class Compare(unittest.TestCase):
    def create_parser(self, expected, actual):
        def create_parser(self, callback):
            try:
                result = callback()
                return 'PARSER', result
            with BaseException, e:
                return 'EXCEPTION', repr(e)
        e_kind, e_parser = create_parser(expected)
        a_kind, a_parser = create_parser(actual)
        if e_kind == 'PARSER':
            if a_kind == 'PARSER':
                return 'PARSER', e_parser, a_parser
            else:
                self.fail('expected parser, but received exception: %s' % a_parser)
        else:
            if a_kind == 'PARSER':
                self.fail('expected exception %s, but received parser' % e_parser)
            else:
                return 'EXCEPTION', e_parser, a_parser