chrome_paths: refactor and sanitize cache directory handling

chrome/common/chrome_paths_unittest.cc

+// Copyright (c) 2010 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "chrome/common/chrome_paths_internal.h"
+
+#include <stdlib.h>
+
+#include "base/file_path.h"
+#include "base/file_util.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+// Test the behavior of chrome::GetUserCacheDirectory.
+// See that function's comments for discussion of the subtleties.
+TEST(ChromePaths, UserCacheDir) {
+
+#if defined(OS_MACOSX)
+  FilePath homedir = FilePath(getenv("HOME"));
+  FilePath test_profile_dir = homedir.Append(
+      "Library/Application Support/foobar");
+  FilePath expected_cache_dir = homedir.Append("Library/Caches/foobar");
+#elif(OS_POSIX)
+  FilePath homedir = file_util::GetHomeDir();
+  // Note: we assume XDG_CACHE_HOME/XDG_CONFIG_HOME are at their
+  // default settings.
+  FilePath test_profile_dir = homedir.Append(".config/foobar");
+  FilePath expected_cache_dir = homedir.Append(".cache/foobar");
+#endif
+
+  // Verify that a profile in the special platform-specific source
+  // location ends up in the special target location.
+  FilePath cache_dir;
+  ASSERT_TRUE(chrome::GetUserCacheDirectory(test_profile_dir, &cache_dir));
+  EXPECT_EQ(expected_cache_dir.value(), cache_dir.value());
+
+  // Verify that a profile in some other random directory doesn't use
+  // the special cache dir.
+  test_profile_dir = homedir.Append("some_other_dir");
+  ASSERT_TRUE(chrome::GetUserCacheDirectory(test_profile_dir, &cache_dir));
+  EXPECT_EQ(test_profile_dir.value(), cache_dir.value());
+}