Refactor audioparam-testing.js

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

-var sampleRate = 44100;
+(function(global) {
 
+
 // Information about the starting/ending times and starting/ending values for
 // each time interval.
-var timeValueInfo;
+let timeValueInfo;
 
 // The difference between starting values between each time interval.
-var startingValueDelta;
+let startingValueDelta;
 
 // For any automation function that has an end or target value, the end value is
 // based the starting value of the time interval.  The starting value will be
 // increased or decreased by |startEndValueChange|. We choose half of
 // |startingValueDelta| so that the ending value will be distinct from the
 // starting value for next time interval.  This allows us to detect where the
 // ramp begins and ends.
-var startEndValueChange;
+let startEndValueChange;
 
 // Default threshold to use for detecting discontinuities that should appear at
 // each time interval.
-var discontinuityThreshold;
+let discontinuityThreshold;
 
-// Time interval between value changes.  It is best if 1 / numberOfTests is not
-// close to timeInterval.
-var timeInterval = .03;
-
-// Some suitable time constant so that we can see a significant change over a
-// timeInterval.  This is only needed by setTargetAtTime() which needs a time
-// constant.
-var timeConstant = timeInterval / 3;
-
-var gainNode;
-
-var context;
+let context;
 
 // Make sure we render long enough to capture all of our test data.
 function renderLength(numberOfTests) {
   return timeToSampleFrame((numberOfTests + 1) * timeInterval, sampleRate);
 }
 
 // Create a constant reference signal with the given |value|.  Basically the
 // same as |createConstantBuffer|, but with the parameters to match the other
 // create functions.  The |endValue| is ignored.
 function createConstantArray(startTime, endTime, value, endValue, sampleRate) {
-  var startFrame = timeToSampleFrame(startTime, sampleRate);
-  var endFrame = timeToSampleFrame(endTime, sampleRate);
-  var length = endFrame - startFrame;
+  let startFrame = timeToSampleFrame(startTime, sampleRate);
+  let endFrame = timeToSampleFrame(endTime, sampleRate);
+  let length = endFrame - startFrame;
 
-  var buffer = createConstantBuffer(context, length, value);
+  let buffer = createConstantBuffer(context, length, value);
 
   return buffer.getChannelData(0);
 }
 
 function getStartEndFrames(startTime, endTime, sampleRate) {
   // Start frame is the ceiling of the start time because the ramp starts at or
   // after the sample frame.  End frame is the ceiling because it's the
   // exclusive ending frame of the automation.
-  var startFrame = Math.ceil(startTime * sampleRate);
-  var endFrame = Math.ceil(endTime * sampleRate);
+  let startFrame = Math.ceil(startTime * sampleRate);
+  let endFrame = Math.ceil(endTime * sampleRate);
 
   return {startFrame: startFrame, endFrame: endFrame};
 }
 
 // Create a linear ramp starting at |startValue| and ending at |endValue|.  The
 // ramp starts at time |startTime| and ends at |endTime|.  (The start and end
 // times are only used to compute how many samples to return.)
 function createLinearRampArray(
     startTime, endTime, startValue, endValue, sampleRate) {
-  var frameInfo = getStartEndFrames(startTime, endTime, sampleRate);
-  var startFrame = frameInfo.startFrame;
-  var endFrame = frameInfo.endFrame;
-  var length = endFrame - startFrame;
-  var array = new Array(length);
+  let frameInfo = getStartEndFrames(startTime, endTime, sampleRate);
+  let startFrame = frameInfo.startFrame;
+  let endFrame = frameInfo.endFrame;
+  let length = endFrame - startFrame;
+  let array = new Array(length);
 
-  var step =
+  let step =
       Math.fround((endValue - startValue) / (endTime - startTime) / sampleRate);
-  var start = Math.fround(
+  let start = Math.fround(
       startValue +
       (endValue - startValue) * (startFrame / sampleRate - startTime) /
           (endTime - startTime));
 
-  var slope = (endValue - startValue) / (endTime - startTime);
+  let slope = (endValue - startValue) / (endTime - startTime);
 
   // v(t) = v0 + (v1 - v0)*(t-t0)/(t1-t0)
   for (k = 0; k < length; ++k) {
     // array[k] = Math.fround(start + k * step);
-    var t = (startFrame + k) / sampleRate;
+    let t = (startFrame + k) / sampleRate;
     array[k] = startValue + slope * (t - startTime);
   }
 
   return array;
 }
 
 // Create an exponential ramp starting at |startValue| and ending at |endValue|.
 // The ramp starts at time |startTime| and ends at |endTime|.  (The start and
 // end times are only used to compute how many samples to return.)
 function createExponentialRampArray(
     startTime, endTime, startValue, endValue, sampleRate) {
-  var deltaTime = endTime - startTime;
+  let deltaTime = endTime - startTime;
 
