chromium/third_party/blink/web_tests/external/wpt/navigation-api/per-entry-events/dispose-cross-document.html

<!doctype html>
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<iframe id="iframe" src="/common/blank.html"></iframe>
<script>
promise_test(async (t) => {
  // Wait for after the load event so that the navigation doesn't get converted
  // into a replace navigation.
  await new Promise(r => window.onload = () => t.step_timeout(r, 0));

  iframe.contentWindow.location.search = "?1";
  await new Promise(r => iframe.onload = () => t.step_timeout(r, 0));

  const keyFor1 = iframe.contentWindow.navigation.currentEntry.key;

  iframe.contentWindow.location.search = "?2";
  await new Promise(r => iframe.onload = () => t.step_timeout(r, 0));
  iframe.contentWindow.location.search = "?3";
  await new Promise(r => iframe.onload = () => t.step_timeout(r, 0));

  iframe.contentWindow.navigation.traverseTo(keyFor1);
  await new Promise(r => iframe.onload = () => t.step_timeout(r, 0));

  assert_equals((new URL(iframe.contentWindow.location.href)).search, "?1");

  assert_equals(iframe.contentWindow.navigation.entries().length, 4);
  const [, entry2, entry3] = iframe.contentWindow.navigation.entries();

  entry2.ondispose = t.unreached_func("entry2 dispose must not fire");
  entry2.addEventListener("dispose", t.unreached_func("entry3 dispose must not fire"));

  iframe.contentWindow.navigation.navigate("/common/blank.html?fork");
  await new Promise(r => iframe.onload = r);

  // Test passes if we reached this point with no dispose events firing.
}, "No dispose events are fired due to cross-document forward pruning");
</script>