mozilla-release/testing/web-platform/tests/mediacapture-record/MediaRecorder-no-sink.https.html

<!doctype html>
<html>

<head>
  <title>MediaRecorder peer connection</title>
  <link rel="help"
        href="https://w3c.github.io/mediacapture-record/MediaRecorder.html#dom-mediarecorder-mimeType">
  <script src="/resources/testharness.js"></script>
  <script src="/resources/testharnessreport.js"></script>
  <script src="utils/peerconnection.js"></script>
</head>

<body>
  <script>

[{name: "audio",        kind: {audio: true, video: false}},
 {name: "video",        kind: {audio: false, video: true}},
 {name: "audio/video",  kind: {audio: true, video: true}}].forEach(args => {
  promise_test(async t => {
    const [localPc, remotePc, stream] = await startConnection(
        t, args.kind.audio, args.kind.video);
    const recorder = new MediaRecorder(stream);
    // Set an arbitrary timeslice interval so the ondataavailable event
    // handler gets invoked repeatedly. Without it, the test would
    // deadlock as it's currently written.
    recorder.start(100);
    let combinedSize = 0;
    const dataPromise = new Promise(r => recorder.ondataavailable = e => {
      // Wait for an arbitrary amount of data to appear before we resolve.
      combinedSize += e.data.size;
      if (combinedSize > 4711) r();
    });
    await dataPromise;
    recorder.stop();
  }, "PeerConnection MediaRecorder records " + args.name +
     " from PeerConnection without sinks");
 });

  </script>
</body>

</html>