-  var frameInfo = getStartEndFrames(startTime, endTime, sampleRate);
-  var startFrame = frameInfo.startFrame;
-  var endFrame = frameInfo.endFrame;
-  var length = endFrame - startFrame;
-  var array = new Array(length);
+  let frameInfo = getStartEndFrames(startTime, endTime, sampleRate);
+  let startFrame = frameInfo.startFrame;
+  let endFrame = frameInfo.endFrame;
+  let length = endFrame - startFrame;
+  let array = new Array(length);
 
-  var ratio = endValue / startValue;
+  let ratio = endValue / startValue;
 
   // v(t) = v0*(v1/v0)^((t-t0)/(t1-t0))
-  for (var k = 0; k < length; ++k) {
-    var t = Math.fround((startFrame + k) / sampleRate);
+  for (let k = 0; k < length; ++k) {
+    let t = Math.fround((startFrame + k) / sampleRate);
     array[k] =
         Math.fround(startValue * Math.pow(ratio, (t - startTime) / deltaTime));
   }
 
   return array;
 }
 
 function discreteTimeConstantForSampleRate(timeConstant, sampleRate) {
   return 1 - Math.exp(-1 / (sampleRate * timeConstant));
 }
 
 // Create a signal that starts at |startValue| and exponentially approaches the
 // target value of |targetValue|, using a time constant of |timeConstant|.  The
 // ramp starts at time |startTime| and ends at |endTime|.  (The start and end
 // times are only used to compute how many samples to return.)
 function createExponentialApproachArray(
     startTime, endTime, startValue, targetValue, sampleRate, timeConstant) {
-  var startFrameFloat = startTime * sampleRate;
-  var frameInfo = getStartEndFrames(startTime, endTime, sampleRate);
-  var startFrame = frameInfo.startFrame;
-  var endFrame = frameInfo.endFrame;
-  var length = Math.floor(endFrame - startFrame);
-  var array = new Array(length);
-  var c = discreteTimeConstantForSampleRate(timeConstant, sampleRate);
+  let startFrameFloat = startTime * sampleRate;
+  let frameInfo = getStartEndFrames(startTime, endTime, sampleRate);
+  let startFrame = frameInfo.startFrame;
+  let endFrame = frameInfo.endFrame;
+  let length = Math.floor(endFrame - startFrame);
+  let array = new Array(length);
+  let c = discreteTimeConstantForSampleRate(timeConstant, sampleRate);
 
-  var delta = startValue - targetValue;
+  let delta = startValue - targetValue;
 
   // v(t) = v1 + (v0 - v1) * exp(-(t-t0)/tau)
-  for (var k = 0; k < length; ++k) {
-    var t = (startFrame + k) / sampleRate;
-    var value = targetValue + delta * Math.exp(-(t - startTime) / timeConstant);
+  for (let k = 0; k < length; ++k) {
+    let t = (startFrame + k) / sampleRate;
+    let value = targetValue + delta * Math.exp(-(t - startTime) / timeConstant);
     array[k] = value;
   }
 
   return array;
 }
 
 // Create a sine wave of the specified duration.
 function createReferenceSineArray(
     startTime, endTime, startValue, endValue, sampleRate) {
   // Ignore |startValue| and |endValue| for the sine wave.
-  var curve = createSineWaveArray(
+  let curve = createSineWaveArray(
       endTime - startTime, freqHz, sineAmplitude, sampleRate);
   // Sample the curve appropriately.
-  var frameInfo = getStartEndFrames(startTime, endTime, sampleRate);
-  var startFrame = frameInfo.startFrame;
-  var endFrame = frameInfo.endFrame;
-  var length = Math.floor(endFrame - startFrame);
-  var array = new Array(length);
+  let frameInfo = getStartEndFrames(startTime, endTime, sampleRate);
+  let startFrame = frameInfo.startFrame;
+  let endFrame = frameInfo.endFrame;
+  let length = Math.floor(endFrame - startFrame);
+  let array = new Array(length);
 
   // v(t) = linearly interpolate between V[k] and V[k + 1] where k =
   // floor((N-1)/duration*(t - t0))
-  var f = (length - 1) / (endTime - startTime);
+  let f = (length - 1) / (endTime - startTime);
 
