basic-border-3.https.html | Explore in Territory

<!DOCTYPE html>
<html>
<body>
  <fencedframe
      style="width: 100%; height: 300px; border: 3px solid black;">
  </fencedframe>
  <script>
    const url = new URL("resources/fenced_frame.php", location.href);
    document.querySelector("fencedframe").config = new FencedFrameConfig(url);
    // Since load events don't quite work the same and WebTest doesn't support
    // fenced frames completely we have to tell the test to wait until the
    // fenced frame is actually ready.
    if (window.testRunner)
      testRunner.waitUntilDone();
  </script>
</body>
</html>

chromium/third_party/blink/web_tests/http/tests/fenced_frame/basic-border-3.https.html