test_weakref.py 文件源码

def test_subclass_refs_dont_replace_standard_refs(self):
        class MyRef(weakref.ref):
            pass
        o = Object(42)
        r1 = MyRef(o)
        r2 = weakref.ref(o)
        self.assertTrue(r1 is not r2)
        self.assertEqual(weakref.getweakrefs(o), [r2, r1])
        self.assertEqual(weakref.getweakrefcount(o), 2)
        r3 = MyRef(o)
        self.assertEqual(weakref.getweakrefcount(o), 3)
        refs = weakref.getweakrefs(o)
        self.assertEqual(len(refs), 3)
        self.assertTrue(r2 is refs[0])
        self.assertIn(r1, refs[1:])
        self.assertIn(r3, refs[1:])