internal { - bool Func(int n); -} - -EXPECT_TRUE(internal::Func(12345)); -``` - -## I would like to run a test several times with different parameters. Do I need to write several similar copies of it? ## - -No. You can use a feature called [value-parameterized tests](V1_7_AdvancedGuide.md#Value_Parameterized_Tests) which -lets you repeat your tests with different parameters, without defining it more than once. - -## How do I test a file that defines main()? ## - -To test a `foo.cc` file, you need to compile and link it into your unit test -program. However, when the file contains a definition for the `main()` -function, it will clash with the `main()` of your unit test, and will result in -a build error. - -The right solution is to split it into three files: - 1. `foo.h` which contains the declarations, - 1. `foo.cc` which contains the definitions except `main()`, and - 1. `foo_main.cc` which contains nothing but the definition of `main()`. - -Then `foo.cc` can be easily tested. - -If you are adding tests to an existing file and don't want an intrusive change -like this, there is a hack: just include the entire `foo.cc` file in your unit -test. For example: -``` -// File foo_unittest.cc - -// The headers section -... - -// Renames main() in foo.cc to make room for the unit test main() -#define main FooMain - -#include "a/b/foo.cc" - -// The tests start here. -... -``` - - -However, please remember this is a hack and should only be used as the last -resort. - -## What can the statement argument in ASSERT\_DEATH() be? ## - -`ASSERT_DEATH(_statement_, _regex_)` (or any death assertion macro) can be used -wherever `_statement_` is valid. So basically `_statement_` can be any C++ -statement that makes sense in the current context. In particular, it can -reference global and/or local variables, and can be: - * a simple function call (often the case), - * a complex expression, or - * a compound statement. - -> Some examples are shown here: - -``` -// A death test can be a simple function call. -TEST(MyDeathTest, FunctionCall) { - ASSERT_DEATH(Xyz(5), "Xyz failed"); -} - -// Or a complex expression that references variables and functions. -TEST(MyDeathTest, ComplexExpression) { - const bool c = Condition(); - ASSERT_DEATH((c ? Func1(0) : object2.Method("test")), - "(Func1|Method) failed"); -} - -// Death assertions can be used any where in a function. In -// particular, they can be inside a loop. -TEST(MyDeathTest, InsideLoop) { - // Verifies that Foo(0), Foo(1), ..., and Foo(4) all die. - for (int i = 0; i < 5; i++) { - EXPECT_DEATH_M(Foo(i), "Foo has \\d+ errors", - ::testing::Message() << "where i is " << i); - } -} - -// A death assertion can contain a compound statement. -TEST(MyDeathTest, CompoundStatement) { - // Verifies that at lease one of Bar(0), Bar(1), ..., and - // Bar(4) dies. - ASSERT_DEATH({ - for (int i = 0; i < 5; i++) { - Bar(i); - } - }, - "Bar has \\d+ errors");} -``` - -`googletest_unittest.cc` contains more examples if you are interested. - -## What syntax does the regular expression in ASSERT\_DEATH use? ## - -On POSIX systems, Google Test uses the POSIX Extended regular -expression syntax -(http://en.wikipedia.org/wiki/Regular_expression#POSIX_Extended_Regular_Expressions). -On Windows, it uses a limited variant of regular expression -syntax. For more details, see the -[regular expression syntax](V1_7_AdvancedGuide.md#Regular_Expression_Syntax). - -## I have a fixture class Foo, but TEST\_F(Foo, Bar) gives me error "no matching function for call to Foo::Foo()". Why? ## - -Google Test needs to be able to create objects of your test fixture class, so -it must have a default constructor. Normally the compiler will define one for -you. However, there are cases where you have to define your own: - * If you explicitly declare a non-default constructor for class `Foo`, then you need to define a default constructor, even if it would be empty. - * If `Foo` has a const non-static data member, then you have to define the default constructor _and_ initialize the const member in the initializer list of the constructor. (Early versions of `gcc` doesn't force you to initialize the const member. It's a bug that has been fixed in `gcc 4`.) - -## Why does ASSERT\_DEATH complain about previous threads that were already joined? ## - -With the Linux pthread library, there is no turning back once you cross the -line from single thread to multiple threads. The first time you create a -thread, a manager thread is created in addition, so you get 3, not 2, threads. -Later when the thread you create joins the main thread, the thread count -decrements by 1, but the manager thread will never be killed, so you still have -2 threads, which means you cannot safely run a death test. - -The new NPTL thread library doesn't suffer from this problem, as it doesn't -create a manager thread. However, if you don't control which machine your test -runs on, you shouldn't depend on this. - -## Why does Google Test require the entire test case, instead of individual tests, to be named FOODeathTest when it uses ASSERT\_DEATH? ## - -Google Test does not interleave tests from different test cases. That is, it -runs all tests in one test case first, and then runs all tests in the next test -case, and so on. Google Test does this because it needs to set up a test case -before the first test in it is run, and tear it down afterwords. Splitting up -the test case would require multiple set-up and tear-down processes, which is -inefficient and makes the semantics unclean. - -If we were to determine the order of tests based on test name instead of test -case name, then we would have a problem with the following situation: - -``` -TEST_F(FooTest, AbcDeathTest) { ... } -TEST_F(FooTest, Uvw) { ... } - -TEST_F(BarTest, DefDeathTest) { ... } -TEST_F(BarTest, Xyz) { ... } -``` - -Since `FooTest.AbcDeathTest` needs to run before `BarTest.Xyz`, and we don't -interleave tests from different test cases, we need to run all tests in the -`FooTest` case before running any test in the `BarTest` case. This contradicts -with the requirement to run `BarTest.DefDeathTest` before `FooTest.Uvw`. - -## But I don't like calling my entire test case FOODeathTest when it contains both death tests and non-death tests. What do I do? ## - -You don't have to, but if you like, you may split up the test case into -`FooTest` and `FooDeathTest`, where the names make it clear that they are -related: - -``` -class FooTest : public ::testing::Test { ... }; - -TEST_F(FooTest, Abc) { ... } -TEST_F(FooTest, Def) { ... } - -typedef FooTest FooDeathTest; - -TEST_F(FooDeathTest, Uvw) { ... EXPECT_DEATH(...) ... } -TEST_F(FooDeathTest, Xyz) { ... ASSERT_DEATH(...) ... } -``` - -## The compiler complains about "no match for 'operator<<'" when I use an assertion. What gives? ## - -If you use a user-defined type `FooType` in an assertion, you must make sure -there is an `std::ostream& operator<<(std::ostream&, const FooType&)` function -defined such that we can print a value of `FooType`. - -In addition, if `FooType` is declared in a name space, the `<<` operator also -needs to be defined in the _same_ name space. - -## How do I suppress the memory leak messages on Windows? ## - -Since the statically initialized Google Test singleton requires allocations on -the heap, the Visual C++ memory leak detector will report memory leaks at the -end of the program run. The easiest way to avoid this is to use the -`_CrtMemCheckpoint` and `_CrtMemDumpAllObjectsSince` calls to not report any -statically initialized heap objects. See MSDN for more details and additional -heap check/debug routines. - -## I am building my project with Google Test in Visual Studio and all I'm getting is a bunch of linker errors (or warnings). Help! ## - -You may get a number of the following linker error or warnings if you -attempt to link your test project with the Google Test library when -your project and the are not built using the same compiler settings. - - * LNK2005: symbol already defined in object - * LNK4217: locally defined symbol 'symbol' imported in function 'function' - * LNK4049: locally defined symbol 'symbol' imported - -The Google Test project (gtest.vcproj) has the Runtime Library option -set to /MT (use multi-threaded static libraries, /MTd for debug). If -your project uses something else, for example /MD (use multi-threaded -DLLs, /MDd for debug), you need to change the setting in the Google -Test project to match your project's. - -To update this setting open the project properties in the Visual -Studio IDE then select the branch Configuration Properties | C/C++ | -Code Generation and change the option "Runtime Library". You may also try -using gtest-md.vcproj instead of gtest.vcproj. - -## I put my tests in a library and Google Test doesn't run them. What's happening? ## -Have you read a -[warning](V1_7_Primer.md#important-note-for-visual-c-users) on -the Google Test Primer page? - -## I want to use Google Test with Visual Studio but don't know where to start. ## -Many people are in your position and one of the posted