test_slowStart.html

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<head>

  <title>Test AudioContext.currentTime</title>

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

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

</head>

<body>

<pre id="test">

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

SimpleTest.waitForExplicitFinish();

SimpleTest.requestFlakyTimeout("This test needs to periodically query the AudioContext's position.");

const CUBEB_INIT_DELAY = 5000;

// Delay audio stream start by a good 5 seconds

SpecialPowers.pushPrefEnv({"set": [["media.cubeb.slow_stream_init_ms",

    CUBEB_INIT_DELAY]]}, runTest);

function runTest() {

  let ac = new AudioContext();

  let notStartedYetCount = 0;

  let startWallClockTime = performance.now();

  is(ac.currentTime, 0, "AudioContext.currentTime should be 0 initially");

  is(ac.state, "suspended", "AudioContext.currentTime is initially suspended");

  let intervalHandle = setInterval(function() {

    if (ac.state == "running" || ac.currentTime > 0) {

      clearInterval(intervalHandle);

      return;

    is(ac.currentTime, 0, "AudioContext.currentTime is still 0");

    is(ac.state, "suspended", "AudioContext.currentTime is still suspended");

    notStartedYetCount++;

});

  ac.onstatechange = function() {

    is(ac.state, "running", "The AudioContext eventually started.");

    var startDuration = performance.now() - startWallClockTime;

    info(`AudioContext start time with a delay of ${CUBEB_INIT_DELAY}): ${startDuration}`);

    ok(notStartedYetCount > 0, "We should have observed the AudioContext in \"suspended\" state");

    ok(startDuration >= CUBEB_INIT_DELAY, "The AudioContext state transition was correct.");

    SimpleTest.finish();

</script>

</pre>

</body>

</html>