<!DOCTYPE html>
<meta charset="utf-8">
<title>Making the incumbent page become non-active must not prevent message transmission</title>
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>

<!-- This is the entry global -->

<iframe src="support/incumbent.html" id="incumbent"></iframe>
<iframe src="support/current.html" id="current"></iframe>

<script>
"use strict";
const incumbentIframe = document.querySelector("#incumbent");
const currentIframe = document.querySelector("#current");

window.addEventListener("load", () => {
  promise_test(async () => {
    // This will invoke the constructor from currentIframe, but with incumbentIframe as the incumbent.
    const messageChannel = incumbentIframe.contentWindow.createMessageChannel();

    await new Promise((resolve, reject) => {
      incumbentIframe.onload = () => resolve();
      incumbentIframe.onerror = () => reject(new Error("Could not navigate the iframe"));
      incumbentIframe.src = "/common/blank.html";
    });

    await new Promise((resolve, reject) => {
      messageChannel.port1.onmessage = () => resolve();
      messageChannel.port1.onmessageerror = () => reject("messageerror event recieved");
      messageChannel.port2.postMessage("boo");
    });
  });
});
</script>