diff --git a/tests/util.py b/tests/util.py
index 454cc0d9c..b3f5e01d9 100644
--- a/tests/util.py
+++ b/tests/util.py
@@ -109,10 +109,10 @@ try:
 except ImportError:
     def assert_in(x, thing, msg=''):
         if x not in thing:
-            assert False, msg or '%r is not in %r%r' % (x, thing)
+            assert False, msg or '%r is not in %r' % (x, thing)
     def assert_not_in(x, thing, msg=''):
         if x in thing:
-            assert False, msg or '%r is in %r%r' % (x, thing)
+            assert False, msg or '%r is in %r' % (x, thing)
 
 
 def skip_if(condition, msg=None):