his solution to -our mailing list. Here is his link: -http://hassanjamilahmad.blogspot.com/2009/07/gtest-starters-help.html. - -## I am seeing compile errors mentioning std::type\_traits when I try to use Google Test on Solaris. ## -Google Test uses parts of the standard C++ library that SunStudio does not support. -Our users reported success using alternative implementations. Try running the build after runing this commad: - -`export CC=cc CXX=CC CXXFLAGS='-library=stlport4'` - -## How can my code detect if it is running in a test? ## - -If you write code that sniffs whether it's running in a test and does -different things accordingly, you are leaking test-only logic into -production code and there is no easy way to ensure that the test-only -code paths aren't run by mistake in production. Such cleverness also -leads to -[Heisenbugs](http://en.wikipedia.org/wiki/Unusual_software_bug#Heisenbug). -Therefore we strongly advise against the practice, and Google Test doesn't -provide a way to do it. - -In general, the recommended way to cause the code to behave -differently under test is [dependency injection](http://jamesshore.com/Blog/Dependency-Injection-Demystified.html). -You can inject different functionality from the test and from the -production code. Since your production code doesn't link in the -for-test logic at all, there is no danger in accidentally running it. - -However, if you _really_, _really_, _really_ have no choice, and if -you follow the rule of ending your test program names with `_test`, -you can use the _horrible_ hack of sniffing your executable name -(`argv[0]` in `main()`) to know whether the code is under test. - -## Google Test defines a macro that clashes with one defined by another library. How do I deal with that? ## - -In C++, macros don't obey namespaces. Therefore two libraries that -both define a macro of the same name will clash if you `#include` both -definitions. In case a Google Test macro clashes with another -library, you can force Google Test to rename its macro to avoid the -conflict. - -Specifically, if both Google Test and some other code define macro -`FOO`, you can add -``` - -DGTEST_DONT_DEFINE_FOO=1 -``` -to the compiler flags to tell Google Test to change the macro's name -from `FOO` to `GTEST_FOO`. For example, with `-DGTEST_DONT_DEFINE_TEST=1`, you'll need to write -``` - GTEST_TEST(SomeTest, DoesThis) { ... } -``` -instead of -``` - TEST(SomeTest, DoesThis) { ... } -``` -in order to define a test. - -Currently, the following `TEST`, `FAIL`, `SUCCEED`, and the basic comparison assertion macros can have alternative names. You can see the full list of covered macros [here](http://www.google.com/codesearch?q=if+!GTEST_DONT_DEFINE_\w%2B+package:http://googletest\.googlecode\.com+file:/include/gtest/gtest.h). More information can be found in the "Avoiding Macro Name Clashes" section of the README file. - - -## Is it OK if I have two separate `TEST(Foo, Bar)` test methods defined in different namespaces? ## - -Yes. - -The rule is **all test methods in the same test case must use the same fixture class**. This means that the following is **allowed** because both tests use the same fixture class (`::testing::Test`). - -``` -namespace foo { -TEST(CoolTest, DoSomething) { - SUCCEED(); -} -} // namespace foo - -namespace bar { -TEST(CoolTest, DoSomething) { - SUCCEED(); -} -} // namespace foo -``` - -However, the following code is **not allowed** and will produce a runtime error from Google Test because the test methods are using different test fixture classes with the same test case name. - -``` -namespace foo { -class CoolTest : public ::testing::Test {}; // Fixture foo::CoolTest -TEST_F(CoolTest, DoSomething) { - SUCCEED(); -} -} // namespace foo - -namespace bar { -class CoolTest : public ::testing::Test {}; // Fixture: bar::CoolTest -TEST_F(CoolTest, DoSomething) { - SUCCEED(); -} -} // namespace foo -``` - -## How do I build Google Testing Framework with Xcode 4? ## - -If you try to build Google Test's Xcode project with Xcode 4.0 or later, you may encounter an error message that looks like -"Missing SDK in target gtest\_framework: /Developer/SDKs/MacOSX10.4u.sdk". That means that Xcode does not support the SDK the project is targeting. See the Xcode section in the [README](../../README.MD) file on how to resolve this. - -## My question is not covered in your FAQ! ## - -If you cannot find the answer to your question in this FAQ, there are -some other resources you can use: - - 1. read other [wiki pages](http://code.google.com/p/googletest/w/list), - 1. search the mailing list [archive](http://groups.google.com/group/googletestframework/topics), - 1. ask it on [googletestframework@googlegroups.com](mailto:googletestframework@googlegroups.com) and someone will answer it (to prevent spam, we require you to join the [discussion group](http://groups.google.com/group/googletestframework) before you can post.). - -Please note that creating an issue in the -[issue tracker](http://code.google.com/p/googletest/issues/list) is _not_ -a good way to get your answer, as it is monitored infrequently by a -very small number of people. - -When asking a question, it's helpful to provide as much of the -following information as possible (people cannot help you if there's -not enough information in your question): - - * the version (or the revision number if you check out from SVN directly) of Google Test you use (Google Test is under active development, so it's possible that your problem has been solved in a later version), - * your operating system, - * the name and version of your compiler, - * the complete command line flags you give to your compiler, - * the complete compiler error messages (if the question is about compilation), - * the _actual_ code (ideally, a minimal but complete program) that has the problem you encounter. diff --git a/googletest/docs/V1_7_Primer.md b/googletest/docs/V1_7_Primer.md deleted file mode 100644 index b1827c73..00000000 --- a/googletest/docs/V1_7_Primer.md +++ /dev/null @@ -1,501 +0,0 @@ - - -# Introduction: Why Google C++ Testing Framework? # - -_Google C++ Testing Framework_ helps you write better C++ tests. - -No matter whether you work on Linux, Windows, or a Mac, if you write C++ code, -Google Test can help you. - -So what makes a good test, and how does Google C++ Testing Framework fit in? We believe: - 1. Tests should be _independent_ and _repeatable_. It's a pain to debug a test that succeeds or fails as a result of other tests. Google C++ Testing Framework isolates the tests by running each of them on a different object. When a test fails, Google C++ Testing Framework allows you to run it in isolation for quick debugging. - 1. Tests should be well _organized_ and reflect the structure of the tested code. Google C++ Testing Framework groups related tests into test cases that can share data and subroutines. This common pattern is easy to recognize and makes tests easy to maintain. Such consistency is especially helpful when people switch projects and start to work on a new code base. - 1. Tests should be _portable_ and _reusable_. The open-source community has a lot of code that is platform-neutral, its tests should also be platform-neutral. Google C++ Testing Framework works on different OSes, with different compilers (gcc, MSVC, and others), with or without exceptions, so Google C++ Testing Framework tests can easily work with a variety of configurations. (Note that the current release only contains build scripts for Linux - we are actively working on scripts for other platforms.) - 1. When tests fail, they should provide as much _information_ about the problem as possible. Google C++ Testing Framework doesn't stop at the first test failure. Instead, it only stops the current test and continues with the next. You can also set up tests that report non-fatal failures after which the current test continues. Thus, you can detect and fix multiple bugs in a single run-edit-compile cycle. - 1. The testing framework should liberate test writers from housekeeping chores and let them focus on the test _content_. Google C++ Testing Framework automatically keeps track of all tests defined, and doesn't require the user to enumerate them in order to run them. - 1. Tests should be _fast_. With Google C++ Testing Framework, you can reuse shared resources across tests and pay for the set-up/tear-down only once, without making tests depend on each other. - -Since Google C++ Testing Framework is based on the popular xUnit -architecture, you'll feel right at home if you've used JUnit or PyUnit before. -If not, it will take you about 10 minutes to learn the basics and get started. -So let's go! - -_Note:_ We sometimes refer to Google C++ Testing Framework informally -as _Google Test_. - -# Setting up a New Test Project # - -To write a test program using Google Test, you need to compile Google -Test into a library and link your test with it. We provide build -files for some popular build systems: `msvc/` for Visual Studio, -`xcode/` for Mac Xcode, `make/` for GNU make, `codegear/` for