code: @Test() public void testNoInvoke(){
    dic=mock(Directory.class);
    given(dic.getUrl()).willReturn(url);
    given(dic.list(invocation)).willReturn(null);
    given(dic.getInterface()).willReturn(FailbackClusterInvokerTest.class);
    invocation.setMethodName("method1");
    invokers.add(invoker);
    resetInvokerToNoException();
    FailbackClusterInvoker<FailbackClusterInvokerTest> invoker=new FailbackClusterInvoker<FailbackClusterInvokerTest>(dic);
    LogUtil.start();
    invoker.invoke(invocation);
    assertEquals(1,LogUtil.findMessage("Failback to invoke"));
    LogUtil.stop();
  }
  