1 files changed, 121 insertions, 0 deletions
diff --git a/testing/web-platform/tests/webaudio/the-audio-api/the-gainnode-interface/no-dezippering.html b/testing/web-platform/tests/webaudio/the-audio-api/the-gainnode-interface/no-dezippering.html
new file mode 100644
index 0000000000..6326d00dfb
--- /dev/null
+++ b/testing/web-platform/tests/webaudio/the-audio-api/the-gainnode-interface/no-dezippering.html
@@ -0,0 +1,121 @@
+<!DOCTYPE html>
+<html>
+  <head>
+    <title>
+      Gain Dezippering Test: Dezippering Removed
+    </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();
+
+      audit.define(
+          {label: 'test0', description: 'Dezippering of GainNode removed'},
+          (task, should) => {
+            // Only need a few frames to verify that dezippering has been
+            // removed from the GainNode.  Sample rate is pretty arbitrary.
+            let context = new OfflineAudioContext(1, 1024, 16000);
+
+            // Send a unit source to the gain node so we can measure the effect
+            // of the gain node.
+            let src = new ConstantSourceNode(context, {offset: 1});
+            let g = new GainNode(context, {gain: 1});
+            src.connect(g).connect(context.destination);
+
+            context.suspend(RENDER_QUANTUM_FRAMES / context.sampleRate)
+                .then(() => {
+                  g.gain.value = .5;
+                })
+                .then(() => context.resume());
+
+            src.start();
+
+            context.startRendering()
+                .then(audio => {
+                  let c = audio.getChannelData(0);
+
+                  // If dezippering has been removed, the gain output should
+                  // instantly jump at frame 128 to 0.5.
+                  should(c.slice(0, 128), 'output[0:127]').beConstantValueOf(1);
+                  should(c.slice(128), 'output[128:]').beConstantValueOf(0.5);
+                })
+                .then(() => task.done());
+          });
+
+      audit.define(
+          {
+            label: 'test2',
+            description: 'Compare value setter and setValueAtTime'
+          },
+          (task, should) => {
+            testWithAutomation(should, {prefix: ''}).then(() => task.done());
+          });
+
+      audit.define(
+          {label: 'test3', description: 'Automation effects'},
+          (task, should) => {
+            testWithAutomation(should, {
+              prefix: 'With modulation: ',
+              modulator: true
+            }).then(() => task.done());
+          });
+
+      audit.run();
+
+      function testWithAutomation(should, options) {
+        // Sample rate must be a power of two to eliminate round-off in
+        // computing the time at render quantum boundaries.
+        let context = new OfflineAudioContext(2, 1024, 16384);
+        let merger = new ChannelMergerNode(context, {numberOfChannels: 2});
+        merger.connect(context.destination);
+
+        let src = new OscillatorNode(context);
+        let gainTest = new GainNode(context);
+        let gainRef = new GainNode(context);
+
+        src.connect(gainTest).connect(merger, 0, 0);
+        src.connect(gainRef).connect(merger, 0, 1);
+
+        if (options.modulator) {
+          let mod = new OscillatorNode(context, {frequency: 1000});
+          let modGain = new GainNode(context);
+          mod.connect(modGain);
+          modGain.connect(gainTest.gain);
+          modGain.connect(gainRef.gain);
+          mod.start();
+        }
+
+        // Change the gains. Must do the change on a render boundary!
+        let changeTime = 3 * RENDER_QUANTUM_FRAMES / context.sampleRate;
+        let newGain = .3;
+
+        gainRef.gain.setValueAtTime(newGain, changeTime);
+        context.suspend(changeTime)
+            .then(() => gainTest.gain.value = newGain)
+            .then(() => context.resume());
+
+        src.start();
+
+        return context.startRendering().then(audio => {
+          let actual = audio.getChannelData(0);
+          let expected = audio.getChannelData(1);
+
+          // The values using the .value setter must be identical to the
+          // values using setValueAtTime.
+          let match = should(actual, options.prefix + '.value setter output')
+                          .beEqualToArray(expected);
+
+          should(
+              match,
+              options.prefix +
+                  '.value setter output matches setValueAtTime output')
+              .beTrue();
+        });
+      }
+    </script>
+  </body>
+</html>