diff --git a/gpio_handler_unittest.h b/gpio_handler_unittest.h
index c98e248..484d1b8 100644
--- a/gpio_handler_unittest.h
+++ b/gpio_handler_unittest.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_GPIO_HANDLER_UNITTEST_H__
-#define CHROMEOS_PLATFORM_UPDATE_ENGINE_GPIO_HANDLER_UNITTEST_H__
+#ifndef CHROMEOS_PLATFORM_UPDATE_ENGINE_GPIO_HANDLER_UNITTEST_H_
+#define CHROMEOS_PLATFORM_UPDATE_ENGINE_GPIO_HANDLER_UNITTEST_H_
 
 // This file contains various definitions that are shared by different mock
 // implementations that emulate GPIO behavior in the system.
@@ -42,4 +42,4 @@
 
 }  // chromeos_update_engine
 
-#endif /* CHROMEOS_PLATFORM_UPDATE_ENGINE_GPIO_HANDLER_UNITTEST_H__ */
+#endif  // CHROMEOS_PLATFORM_UPDATE_ENGINE_GPIO_HANDLER_UNITTEST_H_