<!DOCTYPE html>
<html>
  <head>
    <title>
      Test ABSN Outputs Silence if buffer is null
    </title>
    <script src="/resources/testharness.js"></script>
    <script src="/resources/testharnessreport.js"></script>
    <script src="/webaudio/resources/audit-util.js"></script>
    <script src="/webaudio/resources/audit.js"></script>
  </head>

  <body>
    <script>
      const audit = Audit.createTaskRunner();

      audit.define('ABSN with null buffer', (task, should) => {
        // Create test context.  Length and sampleRate are pretty arbitrary, but
        // we don't need either to be very large.
        const context = new OfflineAudioContext(
            {numberOfChannels: 1, length: 1024, sampleRate: 8192});

        // Just create a constant buffer for testing.  Anything will do as long
        // as the buffer contents are not identically zero.
        const audioBuffer =
            new AudioBuffer({length: 10, sampleRate: context.sampleRate});
        const audioBufferSourceNode = new AudioBufferSourceNode(context);

        audioBuffer.getChannelData(0).fill(1);

        // These two tests are mostly for the informational messages to show
        // what's happening.  They should never fail!
        should(() => {
          audioBufferSourceNode.buffer = audioBuffer;
        }, 'Setting ABSN.buffer to AudioBuffer').notThrow();

        // This is the important part.  Setting the buffer to null after setting
        // it to something else should cause the source to produce silence.
        should(() => {
          audioBufferSourceNode.buffer = null;
        }, 'Setting ABSN.buffer = null').notThrow();

        audioBufferSourceNode.start(0);
        audioBufferSourceNode.connect(context.destination);

        context.startRendering()
            .then(buffer => {
              // Since the buffer is null, the output of the source should be
              // silence.
              should(buffer.getChannelData(0), 'ABSN output')
                  .beConstantValueOf(0);
            })
            .then(() => task.done());
      });

      audit.run();
    </script>
  </body>
</html>
