<!DOCTYPE html>
<meta charset="utf-8">
<title>Making the current page become non-active must 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 t => {
    // This will invoke the constructor from currentIframe, but with incumbentIframe as the incumbent.
    const messageChannel = incumbentIframe.contentWindow.createMessageChannel();

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

    messageChannel.port1.onmessage = t.unreached_func("message event recieved");
    messageChannel.port1.onmessageerror = t.unreached_func("messageerror event recieved");
    messageChannel.port2.postMessage("boo");

    // We are testing that neither of the above two events fire. We assume that a 3 second timeout
    // is good enough. We can't use any other API for an end condition because each MessagePort has
    // its own independent port message queue, which has no ordering guarantees relative to other
    // APIs.
    await new Promise(resolve => t.step_timeout(resolve, 3000));
  });
});
</script>
