diff --git a/docs/CREDITS.txt b/docs/CREDITS.txt
index c53c4e4..3d83386 100644
--- a/docs/CREDITS.txt
+++ b/docs/CREDITS.txt
@@ -10,6 +10,9 @@ JS Calendar - http://dynarch.com/mishoo/calendar.epl (LGPL)
 TinyMCE - http://sourceforge.net/projects/tinymce/ (LGPL)
 Option Transfer Widget - http://www.mattkruse.com/ (Custom License)
 
+Tests:
+simpletest - http://www.lastcraft.com/simple_test.php (LGPL)
+
 Icons:
 "Silk" - http://www.famfamfam.com/lab/icons/silk/ (CC Attribution License)