Borland -C++ Builder, and the autotools script (deprecated) and -`CMakeLists.txt` for CMake (recommended) in the Google Test root -directory. If your build system is not on this list, you can take a -look at `make/Makefile` to learn how Google Test should be compiled -(basically you want to compile `src/gtest-all.cc` with `GTEST_ROOT` -and `GTEST_ROOT/include` in the header search path, where `GTEST_ROOT` -is the Google Test root directory). - -Once you are able to compile the Google Test library, you should -create a project or build target for your test program. Make sure you -have `GTEST_ROOT/include` in the header search path so that the -compiler can find `"gtest/gtest.h"` when compiling your test. Set up -your test project to link with the Google Test library (for example, -in Visual Studio, this is done by adding a dependency on -`gtest.vcproj`). - -If you still have questions, take a look at how Google Test's own -tests are built and use them as examples. - -# Basic Concepts # - -When using Google Test, you start by writing _assertions_, which are statements -that check whether a condition is true. An assertion's result can be _success_, -_nonfatal failure_, or _fatal failure_. If a fatal failure occurs, it aborts -the current function; otherwise the program continues normally. - -_Tests_ use assertions to verify the tested code's behavior. If a test crashes -or has a failed assertion, then it _fails_; otherwise it _succeeds_. - -A _test case_ contains one or many tests. You should group your tests into test -cases that reflect the structure of the tested code. When multiple tests in a -test case need to share common objects and subroutines, you can put them into a -_test fixture_ class. - -A _test program_ can contain multiple test cases. - -We'll now explain how to write a test program, starting at the individual -assertion level and building up to tests and test cases. - -# Assertions # - -Google Test assertions are macros that resemble function calls. You test a -class or function by making assertions about its behavior. When an assertion -fails, Google Test prints the assertion's source file and line number location, -along with a failure message. You may also supply a custom failure message -which will be appended to Google Test's message. - -The assertions come in pairs that test the same thing but have different -effects on the current function. `ASSERT_*` versions generate fatal failures -when they fail, and **abort the current function**. `EXPECT_*` versions generate -nonfatal failures, which don't abort the current function. Usually `EXPECT_*` -are preferred, as they allow more than one failures to be reported in a test. -However, you should use `ASSERT_*` if it doesn't make sense to continue when -the assertion in question fails. - -Since a failed `ASSERT_*` returns from the current function immediately, -possibly skipping clean-up code that comes after it, it may cause a space leak. -Depending on the nature of the leak, it may or may not be worth fixing - so -keep this in mind if you get a heap checker error in addition to assertion -errors. - -To provide a custom failure message, simply stream it into the macro using the -`<<` operator, or a sequence of such operators. An example: -``` -ASSERT_EQ(x.size(), y.size()) << "Vectors x and y are of unequal length"; - -for (int i = 0; i < x.size(); ++i) { - EXPECT_EQ(x[i], y[i]) << "Vectors x and y differ at index " << i; -} -``` - -Anything that can be streamed to an `ostream` can be streamed to an assertion -macro--in particular, C strings and `string` objects. If a wide string -(`wchar_t*`, `TCHAR*` in `UNICODE` mode on Windows, or `std::wstring`) is -streamed to an assertion, it will be translated to UTF-8 when printed. - -## Basic Assertions ## - -These assertions do basic true/false condition testing. -| **Fatal assertion** | **Nonfatal assertion** | **Verifies** | -|:--------------------|:-----------------------|:-------------| -| `ASSERT_TRUE(`_condition_`)`; | `EXPECT_TRUE(`_condition_`)`; | _condition_ is true | -| `ASSERT_FALSE(`_condition_`)`; | `EXPECT_FALSE(`_condition_`)`; | _condition_ is false | - -Remember, when they fail, `ASSERT_*` yields a fatal failure and -returns from the current function, while `EXPECT_*` yields a nonfatal -failure, allowing the function to continue running. In either case, an -assertion failure means its containing test fails. - -_Availability_: Linux, Windows, Mac. - -## Binary Comparison ## - -This section describes assertions that compare two values. - -| **Fatal assertion** | **Nonfatal assertion** | **Verifies** | -|:--------------------|:-----------------------|:-------------| -|`ASSERT_EQ(`_expected_`, `_actual_`);`|`EXPECT_EQ(`_expected_`, `_actual_`);`| _expected_ `==` _actual_ | -|`ASSERT_NE(`_val1_`, `_val2_`);` |`EXPECT_NE(`_val1_`, `_val2_`);` | _val1_ `!=` _val2_ | -|`ASSERT_LT(`_val1_`, `_val2_`);` |`EXPECT_LT(`_val1_`, `_val2_`);` | _val1_ `<` _val2_ | -|`ASSERT_LE(`_val1_`, `_val2_`);` |`EXPECT_LE(`_val1_`, `_val2_`);` | _val1_ `<=` _val2_ | -|`ASSERT_GT(`_val1_`, `_val2_`);` |`EXPECT_GT(`_val1_`, `_val2_`);` | _val1_ `>` _val2_ | -|`ASSERT_GE(`_val1_`, `_val2_`);` |`EXPECT_GE(`_val1_`, `_val2_`);` | _val1_ `>=` _val2_ | - -In the event of a failure, Google Test prints both _val1_ and _val2_ -. In `ASSERT_EQ*` and `EXPECT_EQ*` (and all other equality assertions -we'll introduce later), you should put the expression you want to test -in the position of _actual_, and put its expected value in _expected_, -as Google Test's failure messages are optimized for this convention. - -Value arguments must be comparable by the assertion's comparison -operator or you'll get a compiler error. We used to require the -arguments to support the `<<` operator for streaming to an `ostream`, -but it's no longer necessary since v1.6.0 (if `<<` is supported, it -will be called to print the arguments when the assertion fails; -otherwise Google Test will attempt to print them in the best way it -can. For more details and how to customize the printing of the -arguments, see this Google Mock [recipe](../../googlemock/docs/CookBook.md#teaching-google-mock-how-to-print-your-values).). - -These assertions can work with a user-defined type, but only if you define the -corresponding comparison operator (e.g. `==`, `<`, etc). If the corresponding -operator is defined, prefer using the `ASSERT_*()` macros because they will -print out not only the result of the comparison, but the two operands as well. - -Arguments are always evaluated exactly once. Therefore, it's OK for the -arguments to have side effects. However, as with any ordinary C/C++ function, -the arguments' evaluation order is undefined (i.e. the compiler is free to -choose any order) and your code should not depend on any particular argument -evaluation order. - -`ASSERT_EQ()` does pointer equality on pointers. If used on two C strings, it -tests if they are in the same memory location, not if they have the same value. -Therefore, if you want to compare C strings (e.g. `const char*`) by value, use -`ASSERT_STREQ()` , which will be described later on. In particular, to assert -that a C string is `NULL`, use `ASSERT_STREQ(NULL, c_string)` . However, to -compare two `string` objects, you should use `ASSERT_EQ`. - -Macros in this section work with both narrow and wide string objects (`string` -and `wstring`). - -_Availability_: Linux, Windows, Mac. - -## String Comparison ## - -The assertions in this group compare two **C strings**. If you want to compare -two `string` objects, use `EXPECT_EQ`, `EXPECT_NE`, and etc instead. - -| **Fatal assertion** | **Nonfatal assertion** | **Verifies** | -|:--------------------|:-----------------------|:-------------| -| `ASSERT_STREQ(`_expected\_str_`, `_actual\_str_`);` | `EXPECT_STREQ(`_expected\_str_`, `_actual\_str_`);` | the two C strings have the same content | -| `ASSERT_STRNE(`_str1_`, `_str2_`);` | `EXPECT_STRNE(`_str1_`, `_str2_`);` | the two C strings have different content | -| `ASSERT_STRCASEEQ(`_expected\_str_`, `_actual\_str_`);`| `EXPECT_STRCASEEQ(`_expected\_str_`, `_actual\_str_`);` | the two C strings have the same content, ignoring case | -| `ASSERT_STRCASENE(`_str1_`, `_str2_`);`| `EXPECT_STRCASENE(`_str1_`, `_str2_`);` | the two C strings have different content, ignoring case | - -Note that "CASE" in an assertion name means that case is ignored. - -`*STREQ*` and `*STRNE*` also accept wide C strings (`wchar_t*`). If a -comparison of two wide strings fails, their values will be printed as UTF-8 -narrow strings. - -A `NULL` pointer and an empty string are considered _different_. - -_Availability_: Linux, Windows, Mac. - -See also: For more string comparison tricks (substring, prefix, suffix, and -regular expression matching, for example), see the [Advanced Google Test Guide](V1_7_AdvancedGuide.md). - -# Simple Tests # - -To create a test: - 1. Use the `TEST()` macro to define and name a test function, These are ordinary C++ functions that don't return a value. - 1. In this function, along with any valid C++ statements