'L{DailyLogFile.rotate} doesn\'t do anything if they new log file already
exists on the disk.'

def test_rotateAlreadyExists(self):

    log = RiggedDailyLogFile(self.name, self.dir)
    self.addCleanup(log.close)
    newFilePath = '{0}.{1}'.format(log.path, log.suffix(log.lastDate))
    with open(newFilePath, 'w') as fp:
        fp.write('123')
    previousFile = log._file
    log.rotate()
    self.assertEqual(previousFile, log._file)
