code: @Test public void assertRemoveWithJobName(){
    when(regCenter.isExisted("/test_job")).thenReturn(true);
    when(regCenter.getChildrenKeys("/test_job/servers")).thenReturn(Arrays.asList("ip1","ip2"));
    jobOperateAPI.remove(Optional.of("test_job"),Optional.<String>absent());
    verify(regCenter).getChildrenKeys("/test_job/servers");
    verify(regCenter).remove("/test_job/servers/ip1");
    verify(regCenter).remove("/test_job/servers/ip2");
    assertFalse(regCenter.isExisted("/test_job/servers/ip1"));
    assertFalse(regCenter.isExisted("/test_job/servers/ip2"));
    assertTrue(regCenter.isExisted("/test_job"));
  }
  