Method test_custom_struct_new_and_init

Lib/test/test_struct.py:918–959

(self)

        self.assertEqual(my_struct.pack(12345), b'\x30\x39')

    def test_custom_struct_new_and_init(self):
        # New way, no warnings:
        class MyStruct(struct.Struct):
            def __new__(cls, newargs, initargs):
                return super().__new__(cls, *newargs)
            def __init__(self, newargs, initargs):
                if initargs is not None:
                    super().__init__(*initargs)

        my_struct = MyStruct(('>h',), ('>h',))
        self.assertEqual(my_struct.format, '>h')
        self.assertEqual(my_struct.pack(12345), b'\x30\x39')
        with self.assertRaises(TypeError):
            MyStruct((), ())
        with self.assertRaises(TypeError):
            MyStruct(('>h',), ())
        with self.assertRaises(TypeError):
            MyStruct((), ('>h',))
        with self.assertRaises(TypeError):
            MyStruct((42,), ('>h',))
        with self.assertWarns(FutureWarning):
            with self.assertRaises(TypeError):
                MyStruct(('>h',), (42,))
        with self.assertRaises(struct.error):
            MyStruct(('$',), ('>h',))
        with self.assertWarns(FutureWarning):
            with self.assertRaises(struct.error):
                MyStruct(('>h',), ('$',))
        with self.assertRaises(ValueError):
            MyStruct(('\udc00',), ('>h',))
        with self.assertRaises(ValueError):
            MyStruct((b'\xa4',), ('>h',))
        with self.assertWarns(FutureWarning):
            with self.assertRaises(ValueError):
                MyStruct(('>h',), ('\udc00',))
        with self.assertWarns(FutureWarning):
            with self.assertRaises(ValueError):
                MyStruct(('>h',), (b'\xa4',))
        with self.assertWarns(FutureWarning):
            my_struct = MyStruct(('>h',), ('<h',))
        self.assertEqual(my_struct.format, '<h')
        self.assertEqual(my_struct.pack(12345), b'\x39\x30')

    def test_no_custom_struct_new_or_init(self):
        class MyStruct(struct.Struct):