chromium/third_party/blink/web_tests/external/wpt/fetch/stale-while-revalidate/revalidate-not-blocked-by-csp.html

<!DOCTYPE html>
<meta charset="utf-8">
<title>Test revalidations requests aren't blocked by CSP.</title>
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="/common/utils.js"></script>
<body>
<script>

// Regression test for https://crbug.com/1070117.
var request_token = token();
let image_src = "resources/stale-image.py?token=" + request_token;

let loadImage = async () => {
  let img = document.createElement("img");
  img.src = image_src;
  let loaded = new Promise(r => img.onload = r);
  document.body.appendChild(img);
  await loaded;
  return img;
};

promise_test(async t => {
  await new Promise(r => window.onload = r);

  // No CSP report must be sent from now.
  //
  // TODO(arthursonzogni): Some browser implementations do not support the
  // ReportingObserver yet. Ideally, another way to access the reports should be
  // used to test them.
  const observer = new ReportingObserver(t.unreached_func(
    "CSP reports aren't sent for revalidation requests"));
  if (observer)
    observer.observe();

  let img1 = await loadImage(); // Load initial resource.
  let img2 = loadImage();       // Request stale resource.

  // Insert a <meta> CSP. This will block any image load starting from now.
  const metaCSP = document.createElement("meta");
  metaCSP.httpEquiv = "Content-Security-Policy";
  metaCSP.content = "img-src 'none'";
  document.getElementsByTagName("head")[0].appendChild(metaCSP)

  // The images were requested before the <meta> CSP above was added. So they
  // will load. Nevertheless, the resource will be stale. A revalidation request
  // is going to be made after that.
  assert_equals(img1.width, 16, "(initial version loaded)");
  assert_equals((await img2).width, 16, "(stale version loaded)");

  // At some point, the <img> resource is going to be revalidated. It must not
  // be blocked nor trigger a CSP violation report.

  // Query the server again and again. At some point it must have received the
  // revalidation request. We poll, because we don't know when the revalidation
  // will occur.
  let query = false;
  while(true) {
    await new Promise(r => step_timeout(r, 25));
    let response = await fetch(`${image_src}${query ? "&query" : ""}`);
    let count = response.headers.get("Count");
    if (count == "2")
      break;
    query ^= true;
  }
}, "Request revalidation aren't blocked by CSP");

</script>
</body>