Almost there...
git-svn-id: svn://chrome-svn/chromeos/trunk@24 06c00378-0e64-4dae-be16-12b19f9950a1
diff --git a/mock_file_writer.h b/mock_file_writer.h
new file mode 100644
index 0000000..e6d1612
--- /dev/null
+++ b/mock_file_writer.h
@@ -0,0 +1,59 @@
+// Copyright (c) 2009 The Chromium OS Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef UPDATE_ENGINE_MOCK_FILE_WRITER_H__
+#define UPDATE_ENGINE_MOCK_FILE_WRITER_H__
+
+#include "base/basictypes.h"
+#include "update_engine/file_writer.h"
+
+// MockFileWriter is an implementation of FileWriter. It will succeed
+// calls to Open(), Close(), but not do any work. All calls to Write()
+// will append the passed data to an internal vector.
+
+namespace chromeos_update_engine {
+
+class MockFileWriter : public FileWriter {
+ public:
+ MockFileWriter() : was_opened_(false), was_closed_(false) {}
+
+ virtual int Open(const char* path, int flags, mode_t mode) {
+ CHECK(!was_opened_);
+ CHECK(!was_closed_);
+ was_opened_ = true;
+ return 0;
+ }
+
+ virtual int Write(const void* bytes, size_t count) {
+ CHECK(was_opened_);
+ CHECK(!was_closed_);
+ const char* char_bytes = reinterpret_cast<const char*>(bytes);
+ bytes_.insert(bytes_.end(), char_bytes, char_bytes + count);
+ return count;
+ }
+
+ virtual int Close() {
+ CHECK(was_opened_);
+ CHECK(!was_closed_);
+ was_closed_ = true;
+ return 0;
+ }
+
+ const std::vector<char>& bytes() {
+ return bytes_;
+ }
+ private:
+ // The internal store of all bytes that have been written
+ std::vector<char> bytes_;
+
+ // These are just to ensure FileWriter methods are called properly.
+ bool was_opened_;
+ bool was_closed_;
+
+ DISALLOW_COPY_AND_ASSIGN(MockFileWriter);
+};
+
+} // namespace chromeos_update_engine
+
+#endif // UPDATE_ENGINE_MOCK_FILE_WRITER_H__