code: @Test public void assertFailoverLeaderExecutionCallbackIfNecessary(){
    JobRegistry.getInstance().setJobRunning("test_job",false);
    when(jobNodeStorage.isJobNodeExisted("leader/failover/items")).thenReturn(true);
    when(jobNodeStorage.getJobNodeChildrenKeys("leader/failover/items")).thenReturn(Arrays.asList("0","1","2"));
    JobRegistry.getInstance().registerJob("test_job",jobScheduleController,regCenter);
    failoverService.new FailoverLeaderExecutionCallback().execute();
    verify(jobNodeStorage).isJobNodeExisted("leader/failover/items");
    verify(jobNodeStorage,times(2)).getJobNodeChildrenKeys("leader/failover/items");
    verify(jobNodeStorage).fillEphemeralJobNode("sharding/0/failover","127.0.0.1@-@0");
    verify(jobNodeStorage).removeJobNodeIfExisted("leader/failover/items/0");
    verify(jobScheduleController).triggerJob();
    JobRegistry.getInstance().setJobRunning("test_job",false);
    JobRegistry.getInstance().shutdown("test_job");
  }
  