### Question:
ConsumerGroupConsumerServiceImpl extends AbstractBaseService<ConsumerGroupConsumerEntity> implements ConsumerGroupConsumerService { @Override public List<ConsumerGroupConsumerEntity> getByConsumerIds(List<Long> consumerIds) { if (CollectionUtils.isEmpty(consumerIds)) { return new ArrayList<>(); } return consumerGroupConsumerRepository.getByConsumerIds(consumerIds); }  @Override List<ConsumerGroupConsumerEntity> getByConsumerGroupIds(List<Long> consumerGroupIds); @Override int deleteUnActiveConsumer(); @Override List<ConsumerGroupConsumerEntity> getByConsumerIds(List<Long> consumerIds); @Override void deleteByConsumerId(long consumerId); @Override void deleteByConsumerIds(List<Long> consumerIds);  }### Answer:
@Test public void getByConsumerIdsTest() { assertEquals(true, consumerGroupConsumerServiceImpl.getByConsumerIds(null).size() == 0); when(consumerGroupConsumerRepository.getByConsumerIds(anyList())).thenReturn(new ArrayList()); consumerGroupConsumerServiceImpl.getByConsumerIds(Arrays.asList(1L)); verify(consumerGroupConsumerRepository).getByConsumerIds(anyList()); }