code: @SuppressWarnings("unchecked") @Test public void testNonEcho(){
    Invocation invocation=mock(Invocation.class);
    given(invocation.getMethodName()).willReturn("echo");
    given(invocation.getParameterTypes()).willReturn(new Class<?>[]{Enum.class});
    given(invocation.getArguments()).willReturn(new Object[]{"hello"});
    given(invocation.getAttachments()).willReturn(null);
    Invoker<DemoService> invoker=mock(Invoker.class);
    given(invoker.isAvailable()).willReturn(true);
    given(invoker.getInterface()).willReturn(DemoService.class);
    RpcResult result=new RpcResult();
    result.setValue("High");
    given(invoker.invoke(invocation)).willReturn(result);
    URL url=URL.valueOf("test://test:11/test?group=dubbo&version=1.1");
    given(invoker.getUrl()).willReturn(url);
    Result filterResult=echoFilter.invoke(invoker,invocation);
    assertEquals("High",filterResult.getValue());
  }
  