### Question:
BlockApiImpl implements BlockApi { @Override public long blockNumber(String branchId) { return branchGroup.getLastIndex(BranchId.of(branchId)); } @Autowired  BlockApiImpl(BranchGroup branchGroup); @Override long blockNumber(String branchId); @Override BlockDto getBlockByHash(String branchId, String blockId, Boolean bool); @Override BlockDto getBlockByNumber(String branchId, long numOfBlock, Boolean bool); @Override BlockDto getLastBlock(String branchId);  }### Answer:
@Test public void blockNumberTest() { try { assertThat(BLOCK_API.blockNumber(branchId)).isNotNull(); } catch (Exception exception) { log.debug("blockNumberTest :: exception : " + exception); } }