test_types.py 文件源码

def test_prepare_class(self):
        # Basic test of metaclass derivation
        expected_ns = {}
        class A(type):
            def __new__(*args, **kwargs):
                return type.__new__(*args, **kwargs)

            def __prepare__(*args):
                return expected_ns

        B = types.new_class("B", (object,))
        C = types.new_class("C", (object,), {"metaclass": A})

        # The most derived metaclass of D is A rather than type.
        meta, ns, kwds = types.prepare_class("D", (B, C), {"metaclass": type})
        self.assertIs(meta, A)
        self.assertIs(ns, expected_ns)
        self.assertEqual(len(kwds), 0)