public static Mode defaults() {
    return new Mode(Constants.DEFAULT_FILE_SYSTEM_MODE);
  }
@Test
  public void umaskNotInteger() {
    String umask = "NotInteger";
    mThrown.expect(IllegalArgumentException.class);
    mThrown.expectMessage(ExceptionMessage.INVALID_CONFIGURATION_VALUE.getMessage(umask,
        PropertyKey.SECURITY_AUTHORIZATION_PERMISSION_UMASK));
    ModeUtils.applyDirectoryUMask(Mode.defaults(), umask);
  }