you want to include, use the various Google Test assertions to check values. - 1. The test's result is determined by the assertions; if any assertion in the test fails (either fatally or non-fatally), or if the test crashes, the entire test fails. Otherwise, it succeeds. - -``` -TEST(test_case_name, test_name) { - ... test body ... -} -``` - - -`TEST()` arguments go from general to specific. The _first_ argument is the -name of the test case, and the _second_ argument is the test's name within the -test case. Both names must be valid C++ identifiers, and they should not contain underscore (`_`). A test's _full name_ consists of its containing test case and its -individual name. Tests from different test cases can have the same individual -name. - -For example, let's take a simple integer function: -``` -int Factorial(int n); // Returns the factorial of n -``` - -A test case for this function might look like: -``` -// Tests factorial of 0. -TEST(FactorialTest, HandlesZeroInput) { - EXPECT_EQ(1, Factorial(0)); -} - -// Tests factorial of positive numbers. -TEST(FactorialTest, HandlesPositiveInput) { - EXPECT_EQ(1, Factorial(1)); - EXPECT_EQ(2, Factorial(2)); - EXPECT_EQ(6, Factorial(3)); - EXPECT_EQ(40320, Factorial(8)); -} -``` - -Google Test groups the test results by test cases, so logically-related tests -should be in the same test case; in other words, the first argument to their -`TEST()` should be the same. In the above example, we have two tests, -`HandlesZeroInput` and `HandlesPositiveInput`, that belong to the same test -case `FactorialTest`. - -_Availability_: Linux, Windows, Mac. - -# Test Fixtures: Using the Same Data Configuration for Multiple Tests # - -If you find yourself writing two or more tests that operate on similar data, -you can use a _test fixture_. It allows you to reuse the same configuration of -objects for several different tests. - -To create a fixture, just: - 1. Derive a class from `::testing::Test` . Start its body with `protected:` or `public:` as we'll want to access fixture members from sub-classes. - 1. Inside the class, declare any objects you plan to use. - 1. If necessary, write a default constructor or `SetUp()` function to prepare the objects for each test. A common mistake is to spell `SetUp()` as `Setup()` with a small `u` - don't let that happen to you. - 1. If necessary, write a destructor or `TearDown()` function to release any resources you allocated in `SetUp()` . To learn when you should use the constructor/destructor and when you should use `SetUp()/TearDown()`, read this [FAQ entry](V1_7_FAQ.md#should-i-use-the-constructordestructor-of-the-test-fixture-or-the-set-uptear-down-function). - 1. If needed, define subroutines for your tests to share. - -When using a fixture, use `TEST_F()` instead of `TEST()` as it allows you to -access objects and subroutines in the test fixture: -``` -TEST_F(test_case_name, test_name) { - ... test body ... -} -``` - -Like `TEST()`, the first argument is the test case name, but for `TEST_F()` -this must be the name of the test fixture class. You've probably guessed: `_F` -is for fixture. - -Unfortunately, the C++ macro system does not allow us to create a single macro -that can handle both types of tests. Using the wrong macro causes a compiler -error. - -Also, you must first define a test fixture class before using it in a -`TEST_F()`, or you'll get the compiler error "`virtual outside class -declaration`". - -For each test defined with `TEST_F()`, Google Test will: - 1. Create a _fresh_ test fixture at runtime - 1. Immediately initialize it via `SetUp()` , - 1. Run the test - 1. Clean up by calling `TearDown()` - 1. Delete the test fixture. Note that different tests in the same test case have different test fixture objects, and Google Test always deletes a test fixture before it creates the next one. Google Test does not reuse the same test fixture for multiple tests. Any changes one test makes to the fixture do not affect other tests. - -As an example, let's write tests for a FIFO queue class named `Queue`, which -has the following interface: -``` -template // E is the element type. -class Queue { - public: - Queue(); - void Enqueue(const E& element); - E* Dequeue(); // Returns NULL if the queue is empty. - size_t size() const; - ... -}; -``` - -First, define a fixture class. By convention, you should give it the name -`FooTest` where `Foo` is the class being tested. -``` -class QueueTest : public ::testing::Test { - protected: - virtual void SetUp() { - q1_.Enqueue(1); - q2_.Enqueue(2); - q2_.Enqueue(3); - } - - // virtual void TearDown() {} - - Queue q0_; - Queue q1_; - Queue q2_; -}; -``` - -In this case, `TearDown()` is not needed since we don't have to clean up after -each test, other than what's already done by the destructor. - -Now we'll write tests using `TEST_F()` and this fixture. -``` -TEST_F(QueueTest, IsEmptyInitially) { - EXPECT_EQ(0, q0_.size()); -} - -TEST_F(QueueTest, DequeueWorks) { - int* n = q0_.Dequeue(); - EXPECT_EQ(NULL, n); - - n = q1_.Dequeue(); - ASSERT_TRUE(n != NULL); - EXPECT_EQ(1, *n); - EXPECT_EQ(0, q1_.size()); - delete n; - - n = q2_.Dequeue(); - ASSERT_TRUE(n != NULL); - EXPECT_EQ(2, *n); - EXPECT_EQ(1, q2_.size()); - delete n; -} -``` - -The above uses both `ASSERT_*` and `EXPECT_*` assertions. The rule of thumb is -to use `EXPECT_*` when you want the test to continue to reveal more errors -after the assertion failure, and use `ASSERT_*` when continuing after failure -doesn't make sense. For example, the second assertion in the `Dequeue` test is -`ASSERT_TRUE(n != NULL)`, as we need to dereference the pointer `n` later, -which would lead to a segfault when `n` is `NULL`. - -When these tests run, the following happens: - 1. Google Test constructs a `QueueTest` object (let's call it `t1` ). - 1. `t1.SetUp()` initializes `t1` . - 1. The first test ( `IsEmptyInitially` ) runs on `t1` . - 1. `t1.TearDown()` cleans up after the test finishes. - 1. `t1` is destructed. - 1. The above steps are repeated on another `QueueTest` object, this time running the `DequeueWorks` test. - -_Availability_: Linux, Windows, Mac. - -_Note_: Google Test automatically saves all _Google Test_ flags when a test -object is constructed, and restores them when it is destructed. - -# Invoking the Tests # - -`TEST()` and `TEST_F()` implicitly register their tests with Google Test. So, unlike with many other C++ testing frameworks, you don't have to re-list all your defined tests in order to run them. - -After defining your tests, you can run them with `RUN_ALL_TESTS()` , which returns `0` if all the tests are successful, or `1` otherwise. Note that `RUN_ALL_TESTS()` runs _all tests_ in your link unit -- they can be from different test cases, or even different source files. - -When invoked, the `RUN_ALL_TESTS()` macro: - 1. Saves the state of all Google Test flags. - 1. Creates a test fixture object for the first test. - 1. Initializes it via `SetUp()`. - 1. Runs the test on the fixture object. - 1. Cleans up the fixture via `TearDown()`. - 1. Deletes the fixture. - 1. Restores the state of all Google Test flags. - 1. Repeats the above steps for the next test, until all tests have run. - -In addition, if the text fixture's constructor generates a fatal failure in -step 2, there is no point for step 3 - 5 and they are thus skipped. Similarly, -if step 3 generates a fatal failure, step 4 will be skipped. - -_Important_: You must not ignore the return value of `RUN_ALL_TESTS()`, or `gcc` -will give you a compiler error. The rationale for this design is that the -automated testing service determines whether a test has passed based on its -exit code, not on its stdout/stderr output; thus your `main()` function must -return the value of `RUN_ALL_TESTS()`. - -Also, you should call `RUN_ALL_TESTS()` only **once**. Calling it more than once -conflicts with some advanced Google Test features (e.g. thread-safe death -tests) and thus is not supported. - -_Availability_: Linux, Windows, Mac. - -# Writing the main() Function # - -You can start from this boilerplate: -``` -#include "this/package/foo.h" -#include "gtest/gtest.h" - -namespace { - -// The fixture for testing class Foo. -class FooTest : public ::testing::Test { - protected: - // You can remove any or all of the following functions if its body - // is empty. - - FooTest() { - // You can do set-up work for each test here. - } - - virtual ~FooTest() { - // You can do clean-up work that doesn't throw exceptions here. - } - - // If the constructor and destructor are not enough for setting up - // and cleaning up each test, you can define the following methods: - - virtual void SetUp() { - // Code here will be called immediately after the constructor (right - // before each test). - } - - virtual void TearDown() { - // Code here will be called immediately after each test (right - // before the destructor). - } - - // Objects declared here can be used by all tests in the test case for Foo. -}; - -// Tests that the Foo::Bar() method does Abc. -TEST_F(FooTest, MethodBarDoesAbc) { - const string input_filepath = "this/package/testdata/myinputfile.dat"; - const string output_filepath = "this/package/testdata/myoutputfile.dat"; - Foo f; - EXPECT_EQ(0, f.Bar(input_filepath, output_filepath)); -} - -// Tests that Foo does Xyz. -TEST_F(FooTest, DoesXyz) { - // Exercises the Xyz feature of Foo. -} - -} // namespace - -int main(int argc, char **argv) { - ::testing::InitGoogleTest(&argc, argv); - return RUN_ALL_TESTS(); -} -``` - -The `::testing::InitGoogleTest()` function parses the command line for Google -Test flags, and removes all recognized flags. This allows the user to control a -test program's behavior via various flags, which we'll cover in [AdvancedGuide](V1_7_AdvancedGuide.md). -You must call this function before calling `RUN_ALL_TESTS()`, or the flags -won't be properly initialized. - -On Windows, `InitGoogleTest()` also works with wide strings, so it can be used -in programs compiled in `UNICODE` mode as well. - -But maybe you think that writing all those main() functions is too much work? We agree with you completely and that's why Google Test provides a basic implementation of main(). If it fits your needs, then just link your test with gtest\_main library and you are good to go. - -## Important note for Visual C++ users ## -If you put your tests into a library and your `main()` function is in a different library or in your .exe file, those tests will not run. The reason is a [bug](https://connect.microsoft.com/feedback/viewfeedback.aspx?FeedbackID=244410&siteid=210) in Visual C++. When you define your tests, Google Test creates certain static objects to register them. These objects are not referenced from elsewhere but their constructors are still supposed to run. When Visual C++ linker sees that nothing in the library is referenced from other places it throws the library out. You have to reference your library with tests from your main program to keep the linker from discarding it. Here is how to do it. Somewhere in your library code declare a function: -``` -__declspec(dllexport) int PullInMyLibrary() { return 0; } -``` -If you put your tests in a static library (not DLL) then `__declspec(dllexport)` is not required. Now, in your main program, write a code that invokes that function: -``` -int PullInMyLibrary(); -static int dummy = PullInMyLibrary(); -``` -This will keep your tests referenced and will make them register themselves at startup. - -In addition, if you define your tests in a static library, add `/OPT:NOREF` to your main program linker options. If you use MSVC++ IDE, go to your .exe project properties/Configuration Properties/Linker/Optimization and set References setting to `Keep Unreferenced Data (/OPT:NOREF)`. This will keep Visual C++ linker from discarding individual symbols generated by your tests from the final executable. - -There is one more pitfall, though. If you use Google Test as a static library (that's how it is defined in gtest.vcproj) your tests must also reside in a static library. If you have to have them in a DLL, you _must_ change Google Test to build into a DLL as well. Otherwise your tests will not run correctly or will not run at all. The general conclusion here is: make your life easier - do not write your tests in libraries! - -# Where to Go from Here # - -Congratulations! You've learned the Google Test basics. You can start writing -and running Google Test tests, read some [samples](V1_7_Samples.md), or continue with -[AdvancedGuide](V1_7_AdvancedGuide.md), which describes many more useful Google Test features. - -# Known Limitations # - -Google Test is designed to be thread-safe. The implementation is -thread-safe on systems where the `pthreads` library is available. It -is currently _unsafe_ to use Google Test assertions from two threads -concurrently on other systems (e.g. Windows). In most tests this is -not an issue as usually the assertions are done in the main thread. If -you want to help, you can volunteer to implement the necessary -synchronization primitives in `gtest-port.h` for your platform. diff --git a/googletest/docs/V1_7_PumpManual.md b/googletest/docs/V1_7_PumpManual.md deleted file mode 100644 index 8184f153..00000000 --- a/googletest/docs/V1_7_PumpManual.md +++ /dev/null @@ -1,177 +0,0 @@ - - -Pump is Useful for Meta Programming. - -# The Problem # - -Template and macro libraries often need to define many classes, -functions, or macros that vary only (or almost only) in the number of -arguments they take. It's a lot of repetitive, mechanical, and -error-prone work. - -Variadic templates and variadic macros can alleviate the problem. -However, while both are being considered by the C++ committee, neither -is in the standard yet or widely supported by compilers. Thus they -are often not a good choice, especially when your code needs to be -portable. And their capabilities are still limited. - -As a result, authors of such libraries often have to write scripts to -generate their implementation. However, our experience is that it's -tedious to write such scripts, which tend to reflect the structure of -the generated code poorly and are often hard to read and edit. For -example, a small change needed in the generated code may require some -non-intuitive, non-trivial changes in the script. This is especially -painful when experimenting with the code. - -# Our Solution # - -Pump (for Pump is Useful for Meta Programming, Pretty Useful for Meta -Programming, or Practical Utility for Meta Programming, whichever you -prefer) is a simple meta-programming tool for C++. The idea is that a -programmer writes a `foo.pump` file which contains C++ code plus meta -code that manipulates the C++ code. The meta code can handle -iterations over a range, nested iterations, local meta variable -definitions, simple arithmetic, and conditional expressions. You can -view it as a small Domain-Specific Language. The meta language is -designed to be non-intrusive (s.t. it won't confuse Emacs' C++ mode, -for example) and concise, making Pump code intuitive and easy to -maintain. - -## Highlights ## - - * The implementation is in a single Python script and thus ultra portable: no build or installation is needed and it works cross platforms. - * Pump tries to be smart with respect to [Google's style guide](http://code.google.com/p/google-styleguide/): it breaks long lines (easy to have when they are generated) at acceptable places to fit within 80 columns and indent the continuation lines correctly. - * The format is human-readable and more concise than XML. - * The format works relatively well with Emacs' C++ mode. - -## Examples ## - -The following Pump code (where meta keywords start with `$`, `[[` and `]]` are meta brackets, and `$$` starts a meta comment that ends with the line): - -``` -$var n = 3 $$ Defines a meta variable n. -$range i 0..n $$ Declares the range of meta iterator i (inclusive). -$for i [[ - $$ Meta loop. -// Foo$i does blah for $i-ary predicates. -$range j 1..i -template -class Foo$i { -$if i == 0 [[ - blah a; -]] $elif i <= 2 [[ - blah b; -]] $else [[ - blah c; -]] -}; - -]] -``` - -will be translated by the Pump compiler to: - -``` -// Foo0 does blah for 0-ary predicates. -template -class Foo0 { - blah a; -}; - -// Foo1 does blah for 1-ary predicates. -template -class Foo1 { - blah b; -}; - -// Foo2 does blah for 2-ary predicates. -template -class Foo2 { - blah b; -}; - -// Foo3 does blah for 3-ary predicates. -template -class Foo3 { - blah c; -}; -``` - -In another example, - -``` -$range i 1..n -Func($for i + [[a$i]]); -$$ The text between i and [[ is the separator between iterations. -``` - -will generate one of the following lines (without the comments), depending on the value of `n`: - -``` -Func(); // If n is 0. -Func(a1); // If n is 1. -Func(a1 + a2); // If n is 2. -Func(a1 + a2 + a3); // If n is 3. -// And so on... -``` - -## Constructs ## - -We support the following meta programming constructs: - -| `$var id = exp` | Defines a named constant value. `$id` is valid util the end of the current meta lexical block. | -|:----------------|:-----------------------------------------------------------------------------------------------| -| `$range id exp..exp` | Sets the range of an iteration variable, which can be reused in multiple loops later. | -| `$for id sep [[ code ]]` | Iteration. The range of `id` must have been defined earlier. `$id` is valid in `code`. | -| `$($)` | Generates a single `$` character. | -| `$id` | Value of the named constant or iteration variable. | -| `$(exp)` | Value of the expression. | -| `$if exp [[ code ]] else_branch` | Conditional. | -| `[[ code ]]` | Meta lexical block. | -| `cpp_code` | Raw C++ code. | -| `$$ comment` | Meta comment. | - -**Note:** To give the user some freedom in formatting the Pump source -code, Pump ignores a new-line character if it's right after `$for foo` -or next to `[[` or `]]`. Without this rule you'll often be forced to write -very long lines to get the desired output. Therefore sometimes you may -need to insert an extra new-line in such places for a new-line to show -up in your output. - -## Grammar ## - -``` -code ::= atomic_code* -atomic_code ::= $var id = exp - | $var id = [[ code ]] - | $range id exp..exp - | $for id sep [[ code ]] - | $($) - | $id - | $(exp) - | $if exp [[ code ]] else_branch - | [[ code ]] - | cpp_code -sep ::= cpp_code | empty_string -else_branch ::= $else [[ code ]] - | $elif exp [[ code ]] else_branch - | empty_string -exp ::= simple_expression_in_Python_syntax -``` - -## Code ## - -You can find the source code of Pump in [scripts/pump.py](../scripts/pump.py). It is still -very unpolished and lacks automated tests, although it has been -successfully used many times. If you find a chance to use it in your -project, please let us know what you think! We also welcome help on -improving Pump. - -## Real Examples ## - -You can find real-world applications of Pump in [Google Test](http://www.google.com/codesearch?q=file%3A\.pump%24+package%3Ahttp%3A%2F%2Fgoogletest\.googlecode\.com) and [Google Mock](http://www.google.com/codesearch?q=file%3A\.pump%24+package%3Ahttp%3A%2F%2Fgooglemock\.googlecode\.com). The source file `foo.h.pump` generates `foo.h`. - -## Tips ## - - * If a meta variable is followed by a letter or digit, you can separate them using `[[]]`, which inserts an empty string. For example `Foo$j[[]]Helper` generate `Foo1Helper` when `j` is 1. - * To avoid extra-long Pump source lines, you can break a line anywhere you want by inserting `[[]]` followed by a new line. Since any new-line character next to `[[` or `]]` is ignored, the generated code won't contain this new line. diff --git a/googletest/docs/V1_7_Samples.md b/googletest/docs/V1_7_Samples.md deleted file mode 100644 index f21d2005..00000000 --- a/googletest/docs/V1_7_Samples.md +++ /dev/null @@ -1,14 +0,0 @@ -If you're like us, you'd like to look at some Google Test sample code. The -[samples folder](../samples) has a number of well-commented samples showing how to use a -variety of Google Test features. - - * [Sample #1](../samples/sample1_unittest.cc) shows the basic steps of using Google Test to test C++ functions. - * [Sample #2](../samples/sample2_unittest.cc) shows a more complex unit test for a class with multiple member functions. - * [Sample #3](../samples/sample3_unittest.cc) uses a test fixture. - * [Sample #4](../samples/sample4_unittest.cc) is another basic example of using Google Test. - * [Sample #5](../samples/sample5_unittest.cc) teaches how to reuse a test fixture in multiple test cases by deriving sub-fixtures from it. - * [Sample #6](../samples/sample6_unittest.cc) demonstrates type-parameterized tests. - * [Sample #7](../samples/sample7_unittest.cc) teaches the basics of value-parameterized tests. - * [Sample #8](../samples/sample8_unittest.cc) shows using `Combine()` in value-parameterized tests. - * [Sample #9](../samples/sample9_unittest.cc) shows use of the listener API to modify Google Test's console output and the use of its reflection API to inspect test results. - * [Sample #10](../samples/sample10_unittest.cc) shows use of the listener API to implement a primitive memory leak checker. diff --git a/googletest/docs/V1_7_XcodeGuide.md b/googletest/docs/V1_7_XcodeGuide.md deleted file mode 100644 index bf24bf51..00000000 --- a/googletest/docs/V1_7_XcodeGuide.md +++ /dev/null @@ -1,93 +0,0 @@ - - -This guide will explain how to use the Google Testing Framework in your Xcode projects on Mac OS X. This tutorial begins by quickly explaining what to do for experienced users. After the quick start, the guide goes provides additional explanation about each step. - -# Quick Start # - -Here is the quick guide for using Google Test in your Xcode project. - - 1. Download the source from the [website](http://code.google.com/p/googletest) using this command: `svn checkout http://googletest.googlecode.com/svn/trunk/ googletest-read-only` - 1. Open up the `gtest.xcodeproj` in the `googletest-read-only/xcode/` directory and build the gtest.framework. - 1. Create a new "Shell Tool" target in your Xcode project called something like "UnitTests" - 1. Add the gtest.framework to your project and add it to the "Link Binary with Libraries" build phase of "UnitTests" - 1. Add your unit test source code to the "Compile Sources" build phase of "UnitTests" - 1. Edit the "UnitTests" executable and add an environment variable named "DYLD\_FRAMEWORK\_PATH" with a value equal to the path to the framework containing the gtest.framework relative to the compiled executable. - 1. Build and Go - -The following sections further explain each of the steps listed above in depth, describing in more detail how to complete it including some variations. - -# Get the Source # - -Currently, the gtest.framework discussed here isn't available in a tagged release of Google Test, it is only available in the trunk. As explained at the Google Test [site](http://code.google.com/p/googletest/source/checkout">svn), you can get the code from anonymous SVN with this command: - -``` -svn checkout http://googletest.googlecode.com/svn/trunk/ googletest-read-only -``` - -Alternatively, if you are working with Subversion in your own code base, you can add Google Test as an external dependency to your own Subversion repository. By following this approach, everyone that checks out your svn repository will also receive a copy of Google Test (a specific version, if you wish) without having to check it out explicitly. This makes the set up of your project simpler and reduces the copied code in the repository. - -To use `svn:externals`, decide where you would like to have the external source reside. You might choose to put the external source inside the trunk, because you want it to be part of the branch when you make a release. However, keeping it outside the trunk in a version-tagged directory called something like `third-party/googletest/1.0.1`, is another option. Once the location is established, use `svn propedit svn:externals _directory_` to set the svn:externals property on a directory in your repository. This directory won't contain the code, but be its versioned parent directory. - -The command `svn propedit` will bring up your Subversion editor, making editing the long, (potentially multi-line) property simpler. This same method can be used to check out a tagged branch, by using the appropriate URL (e.g. `http://googletest.googlecode.com/svn/tags/release-1.0.1`). Additionally, the svn:externals property allows the specification of a particular revision of the trunk with the `-r_##_` option (e.g. `externals/src/googletest -r60 http://googletest.googlecode.com/svn/trunk`). - -Here is an example of using the svn:externals properties on a trunk (read via `svn propget`) of a project. This value checks out a copy of Google Test into the `trunk/externals/src/googletest/` directory. - -``` -[Computer:svn] user$ svn propget svn:externals trunk -externals/src/googletest http://googletest.googlecode.com/svn/trunk -``` - -# Add the Framework to Your Project # - -The next step is to build and add the gtest.framework to your own project. This guide describes two common ways below. - - * **Option 1** --- The simplest way to add Google Test to your own project, is to open gtest.xcodeproj (found in the xcode/ directory of the Google Test trunk) and build the framework manually. Then, add the built framework into your project using the "Add->Existing Framework..." from the context menu or "Project->Add..." from the main menu. The gtest.framework is relocatable and contains the headers and object code that you'll need to make tests. This method requires rebuilding every time you upgrade Google Test in your project. - * **Option 2** --- If you are going to be living off the trunk of Google Test, incorporating its latest features into your unit tests (or are a Google Test developer yourself). You'll want to rebuild the framework every time the source updates. to do this, you'll need to add the gtest.xcodeproj file, not the framework itself, to your own Xcode project. Then, from the build products that are revealed by the project's disclosure triangle, you can find the gtest.framework, which can be added to your targets (discussed below). - -# Make a Test Target # - -To start writing tests, make a new "Shell Tool" target. This target template is available under BSD, Cocoa, or Carbon. Add your unit test source code to the "Compile Sources" build phase of the target. - -Next, you'll want to add gtest.framework in two different ways, depending upon which option you chose above. - - * **Option 1** --- During compilation, Xcode will need to know that you are linking against the gtest.framework. Add the gtest.framework to the "Link Binary with Libraries" build phase of your test target. This will include the Google Test headers in your header search path, and will tell the linker where to find the library. - * **Option 2** --- If your working out of the trunk, you'll also want to add gtest.framework to your "Link Binary with Libraries" build phase of your test target. In addition, you'll want to add the gtest.framework as a dependency to your unit test target. This way, Xcode will make sure that