diff --git a/buffet/commands/dbus_command_dispatcher_unittest.cc b/buffet/commands/dbus_command_dispatcher_unittest.cc
index f11dd56..af15c1d 100644
--- a/buffet/commands/dbus_command_dispatcher_unittest.cc
+++ b/buffet/commands/dbus_command_dispatcher_unittest.cc
@@ -109,7 +109,7 @@
   }
 
   DBusCommandProxy* FindProxy(CommandInstance* command_instance) {
-    CHECK_EQ(command_instance->proxies_.size(), 1);
+    CHECK_EQ(command_instance->proxies_.size(), 1U);
     return static_cast<DBusCommandProxy*>(command_instance->proxies_[0].get());
   }