### Question:
RemitSyncExecutor implements Handler.Callback { void shutdown() { this.handler.getLooper().quit(); } RemitSyncExecutor(@NonNull RemitAgent agent);   RemitSyncExecutor(@NonNull RemitAgent agent, @Nullable Handler handler,
                      @NonNull Set<Integer> freeToDBIdList); void postSyncInfoDelay(int id, long delayMillis); void postSync(int id); void postSync(List<Integer> idList); void postRemoveInfo(int id); void postRemoveFreeIds(List<Integer> idList); void postRemoveFreeId(int id); boolean handleMessage(Message msg);  }### Answer:
@Test public void shutdown() { executor.shutdown(); verify(handler.getLooper()).quit(); }