Simple utility method for finding the project root dir (to be used by tests loading resource files)

The code has no intent to be superportable in all possible scenarios, since it will only be used by our own test code.
I reviewed more sophisticated libraries for doing similar things but came to the conclusion that they introduced more dependencies than motivated for this single purpose.

The unit test has been tested successfully executed on Linux (cmd line and Eclipse), Mac (XCode) and Windows (VS2008).

Review URL: http://webrtc-codereview.appspot.com/223002

git-svn-id: http://webrtc.googlecode.com/svn/trunk@734 4adac7df-926f-26a2-2b94-8c16560cd09d

test/test.gyp

@@ -16,11 +16,30 @@
       'target_name': 'test_support',
       'type': 'static_library',
       'dependencies': [
-        '../testing/gtest.gyp:gtest',
+        '<(webrtc_root)/../testing/gtest.gyp:gtest',
       ],
+      'direct_dependent_settings': {
+        'include_dirs': [
+          '.',
+        ],
+      },
       'sources': [
         'test_suite.cc',
         'test_suite.h',
+        'testsupport/fileutils.h',
+        'testsupport/fileutils.cc',
+      ],
+    },
+    {
+      'target_name': 'test_support_unittests',
+      'type': 'executable',
+      'dependencies': [
+        'test_support',
+        '<(webrtc_root)/../testing/gtest.gyp:gtest',
+      ],
+       'sources': [
+        'run_all_unittests.cc',
+        'testsupport/fileutils_unittest.cc',
       ],
     },
   ],

test/testsupport/fileutils.cc

@@ -0,0 +1,58 @@
+/*
+ *  Copyright (c) 2011 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "fileutils.h"
+
+#ifdef WIN32
+#include <direct.h>
+#define GET_CURRENT_DIR _getcwd
+#define PATH_DELIMITER "\\"
+#else
+#include <unistd.h>
+#define GET_CURRENT_DIR getcwd
+#define PATH_DELIMITER "/"
+#endif
+
+#include <cstdio>
+
+namespace webrtc {
+namespace test {
+
+const std::string GetProjectRootPath() {
+  char path_buffer[FILENAME_MAX];
+  if (!GET_CURRENT_DIR(path_buffer, sizeof(path_buffer))) {
+    fprintf(stderr, "Cannot get current directory!\n");
+    return kCannotFindProjectRootDir;
+  }
+
+  // Check for our file that verifies the root dir.
+  std::string current_path(path_buffer);
+  FILE* file = NULL;
+  int path_delimiter_index = current_path.find_last_of(PATH_DELIMITER);
+  while (path_delimiter_index > -1) {
+    std::string root_filename = current_path + PATH_DELIMITER +
+        kProjectRootFileName;
+    file = fopen(root_filename.c_str(), "r");
+    if (file != NULL) {
+      return current_path + PATH_DELIMITER;
+    }
+
+    // Move up one directory in the directory tree.
+    current_path = current_path.substr(0, path_delimiter_index);
+    path_delimiter_index = current_path.find_last_of(PATH_DELIMITER);
+  }
+
+  // Reached the root directory.
+  fprintf(stderr, "Cannot find project root directory!\n");
+  return kCannotFindProjectRootDir;
+}
+
+}  // namespace webrtc
+}  // namespace test

