diff --git a/lib/simpletestlib.php b/lib/simpletestlib.php
index 1dc47606a03..27345e94923 100644
--- a/lib/simpletestlib.php
+++ b/lib/simpletestlib.php
@@ -1,4 +1,4 @@
-<?php
+<?php // $Id$
 /**
  * Utility functions to make unit testing easier.
  *