test_weakref.py 文件源码

def test_callback_when_method_dead(self):
        # Test callback behaviour when method dies first.
        C = self._subclass()
        calls = []
        def cb(arg):
            calls.append(arg)
        o = C(1)
        r = weakref.WeakMethod(o.some_method, cb)
        del C.some_method
        gc.collect()
        self.assertEqual(calls, [r])
        # Callback is only called once.
        del o
        gc.collect()
        self.assertEqual(calls, [r])