Method test_better_error_message_format

Lib/test/test_format.py:687–706

(self)

            '{:._,f}'.format(1.1)

    def test_better_error_message_format(self):
        # https://bugs.python.org/issue20524
        for value in [12j, 12, 12.0, "12"]:
            with self.subTest(value=value):
                # The format spec must be invalid for all types we're testing.
                # '%M' will suffice.
                bad_format_spec = '%M'
                err = re.escape("Invalid format specifier "
                                f"'{bad_format_spec}' for object of type "
                                f"'{type(value).__name__}'")
                with self.assertRaisesRegex(ValueError, err):
                    f"xx{{value:{bad_format_spec}}}yy".format(value=value)

                # Also test the builtin format() function.
                with self.assertRaisesRegex(ValueError, err):
                    format(value, bad_format_spec)

                # Also test f-strings.
                with self.assertRaisesRegex(ValueError, err):
                    eval("f'xx{value:{bad_format_spec}}yy'")

    def test_unicode_in_error_message(self):
        str_err = re.escape(