1 files changed, 66 insertions, 0 deletions
diff --git a/testing/web-platform/tests/webaudio/resources/delay-testing.js b/testing/web-platform/tests/webaudio/resources/delay-testing.js
new file mode 100644
index 0000000000..9033da6730
--- /dev/null
+++ b/testing/web-platform/tests/webaudio/resources/delay-testing.js
@@ -0,0 +1,66 @@
+let sampleRate = 44100.0;
+
+let renderLengthSeconds = 4;
+let delayTimeSeconds = 0.5;
+let toneLengthSeconds = 2;
+
+function createToneBuffer(context, frequency, numberOfCycles, sampleRate) {
+  let duration = numberOfCycles / frequency;
+  let sampleFrameLength = duration * sampleRate;
+
+  let audioBuffer = context.createBuffer(1, sampleFrameLength, sampleRate);
+
+  let n = audioBuffer.length;
+  let data = audioBuffer.getChannelData(0);
+
+  for (let i = 0; i < n; ++i)
+    data[i] = Math.sin(frequency * 2.0 * Math.PI * i / sampleRate);
+
+  return audioBuffer;
+}
+
+function checkDelayedResult(renderedBuffer, toneBuffer, should) {
+  let sourceData = toneBuffer.getChannelData(0);
+  let renderedData = renderedBuffer.getChannelData(0);
+
+  let delayTimeFrames = delayTimeSeconds * sampleRate;
+  let toneLengthFrames = toneLengthSeconds * sampleRate;
+
+  let success = true;
+
+  let n = renderedBuffer.length;
+
+  for (let i = 0; i < n; ++i) {
+    if (i < delayTimeFrames) {
+      // Check that initial portion is 0 (since signal is delayed).
+      if (renderedData[i] != 0) {
+        should(
+            renderedData[i], 'Initial portion expected to be 0 at frame ' + i)
+            .beEqualTo(0);
+        success = false;
+        break;
+      }
+    } else if (i >= delayTimeFrames && i < delayTimeFrames + toneLengthFrames) {
+      // Make sure that the tone data is delayed by exactly the expected number
+      // of frames.
+      let j = i - delayTimeFrames;
+      if (renderedData[i] != sourceData[j]) {
+        should(renderedData[i], 'Actual data at frame ' + i)
+            .beEqualTo(sourceData[j]);
+        success = false;
+        break;
+      }
+    } else {
+      // Make sure we have silence after the delayed tone.
+      if (renderedData[i] != 0) {
+        should(renderedData[j], 'Final portion at frame ' + i).beEqualTo(0);
+        success = false;
+        break;
+      }
+    }
+  }
+
+  should(
+      success, 'Delaying test signal by ' + delayTimeSeconds + ' sec was done')
+      .message('correctly', 'incorrectly')
+}