public OpenConfigChannelHandler addConfig(OpenConfigConfigOfChannelHandler config) {
        modelObject.config(config.getModelObject());
        return this;
    }
@Test
    public void testAddConfig() {
        // test Handler
        OpenConfigChannelHandler channel = new OpenConfigChannelHandler(1, parent);

        // call addConfig
        OpenConfigConfigOfChannelHandler configOfChannel =
            new OpenConfigConfigOfChannelHandler(channel);

        // expected ModelObject
        DefaultChannel modelObject = new DefaultChannel();
        modelObject.index(1);
        DefaultConfig config = new DefaultConfig();
        modelObject.config(config);

        assertEquals("[NG]addConfig:ModelObject(Config added) is not an expected one.\n",
                     modelObject, channel.getModelObject());
    }