'Errors can be identified by ``is_error``.'

@capture_logging(None)
def test_errors_identifiable(self, logger):

    log_info(info='message')
    log_error(error='message')
    self.assertThat(logger.messages, MatchesSetwise(MatchesAll(_dict_values_match(info=Equals('message')), AfterPreprocessing(is_error, Equals(False))), MatchesAll(_dict_values_match(error=Equals('message')), AfterPreprocessing(is_error, Equals(True)))))
