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

<body>
<script>
"use strict";
promise_test(async t => {
  // Generating a new one instead of hard-coding makes running tests manually a bit easier.
  const windowName = token();

  const code = `
    window.onpageshow = () => opener.navigateMe();
    opener.postMessage("arrived at start URL", "*");
  `;

  const startURL = "resources/slow-code-injector.html?pipe=sub(none)&code=" + encodeURIComponent(code);
  const absoluteStartURL = (new URL(startURL, location.href)).href;

  const afterReplacementURL = "resources/message-opener.html";
  const absoluteAfterReplacementURL = (new URL(afterReplacementURL, location.href)).href;

  window.navigateMe = () => {
    window.open(absoluteAfterReplacementURL, windowName);
  };

  // First message sent is ignored; we only check it after navigating back.
  const w = window.open(startURL, windowName);
  t.add_cleanup(() => w.close());

  // Wait to get past any initial about:blank
  while (true) {
    if (w.location.href === absoluteStartURL) {
      break;
    }
    await new Promise(r => t.step_timeout(r, 0));
  }

  assert_equals(w.onloadFired, undefined, "onload must not yet have fired");
  assert_equals(w.history.length, 1, "history.length for the opened window must start at 1");

  await new Promise(r => {
    window.addEventListener("message", t.step_func(e => {
      if (e.data === "ready") {
        resolve();
      }
    }));
  });

  assert_equals(w.history.length, 2, "history.length must increase");
  assert_equals(w.location.href, absoluteAfterReplacementURL);

  const promise = new Promise(resolve => {
    window.addEventListener("message", t.step_func(e => {
      assert_equals(e.data, "arrived at start URL");
      resolve();
    }));
  });

  w.history.back();

  await promise;
  assert_equals(w.location.href, absoluteStartURL, "1 second after attempting to go back, it indeed went back");
}, "No replace before load, triggered by window.open() on a non-_self window");
</script>