gtest.framework is up to date, every time your build your target. Finally, if you don't share build directories with Google Test, you'll have to copy the gtest.framework into your own build products directory using a "Run Script" build phase. - -# Set Up the Executable Run Environment # - -Since the unit test executable is a shell tool, it doesn't have a bundle with a `Contents/Frameworks` directory, in which to place gtest.framework. Instead, the dynamic linker must be told at runtime to search for the framework in another location. This can be accomplished by setting the "DYLD\_FRAMEWORK\_PATH" environment variable in the "Edit Active Executable ..." Arguments tab, under "Variables to be set in the environment:". The path for this value is the path (relative or absolute) of the directory containing the gtest.framework. - -If you haven't set up the DYLD\_FRAMEWORK\_PATH, correctly, you might get a message like this: - -``` -[Session started at 2008-08-15 06:23:57 -0600.] - dyld: Library not loaded: @loader_path/../Frameworks/gtest.framework/Versions/A/gtest - Referenced from: /Users/username/Documents/Sandbox/gtestSample/build/Debug/WidgetFrameworkTest - Reason: image not found -``` - -To correct this problem, got to the directory containing the executable named in "Referenced from:" value in the error message above. Then, with the terminal in this location, find the relative path to the directory containing the gtest.framework. That is the value you'll need to set as the DYLD\_FRAMEWORK\_PATH. - -# Build and Go # - -Now, when you click "Build and Go", the test will be executed. Dumping out something like this: - -``` -[Session started at 2008-08-06 06:36:13 -0600.] -[==========] Running 2 tests from 1 test case. -[----------] Global test environment set-up. -[----------] 2 tests from WidgetInitializerTest -[ RUN ] WidgetInitializerTest.TestConstructor -[ OK ] WidgetInitializerTest.TestConstructor -[ RUN ] WidgetInitializerTest.TestConversion -[ OK ] WidgetInitializerTest.TestConversion -[----------] Global test environment tear-down -[==========] 2 tests from 1 test case ran. -[ PASSED ] 2 tests. - -The Debugger has exited with status 0. -``` - -# Summary # - -Unit testing is a valuable way to ensure your data model stays valid even during rapid development or refactoring. The Google Testing Framework is a great unit testing framework for C and C++ which integrates well with an Xcode development environment. \ No newline at end of file diff --git a/googletest/docs/XcodeGuide.md b/googletest/docs/XcodeGuide.md index bf24bf51..117265c5 100644 --- a/googletest/docs/XcodeGuide.md +++ b/googletest/docs/XcodeGuide.md @@ -6,13 +6,13 @@ This guide will explain how to use the Google Testing Framework in your Xcode pr Here is the quick guide for using Google Test in your Xcode project. - 1. Download the source from the [website](http://code.google.com/p/googletest) using this command: `svn checkout http://googletest.googlecode.com/svn/trunk/ googletest-read-only` + 1. Download the source from the [website](http://code.google.com/p/googletest) using this command: `svn checkout http://googletest.googlecode.com/svn/trunk/ googletest-read-only`. 1. Open up the `gtest.xcodeproj` in the `googletest-read-only/xcode/` directory and build the gtest.framework. - 1. Create a new "Shell Tool" target in your Xcode project called something like "UnitTests" - 1. Add the gtest.framework to your project and add it to the "Link Binary with Libraries" build phase of "UnitTests" - 1. Add your unit test source code to the "Compile Sources" build phase of "UnitTests" + 1. Create a new "Shell Tool" target in your Xcode project called something like "UnitTests". + 1. Add the gtest.framework to your project and add it to the "Link Binary with Libraries" build phase of "UnitTests". + 1. Add your unit test source code to the "Compile Sources" build phase of "UnitTests". 1. Edit the "UnitTests" executable and add an environment variable named "DYLD\_FRAMEWORK\_PATH" with a value equal to the path to the framework containing the gtest.framework relative to the compiled executable. - 1. Build and Go + 1. Build and Go. The following sections further explain each of the steps listed above in depth, describing in more detail how to complete it including some variations. @@ -66,7 +66,7 @@ If you haven't set up the DYLD\_FRAMEWORK\_PATH, correctly, you might get a mess Reason: image not found ``` -To correct this problem, got to the directory containing the executable named in "Referenced from:" value in the error message above. Then, with the terminal in this location, find the relative path to the directory containing the gtest.framework. That is the value you'll need to set as the DYLD\_FRAMEWORK\_PATH. +To correct this problem, go to to the directory containing the executable named in "Referenced from:" value in the error message above. Then, with the terminal in this location, find the relative path to the directory containing the gtest.framework. That is the value you'll need to set as the DYLD\_FRAMEWORK\_PATH. # Build and Go # diff --git a/googletest/include/gtest/internal/gtest-port.h b/googletest/include/gtest/internal/gtest-port.h index f6cd3c03..448c4c86 100644 --- a/googletest/include/gtest/internal/gtest-port.h +++ b/googletest/include/gtest/internal/gtest-port.h @@ -2210,12 +2210,13 @@ class ThreadLocal { GTEST_API_ size_t GetThreadCount(); // Passing non-POD classes through ellipsis (...) crashes the ARM -// compiler and generates a warning in Sun Studio. The Nokia Symbian +// compiler and generates a warning in Sun Studio before 12u4. The Nokia Symbian // and the IBM XL C/C++ compiler try to instantiate a copy constructor // for objects passed through ellipsis (...), failing for uncopyable // objects. We define this to ensure that only POD is passed through // ellipsis on these systems. -#if defined(__SYMBIAN32__) || defined(__IBMCPP__) || defined(__SUNPRO_CC) +#if defined(__SYMBIAN32__) || defined(__IBMCPP__) || \ + (defined(__SUNPRO_CC) && __SUNPRO_CC < 0x5130) // We lose support for NULL detection where the compiler doesn't like // passing non-POD classes through ellipsis (...). # define GTEST_ELLIPSIS_NEEDS_POD_ 1 @@ -2417,7 +2418,7 @@ inline int Close(int fd) { return close(fd); } inline const char* StrError(int errnum) { return strerror(errnum); } #endif inline const char* GetEnv(const char* name) { -#if GTEST_OS_WINDOWS_MOBILE || GTEST_OS_WINDOWS_PHONE | GTEST_OS_WINDOWS_RT +#if GTEST_OS_WINDOWS_MOBILE || GTEST_OS_WINDOWS_PHONE || GTEST_OS_WINDOWS_RT // We are on Windows CE, which has no environment variables. static_cast(name); // To prevent 'unused argument' warning. return NULL; diff --git a/googletest/samples/sample1.cc b/googletest/samples/sample1.cc index f171e260..7c08b28f 100644 --- a/googletest/samples/sample1.cc +++ b/googletest/samples/sample1.cc @@ -55,7 +55,7 @@ bool IsPrime(int n) { // Try to divide n by every odd number i, starting from 3 for (int i = 3; ; i += 2) { - // We only have to try i up to the squre root of n + // We only have to try i up to the square root of n if (i > n/i) break; // Now, we have i <= n/i < n. diff --git a/googletest/samples/sample3_unittest.cc b/googletest/samples/sample3_unittest.cc index 284bb476..7f51fd89 100644 --- a/googletest/samples/sample3_unittest.cc +++ b/googletest/samples/sample3_unittest.cc @@ -72,7 +72,7 @@ class QueueTestSmpl3 : public testing::Test { // accessed from sub-classes. // virtual void SetUp() will be called before each test is run. You - // should define it if you need to initialize the varaibles. + // should define it if you need to initialize the variables. // Otherwise, this can be skipped. virtual void SetUp() { q1_.Enqueue(1); diff --git a/googletest/scripts/upload.py b/googletest/scripts/upload.py index 6e6f9a14..81e8e04d 100755 --- a/googletest/scripts/upload.py +++ b/googletest/scripts/upload.py @@ -732,7 +732,7 @@ class SubversionVCS(VersionControlSystem): else: self.rev_start = self.rev_end = None # Cache output from "svn list -r REVNO dirname". - # Keys: dirname, Values: 2-tuple (ouput for start rev and end rev). + # Keys: dirname, Values: 2-tuple (output for start rev and end rev). self.svnls_cache = {} # SVN base URL is required to fetch files deleted in an older revision. # Result is cached to not guess it over and over again in GetBaseFile(). diff --git a/googletest/src/gtest-death-test.cc b/googletest/src/gtest-death-test.cc index fd1cc3fc..fca10355 100644 --- a/googletest/src/gtest-death-test.cc +++ b/googletest/src/gtest-death-test.cc @@ -1242,7 +1242,7 @@ int GetStatusFileDescriptor(unsigned int parent_process_id, reinterpret_cast(write_handle_as_size_t); HANDLE dup_write_handle; - // The newly initialized handle is accessible only in in the parent + // The newly initialized handle is accessible only in the parent // process. To obtain one accessible within the child, we need to use // DuplicateHandle. if (!::DuplicateHandle(parent_process_handle.Get(), write_handle, diff --git a/googletest/src/gtest-port.cc b/googletest/src/gtest-port.cc index d80bd80c..5a6eb873 