I see that there is websocket endpoint which works out fins with Java tests. In logs I see
Connecting to: ws://127.0.0.1:8080/76f48a44-0af8-444c-ba97-3f1ed34af
If you mean literally to test the implementation of websockets, I found Autobahn's test suite to be very useful: http://autobahn.ws/
If you just want to noodle with a websocket I would recommend using the developer tools in a browser like chrome to make a connection and send/recv data:
var ws = new WebSocket("ws://127.0.0.1:8080/76f48a44-0af8-444c-ba97-3f1ed34afc91/tweets");
ws.onclose = function() { // thing to do on close
};
ws.onerror = function() { // thing to do on error
};
ws.onmessage = function() { // thing to do on message
};
ws.onopen = function() { // thing to do on open
};
ws.send("Hello World");