test_weakref.py 文件源码

def test_hashing(self):
        # Alive WeakMethods are hashable if the underlying object is
        # hashable.
        x = Object(1)
        y = Object(1)
        a = weakref.WeakMethod(x.some_method)
        b = weakref.WeakMethod(y.some_method)
        c = weakref.WeakMethod(y.other_method)
        # Since WeakMethod objects are equal, the hashes should be equal.
        self.assertEqual(hash(a), hash(b))
        ha = hash(a)
        # Dead WeakMethods retain their old hash value
        del x, y
        gc.collect()
        self.assertEqual(hash(a), ha)
        self.assertEqual(hash(b), ha)
        # If it wasn't hashed when alive, a dead WeakMethod cannot be hashed.
        self.assertRaises(TypeError, hash, c)