Introduce drive::DummyFileSystem and rewrite some tests.

chrome/browser/chromeos/drive/file_write_helper_unittest.cc

Index: chrome/browser/chromeos/drive/file_write_helper_unittest.cc
diff --git a/chrome/browser/chromeos/drive/file_write_helper_unittest.cc b/chrome/browser/chromeos/drive/file_write_helper_unittest.cc
index bd02b55343dbce837f248937db9dbd87ea9551bb..bb68996d5fa71873c0f6448c181c209a1f43d646 100644
--- a/chrome/browser/chromeos/drive/file_write_helper_unittest.cc
+++ b/chrome/browser/chromeos/drive/file_write_helper_unittest.cc
@@ -7,43 +7,65 @@
 #include "base/bind.h"
 #include "base/message_loop.h"
 #include "base/threading/thread_restrictions.h"
-#include "chrome/browser/chromeos/drive/mock_file_system.h"
+#include "chrome/browser/chromeos/drive/dummy_file_system.h"
 #include "chrome/browser/chromeos/drive/test_util.h"
 #include "content/public/browser/browser_thread.h"
 #include "content/public/test/test_browser_thread.h"
-#include "testing/gmock/include/gmock/gmock.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
-using ::testing::StrictMock;
-using ::testing::_;
-
 namespace drive {
 
 namespace {
 
-ACTION_P(MockCreateFile, error) {
-  DCHECK(!arg2.is_null());
-  arg2.Run(error);
-}
+const base::FilePath::CharType kDrivePath[] =
+    FILE_PATH_LITERAL("drive/root/file.txt");
+const base::FilePath::CharType kInvalidPath[] =
+    FILE_PATH_LITERAL("drive/invalid/path");
+const base::FilePath::CharType kLocalPath[] =
+    FILE_PATH_LITERAL("/tmp/local.txt");
 
-ACTION_P2(MockOpenFile, error, local_path) {
-  DCHECK(!arg1.is_null());
-  arg1.Run(error, local_path);
-}
+class TestFileSystem : public DummyFileSystem {
+ public:
+  // Mimics CreateFile. It always succeeds unless kInvalidPath is passed.
+  virtual void CreateFile(const base::FilePath& file_path,
+                          bool is_exclusive,
+                          const FileOperationCallback& callback) OVERRIDE {
+   if (file_path == base::FilePath(kInvalidPath)) {
+     callback.Run(FILE_ERROR_ACCESS_DENIED);
+     return;
+   }
+   created.insert(file_path);
+   callback.Run(FILE_ERROR_OK);
+  }
 
-ACTION_P(MockCloseFile, error) {
-  DCHECK(!arg1.is_null());
-  arg1.Run(error);
-}
+  // Mimics OpenFile. It fails if the |file_path| is a path that is not
+  // passed to CreateFile before. This tests that FileWriteHelper always
+  // ensures file existence before trying to open. It also fails if the
+  // path is already opened, to match the behavior of real FileSystem.
+  virtual void OpenFile(const base::FilePath& file_path,
+                        const OpenFileCallback& callback) OVERRIDE {
+    // Files failed to create should never be opened.
+    EXPECT_TRUE(created.count(file_path));
+    created.erase(file_path);
+    if (opened.count(file_path)) {
+      callback.Run(FILE_ERROR_IN_USE, base::FilePath());
+    } else {
+      opened.insert(file_path);
+      callback.Run(FILE_ERROR_OK, base::FilePath(kLocalPath));
+    }
+  }
 
-void RecordOpenFileCallbackArguments(FileError* error,
-                                     base::FilePath* path,
-                                     FileError error_arg,
-                                     const base::FilePath& path_arg) {
-  base::ThreadRestrictions::AssertIOAllowed();
-  *error = error_arg;
-  *path = path_arg;
-}
+  // Mimics CloseFile. It fails if it is passed a path not OpenFile'd.
+  virtual void CloseFile(const base::FilePath& file_path,
+                         const FileOperationCallback& callback) OVERRIDE {
+    // Files failed to open should never be closed.
+    EXPECT_TRUE(opened.count(file_path));
+    opened.erase(file_path);
+    callback.Run(FILE_ERROR_OK);
+  }
+  std::set<base::FilePath> created;
+  std::set<base::FilePath> opened;
+};
 
 }  // namespace
 
@@ -51,74 +73,69 @@ class FileWriteHelperTest : public testing::Test {
  public:
   FileWriteHelperTest()
       : ui_thread_(content::BrowserThread::UI, &message_loop_),
-        mock_file_system_(new StrictMock<MockFileSystem>) {
+        test_file_system_(new TestFileSystem) {
   }
 
  protected:
   MessageLoopForUI message_loop_;
   content::TestBrowserThread ui_thread_;
-  scoped_ptr< StrictMock<MockFileSystem> > mock_file_system_;
+  scoped_ptr<TestFileSystem> test_file_system_;
 };
 