-  for (var k = 0; k < length; ++k) {
-    var t = (startFrame + k) / sampleRate;
-    var indexFloat = f * (t - startTime);
-    var index = Math.floor(indexFloat);
+  for (let k = 0; k < length; ++k) {
+    let t = (startFrame + k) / sampleRate;
+    let indexFloat = f * (t - startTime);
+    let index = Math.floor(indexFloat);
     if (index + 1 < length) {
-      var v0 = curve[index];
-      var v1 = curve[index + 1];
+      let v0 = curve[index];
+      let v1 = curve[index + 1];
       array[k] = v0 + (v1 - v0) * (indexFloat - index);
     } else {
       array[k] = curve[length - 1];
     }
   }
 
   return array;
 }
 
 // Create a sine wave of the given frequency and amplitude.  The sine wave is
 // offset by half the amplitude so that result is always positive.
 function createSineWaveArray(durationSeconds, freqHz, amplitude, sampleRate) {
-  var length = timeToSampleFrame(durationSeconds, sampleRate);
-  var signal = new Float32Array(length);
-  var omega = 2 * Math.PI * freqHz / sampleRate;
-  var halfAmplitude = amplitude / 2;
+  let length = timeToSampleFrame(durationSeconds, sampleRate);
+  let signal = new Float32Array(length);
+  let omega = 2 * Math.PI * freqHz / sampleRate;
+  let halfAmplitude = amplitude / 2;
 
-  for (var k = 0; k < length; ++k) {
+  for (let k = 0; k < length; ++k) {
     signal[k] = halfAmplitude + halfAmplitude * Math.sin(omega * k);
   }
 
   return signal;
 }
 
 // Return the difference between the starting value and the ending value for
 // time interval |timeIntervalIndex|.  We alternate between an end value that is
 // above or below the starting value.
 function endValueDelta(timeIntervalIndex) {
@@ skipping 18 matching lines @@
 // the starting value at the next time interval.  Since we started at a large
 // initial value, we decrease the value at each time interval.
 function valueUpdate(timeIntervalIndex) {
   return -startingValueDelta;
 }
 
 // Compare a section of the rendered data against our expected signal.
 function comparePartialSignals(
     should, rendered, expectedFunction, startTime, endTime, valueInfo,
     sampleRate, errorMetric) {
-  var startSample = timeToSampleFrame(startTime, sampleRate);
-  var expected = expectedFunction(
+  let startSample = timeToSampleFrame(startTime, sampleRate);
+  let expected = expectedFunction(
       startTime, endTime, valueInfo.startValue, valueInfo.endValue, sampleRate,
       timeConstant);
 
-  var n = expected.length;
-  var maxError = -1;
-  var maxErrorIndex = -1;
+  let n = expected.length;
+  let maxError = -1;
+  let maxErrorIndex = -1;
 
-  for (var k = 0; k < n; ++k) {
+  for (let k = 0; k < n; ++k) {
     // Make sure we don't pass these tests because a NaN has been generated in
     // either the
     // rendered data or the reference data.
     if (!isValidNumber(rendered[startSample + k])) {
       maxError = Infinity;
       maxErrorIndex = startSample + k;
       should(
           isValidNumber(rendered[startSample + k]),
           'NaN or infinity for rendered data at ' + maxErrorIndex)
           .beTrue();
       break;
     }
     if (!isValidNumber(expected[k])) {
       maxError = Infinity;
       maxErrorIndex = startSample + k;
       should(
           isValidNumber(expected[k]),
           'NaN or infinity for rendered data at ' + maxErrorIndex)
           .beTrue();
       break;
     }
-    var error = Math.abs(errorMetric(rendered[startSample + k], expected[k]));
+    let error = Math.abs(errorMetric(rendered[startSample + k], expected[k]));
     if (error > maxError) {
       maxError = error;
       maxErrorIndex = k;
     }
   }
 
   return {maxError: maxError, index: maxErrorIndex, expected: expected};
 }
 
 // Find the discontinuities in the data and compare the locations of the
 // discontinuities with the times that define the time intervals. There is a
 // discontinuity if the difference between successive samples exceeds the
 // threshold.
 function verifyDiscontinuities(should, values, times, threshold) {
-  var n = values.length;
-  var success = true;
-  var badLocations = 0;
-  var breaks = [];
+  let n = values.length;
+  let success = true;
+  let badLocations = 0;
+  let breaks = [];
 
