@Override
    protected void doUpdate(final List<MetaData> dataList) {
        dataList.forEach(metaData -> metaDataSubscribers.forEach(metaDataSubscriber -> metaDataSubscriber.onSubscribe(metaData)));
    }
@Test
    public void testDoUpdate() {
        List<MetaData> metaDataList = createFakeMetaDataObjects(4);
        metaDataHandler.doUpdate(metaDataList);
        metaDataList.forEach(metaData ->
                subscribers.forEach(subscriber -> verify(subscriber).onSubscribe(metaData)));
    }