chromium/third_party/blink/web_tests/external/wpt/html/browsers/browsing-the-web/navigating-across-documents/replace-before-load/history-pushstate.html

<!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 startURL = "resources/code-injector.html?pipe=sub(none)&code=" + encodeURIComponent("history.pushState(null, null, `/common/blank.html?thereplacement`);");
  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 waitForLoad(t, iframe, afterReplacementURL);
  assert_equals(history.length, startingHistoryLength + 1, "history.length must change after waiting for the replacement");
}, "history.pushState() before the load event must NOT replace");
</script>