speculation-rules/prerender/about-blank-iframes.https.html

<!DOCTYPE html>
<title>Test about:blank iframes prerendering state</title>
<meta name="timeout" content="long">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="/common/utils.js"></script>
<script src="../resources/utils.js"></script>
<script src="resources/utils.js"></script>

<body>
<script>
setup(() => assertSpeculationRulesIsSupported());

promise_test(async t => {
  const uid = token();
  const channel = new PrerenderChannel('test-channel', uid);

  const gotMessage = new Promise(resolve => {
    channel.addEventListener('message', e => {
      resolve(e.data);
    }, {once: true});
  });

  // Make the window to start the prerender.
  const url = `resources/about-blank-iframes.html?uid=${uid}`;
  window.open(url, '_blank', 'noopener');

  const msg = await gotMessage;
  assert_equals(msg, 'PASS');
}, 'about:blank iframes');
</script>