third_party/blink/web_tests/webaudio/test-runner-set-audio-data-basic.html

<!DOCTYPE html>
<html>
  <head>
    <title>test-runner-set-audio-data-basic.html</title>
    <script src="../resources/testharness.js"></script>
    <script src="../resources/testharnessreport.js"></script>
    <script src="resources/audio-file-utils.js"></script>
  </head>
  <body>
    <script>

      // This is a very basic test to make sure
      // testRunner.setAudioData() works correctly.
      // It generates a 2-second-long stereo result @44.1KHz
      // The left channel will be a 880Hz tone,
      // while the right will be a 440Hz tone.

      const sampleRate = 44100.0;
      const lengthInSeconds = 2;

      function generateSineWave(audioBuffer) {
        const channelLeft = audioBuffer.getChannelData(0);
        const channelRight = audioBuffer.getChannelData(1);

        for (let i = 0; i < audioBuffer.length; ++i) {
          channelLeft[i] = Math.sin(880.0 * 2.0 * Math.PI * i / sampleRate);
          channelRight[i] = Math.sin(440.0 * 2.0 * Math.PI * i / sampleRate);
        }
      }

      test(() => {
        if (!window.testRunner) {
          // If you run this test with an actual browser,
          // the testRunner won't be available. This checks such case.
          assert_true(!window.testRunner, 'window.testRunner is not defined');
          return;
        }

        let audioBuffer = new AudioBuffer({
          length: lengthInSeconds * sampleRate,
          sampleRate: sampleRate,
          numberOfChannels: 2
        });
        generateSineWave(audioBuffer);

        let audioData = createAudioData(audioBuffer);
        testRunner.setAudioData(audioData);

        testRunner.notifyDone();
      }, 'Basic audio test infrastructure: testRunner.setAudioData()');
    </script>
  </body>
</html>