<!DOCTYPE html>
<meta charset="utf-8">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="resources/helpers.js"></script>

<body>
<script>
"use strict";
promise_test(async t => {
  const sentinelIframe = await setupSentinelIframe(t);
  const startingHistoryLength = history.length;

  const code = `
    window.onpageshow = () => {
      parent.document.querySelectorAll("iframe")[1].src = "/common/blank.html?thereplacement";
    };
  `;
  const startURL = "resources/code-injector.html?pipe=sub(none)&code=" + encodeURIComponent(code);
  const afterReplacementURL = "/common/blank.html?thereplacement";
  const iframe = insertIframe(t, startURL);

  assert_equals(history.length, startingHistoryLength, "Inserting the under-test iframe must not change history.length");

  await waitForLoadAllowingIntermediateLoads(t, iframe, afterReplacementURL);
  assert_equals(history.length, startingHistoryLength, "history.length must not change after waiting for the replacement");

  await checkSentinelIframe(t, sentinelIframe);
  assert_equals(history.length, startingHistoryLength, "history.length must not change after checking the sentinel iframe");
}, "Replace during the pageshow event, triggered by setting iframeElement.src");
</script>
