diff --git a/test_utils.cc b/test_utils.cc
new file mode 100644
index 0000000..2791d44
--- /dev/null
+++ b/test_utils.cc
@@ -0,0 +1,73 @@
+// 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.
+
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <string>
+#include <vector>
+#include "update_engine/test_utils.h"
+#include "glog/logging.h"
+
+#include "update_engine/file_writer.h"
+
+using std::string;
+using std::vector;
+
+namespace chromeos_update_engine {
+
+vector<char> ReadFile(const string& path) {
+  vector<char> ret;
+  FILE* fp = fopen(path.c_str(), "r");
+  if (!fp)
+    return ret;
+  const size_t kChunkSize(1024);
+  size_t read_size;
+  do {
+    char buf[kChunkSize];
+    read_size = fread(buf, 1, kChunkSize, fp);
+    ret.insert(ret.end(), buf, buf + read_size);
+  } while (read_size == kChunkSize);
+  fclose(fp);
+  return ret;
+}
+
+bool WriteFile(const std::string& path, const std::vector<char>& data) {
+  DirectFileWriter writer;
+  if (0 != writer.Open(path.c_str(), O_WRONLY | O_CREAT | O_TRUNC, 0644)) {
+    return false;
+  }
+  if (static_cast<int>(data.size()) != writer.Write(&data[0], data.size())) {
+    writer.Close();
+    return false;
+  }
+  writer.Close();
+  return true;
+}
+
+off_t FileSize(const string& path) {
+  struct stat stbuf;
+  int rc = stat(path.c_str(), &stbuf);
+  CHECK_EQ(0, rc);
+  if (rc < 0)
+    return rc;
+  return stbuf.st_size;
+}
+
+std::vector<char> GzipCompressData(const std::vector<char>& data) {
+  const char fname[] = "/tmp/GzipCompressDataTemp";
+  if (!WriteFile(fname, data)) {
+    system((string("rm ") + fname).c_str());
+    return vector<char>();
+  }
+  system((string("cat ") + fname + "|gzip>" + fname + ".gz").c_str());
+  system((string("rm ") + fname).c_str());
+  vector<char> ret = ReadFile(string(fname) + ".gz");
+  system((string("rm ") + fname + ".gz").c_str());
+  return ret;
+}
+
+}  // namespace chromeos_update_engine