diff --git a/tests/__init__.py b/tests/__init__.py
index b0b7cd0f..2bdfdd81 100755
--- a/tests/__init__.py
+++ b/tests/__init__.py
@@ -55,4 +55,4 @@ def test_suite():
     return suite
 
 if __name__ == '__main__':
-    unittest.main(defaultTest=test_suite)
+    unittest.main(defaultTest='test_suite')