   // Find discontinuities.
-  for (var k = 1; k < n; ++k) {
+  for (let k = 1; k < n; ++k) {
     if (Math.abs(values[k] - values[k - 1]) > threshold) {
       breaks.push(k);
     }
   }
 
-  var testCount;
+  let testCount;
 
   // If there are numberOfTests intervals, there are only numberOfTests - 1
   // internal interval boundaries. Hence the maximum number of discontinuties we
   // expect to find is numberOfTests - 1. If we find more than that, we have no
   // reference to compare against. We also assume that the actual
   // discontinuities are close to the expected ones.
   //
   // This is just a sanity check when something goes really wrong.  For example,
   // if the threshold is too low, every sample frame looks like a discontinuity.
   if (breaks.length >= numberOfTests) {
     testCount = numberOfTests - 1;
     should(breaks.length, 'Number of discontinuities')
         .beLessThan(numberOfTests);
     success = false;
   } else {
     testCount = breaks.length;
   }
 
   // Compare the location of each discontinuity with the end time of each
   // interval. (There is no discontinuity at the start of the signal.)
-  for (var k = 0; k < testCount; ++k) {
-    var expectedSampleFrame = timeToSampleFrame(times[k + 1], sampleRate);
+  for (let k = 0; k < testCount; ++k) {
+    let expectedSampleFrame = timeToSampleFrame(times[k + 1], sampleRate);
     if (breaks[k] != expectedSampleFrame) {
       success = false;
       ++badLocations;
       should(breaks[k], 'Discontinuity at index')
           .beEqualTo(expectedSampleFrame);
     }
   }
 
   if (badLocations) {
     should(badLocations, 'Number of discontinuites at incorrect locations')
@@ skipping 20 matching lines @@
 //
 // expectedFunction - function to compute the expected data
 //
 // timeValueInfo - array containing information about the start and end times
 // and the start and end values of each interval.
 //
 // breakThreshold - threshold to use for determining discontinuities.
 function compareSignals(
     should, testName, maxError, renderedData, expectedFunction, timeValueInfo,
     breakThreshold, errorMetric) {
-  var success = true;
-  var failedTestCount = 0;
-  var times = timeValueInfo.times;
-  var values = timeValueInfo.values;
-  var n = values.length;
-  var expectedSignal = [];
+  let success = true;
+  let failedTestCount = 0;
+  let times = timeValueInfo.times;
+  let values = timeValueInfo.values;
+  let n = values.length;
+  let expectedSignal = [];
 
   success = verifyDiscontinuities(should, renderedData, times, breakThreshold);
 
-  for (var k = 0; k < n; ++k) {
-    var result = comparePartialSignals(
+  for (let k = 0; k < n; ++k) {
+    let result = comparePartialSignals(
         should, renderedData, expectedFunction, times[k], times[k + 1],
         values[k], sampleRate, errorMetric);
 
     expectedSignal =
         expectedSignal.concat(Array.prototype.slice.call(result.expected));
 
     should(
         result.maxError,
         'Max error for test ' + k + ' at offset ' +
             (result.index + timeToSampleFrame(times[k], sampleRate)))
@@ skipping 17 matching lines @@
 // with the rendered data.
 //
 // jumpThreshold - optional parameter that specifies the threshold to use for
 // detecting discontinuities.  If not specified, defaults to
 // discontinuityThreshold.
 //
 function checkResultFunction(
     task, should, testName, error, referenceFunction, jumpThreshold,
     errorMetric) {
   return function(event) {
-    var buffer = event.renderedBuffer;
+    let buffer = event.renderedBuffer;
     renderedData = buffer.getChannelData(0);
 
-    var threshold;
+    let threshold;
 
     if (!jumpThreshold) {
       threshold = discontinuityThreshold;
     } else {
       threshold = jumpThreshold;
     }
 
     compareSignals(
         should, testName, error, renderedData, referenceFunction, timeValueInfo,
         threshold, errorMetric);
@@ skipping 10 matching lines @@
 // setValueFunction - function that sets the specified value at the start of a
 // time interval.
 //
 // automationFunction - function that sets the end value for the time interval.
 // It specifies how the value approaches the end value.
 //
 // An object is returned containing an array of start times for each time
 // interval, and an array giving the start and end values for the interval.
 function doAutomation(
     numberOfTests, initialValue, setValueFunction, automationFunction) {
-  var timeInfo = [0];
-  var valueInfo = [];
-  var value = initialValue;
+  let timeInfo = [0];
+  let valueInfo = [];
+  let value = initialValue;
 
