Bug 1669503 - Add various test cases for mp3 trimming. r=jya

Differential Revision: https://phabricator.services.mozilla.com/D94470

dom/media/webaudio/test/mochitest.ini

@@ -33,6 +33,8 @@ support-files =
   sine-440-10s.opus
   half-a-second-8000.mp3
   half-a-second-48000.mp3
+  cropped_8000hz_8kbs_mono_lame3.100.abr.mp3
+  v3.mp3
   webaudio.js
   ../../webrtc/tests/mochitests/mediaStreamPlayback.js
   ../../webrtc/tests/mochitests/head.js

dom/media/webaudio/test/test_decoderDelay.html

@@ -12,18 +12,33 @@
 SimpleTest.waitForExplicitFinish();
 
 var tests = [
-  "half-a-second-8000.mp3",
-  "half-a-second-48000.mp3",
+  {
+    name: "half-a-second-8000.mp3",
+    duration: 0.5
+  },
+  {
+    name: "half-a-second-48000.mp3",
+    duration: 0.5
+  },
+  {
+    name: "v3.mp3",
+    duration: 3
+  },
+  {
+    // Weird file that has the end padding larger than a packet size.
+    name: "cropped_8000hz_8kbs_mono_lame3.100.abr.mp3",
+    duration: 28.65675
+  }
 ];
 
 async function doit(t) {
   var count = 0;
   var context = new OfflineAudioContext(1, 128, 48000);
-  tests.forEach(async testfile => {
-    var response = await fetch(testfile);
+  tests.forEach(async testcase => {
+    var response = await fetch(testcase.name);
     var buffer = await response.arrayBuffer();
     var decoded = await context.decodeAudioData(buffer);
-    is(decoded.duration, 0.5, "The file is half a second.");
+    is(decoded.duration, testcase.duration, "The file has the correct duration.");
     if (++count == tests.length) {
       SimpleTest.finish();
     }