diff --git a/openerp/modules/module.py b/openerp/modules/module.py
index 1d8bbfde7bb..c8ea40dc17b 100644
--- a/openerp/modules/module.py
+++ b/openerp/modules/module.py
@@ -332,6 +332,7 @@ def get_test_modules(module):
 
     # include submodules too
     result = [mod_obj for name, mod_obj in sys.modules.iteritems()
+              if mod_obj # mod_obj can be None
               if name.startswith(module)]
     return result