test/testsupport/fileutils.h

@@ -0,0 +1,98 @@
+/*
+ *  Copyright (c) 2011 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+// File utilities for testing purposes.
+// The GetProjectRootPath() method is a convenient way of getting an absolute
+// path to the project source tree root directory. Using this, it is easy to
+// refer to test resource files in a portable way.
+//
+// Notice that even if Windows platforms use backslash as path delimiter, it is
+// also supported to use slash, so there's no need for #ifdef checks in test
+// code for setting up the paths to the resource files.
+//
+// Example use:
+// Assume we have the following code being used in a test source file:
+// const std::string kInputFile = webrtc::testing::GetProjectRootPath() +
+//     "test/data/voice_engine/audio_long16.wav";
+// // Use the kInputFile for the tests...
+//
+// Then here's some example outputs for different platforms:
+// Linux:
+// * Source tree located in /home/user/webrtc/trunk
+// * Test project located in /home/user/webrtc/trunk/src/testproject
+// * Test binary compiled as:
+//   /home/user/webrtc/trunk/out/Debug/testproject_unittests
+// Then GetProjectRootPath() will return /home/user/webrtc/trunk/ no matter if
+// the test binary is executed from standing in either of:
+// /home/user/webrtc/trunk
+// or
+// /home/user/webrtc/trunk/out/Debug
+// (or any other directory below the trunk for that matter).
+//
+// Windows:
+// * Source tree located in C:\Users\user\webrtc\trunk
+// * Test project located in C:\Users\user\webrtc\trunk\src\testproject
+// * Test binary compiled as:
+//   C:\Users\user\webrtc\trunk\src\testproject\Debug\testproject_unittests.exe
+// Then GetProjectRootPath() will return C:\Users\user\webrtc\trunk\ when the
+// test binary is executed from inside Visual Studio.
+// It will also return the same path if the test is executed from a command
+// prompt standing in C:\Users\user\webrtc\trunk\src\testproject\Debug
+//
+// Mac:
+// * Source tree located in /Users/user/webrtc/trunk
+// * Test project located in /Users/user/webrtc/trunk/src/testproject
+// * Test binary compiled as:
+//   /Users/user/webrtc/trunk/xcodebuild/Debug/testproject_unittests
+// Then GetProjectRootPath() will return /Users/user/webrtc/trunk/ no matter if
+// the test binary is executed from standing in either of:
+// /Users/user/webrtc/trunk
+// or
+// /Users/user/webrtc/trunk/out/Debug
+// (or any other directory below the trunk for that matter).
+
+#ifndef TEST_TESTSUPPORT_FILEUTILS_H_
+#define TEST_TESTSUPPORT_FILEUTILS_H_
+
+#include <string>
+
+namespace webrtc {
+namespace test {
+
+// The file we're looking for to identify the project root dir.
+const std::string kProjectRootFileName = "DEPS";
+
+// This is the "directory" returned if the GetProjectPath() function fails
+// to find the project root.
+const std::string kCannotFindProjectRootDir =
+    "ERROR_CANNOT_FIND_PROJECT_ROOT_DIR";
+
+// Finds the root dir of the project, to be able to set correct paths to
+// resource files used by tests.
+// The implementation is simple: it just looks for the file defined by
+// kProjectRootFileName, starting in the current directory (the working
+// directory) and then steps upward until it is found (or it is at the root of
+// the file system).
+// If the current working directory is above the project root dir, it will not
+// be found.
+//
+// If symbolic links occur in the path they will be resolved and the actual
+// directory will be returned.
+//
+// Returns the absolute path to the project root dir (usually the trunk dir)
+// WITH a trailing path delimiter.
+// If the project root is not found, the string specified by
+// kCannotFindProjectRootDir is returned.
+const std::string GetProjectRootPath();
+
+}  // namespace webrtc
+}  // namespace test
+
+#endif  // TEST_TESTSUPPORT_FILEUTILS_H_

test/testsupport/fileutils_unittest.cc

@@ -0,0 +1,59 @@
+/*
+ *  Copyright (c) 2011 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+#include "fileutils.h"
+#include "gtest/gtest.h"
+
+#ifdef WIN32
+#define PATH_DELIMITER "\\"
+#else
+#define PATH_DELIMITER "/"
+#endif
+
+namespace webrtc {
+namespace test {
+
+// Tests that the project root path is returnd for the default working directory
+// that is automatically set when the test executable is launched.
+// The test is not fully testing the implementation, since we cannot be sure
+// of where the executable was launched from.
+// The test will fail if the top level directory is not named "trunk".
+TEST(FileUtilsTest, GetProjectRootPathFromUnchangedWorkingDir) {
+  std::string path = GetProjectRootPath();
+  std::string expected_end = "trunk";
+  expected_end = PATH_DELIMITER + expected_end + PATH_DELIMITER;
+  ASSERT_EQ(path.length() - expected_end.length(), path.find(expected_end));
+}
+
+// Tests setting the current working directory to a directory three levels
+// deeper from the current one. Then testing that the project path returned
+// is still the same, when the function under test is called again.
+TEST(FileUtilsTest, GetProjectRootPathFromDeeperWorkingDir) {
+  std::string path = GetProjectRootPath();
+  std::string original_working_dir = path;  // This is the correct project root
+
+  // Change to a subdirectory path (the full path doesn't have to exist).
+  path += "foo/bar/baz";
+  chdir(path.c_str());
+
+  ASSERT_EQ(original_working_dir, GetProjectRootPath());
+}
+
+// Tests with current working directory set to a directory higher up in the
+// directory tree than the project root dir. This case shall return a specified
+// error string as a directory (which will be an invalid path).
+TEST(FileUtilsTest, GetProjectRootPathFromRootWorkingDir) {
+  // Change current working dir to the root of the current file system
+  // (this will always be "above" our project root dir).
+  chdir(PATH_DELIMITER);
+  ASSERT_EQ(kCannotFindProjectRootDir, GetProjectRootPath());
+}
+
+}  // namespace test
+}  // namespace webrtc