100644 --- a/googletest/src/gtest-port.cc +++ b/googletest/src/gtest-port.cc @@ -496,7 +496,7 @@ class ThreadLocalRegistryImpl { FALSE, thread_id); GTEST_CHECK_(thread != NULL); - // We need to to pass a valid thread ID pointer into CreateThread for it + // We need to pass a valid thread ID pointer into CreateThread for it // to work correctly under Win98. DWORD watcher_thread_id; HANDLE watcher_thread = ::CreateThread( diff --git a/googletest/src/gtest.cc b/googletest/src/gtest.cc index a0308d43..b6087f9b 100644 --- a/googletest/src/gtest.cc +++ b/googletest/src/gtest.cc @@ -310,7 +310,8 @@ namespace internal { // than kMaxRange. UInt32 Random::Generate(UInt32 range) { // These constants are the same as are used in glibc's rand(3). - state_ = (1103515245U*state_ + 12345U) % kMaxRange; + // Use wider types than necessary to prevent unsigned overflow diagnostics. + state_ = static_cast(1103515245ULL*state_ + 12345U) % kMaxRange; GTEST_CHECK_(range > 0) << "Cannot generate a number in the range [0, 0)."; @@ -1168,7 +1169,7 @@ class Hunk { // Print a unified diff header for one hunk. // The format is // "@@ -, +, @@" - // where the left/right parts are ommitted if unnecessary. + // where the left/right parts are omitted if unnecessary. void PrintHeader(std::ostream* ss) const { *ss << "@@ "; if (removes_) { @@ -1781,7 +1782,7 @@ std::string CodePointToUtf8(UInt32 code_point) { return str; } -// The following two functions only make sense if the the system +// The following two functions only make sense if the system // uses UTF-16 for wide string encoding. All supported systems // with 16 bit wchar_t (Windows, Cygwin, Symbian OS) do use UTF-16. @@ -2894,6 +2895,33 @@ WORD GetColorAttribute(GTestColor color) { } } +int GetBitOffset(WORD color_mask) { + if (color_mask == 0) return 0; + + int bitOffset = 0; + while((color_mask & 1) == 0) { + color_mask >>= 1; + ++bitOffset; + } + return bitOffset; +} + +WORD GetNewColor(GTestColor color, WORD old_color_attrs) { + // Let's reuse the BG + static const WORD background_mask = BACKGROUND_BLUE | BACKGROUND_GREEN | BACKGROUND_RED | BACKGROUND_INTENSITY; + static const WORD foreground_mask = FOREGROUND_BLUE | FOREGROUND_GREEN | FOREGROUND_RED | FOREGROUND_INTENSITY; + const WORD existing_bg = old_color_attrs & background_mask; + + WORD new_color = GetColorAttribute(color) | existing_bg | FOREGROUND_INTENSITY; + static const int bg_bitOffset = GetBitOffset(background_mask); + static const int fg_bitOffset = GetBitOffset(foreground_mask); + + if (((new_color & background_mask) >> bg_bitOffset) == ((new_color & foreground_mask) >> fg_bitOffset)) { + new_color ^= FOREGROUND_INTENSITY; //invert intensity + } + return new_color; +} + #else // Returns the ANSI color code for the given color. COLOR_DEFAULT is @@ -2979,13 +3007,14 @@ void ColoredPrintf(GTestColor color, const char* fmt, ...) { CONSOLE_SCREEN_BUFFER_INFO buffer_info; GetConsoleScreenBufferInfo(stdout_handle, &buffer_info); const WORD old_color_attrs = buffer_info.wAttributes; - + const WORD new_color = GetNewColor(color, old_color_attrs); + // We need to flush the stream buffers into the console before each // SetConsoleTextAttribute call lest it affect the text that is already // printed but has not yet reached the console. fflush(stdout); - SetConsoleTextAttribute(stdout_handle, - GetColorAttribute(color) | FOREGROUND_INTENSITY); + SetConsoleTextAttribute(stdout_handle, new_color); + vprintf(fmt, args); fflush(stdout); @@ -5188,7 +5217,7 @@ static const char kColorEncodedHelpMessage[] = " @G--" GTEST_FLAG_PREFIX_ "output=xml@Y[@G:@YDIRECTORY_PATH@G" GTEST_PATH_SEP_ "@Y|@G:@YFILE_PATH]@D\n" " Generate an XML report in the given directory or with the given file\n" -" name. @YFILE_PATH@D defaults to @Gtest_details.xml@D.\n" +" name. @YFILE_PATH@D defaults to @Gtest_detail.xml@D.\n" #if GTEST_CAN_STREAM_RESULTS_ " @G--" GTEST_FLAG_PREFIX_ "stream_result_to=@YHOST@G:@YPORT@D\n" " Stream test results to the given server.\n" diff --git a/googletest/test/gtest-port_test.cc b/googletest/test/gtest-port_test.cc index c5067a40..1d25ee6b 100644 --- a/googletest/test/gtest-port_test.cc +++ b/googletest/test/gtest-port_test.cc @@ -1209,7 +1209,7 @@ class DestructorTracker { : index_(GetNewIndex()) {} ~DestructorTracker() { // We never access DestructorCall::List() concurrently, so we don't need - // to protect this acccess with a mutex. + // to protect this access with a mutex. DestructorCall::List()[index_]->ReportDestroyed(); } diff --git a/googletest/test/gtest_test_utils.py b/googletest/test/gtest_test_utils.py index 4acd36c9..d2b6748d 100755 --- a/googletest/test/gtest_test_utils.py +++ b/googletest/test/gtest_test_utils.py @@ -245,7 +245,7 @@ class Subprocess: p = subprocess.Popen(command, stdout=subprocess.PIPE, stderr=stderr, cwd=working_dir, universal_newlines=True, env=env) - # communicate returns a tuple with the file obect for the child's + # communicate returns a tuple with the file object for the child's # output. self.output = p.communicate()[0] self._return_code = p.returncode diff --git a/googletest/test/gtest_unittest.cc b/googletest/test/gtest_unittest.cc index 7627b880..1d3c7c7a 100644 --- a/googletest/test/gtest_unittest.cc +++ b/googletest/test/gtest_unittest.cc @@ -1388,7 +1388,7 @@ class TestResultTest : public Test { delete r2; } - // Helper that compares two two TestPartResults. + // Helper that compares two TestPartResults. static void CompareTestPartResult(const TestPartResult& expected, const TestPartResult& actual) { EXPECT_EQ(expected.type(), actual.type()); @@ -3689,7 +3689,7 @@ TEST(AssertionTest, ASSERT_EQ) { TEST(AssertionTest, ASSERT_EQ_NULL) { // A success. const char* p = NULL; - // Some older GCC versions may issue a spurious waring in this or the next + // Some older GCC versions may issue a spurious warning in this or the next // assertion statement. This warning should not be suppressed with // static_cast since the test verifies the ability to use bare NULL as the // expected parameter to the macro. diff --git a/googletest/test/gtest_xml_outfiles_test.py b/googletest/test/gtest_xml_outfiles_test.py index 524e437e..678f546c 100755 --- a/googletest/test/gtest_xml_outfiles_test.py +++ b/googletest/test/gtest_xml_outfiles_test.py @@ -105,7 +105,7 @@ class GTestXMLOutFilesTest(gtest_xml_test_utils.GTestXMLTestCase): # TODO(wan@google.com): libtool causes the built test binary to be # named lt-gtest_xml_outfiles_test_ instead of - # gtest_xml_outfiles_test_. To account for this possibillity, we + # gtest_xml_outfiles_test_. To account for this possibility, we # allow both names in the following code. We should remove this # hack when Chandler Carruth's libtool replacement tool is ready. output_file_name1 = test_name + ".xml" diff --git a/googletest/test/gtest_xml_output_unittest.py b/googletest/test/gtest_xml_output_unittest.py index bcd59759..e940a5aa 100755 --- a/googletest/test/gtest_xml_output_unittest.py +++ b/googletest/test/gtest_xml_output_unittest.py @@ -237,7 +237,7 @@ class GTestXMLOutputUnitTest(gtest_xml_test_utils.GTestXMLTestCase): '--shut_down_xml'] p = gtest_test_utils.Subprocess(command) if p.terminated_by_signal: - # p.signal is avalable only if p.terminated_by_signal is True. + # p.signal is available only if p.terminated_by_signal is True. self.assertFalse( p.terminated_by_signal, '%s was killed by signal %d' % (GTEST_PROGRAM_NAME, p.signal)) diff --git a/googletest/xcode/Scripts/versiongenerate.py b/googletest/xcode/Scripts/versiongenerate.py index 81de8c96..16791d25 100755 --- a/googletest/xcode/Scripts/versiongenerate.py +++ b/googletest/xcode/Scripts/versiongenerate.py @@ -42,7 +42,7 @@ 1. The AC_INIT macro will be contained within the first 1024 characters of configure.ac 2. The version string will be 3 integers separated by periods and will be - surrounded by squre brackets, "[" and "]" (e.g. [1.0.1]). The first + surrounded by square brackets, "[" and "]" (e.g. [1.0.1]). The first segment represents the major version, the second represents the minor version and the third represents the fix version. 3. No ")" character exists between the opening "(" and closing ")" of @@ -68,7 +68,7 @@ config_file.close() # Extract the version string from the AC_INIT macro # The following init_expression means: -# Extract three integers separated by periods and surrounded by squre +# Extract three integers separated by periods and surrounded by square # brackets(e.g. "[1.0.1]") between "AC_INIT(" and ")". Do not be greedy # (*? is the non-greedy flag) since that would pull in everything between # the first "(" and the last ")" in the file. @@ -88,7 +88,7 @@ file_data = """// // is executed in a "Run Script" build phase when creating gtest.framework. This // header file is not used during compilation of C-source. Rather, it simply // defines some version strings for substitution in the Info.plist. Because of -// this, we are not not restricted to C-syntax nor are we using include guards. +// this, we are not restricted to C-syntax nor are we using include guards. // #define GTEST_VERSIONINFO_SHORT %s.%s