<!doctype html>
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="resources/helpers.js"></script>

<iframe id="i" 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(resolve => window.onload = () => t.step_timeout(resolve, 0));

  assert_equals(i.contentWindow.navigation.entries().length, 1);
  let key = i.contentWindow.navigation.currentEntry.key;

  i.contentWindow.navigation.navigate("?1");
  await new Promise(resolve => i.onload = resolve);

  i.contentWindow.navigation.back();
  await new Promise(resolve => i.onload = resolve);

  assert_equals(i.contentWindow.navigation.entries().length, 2);
  assert_equals(i.contentWindow.navigation.currentEntry, i.contentWindow.navigation.entries()[0]);

  const iWindow = i.contentWindow;
  const iDOMException = iWindow.DOMException;

  i.remove();

  await assertBothRejectDOM(t, iWindow.navigation.forward(), "InvalidStateError", iWindow, iDOMException);
}, "forward() in a detached window");
</script>
