#13531: add a test for defaultdict with a non-callable arg.  Patch by Mike Cheng.
diff --git a/Lib/test/test_defaultdict.py b/Lib/test/test_defaultdict.py
index a524ad7..3d760b9 100644
--- a/Lib/test/test_defaultdict.py
+++ b/Lib/test/test_defaultdict.py
@@ -171,6 +171,8 @@
         finally:
             os.remove(tfn)
 
+    def test_callable_arg(self):
+        self.assertRaises(TypeError, defaultdict, {})
 
 def test_main():
     test_support.run_unittest(TestDefaultDict)