pickletester.py 文件源码

def test_proto(self):
        build_none = pickle.NONE + pickle.STOP
        for proto in protocols:
            expected = build_none
            if proto >= 2:
                expected = pickle.PROTO + bytes([proto]) + expected
            p = self.dumps(None, proto)
            self.assertEqual(p, expected)

        oob = protocols[-1] + 1     # a future protocol
        badpickle = pickle.PROTO + bytes([oob]) + build_none
        try:
            self.loads(badpickle)
        except ValueError as detail:
            self.assertTrue(str(detail).startswith(
                                            "unsupported pickle protocol"))
        else:
            self.fail("expected bad protocol number to raise ValueError")