Method testObjectAttributeAccessErrorMessages

Lib/test/test_class.py:693–740

(self)

            del A.x

    def testObjectAttributeAccessErrorMessages(self):
        class A:
            pass
        class B:
            y = 0
            __slots__ = ('z',)
        class C:
            __slots__ = ("y",)

            def __setattr__(self, name, value) -> None:
                if name == "z":
                    super().__setattr__("y", 1)
                else:
                    super().__setattr__(name, value)

        error_msg = "'A' object has no attribute 'x'"
        with self.assertRaisesRegex(AttributeError, error_msg):
            A().x
        with self.assertRaisesRegex(AttributeError, error_msg):
            del A().x

        error_msg = "'B' object has no attribute 'x'"
        with self.assertRaisesRegex(AttributeError, error_msg):
            B().x
        with self.assertRaisesRegex(AttributeError, error_msg):
            del B().x
        with self.assertRaisesRegex(
            AttributeError,
            "'B' object has no attribute 'x' and no __dict__ for setting new attributes"
        ):
            B().x = 0
        with self.assertRaisesRegex(
            AttributeError,
            "'C' object has no attribute 'x'"
        ):
            C().x = 0

        error_msg = "'B' object attribute 'y' is read-only"
        with self.assertRaisesRegex(AttributeError, error_msg):
            del B().y
        with self.assertRaisesRegex(AttributeError, error_msg):
            B().y = 0

        error_msg = 'z'
        with self.assertRaisesRegex(AttributeError, error_msg):
            B().z
        with self.assertRaisesRegex(AttributeError, error_msg):
            del B().z

    def testConstructorErrorMessages(self):
        # bpo-31506: Improves the error message logic for object_new & object_init