code: @Test public void assertShutdownWithServerIp(){
    when(regCenter.getChildrenKeys("/")).thenReturn(Arrays.asList("test_job1","test_job2"));
    when(regCenter.getChildrenKeys("/test_job1/instances")).thenReturn(Collections.singletonList("localhost@-@defaultInstance"));
    when(regCenter.getChildrenKeys("/test_job2/instances")).thenReturn(Collections.singletonList("localhost@-@defaultInstance"));
    jobOperateAPI.shutdown(Optional.<String>absent(),Optional.of("localhost"));
    verify(regCenter).getChildrenKeys("/");
    verify(regCenter).remove("/test_job1/instances/localhost@-@defaultInstance");
    verify(regCenter).remove("/test_job2/instances/localhost@-@defaultInstance");
  }
  