1 files changed, 103 insertions, 0 deletions
diff --git a/testing/web-platform/tests/webaudio/the-audio-api/the-waveshapernode-interface/silent-inputs.html b/testing/web-platform/tests/webaudio/the-audio-api/the-waveshapernode-interface/silent-inputs.html
new file mode 100644
index 0000000000..45d2c9ad4b
--- /dev/null
+++ b/testing/web-platform/tests/webaudio/the-audio-api/the-waveshapernode-interface/silent-inputs.html
@@ -0,0 +1,103 @@
+<!doctype html>
+<html>
+  <head>
+    <title>
+      Test Silent Inputs to WaveShaperNode
+    </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();
+      let sampleRate = 16000;
+
+      // Identity curve for the wave shaper: the input value is mapped directly
+      // to the output value.
+      let identityCurve = [-1, 0, 1];
+      let nonZeroCurve = [0.5, 0.5, 0.5];
+
+      audit.define(
+          {
+            label: 'test-0',
+            description: 'curve output is non-zero for silent inputs'
+          },
+          (task, should) => {
+            let {context, source, shaper} =
+                setupGraph(nonZeroCurve, sampleRate, sampleRate);
+
+            source.offset.setValueAtTime(0, 0);
+
+            context.startRendering()
+                .then(audioBuffer => {
+                  should(
+                      audioBuffer.getChannelData(0),
+                      'WaveShaper with silent inputs and curve ' +
+                          JSON.stringify(shaper.curve))
+                      .beConstantValueOf(0.5);
+                })
+                .then(() => task.done());
+          });
+
+      audit.define(
+          {
+            label: 'test-1',
+            description: '2x curve output is non-zero for silent inputs'
+          },
+          (task, should) => {
+            let {context, source, shaper} =
+                setupGraph(nonZeroCurve, sampleRate, sampleRate);
+
+            source.offset.setValueAtTime(0, 0);
+            shaper.overSample = '2x';
+
+            context.startRendering()
+                .then(audioBuffer => {
+                  should(
+                      audioBuffer.getChannelData(0),
+                      'WaveShaper with ' + shaper.overSample +
+                          ' oversample, silent inputs, and curve ' +
+                          JSON.stringify(shaper.curve))
+                      .beConstantValueOf(0.5);
+                })
+                .then(() => task.done());
+          });
+
+      audit.define(
+          {
+            label: 'test-2',
+            description: 'curve output is non-zero for no inputs'
+          },
+          (task, should) => {
+            let {context, source, shaper} =
+                setupGraph(nonZeroCurve, sampleRate, sampleRate);
+
+            source.disconnect();
+
+            context.startRendering()
+                .then(audioBuffer => {
+                  should(
+                      audioBuffer.getChannelData(0),
+                      'WaveShaper with no inputs and curve ' +
+                          JSON.stringify(shaper.curve))
+                      .beConstantValueOf(0.5);
+                })
+                .then(() => task.done());
+          });
+
+      function setupGraph(curve, testFrames, sampleRate) {
+        let context = new OfflineAudioContext(1, testFrames, sampleRate);
+        let source = new ConstantSourceNode(context);
+        let shaper = new WaveShaperNode(context, {curve: curve});
+
+        source.connect(shaper).connect(context.destination);
+
+        return {context: context, source: source, shaper: shaper};
+      }
+
+      audit.run();
+    </script>
+  </body>
+</html>