def test_regex_mixed_list(self):
        '''
            Tests  the corner case occurs when the send_always setting is True
            and no Origin header in the request, it is not possible to match
            the regular expression(s) to determine the correct
            Access-Control-Allow-Origin header to be returned. Instead, the
            list of origins is serialized, and any strings which seem like
            regular expressions (e.g. are not a '*' and contain either '*'
            or '?') will be skipped.

            Thus, the list of returned Access-Control-Allow-Origin header
            is garaunteed to be 'null', the origin or "*", as per the w3
            http://www.w3.org/TR/cors/#access-control-allow-origin-response-header

        '''
        for sub in letters:
            domain = sub % "http://%s.otherexample.com"
            for resp in self.iter_responses('/test_regex_mixed_list',
                                            origin=domain):
                self.assertEqual(domain, resp.headers.get(ACL_ORIGIN))

        self.assertEquals("http://example.com",
            self.get('/test_regex_mixed_list', origin='http://example.com').headers.get(ACL_ORIGIN))
dataset/ETHPy150Open corydolphin/flask-cors/tests/extension/test_app_extension.py/AppExtensionRegexp.test_regex_mixed_list/swapped operands of `%`