Apply layout-test-tidy to LayoutTests/webaudio

third_party/WebKit/LayoutTests/webaudio/resources/oscillator-testing.js

 // Notes about generated waveforms:
 //
-// QUESTION: Why does the wave shape not look like the exact shape (sharp edges)?
-// ANSWER: Because a shape with sharp edges has infinitely high frequency content.
-// Since a digital audio signal must be band-limited based on the nyquist frequency (half the sample-rate)
-// in order to avoid aliasing, this creates more rounded edges and "ringing" in the
-// appearance of the waveform.  See Nyquist-Shannon sampling theorem:
+// QUESTION: Why does the wave shape not look like the exact shape (sharp
+// edges)? ANSWER: Because a shape with sharp edges has infinitely high
+// frequency content. Since a digital audio signal must be band-limited based on
+// the nyquist frequency (half the sample-rate) in order to avoid aliasing, this
+// creates more rounded edges and "ringing" in the appearance of the waveform.
+// See Nyquist-Shannon sampling theorem:
 // http://en.wikipedia.org/wiki/Nyquist%E2%80%93Shannon_sampling_theorem
 //
-// QUESTION: Why does the very end of the generated signal appear to get slightly weaker?
-// ANSWER: This is an artifact of the algorithm to avoid aliasing.
+// QUESTION: Why does the very end of the generated signal appear to get
+// slightly weaker? ANSWER: This is an artifact of the algorithm to avoid
+// aliasing.
 //
-// QUESTION: Since the tests compare the actual result with an expected reference file, how are the
-// reference files created?
-// ANSWER: Run the test in a browser.  When the test completes, a
-// generated reference file with the name "<file>-actual.wav" is
-// automatically downloaded.  Use this as the new reference, after
-// carefully inspecting to see if this is correct.
+// QUESTION: Since the tests compare the actual result with an expected
+// reference file, how are the reference files created? ANSWER: Run the test in
+// a browser.  When the test completes, a generated reference file with the name
+// "<file>-actual.wav" is automatically downloaded.  Use this as the new
+// reference, after carefully inspecting to see if this is correct.
 //
 
-OscillatorTestingUtils = (function () {
+OscillatorTestingUtils = (function() {
 
-var sampleRate = 44100.0;
-var nyquist = 0.5 * sampleRate;
-var lengthInSeconds = 4;
-var lowFrequency = 10;
-var highFrequency = nyquist + 2000; // go slightly higher than nyquist to make sure we generate silence there
-var context = 0;
+  let sampleRate = 44100.0;
+  let nyquist = 0.5 * sampleRate;
+  let lengthInSeconds = 4;
+  let lowFrequency = 10;
+  let highFrequency = nyquist + 2000;  // go slightly higher than nyquist to
+                                       // make sure we generate silence there
+  let context = 0;
 
-// Scaling factor for converting the 16-bit WAV data to float (and vice-versa).
-var waveScaleFactor = 32768;
+  // Scaling factor for converting the 16-bit WAV data to float (and
+  // vice-versa).
+  let waveScaleFactor = 32768;
 
-// Thresholds for verifying the test passes.  The thresholds are experimentally determined. The
-// default values here will cause the test to fail, which is useful for determining new thresholds,
-// if needed.
+  // Thresholds for verifying the test passes.  The thresholds are
+  // experimentally determined. The default values here will cause the test to
+  // fail, which is useful for determining new thresholds, if needed.
 
-// SNR must be greater than this to pass the test.
-// Q: Why is the SNR threshold not infinity?
-// A: The reference result is a 16-bit WAV file, so it won't compare exactly with the
-//    floating point result.
-var thresholdSNR = 10000;
+  // SNR must be greater than this to pass the test.
+  // Q: Why is the SNR threshold not infinity?
+  // A: The reference result is a 16-bit WAV file, so it won't compare exactly
+  // with the
+  //    floating point result.
+  let thresholdSNR = 10000;
 
-// Max diff must be less than this to pass the test.
-var thresholdDiff = 0;
+  // Max diff must be less than this to pass the test.
+  let thresholdDiff = 0;
 
-// Mostly for debugging
+  // Mostly for debugging
 
-// An AudioBuffer for the reference (expected) result.
-var reference = 0;
+  // An AudioBuffer for the reference (expected) result.
+  let reference = 0;
 
-// Signal power of the reference
-var signalPower = 0;
+  // Signal power of the reference
+  let signalPower = 0;
 
-// Noise power of the difference between the reference and actual result.
-var noisePower = 0;
+  // Noise power of the difference between the reference and actual result.
+  let noisePower = 0;
 
-function generateExponentialOscillatorSweep(context, oscillatorType) {
-    var osc = context.createOscillator();
-    if (oscillatorType == "custom") {
-        // Create a simple waveform with three Fourier coefficients.
-        // Note the first values are expected to be zero (DC for coeffA and Nyquist for coeffB).
-        var coeffA = new Float32Array([0, 1, 0.5]);
-        var coeffB = new Float32Array([0, 0, 0]);
-        var wave = context.createPeriodicWave(coeffA, coeffB);
-        osc.setPeriodicWave(wave);
+  function generateExponentialOscillatorSweep(context, oscillatorType) {
+    let osc = context.createOscillator();
+    if (oscillatorType == 'custom') {
+      // Create a simple waveform with three Fourier coefficients.
+      // Note the first values are expected to be zero (DC for coeffA and
+      // Nyquist for coeffB).
+      let coeffA = new Float32Array([0, 1, 0.5]);
+      let coeffB = new Float32Array([0, 0, 0]);
+      let wave = context.createPeriodicWave(coeffA, coeffB);
+      osc.setPeriodicWave(wave);
     } else {
-        osc.type = oscillatorType;
+      osc.type = oscillatorType;
     }
 
