public static DeletePOptions deleteDefaults(AlluxioConfiguration conf) {
    return deleteDefaults(conf, true);
  }
@Test
  public void deleteOptionsDefaults() {
    DeletePOptions options = FileSystemOptionsUtils.deleteDefaults(mConf);
    assertNotNull(options);
    assertFalse(options.getRecursive());
    assertFalse(options.getAlluxioOnly());
    assertFalse(options.getUnchecked());
  }