@Override
    public void channelActive(final ChannelHandlerContext ctx) {
        ctx.channel().attr(CommonConstants.CHARSET_ATTRIBUTE_KEY).setIfAbsent(Charset.defaultCharset());
        ctx.fireChannelActive();
    }
@Test
    void assertChannelActive() {
        ChannelHandlerContext context = mock(ChannelHandlerContext.class, RETURNS_DEEP_STUBS);
        new ChannelAttrInitializer().channelActive(context);
        verify(context.channel().attr(CommonConstants.CHARSET_ATTRIBUTE_KEY)).setIfAbsent(any(Charset.class));
        verify(context).fireChannelActive();
    }