✅ Test that recording has audio

karma.conf.js

@@ -57,7 +57,8 @@ module.exports = function (config) {
         base: 'Firefox',
         flags: ['-headless'],
         prefs: {
-          'network.proxy.type': 0
+          'network.proxy.type': 0,
+          'media.autoplay.default': 0  // Allow all autoplay
         }
       }
     },

spec/integration/movie.spec.ts

@@ -33,6 +33,36 @@ function validateVideoData (video: HTMLVideoElement) {
   expect(maxDiff).toBeLessThanOrEqual(5)
 }
 
+/**
+ * Resolves to true if the audio is completely silent.
+ * @param audio
+ * @returns
+ */
+async function isAudioSilent (audio: HTMLAudioElement) {
+  // Set up audio context
+  const audioCtx = new AudioContext()
+  const source = audioCtx.createMediaElementSource(audio)
+  const analyser = audioCtx.createAnalyser()
+  source.connect(analyser)
+  analyser.connect(audioCtx.destination)
+
+  // Play audio
+  audio.play()
+  if (!audio.paused) {
+    await new Promise<void>(resolve => {
+      audio.addEventListener('pause', () => {
+        resolve()
+      })
+    })
+  }
+
+  // Check if audio is silent
+  const bufferLength = analyser.frequencyBinCount
+  const dataArray = new Uint8Array(bufferLength)
+  analyser.getByteTimeDomainData(dataArray)
+  return dataArray.every(x => x === 128)
+}
+
 describe('Integration Tests ->', function () {
   describe('Movie', function () {
     let movie, canvas
@@ -197,6 +227,47 @@ describe('Integration Tests ->', function () {
         // Clean up
         URL.revokeObjectURL(video.src)
       })
+
+      it('should produce audio when recording', async function () {
+        // Remove all existing layers (optional)
+        movie.layers.length = 0
+
+        // Add an audio layer
+        const audio = new Audio('/base/spec/integration/assets/layer/audio.wav')
+        await new Promise(resolve => {
+          audio.onloadeddata = resolve
+        })
+        const layer = new etro.layer.Audio({
+          source: audio,
+          startTime: 0
+        })
+        movie.layers.push(layer)
+
+        // Record audio
+        const blob = await movie.record({
+          frameRate: 30,
+          video: false,
+          type: 'audio/ogg'
+        })
+
+        // Make sure the audio blob is not empty
+        expect(blob.size).toBeGreaterThan(0)
+
+        // Load blob into html audio element
+        const audioElement = document.createElement('audio')
+        audioElement.src = URL.createObjectURL(blob)
+        await new Promise<void>(resolve => {
+          audioElement.addEventListener('canplaythrough', () => {
+            resolve()
+          })
+        })
+
+        // Make sure the audio is not completely silent
+        expect(await isAudioSilent(audioElement)).toBe(false)
+
+        // Clean up
+        URL.revokeObjectURL(audioElement.src)
+      })
     })
 
     describe('events ->', function () {