### Question:
ConsumerGroupConsumerServiceImpl extends AbstractBaseService<ConsumerGroupConsumerEntity> implements ConsumerGroupConsumerService { @Override public List<ConsumerGroupConsumerEntity> getByConsumerGroupIds(List<Long> consumerGroupIds) { if (CollectionUtils.isEmpty(consumerGroupIds)) { return new ArrayList<>(); } return consumerGroupConsumerRepository.getByConsumerGroupIds(consumerGroupIds); }  @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 getByConsumerGroupIdsTest() { assertEquals(true, consumerGroupConsumerServiceImpl.getByConsumerGroupIds(null).size() == 0); when(consumerGroupConsumerRepository.getByConsumerGroupIds(anyList())).thenReturn(new ArrayList()); consumerGroupConsumerServiceImpl.getByConsumerGroupIds(Arrays.asList(1L)); verify(consumerGroupConsumerRepository).getByConsumerGroupIds(anyList()); }