retrospective-setTargetAtTime.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-audioparam-interface/retrospective-setTargetAtTime.html - WPT Dashboard Interop Dashboard

<!doctype html>

<meta charset=utf-8>

<html>

  <head>

    <title>Test setTargetAtTime with start time in the past</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>

      let audit = Audit.createTaskRunner();

      audit.define(

            label: 'test',

            description: 'Test setTargetAtTime with start time in the past'

},

          (task, should) => {

            // Use a sample rate that is a power of two to eliminate round-off

            // in computing the currentTime.

            let context = new OfflineAudioContext(2, 16384, 16384);

            let source = new ConstantSourceNode(context);

            // Suspend the context at this frame so we can synchronously set up

            // automations.

            const suspendFrame = 128;

            let test = new GainNode(context);

            let reference = new GainNode(context);

            source.connect(test);

            source.connect(reference);

            let merger = new ChannelMergerNode(

                context, {numberOfInputs: context.destination.channelCount});

            test.connect(merger, 0, 0);

            reference.connect(merger, 0, 1);

            merger.connect(context.destination);

            context.suspend(suspendFrame / context.sampleRate)

                .then(() => {

                  // Call setTargetAtTime with a time in the past

                  test.gain.setTargetAtTime(0.1, 0.5*context.currentTime, 0.1);

                  reference.gain.setTargetAtTime(0.1, context.currentTime, 0.1);

})

                .then(() => context.resume());

            source.start();

            context.startRendering()

                .then(resultBuffer => {

                  let testValue = resultBuffer.getChannelData(0);

                  let referenceValue = resultBuffer.getChannelData(1);

                  // Until the suspendFrame, both should be exactly equal to 1.

                  should(

                      testValue.slice(0, suspendFrame),

                      `Test[0:${suspendFrame - 1}]`)

                      .beConstantValueOf(1);

                  should(

                      referenceValue.slice(0, suspendFrame),

                      `Reference[0:${suspendFrame - 1}]`)

                      .beConstantValueOf(1);

                  // After the suspendFrame, both should be equal (and not

                  // constant)

                  should(

                      testValue.slice(suspendFrame), `Test[${suspendFrame}:]`)

                      .beEqualToArray(referenceValue.slice(suspendFrame));

})

                .then(() => task.done());

});

      audit.run();

    </script>

  </body>

</html>