Docker-image for WebSocket connectivity test.
$ docker run -d -p 8010:8010 --name websocket-test jmnote/websocket-test
$ npm install wscat
$ wscat --connect ws://$(CONTAINER_HOST_IP_ADDRESS):8010
connected (press CTRL+C to quit)
> Hello world
< Server received from client: Hello world
>
npm info ok
Server started
Received from client: Hello world
It works!!!