'Failures in the supplied ``deferreds`` are all logged.'

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

    expected_failure1 = Failure(ZeroDivisionError('test_logging1'))
    expected_failure2 = Failure(ZeroDivisionError('test_logging2'))
    self.failureResultOf(gather_deferreds([fail(expected_failure1), fail(expected_failure2)]))
    failures = logger.flush_tracebacks(ZeroDivisionError)
    self.assertEqual([expected_failure1.value, expected_failure2.value], list((failure['reason'] for failure in failures)))
