Make WaveShaper test output more self-explanatory

When reading the output of the waveshaper tests, it's kind of hard to
tell exactly what's being tested.  Add a few more test messages and/or
labels to make it a bit clearer.

Bug: 789197
Test: WaveShaper/waveshaper-{copy-curve,simple}.html
Change-Id: Ic90ebe94282d4b416321766bc16daa3cbc53299c
Reviewed-on: https://chromium-review.googlesource.com/794018
Commit-Queue: Raymond Toy <rtoy@chromium.org>
Reviewed-by: Hongchan Choi <hongchan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#519891}

third_party/WebKit/LayoutTests/webaudio/WaveShaper/waveshaper-copy-curve.html

@@ -18,14 +18,20 @@
 
       let audit = Audit.createTaskRunner();
 
-      audit.define('test copying', (task, should) => {
-        // Two-channel context; channel 0 contains the test data and channel 1
-        // contains the expected result.  Channel 1 has the normal WaveShaper
-        // output and channel 0 has the WaveShaper output with a modified curve.
+      audit.define(
+          {
+            label: 'test copying',
+            description: 'Modifying curve should not modify WaveShaper'
+          },
+          (task, should) => {
+            // Two-channel context; channel 0 contains the test data and channel
+            // 1 contains the expected result.  Channel 1 has the normal
+            // WaveShaper output and channel 0 has the WaveShaper output with a
+            // modified curve.
             let context = new OfflineAudioContext(2, renderFrames, sampleRate);
 
-        // Just use a default oscillator as the source.  Doesn't really matter
-        // what we use.
+            // Just use a default oscillator as the source.  Doesn't really
+            // matter what we use.
             let src = context.createOscillator();
             src.type = 'sawtooth';
 
@@ -34,9 +40,9 @@
             let ws0 = context.createWaveShaper();
             let ws1 = context.createWaveShaper();
 
-        // Wave shaper curves.  Doesn't really matter what we use as long as it
-        // modifies the input in some way.  Thus, keep it simple and just invert
-        // the input.
+            // Wave shaper curves.  Doesn't really matter what we use as long as
+            // it modifies the input in some way.  Thus, keep it simple and just
+            // invert the input.
             let desiredCurve = [1, 0, -1];
             let curve0 = Float32Array.from(desiredCurve);
             let curve1 = Float32Array.from(desiredCurve);
@@ -59,10 +65,15 @@
             // Doesn't really matter what we modify the curve to as long as it's
             // different.
             context.suspend(256 / context.sampleRate)
-            .then(function() {
+                .then(() => {
+                  should(
+                      () => {
                         curve0[0] = -0.5;
                         curve0[1] = 0.125;
                         curve0[2] = 0.75;
+                      },
+                      `Modifying curve array at time ${context.currentTime}`)
+                      .notThrow();
                 })
                 .then(context.resume.bind(context));
 
@@ -73,10 +84,10 @@
                   let actual = renderedBuffer.getChannelData(0);
                   let expected = renderedBuffer.getChannelData(1);
 
-              // Modifying the wave shaper curve should not modify the output so
-              // the outputs from the two wave shaper nodes should be exactly
-              // identical.
-              should(actual, 'WaveShaper with modified curve')
+                  // Modifying the wave shaper curve should not modify the
+                  // output so the outputs from the two wave shaper nodes should
+                  // be exactly identical.
+                  should(actual, 'Output of WaveShaper with modified curve')
                       .beEqualToArray(expected);
 
                 })

third_party/WebKit/LayoutTests/webaudio/WaveShaper/waveshaper-simple.html

@@ -18,30 +18,38 @@
         let shaper = context.createWaveShaper();
 
         // Verify default values are correct.
-        should(shaper.curve, 'WaveShaper.curve').beEqualTo(null);
-        should(shaper.oversample, 'WaveShaper.oversample').beEqualTo('none');
+        should(shaper.curve, 'Initial WaveShaper.curve').beEqualTo(null);
+        should(shaper.oversample, 'Initial WaveShaper.oversample')
+            .beEqualTo('none');
 
         // Set oversample and verify that it is set correctly.
-        shaper.oversample = '2x';
+        should(() => shaper.oversample = '2x', 'Setting oversample to "2x"')
+            .notThrow();
         should(shaper.oversample, 'Waveshaper.oversample = "2x"')
             .beEqualTo('2x');
 
-        shaper.oversample = '4x';
+        should(() => shaper.oversample = '4x', 'Setting oversample to "4x"')
+            .notThrow();
         should(shaper.oversample, 'Waveshaper.oversample = "4x"')
             .beEqualTo('4x');
 
-        shaper.oversample = 'invalid';
+        should(
+            () => shaper.oversample = 'invalid',
+            'Setting oversample to "invalid"')
+            .notThrow();
         should(shaper.oversample, 'Waveshaper.oversample = "invalid"')
             .beEqualTo('4x');
 
         // Set the curve and verify that the returned curve is the same as what
         // it was set to.
         let curve = Float32Array.from([-1, 0.25, .75]);
-        shaper.curve = curve;
+        should(() => shaper.curve = curve, 'Setting curve to [' + curve + ']')
+            .notThrow();
         should(shaper.curve, 'WaveShaper.curve').beEqualToArray(curve);
 
         // Verify setting the curve to null works.
-        shaper.curve = null;
+        should(() => shaper.curve = null, 'Setting curve back to null')
+            .notThrow();
         should(shaper.curve, 'Waveshaper.curve = null').beEqualTo(null);
 
         task.done();