diff --git a/tests/test_multidict.py b/tests/test_multidict.py
index 93e1efa1..0f30ae5e 100644
--- a/tests/test_multidict.py
+++ b/tests/test_multidict.py
@@ -367,7 +367,7 @@ def _makeOne(self, *arg, **kw):
 
     def test_is_dict(self):
         inst = self._makeOne()
-        isinstance(inst, dict)
+        self.assertTrue(isinstance(inst, dict))
 
     def test___setitem__(self):
         inst = self._makeOne({'a':1})