chromium/third_party/blink/web_tests/wpt_internal/prerender/unload-on-prerender-same-origin-subframe-navigation.html

<!DOCTYPE html>
<!--
This file cannot be upstreamed to WPT until:
* `unload` event handling matches what the specification expects. The current
  specification expects that the unload event handler is never fired, and the
  test passes whether or not it is fired.
* `pageshow` and `pagehide` behaviors during prerendering is clearly defined
  in the specification. This test just checks current behaviors.
  (https://crbug.com/1222551)
-->
<title>unload event handlers</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="/speculation-rules/prerender/resources/utils.js"></script>
<script src="resources/unload-utils.js"></script>
<script>
promise_test(async t => {
  const uid = token();
  const gotMessages = waitChannelMessage('load same-origin-frame2', uid);
  const url =
      `resources/unload-on-prerender-same-origin-subframe-navigation.html?uid=${uid}`;
  window.open(url, '_blank', 'noopener');
  const result = await gotMessages;

  const expected = [
    'load start',
    'load prerendering',
    'load same-origin-frame1',
    'load same-origin-frame2',
  ];
  assert_array_equals(result, expected, 'gotMessages');
}, 'unload on same origin subframe navigation');
</script>