@Override
    protected void handleCommandWatchTopicListClose(CommandWatchTopicListClose commandWatchTopicListClose) {
        checkArgument(state == State.Connected);
        topicListService.handleWatchTopicListClose(commandWatchTopicListClose);
    }
@Test(expectedExceptions = IllegalArgumentException.class)
    public void shouldFailHandleCommandWatchTopicListClose() throws Exception {
        ServerCnx serverCnx = mock(ServerCnx.class, CALLS_REAL_METHODS);
        Field stateUpdater = ServerCnx.class.getDeclaredField("state");
        stateUpdater.setAccessible(true);
        stateUpdater.set(serverCnx, ServerCnx.State.Failed);
        serverCnx.handleCommandWatchTopicListClose(any());
    }