SlackBackfillSpout extends BaseRichSpout { @Override public void declareOutputFields(OutputFieldsDeclarer fields) { fields.declare(new Fields(BACKFILL_SLACK_MESSAGE_FIELD_STR)); }  @Override void open(@SuppressWarnings("rawtypes") Map conf, TopologyContext context,
                     SpoutOutputCollector collector); @Override void nextTuple(); @Override void declareOutputFields(OutputFieldsDeclarer fields); @Override void close(); static final String SPOUT_ID; static final String BACKFILL_SLACK_MESSAGE_FIELD_STR; }
@Test public void testDeclareOutputFields() { OutputFieldsDeclarer fields = mock(OutputFieldsDeclarer.class); underTest.declareOutputFields(fields); verify(fields).declare(any(Fields.class)); }