diff --git a/test_utils.h b/test_utils.h
index 32ae19d..0ca4639 100644
--- a/test_utils.h
+++ b/test_utils.h
@@ -2,8 +2,8 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#ifndef CHROMEOS_PLATFORM_UPDATE_ENGINE_TEST_UTILS_H__
-#define CHROMEOS_PLATFORM_UPDATE_ENGINE_TEST_UTILS_H__
+#ifndef CHROMEOS_PLATFORM_UPDATE_ENGINE_TEST_UTILS_H_
+#define CHROMEOS_PLATFORM_UPDATE_ENGINE_TEST_UTILS_H_
 
 #include <sys/stat.h>
 #include <sys/types.h>
@@ -290,4 +290,4 @@
 
 }  // namespace chromeos_update_engine
 
-#endif  // CHROMEOS_PLATFORM_UPDATE_ENGINE_TEST_UTILS_H__
+#endif  // CHROMEOS_PLATFORM_UPDATE_ENGINE_TEST_UTILS_H_