test_not_reset_playbackRate_when_removing_nonloaded_media_from_document.html

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<!DOCTYPE HTML>

<html>

<head>

  <title>Do not reset playback rate when removing non-loaded media from a document</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">

/**

 * When removing media from a document, it should only trigger internal pause,

 * instead of the pause method, which would trigger loading process and reset

 * the media's playback rate for non-loaded media.

*/

async function startTest() {

  info(`create a media and append it to a document`);

  const audio = document.createElement("audio");

  document.body.appendChild(audio);

  info(`change audio's playbackRate and remove it from a document`);

  const expectedRate = 0.1;

  audio.playbackRate = expectedRate;

  await once(audio, "ratechange");

  is(audio.playbackRate, expectedRate,

    `${audio.playbackRate} is equal to ${expectedRate}`);

  audio.remove();

  info(`queue a macrotask to check if the playback rate is still unchanged`);

  setTimeout(() => {

    // If we unexpectedly reset the playback rate, it would happen in a

    // microtask when removing media from a document [1] (Await a stable state),

    // which would always be run before the macrotask.

    // [1] https://html.spec.whatwg.org/#playing-the-media-resource:remove-an-element-from-a-document

    is(audio.playbackRate, expectedRate,

      `${audio.playbackRate} is equal to ${expectedRate}`);

    SimpleTest.finish();

  }, 0);

SimpleTest.waitForExplicitFinish();

onload = startTest;

</script>

</body>

</html>