private RemotingCommand getSystemTopicListFromBroker(ChannelHandlerContext ctx, RemotingCommand request)
        throws RemotingCommandException {
        final RemotingCommand response = RemotingCommand.createResponseCommand(null);

        Set<String> topics = TopicValidator.getSystemTopicSet();
        TopicList topicList = new TopicList();
        topicList.setTopicList(topics);
        response.setBody(topicList.encode());
        response.setCode(ResponseCode.SUCCESS);
        response.setRemark(null);
        return response;
    }
@Test
    public void testGetSystemTopicListFromBroker() throws RemotingCommandException {
        RemotingCommand request = RemotingCommand.createRequestCommand(RequestCode.GET_SYSTEM_TOPIC_LIST_FROM_BROKER, null);
        RemotingCommand response = adminBrokerProcessor.processRequest(handlerContext, request);
        assertThat(response.getCode()).isEqualTo(ResponseCode.SUCCESS);
    }