chromium/third_party/blink/web_tests/external/wpt/webaudio/the-audio-api/the-convolvernode-interface/convolver-cascade.html

<!DOCTYPE html>
<html>
  <head>
    <title>
      Test Cascade of Mono Convolvers
    </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 id="layout-test-code">
      let audit = Audit.createTaskRunner();

      // Arbitrary sample rate and reasonably short duration
      let sampleRate = 8000;
      let duration = 0.25;
      let renderFrames = duration * sampleRate;

      audit.define(
          {label: 'cascade-mono', description: 'Cascaded mono convolvers'},
          (task, should) => {
            // Cascade two convolvers with mono responses and verify that the
            // output is not silent.
            let context = new OfflineAudioContext(1, renderFrames, sampleRate);

            let b0 =
                new AudioBuffer({length: 5, sampleRate: context.sampleRate});
            b0.getChannelData(0)[1] = 1;
            let c0 = new ConvolverNode(
                context, {disableNormalization: true, buffer: b0});

            let b1 =
                new AudioBuffer({length: 5, sampleRate: context.sampleRate});
            b1.getChannelData(0)[2] = 1;

            let c1 = new ConvolverNode(
                context, {disableNormalization: true, buffer: b1});

            let src = new OscillatorNode(context);

            src.connect(c0).connect(c1).connect(context.destination);

            src.start();

            context.startRendering()
                .then(audioBuffer => {
                  // Just verify the output is not silent
                  let audio = audioBuffer.getChannelData(0);

                  should(audio, 'Output of cascaded mono convolvers')
                      .notBeConstantValueOf(0);
                })
                .then(() => task.done());
          });

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