| <!DOCTYPE html> | 
 | <title>Incumbent page used as a test helper</title> | 
 |  | 
 | <iframe src="relevant.html" id="r"></iframe> | 
 |  | 
 | <script> | 
 | "use strict"; | 
 |  | 
 | const relevant = document.querySelector("#r").contentWindow; | 
 |  | 
 | window.setupWebSocket = (binaryType, fn) => { | 
 |     const wsocket = new relevant.WebSocket("ws://{{host}}:{{ports[ws][0]}}/echo"); | 
 |  | 
 |     wsocket.addEventListener("open", () => { | 
 |         wsocket.binaryType = binaryType; | 
 |         wsocket.send(new ArrayBuffer(15)); | 
 |     }); | 
 |  | 
 |     wsocket.addEventListener("message", ev => { | 
 |         fn(relevant, ev); | 
 |     }); | 
 | }; | 
 |  | 
 | </script> |