chromium/third_party/blink/web_tests/external/wpt/html/browsers/browsing-the-web/navigating-across-documents/multiple-globals/context-for-window-open.html

<!DOCTYPE html>
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="resources/context-helper.js"></script>
<script>
window.scriptToRun =
    'relevantWindow.open("target.html", "target");';

async_test(t => {
  window.addEventListener("message", t.step_func_done(function(e) {
    // Base URL used for parsing a relative URL to `target.html`
    // should be the base URL of the entry settings object in
    // https://html.spec.whatwg.org/C/#window-open-steps
    assert_equals(
        e.data.location,
        new URL('target.html', entryUrl).href,
        'Base URL should use the entry settings object');

    // `document.referrer` should reflect the source browsing context,
    // which is the entry in
    // https://html.spec.whatwg.org/C/#window-open-steps
    assert_equals(
        e.data.referrer, entryUrl,
       'Referrer should use the entry settings object');
  }));
}, 'Fetch client and URL resolution for window.open()');
</script>
<iframe id="entry" src="entry/entry.html"></iframe>