 TEST_F(FileWriteHelperTest, PrepareFileForWritingSuccess) {
-  const base::FilePath kDrivePath(FILE_PATH_LITERAL("/drive/file.txt"));
-  const base::FilePath kLocalPath(FILE_PATH_LITERAL("/tmp/dummy.txt"));
-
-  EXPECT_CALL(*mock_file_system_, CreateFile(kDrivePath, false, _))
-      .WillOnce(MockCreateFile(FILE_ERROR_OK));
-  EXPECT_CALL(*mock_file_system_, OpenFile(kDrivePath, _))
-      .WillOnce(MockOpenFile(FILE_ERROR_OK, kLocalPath));
-  EXPECT_CALL(*mock_file_system_, CloseFile(kDrivePath, _))
-      .WillOnce(MockCloseFile(FILE_ERROR_OK));
-
-  FileWriteHelper file_write_helper(mock_file_system_.get());
+  FileWriteHelper file_write_helper(test_file_system_.get());
   FileError error = FILE_ERROR_FAILED;
   base::FilePath path;
+  // The file should successfully be opened.
   file_write_helper.PrepareWritableFileAndRun(
-      kDrivePath, base::Bind(&RecordOpenFileCallbackArguments, &error, &path));
+      base::FilePath(kDrivePath),
+      google_apis::test_util::CreateCopyResultCallback(&error, &path));
   google_apis::test_util::RunBlockingPoolTask();
 
   EXPECT_EQ(FILE_ERROR_OK, error);
-  EXPECT_EQ(kLocalPath, path);
+  EXPECT_EQ(kLocalPath, path.value());
 }
 
 TEST_F(FileWriteHelperTest, PrepareFileForWritingCreateFail) {
-  const base::FilePath kDrivePath(FILE_PATH_LITERAL("/drive/file.txt"));
-
-  EXPECT_CALL(*mock_file_system_, CreateFile(kDrivePath, false, _))
-      .WillOnce(MockCreateFile(FILE_ERROR_ACCESS_DENIED));
-  EXPECT_CALL(*mock_file_system_, OpenFile(_, _)).Times(0);
-  EXPECT_CALL(*mock_file_system_, CloseFile(_, _)).Times(0);
-
-  FileWriteHelper file_write_helper(mock_file_system_.get());
+  FileWriteHelper file_write_helper(test_file_system_.get());
   FileError error = FILE_ERROR_FAILED;
   base::FilePath path;
+  // Access to kInvalidPath should fail, and FileWriteHelper should not try to
+  // open or close the file.
   file_write_helper.PrepareWritableFileAndRun(
-      kDrivePath, base::Bind(&RecordOpenFileCallbackArguments, &error, &path));
+      base::FilePath(kInvalidPath),
+      google_apis::test_util::CreateCopyResultCallback(&error, &path));
   google_apis::test_util::RunBlockingPoolTask();
 
   EXPECT_EQ(FILE_ERROR_ACCESS_DENIED, error);
-  EXPECT_EQ(base::FilePath(), path);
+  EXPECT_TRUE(path.empty());
 }
 
 TEST_F(FileWriteHelperTest, PrepareFileForWritingOpenFail) {
-  const base::FilePath kDrivePath(FILE_PATH_LITERAL("/drive/file.txt"));
-
-  EXPECT_CALL(*mock_file_system_, CreateFile(kDrivePath, false, _))
-      .WillOnce(MockCreateFile(FILE_ERROR_OK));
-  EXPECT_CALL(*mock_file_system_, OpenFile(kDrivePath, _))
-      .WillOnce(MockOpenFile(FILE_ERROR_IN_USE, base::FilePath()));
-  EXPECT_CALL(*mock_file_system_, CloseFile(_, _)).Times(0);
-
-  FileWriteHelper file_write_helper(mock_file_system_.get());
+  // Externally open the path beforehand.
   FileError error = FILE_ERROR_FAILED;
   base::FilePath path;
+  test_file_system_->CreateFile(
+      base::FilePath(kDrivePath),
+      false,
+      google_apis::test_util::CreateCopyResultCallback(&error));
+  ASSERT_EQ(FILE_ERROR_OK, error);
+  error = FILE_ERROR_FAILED;
+  test_file_system_->OpenFile(
+      base::FilePath(kDrivePath),
+      google_apis::test_util::CreateCopyResultCallback(&error, &path));
+  ASSERT_EQ(FILE_ERROR_OK, error);
+
+  // Run FileWriteHelper on a file already opened in somewhere else.
+  // It should fail to open the file, and should not try to close it.
+  FileWriteHelper file_write_helper(test_file_system_.get());
   file_write_helper.PrepareWritableFileAndRun(
-      kDrivePath, base::Bind(&RecordOpenFileCallbackArguments, &error, &path));
+      base::FilePath(kDrivePath),
+      google_apis::test_util::CreateCopyResultCallback(&error, &path));
   google_apis::test_util::RunBlockingPoolTask();
 
   EXPECT_EQ(FILE_ERROR_IN_USE, error);
-  EXPECT_EQ(base::FilePath(), path);
+  EXPECT_TRUE(path.empty());
 }
 
 }   // namespace drive