-  for (var k = 0; k < numberOfTests; ++k) {
-    var startTime = k * timeInterval;
-    var endTime = (k + 1) * timeInterval;
-    var endValue = value + endValueDelta(k);
+  for (let k = 0; k < numberOfTests; ++k) {
+    let startTime = k * timeInterval;
+    let endTime = (k + 1) * timeInterval;
+    let endValue = value + endValueDelta(k);
 
     // Set the value at the start of the time interval.
     setValueFunction(value, startTime);
 
     // Specify the end or target value, and how we should approach it.
     automationFunction(endValue, startTime, endTime);
 
     // Keep track of the start times, and the start and end values for each time
     // interval.
     timeInfo.push(endTime);
@@ skipping 27 matching lines @@
 // jumpThreshold - optional parameter that specifies the threshold to use for
 // detecting discontinuities.  If not specified, defaults to
 // discontinuityThreshold.
 //
 function createAudioGraphAndTest(
     task, should, numberOfTests, initialValue, setValueFunction,
     automationFunction, testName, maxError, referenceFunction, jumpThreshold,
     errorMetric) {
   // Create offline audio context.
   context = new OfflineAudioContext(2, renderLength(numberOfTests), sampleRate);
-  var constantBuffer =
+  let constantBuffer =
       createConstantBuffer(context, renderLength(numberOfTests), 1);
 
   // We use an AudioGainNode here simply as a convenient way to test the
   // AudioParam automation, since it's easy to pass a constant value through the
   // node, automate the .gain attribute and observe the resulting values.
 
   gainNode = context.createGain();
 
-  var bufferSource = context.createBufferSource();
+  let bufferSource = context.createBufferSource();
   bufferSource.buffer = constantBuffer;
   bufferSource.connect(gainNode);
   gainNode.connect(context.destination);
 
   // Set up default values for the parameters that control how the automation
   // test values progress for each time interval.
   startingValueDelta = initialValue / numberOfTests;
   startEndValueChange = startingValueDelta / 2;
   discontinuityThreshold = startEndValueChange / 2;
 
   // Run the automation tests.
   timeValueInfo = doAutomation(
       numberOfTests, initialValue, setValueFunction, automationFunction);
   bufferSource.start(0);
 
   context.oncomplete = checkResultFunction(
       task, should, testName, maxError, referenceFunction, jumpThreshold,
       errorMetric || relativeErrorMetric);
   context.startRendering();
 }
+
+
+// Export local references to global scope. All the new objects in this file
+// must be exported through this if it is to be used in the actual test HTML
+// page.
+let exports = {
+  'sampleRate': 44100,
+  'gainNode': null,
+
+  // Time interval between value changes.  It is best if 1 / numberOfTests is not
+  // close to timeInterval.
+  'timeInterval': .03,
+
+  // Some suitable time constant so that we can see a significant change over a
+  // timeInterval.  This is only needed by setTargetAtTime() which needs a time
+  // constant.
+  'timeConstant': .03 / 3,

[Raymond Toy, 2017/05/16 18:03:45]

This was previously computed from timeInterval.  I think we should preserve
that.

[hongchan, 2017/05/16 18:10:07]

I can certainly do that, but it does not add much of value since it is almost
alway will be overriden by the actual test code.

Here I am assigning values, but it is more for the sake of declaration.

+
+  'renderLength': renderLength,
+  'createConstantArray': createConstantArray,
+  'getStartEndFrames': getStartEndFrames,
+  'createLinearRampArray': createLinearRampArray,
+  'createExponentialRampArray': createExponentialRampArray,
+  'discreteTimeConstantForSampleRate': discreteTimeConstantForSampleRate,
+  'createExponentialApproachArray': createExponentialApproachArray,
+  'createReferenceSineArray': createReferenceSineArray,
+  'createSineWaveArray': createSineWaveArray,
+  'endValueDelta': endValueDelta,
+  'relativeErrorMetric': relativeErrorMetric,
+  'differenceErrorMetric': differenceErrorMetric,
+  'valueUpdate': valueUpdate,
+  'comparePartialSignals': comparePartialSignals,
+  'verifyDiscontinuities': verifyDiscontinuities,
+  'compareSignals': compareSignals,
+  'checkResultFunction': checkResultFunction,
+  'doAutomation': doAutomation,
+  'createAudioGraphAndTest': createAudioGraphAndTest
+};
+
+
+for (let reference in exports) {
+  global[reference] = exports[reference];
+}
+
+
+})(window);