@Test(expected = IllegalStateException.class)
public void testInitNotCalledBeforeAdded() throws Exception {

    CombinedChannelDuplexHandler<ChannelInboundHandler, ChannelOutboundHandler> handler =
            new CombinedChannelDuplexHandler<ChannelInboundHandler, ChannelOutboundHandler>() { };
    handler.handlerAdded(null);
}