@Test
  public void ackShouldRemoveBatch() {
    spout.emitBatch(0L, collector);
    Map<Long, List<String>> batches = spout.getBatches();
    assertThat(batches).containsKey(0L);

    spout.ack(0L);
    assertThat(batches).isEmpty();
  }
  @Test
  public void testEmitBatch() {
    spout.emitBatch(0L, collector);
    spout.emitBatch(1L, collector);

    verify(collector, times(20)).emit(any(Values.class));

    Map<Long, List<String>> batches = spout.getBatches();
    assertThat(batches).hasSize(2).containsKey(0L).containsKey(1L);
    assertThat(batches.get(0L)).hasSize(10);
    assertThat(batches.get(1L)).hasSize(10);
  }