Enhance tests

Author: vstinner

Lib/test/test_capi/test_object.py

@@ -254,12 +254,14 @@ def test_object_getdict(self):
         class MyClass:
             pass
         obj = MyClass()
-        obj.attr = 123
 
         dict1 = object_getdict(obj)
         dict2 = obj.__dict__
         self.assertIs(dict1, dict2)
 
+        obj.attr = 123
+        self.assertEqual(dict1, {'attr': 123})
+
         class NoDict:
             __slots__ = ()
         obj = NoDict()