1 files changed, 95 insertions, 0 deletions
diff --git a/dom/media/webaudio/test/test_webAudio_muteTab.html b/dom/media/webaudio/test/test_webAudio_muteTab.html
new file mode 100644
index 0000000000..ced5c20c9d
--- /dev/null
+++ b/dom/media/webaudio/test/test_webAudio_muteTab.html
@@ -0,0 +1,95 @@
+<!DOCTYPE HTML>
+<html>
+<head>
+  <script type="application/javascript" src="mediaStreamPlayback.js"></script>
+</head>
+<body>
+<pre id="test">
+
+<script>
+createHTML({
+  title: "Check tab muting when the tab plays audio via the Web Audio API",
+  bug: "1346880",
+  visible: false
+});
+
+/**
+ * Check that muting a tab results in no audible audio: mute a tab, in which
+ * an OscillatorNode is playing. The default audio output device is a
+ * pulseaudio null-sink. Simulateously, record the other side of the null
+ * sink, and check that no audio has been written to the sink, because the tab
+ * was muted. Then, umute the tab and check that audio is being sent to the
+ * null-sink. */
+runTest(async () => {
+  if (!SpecialPowers.getCharPref("media.audio_loopback_dev", "")) {
+    todo(false, "No loopback device set by framework. Try --use-test-media-devices");
+    return;
+  }
+
+  // Mute the tab
+  await SpecialPowers.toggleMuteState(true, window.top);
+  // Don't use a loopback tone, the loopback device is here to check that
+  // nothing is output because the tab is muted.
+  DISABLE_LOOPBACK_TONE = true;
+
+  const stream = await getUserMedia({audio: {
+      noiseSuppression: false,
+      echoCancellation: false,
+      autoGainControl: false,
+  }});
+  try {
+    const ac = new AudioContext();
+    const osc = new OscillatorNode(ac);
+    osc.connect(ac.destination);
+    osc.start();
+
+    const analyser = new AudioStreamAnalyser(ac, stream);
+    // Wait for some time, checking there is only ever silent audio in the
+    // loopback stream. `waitForAnalysisSuccess` runs off requestAnimationFrame
+    let silenceFor = 3 / (1 / 60);
+    await analyser.waitForAnalysisSuccess(array => {
+        // `array` has values between 0 and 255, 0 being silence.
+        const sum = array.reduce((acc, v) => { return acc + v; });
+        if (sum == 0) {
+          silenceFor--;
+        } else {
+          info(`Sum of the array values ${sum}`);
+          ok(false, `Found non-silent data in the loopback stream while the tab was muted.`);
+          return true;
+        }
+        if (silenceFor == 0) {
+          ok(true, "Muting the tab was effective");
+        }
+        return silenceFor == 0;
+    });
+
+    // Unmute the tab
+    await SpecialPowers.toggleMuteState(false, window.top);
+
+    await analyser.waitForAnalysisSuccess(array => {
+        // `array` has values between 0 and 255, 0 being silence.
+        const sum = array.reduce((acc, v) => { return acc + v; });
+        if (sum != 0) {
+          info(`Sum after unmuting ${sum}`);
+          ok(true, "Unmuting the tab was effective");
+          return true;
+        } else {
+          // Increment again if we find silence.
+          silenceFor++;
+          if (silenceFor > 100) {
+            ok(false, "Unmuting wasn't effective")
+            return true;
+          }
+          return false;
+        }
+    });
+  } finally {
+    for (let t of stream.getTracks()) {
+      t.stop();
+    }
+  }
+});
+</script>
+</pre>
+</body>
+</html>