retrospective-setValueAtTime.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-setValueAtTime.html - WPT Dashboard Interop Dashboard

<!DOCTYPE html>

<html>

  <head>

    <title>Test setValueAtTime with startTime 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>

    <script src="retrospective-test.js"></script>

  </head>

  <body>

    <script>

      let audit = Audit.createTaskRunner();

      audit.define(

            label: 'test',

            description: 'Test setValueAtTime with startTime in the past'

},

          (task, should) => {

            let {context, source, test, reference} = setupRetrospectiveGraph();

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

            // automations.

            const suspendFrame = 128;

            // Use a ramp of slope 1 per frame to measure time.

            // The end value is the extent of exact precision in single

            // precision float.

            const rampEnd = context.length - suspendFrame;

            const rampEndSeconds = context.length / context.sampleRate;

            context.suspend(suspendFrame / context.sampleRate)

                .then(() => {

                  // Call setValueAtTime with a time in the past

                  test.gain.setValueAtTime(0.0, 0.5 * context.currentTime);

                  test.gain.linearRampToValueAtTime(rampEnd, rampEndSeconds);

                  reference.gain.setValueAtTime(0.0, context.currentTime);

                  reference.gain.linearRampToValueAtTime(

                      rampEnd, rampEndSeconds);

})

                .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>