Googletest export

Replace ByRef with std::ref everywhere in docs.

PiperOrigin-RevId: 320002303
This commit is contained in:
ofats 2020-07-07 12:47:27 -04:00 committed by Gennadiy Rozental
parent 9aaaaf3f3d
commit 08b787796c
2 changed files with 18 additions and 21 deletions

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@ -279,9 +279,10 @@ Matcher | Description
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.
copy constructor, try wrap it in `std::ref()`, e.g.
`Eq(std::ref(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.
`IsTrue` and `IsFalse` are useful when you need to use a matcher, or for types
that can be explicitly converted to Boolean, but are not implicitly converted to
@ -586,13 +587,12 @@ callback type instead of a derived one, e.g.
```
In `InvokeArgument<N>(...)`, if an argument needs to be passed by reference,
wrap it inside `ByRef()`. For example,
wrap it inside `std::ref()`. For example,
```cpp
using ::testing::ByRef;
using ::testing::InvokeArgument;
...
InvokeArgument<2>(5, string("Hi"), ByRef(foo))
InvokeArgument<2>(5, string("Hi"), std::ref(foo))
```
calls the mock function's #2 argument, passing to it `5` and `string("Hi")` by

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@ -1180,15 +1180,14 @@ executed. Just tell gMock that it should save a reference to `bar`, instead of a
copy of it. Here's how:
```cpp
using ::testing::ByRef;
using ::testing::Eq;
using ::testing::Lt;
...
// Expects that Foo()'s argument == bar.
EXPECT_CALL(mock_obj, Foo(Eq(ByRef(bar))));
EXPECT_CALL(mock_obj, Foo(Eq(std::ref(bar))));
// Expects that Foo()'s argument < bar.
EXPECT_CALL(mock_obj, Foo(Lt(ByRef(bar))));
EXPECT_CALL(mock_obj, Foo(Lt(std::ref(bar))));
```
Remember: if you do this, don't change `bar` after the `EXPECT_CALL()`, or the
@ -1851,10 +1850,9 @@ Methods"). However, gMock 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?
Though you may be tempted, DO NOT use `ByRef()`:
Though you may be tempted, DO NOT use `std::ref()`:
```cpp
using testing::ByRef;
using testing::Return;
class MockFoo : public Foo {
@ -1865,7 +1863,7 @@ class MockFoo : public Foo {
int x = 0;
MockFoo foo;
EXPECT_CALL(foo, GetValue())
.WillRepeatedly(Return(ByRef(x))); // Wrong!
.WillRepeatedly(Return(std::ref(x))); // Wrong!
x = 42;
EXPECT_EQ(42, foo.GetValue());
```
@ -1881,9 +1879,9 @@ 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.
a proxy object that references some temporary objects.) As a result,
`std::ref(x)` is converted to an `int` value (instead of a `const int&`) when
the expectation is set, and `Return(std::ref(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*:
@ -2376,7 +2374,7 @@ using ::testing::InvokeArgument;
```
What if the callable takes an argument by reference? No problem - just wrap it
inside `ByRef()`:
inside `std::ref()`:
```cpp
...
@ -2385,20 +2383,19 @@ inside `ByRef()`:
(override));
...
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 callback.
.WillOnce(InvokeArgument<0>(5, std::ref(helper)));
// std::ref(helper) guarantees that a reference to helper, not a copy of
// it, will be passed to the callback.
```
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 in `std::ref()`? 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: