@Override
  public boolean tryAcquireJobLock(Configuration conf) {
    Path path = new Path(locksDir, String.format(LOCKS_DIR_JOB_FILENAME, getJobJtIdentifier(conf)));

    return tryCreateFile(conf, path);
  }
@Test(expected = NullPointerException.class)
  public void testMissingJobId() {
    Configuration conf = new Configuration();
    tested.tryAcquireJobLock(conf);
  }