test_texttrack_mode_change_during_loading.html

Enable keyboard shortcuts

<!DOCTYPE HTML>

<html>

<head>

  <title>WebVTT : changing track's mode during loading</title>

  <script src="/tests/SimpleTest/SimpleTest.js"></script>

  <script src="manifest.js"></script>

  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>

</head>

<body>

<script class="testbody" type="text/javascript">

/**

 * This test is to ensure that we won't get `error` event when we change track's

 * mode during loading. In this test, track element starts loading after setting

 * the src and we would start another load later just after the channel which is

 * used to fetch data starts. The second load is triggered by mode changes, and

 * it should stop the prevous load and won't generate any error.

*/

async function startTest() {

  const video = createVideo();

  const trackElement = createAndAppendtrackElemententToVideo(video);

  await changeTrackModeDuringLoading(trackElement);

  await waitUntilTrackLoaded(trackElement);

  removeNodeAndSource(video);

  SimpleTest.finish();

SimpleTest.waitForExplicitFinish();

SpecialPowers.pushPrefEnv({"set": [["media.webvtt.testing.events", true]]},

                            startTest);

/**

 * The following are test helper functions.

*/

function createVideo() {

  info(`create video`);

  let video = document.createElement("video");

  video.src = "gizmo.mp4";

  document.body.appendChild(video);

  return video;

function createAndAppendtrackElemententToVideo(video) {

  let trackElement = document.createElement("track");

  trackElement.default = true;

  video.append(trackElement);

  return trackElement;

async function changeTrackModeDuringLoading(trackElement) {

  info(`set src to start loading`);

  trackElement.src = "basic.vtt";

  info(`wait until starting loading resource.`);

  await once(trackElement, "mozStartedLoadingTextTrack");

  info(`changeing track's mode during loading should not cause loading failed.`);

  trackElement.onerror = () => {

    ok(false, `Should not get error event!`);

  trackElement.track.mode = "hidden";

async function waitUntilTrackLoaded(trackElement) {

  if (trackElement.readyState != 2) {

    info(`wait until the track finishes loading`);

    await once(trackElement, "load");

  is(trackElement.readyState, 2, "Track::ReadyState should be set to LOADED.");

  is(trackElement.track.cues.length, 6, "Cue list length should be 6.");

</script>

</body>

</html>