code: @Test public void isPersisted(){
    Settings settings=new Settings();
    assertFalse(settings.isPersisted(Settings.ROUND_TRIP_TIME));
    settings.set(Settings.ROUND_TRIP_TIME,0,0);
    assertFalse(settings.isPersisted(Settings.ROUND_TRIP_TIME));
    settings.set(Settings.ROUND_TRIP_TIME,PERSIST_VALUE,0);
    assertFalse(settings.isPersisted(Settings.ROUND_TRIP_TIME));
    settings.set(Settings.ROUND_TRIP_TIME,PERSISTED,0);
    assertTrue(settings.isPersisted(Settings.ROUND_TRIP_TIME));
    settings.set(Settings.ROUND_TRIP_TIME,PERSIST_VALUE | PERSISTED,0);
    assertTrue(settings.isPersisted(Settings.ROUND_TRIP_TIME));
    settings.set(Settings.ROUND_TRIP_TIME,PERSIST_VALUE,0);
    assertFalse(settings.isPersisted(Settings.ROUND_TRIP_TIME));
    settings.set(Settings.ROUND_TRIP_TIME,0,0);
    assertFalse(settings.isPersisted(Settings.ROUND_TRIP_TIME));
  }
  