audiobuffersource-start-null-buffer.html

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This test has a WPT meta file that expects 1 subtest issues.
This WPT test may be referenced by the following Test IDs:
- /webaudio/the-audio-api/the-audiobuffersourcenode-interface/audiobuffersource-start-null-buffer.html - WPT Dashboard Interop Dashboard

<!DOCTYPE html>

<title>AudioBufferSourceNode: start() with null buffer</title>

<script src="/resources/testharness.js"></script>

<script src="/resources/testharnessreport.js"></script>

<script>

  promise_test(async t => {

    const sampleRate = 44100;

    const renderDuration = 10;

    const context =

        new OfflineAudioContext(1, sampleRate * renderDuration, sampleRate);

    const source = context.createBufferSource();

    source.buffer = null;

    source.connect(context.destination);

    let endedFired = false;

    let endedFiredTime = -1;

    const endedPromise = new Promise((resolve) => {

      source.onended = () => {

        endedFired = true;

        endedFiredTime = context.currentTime;

        resolve();

};

});

    const startTime = 5.0;

    source.start(startTime);

    // After 0.5 seconds, assign a buffer. This should be ignored by the

    // AudioBufferSourceNode because the source should have already finished

    // because it was started with a null buffer.

    // Per the spec, the buffer content is acquired at the moment start() is

    // called, so subsequent assignments are ignored.

    context.suspend(0.5).then(() => {

      source.buffer = context.createBuffer(1, 1, context.sampleRate);

      context.resume();

});

    await context.startRendering();

    assert_true(endedFired, 'ended event fired');

    assert_less_than(

        endedFiredTime, startTime,

        'ended event fired before scheduled start time');

  }, 'start() with null buffer fires ended event immediately and ignores ' +

     'subsequent buffer assignment');

</script>