chromium/third_party/blink/web_tests/external/wpt/fetch/api/response/multi-globals/url-parsing.html

<!DOCTYPE html>
<title>Response.redirect URL parsing, with multiple globals in play</title>
<link rel="help" href="https://fetch.spec.whatwg.org/#dom-response-redirect">
<link rel="author" title="Domenic Denicola" href="mailto:[email protected]">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>

<!-- This is the entry global -->

<iframe src="incumbent/incumbent.html"></iframe>

<script>
'use strict';

const loadPromise = new Promise(resolve => {
    window.addEventListener("load", () => resolve());
});

promise_test(() => {
    return loadPromise.then(() => {
        const res = document.querySelector('iframe').contentWindow.createRedirectResponse("url");

        assert_equals(res.headers.get("Location"), new URL("current/success/url", location.href).href);
    });
}, "should parse the redirect Location URL relative to the current settings object");

</script>