'L{DailyLogFile.rotate} doesn\'t do anything if the log file can\'t be
written to.'

def test_rotatePermissionFileNotOk(self):

    log = logfile.DailyLogFile(self.name, self.dir)
    self.addCleanup(log.close)
    os.chmod(log.path, 292)
    previousFile = log._file
    log.rotate()
    self.assertEqual(previousFile, log._file)