-    // Scale by 1/2 to better visualize the waveform and to avoid clipping past full scale.
-    var gainNode = context.createGain();
+    // Scale by 1/2 to better visualize the waveform and to avoid clipping past
+    // full scale.
+    let gainNode = context.createGain();
     gainNode.gain.value = 0.5;
     osc.connect(gainNode);
     gainNode.connect(context.destination);
 
     osc.start(0);
 
     osc.frequency.setValueAtTime(10, 0);
     osc.frequency.exponentialRampToValueAtTime(highFrequency, lengthInSeconds);
-}
+  }
 
-function calculateSNR(sPower, nPower)
-{
+  function calculateSNR(sPower, nPower) {
     return 10 * Math.log10(sPower / nPower);
-}
+  }
 
-function loadReferenceAndRunTest(context, oscType, task, should) {
+  function loadReferenceAndRunTest(context, oscType, task, should) {
     Audit
         .loadFileFromUrl(
             '../Oscillator/oscillator-' + oscType + '-expected.wav')
         .then(response => {
-            return context.decodeAudioData(response);
+          return context.decodeAudioData(response);
         })
         .then(audioBuffer => {
-            reference = audioBuffer.getChannelData(0);
-            generateExponentialOscillatorSweep(context, oscType);
-            return context.startRendering();
+          reference = audioBuffer.getChannelData(0);
+          generateExponentialOscillatorSweep(context, oscType);
+          return context.startRendering();
         })
         .then(resultBuffer => {
-            checkResult(resultBuffer, should, oscType);
+          checkResult(resultBuffer, should, oscType);
         })
         .then(() => task.done());
-}
+  }
 
-function checkResult (renderedBuffer, should, oscType) {
+  function checkResult(renderedBuffer, should, oscType) {
     let renderedData = renderedBuffer.getChannelData(0);
-    // Compute signal to noise ratio between the result and the reference. Also keep track
-    // of the max difference (and position).
+    // Compute signal to noise ratio between the result and the reference. Also
+    // keep track of the max difference (and position).
 
-    var maxError = -1;
-    var errorPosition = -1;
-    var diffCount = 0;
+    let maxError = -1;
+    let errorPosition = -1;
+    let diffCount = 0;
 
-    for (var k = 0; k < renderedData.length; ++k) {
-        var diff = renderedData[k] - reference[k];
-        noisePower += diff * diff;
-        signalPower += reference[k] * reference[k];
-        if (Math.abs(diff) > maxError) {
-            maxError = Math.abs(diff);
-            errorPosition = k;
-        }
+    for (let k = 0; k < renderedData.length; ++k) {
+      let diff = renderedData[k] - reference[k];
+      noisePower += diff * diff;
+      signalPower += reference[k] * reference[k];
+      if (Math.abs(diff) > maxError) {
+        maxError = Math.abs(diff);
+        errorPosition = k;
+      }
     }
 
-    var snr = calculateSNR(signalPower, noisePower);
-    should(snr, "SNR")
-        .beGreaterThanOrEqualTo(thresholdSNR);
-    should(maxError, "Maximum difference")
-        .beLessThanOrEqualTo(thresholdDiff);
+    let snr = calculateSNR(signalPower, noisePower);
+    should(snr, 'SNR').beGreaterThanOrEqualTo(thresholdSNR);
+    should(maxError, 'Maximum difference').beLessThanOrEqualTo(thresholdDiff);
 
-    var filename = "oscillator-" + oscType + "-actual.wav";
+    let filename = 'oscillator-' + oscType + '-actual.wav';
     if (downloadAudioBuffer(renderedBuffer, filename, true))
-      should(true, "Saved reference file").message(filename, "");
-}
+      should(true, 'Saved reference file').message(filename, '');
+  }
 
-function setThresholds(thresholds) {
+  function setThresholds(thresholds) {
     thresholdSNR = thresholds.snr;
     thresholdDiff = thresholds.maxDiff;
     thresholdDiffCount = thresholds.diffCount;
-}
+  }
 
-function runTest(context, oscType, description, task, should) {
-  loadReferenceAndRunTest(context, oscType, task, should);
-}
+  function runTest(context, oscType, description, task, should) {
+    loadReferenceAndRunTest(context, oscType, task, should);
+  }
 
-return {
+  return {
     sampleRate: sampleRate,
     lengthInSeconds: lengthInSeconds,
     thresholdSNR: thresholdSNR,
     thresholdDiff: thresholdDiff,
     waveScaleFactor: waveScaleFactor,
     setThresholds: setThresholds,
     runTest: runTest,
-};
+  };
 
 }());