<!doctype html>
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="return-value/resources/helpers.js"></script>
<iframe id="i" src="/common/blank.html?startI" sandbox="allow-scripts allow-same-origin"></iframe>

<script>
// Intended setup:
// Step 0:
// - Parent: (current URL)
// - i:     /common/blank.html?startI
// Step 1:
// - Parent: (current URL)
// - i:     resources/navigation-back.html
// Step 2:
// - Parent: (current URL)#end
// - i:     resources/navigation-back.html
//
// Then, calling navigation.back() in i will take is from step 2 to step 0, which would navigate the parent.
// That is not allowed, so the call to back() must reject.

promise_test(async t => {
  await new Promise(resolve => window.onload = resolve);

  i.contentWindow.location.href = new URL("resources/navigation-back.html", location.href);
  await new Promise(resolve => i.onload = resolve);

  location.hash = "#end";
  await new Promise(resolve => window.onhashchange = resolve);

  navigation.onnavigate = t.unreached_func("navigate must not fire");
  navigation.onnavigateerror = t.unreached_func("navigateerror must not fire");
  window.onpopstate = t.unreached_func("popstate must not fire");
  window.onhashchange = t.unreached_func("hashchange must not fire");

  await assertBothRejectDOM(t, i.contentWindow.doNavigationBack(), "SecurityError", i.contentWindow);
}, "A sandboxed iframe cannot navigate its parent via its own navigation object by using back()");
</script>
