diff -r bda5a87df1c8 Lib/unittest/test/testmock/testmock.py
--- a/Lib/unittest/test/testmock/testmock.py	Fri Sep 13 06:27:52 2013 -0700
+++ b/Lib/unittest/test/testmock/testmock.py	Sat Sep 14 17:01:32 2013 +0800
@@ -1302,18 +1302,19 @@
             self.assertEqual(m.method_calls, [])
 
 
-    def test_attribute_deletion(self):
-        # this behaviour isn't *useful*, but at least it's now tested...
+    def test_attribute_deletion_after_getattr(self):
         for Klass in Mock, MagicMock, NonCallableMagicMock, NonCallableMock:
             m = Klass()
             original = m.foo
             m.foo = 3
             del m.foo
-            self.assertEqual(m.foo, original)
+            self.assertIsInstance(original, Mock)
+            self.assertFalse(hasattr(mock, 'foo'))
 
             new = m.foo = Mock()
             del m.foo
-            self.assertEqual(m.foo, new)
+            self.assertIsInstance(new, Mock)
+            self.assertFalse(hasattr(mock, 'foo'))
 
 
     def test_mock_parents(self):