dom/media/webvtt/test/mochitest/test_texttrack_mode_change_during_loading.html

   1 <!DOCTYPE HTML>
   2 <html>
   3 <head>
   4   <title>WebVTT : changing track's mode during loading</title>
   5   <script src="/tests/SimpleTest/SimpleTest.js"></script>
   6   <script src="manifest.js"></script>
   7   <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
   8 </head>
   9 <body>
  10 <script class="testbody" type="text/javascript">
  11 /**
  12  * This test is to ensure that we won't get `error` event when we change track's
  13  * mode during loading. In this test, track element starts loading after setting
  14  * the src and we would start another load later just after the channel which is
  15  * used to fetch data starts. The second load is triggered by mode changes, and
  16  * it should stop the prevous load and won't generate any error.
  17  */
  18 async function startTest() {
  19   const video = createVideo();
  20   const trackElement = createAndAppendtrackElemententToVideo(video);
  21
  22   await changeTrackModeDuringLoading(trackElement);
  23   await waitUntilTrackLoaded(trackElement);
  24
  25   removeNodeAndSource(video);
  26   SimpleTest.finish();
  27 }
  28
  29 SimpleTest.waitForExplicitFinish();
  30 SpecialPowers.pushPrefEnv({"set": [["media.webvtt.testing.events", true]]},
  31                             startTest);
  32
  33 /**
  34  * The following are test helper functions.
  35  */
  36 function createVideo() {
  37   info(`create video`);
  38   let video = document.createElement("video");
  39   video.src = "gizmo.mp4";
  40   document.body.appendChild(video);
  41   return video;
  42 }
  43
  44 function createAndAppendtrackElemententToVideo(video) {
  45   let trackElement = document.createElement("track");
  46   trackElement.default = true;
  47   video.append(trackElement);
  48   return trackElement;
  49 }
  50
  51 async function changeTrackModeDuringLoading(trackElement) {
  52   info(`set src to start loading`);
  53   trackElement.src = "basic.vtt";
  54
  55   info(`wait until starting loading resource.`);
  56   await once(trackElement, "mozStartedLoadingTextTrack");
  57
  58   info(`changeing track's mode during loading should not cause loading failed.`);
  59   trackElement.onerror = () => {
  60     ok(false, `Should not get error event!`);
  61   }
  62   trackElement.track.mode = "hidden";
  63 }
  64
  65 async function waitUntilTrackLoaded(trackElement) {
  66   if (trackElement.readyState != 2) {
  67     info(`wait until the track finishes loading`);
  68     await once(trackElement, "load");
  69   }
  70   is(trackElement.readyState, 2, "Track::ReadyState should be set to LOADED.");
  71   is(trackElement.track.cues.length, 6, "Cue list length should be 6.");
  72 }
  73 </script>
  74 </body>
  75 </html>