Method test_custom_format_specifier

Lib/test/test_fstring.py:853–861

(self)

                             ])

    def test_custom_format_specifier(self):
        class CustomFormat:
            def __format__(self, format_spec):
                return format_spec

        self.assertEqual(f'{CustomFormat():\n}', '\n')
        self.assertEqual(f'{CustomFormat():\u2603}', '☃')
        with self.assertWarns(SyntaxWarning):
            exec(r'f"{F():¯\_(ツ)_/¯}"', {'F': CustomFormat})

    def test_side_effect_order(self):
        class X: