Fix unit test

src/extensions/scratch3_music/index.js

@@ -68,6 +68,8 @@ class Scratch3MusicBlocks {
      * @return {Promise} - a promise which will resolve once the sound has loaded.
      */
     _loadSound (fileName, index, bufferArray) {
+        if (!this.runtime.storage) return;
+        if (!this.runtime.audioEngine) return;
         return this.runtime.storage.load(this.runtime.storage.AssetType.Sound, fileName, 'mp3')
             .then(soundAsset =>
                 this.runtime.audioEngine.audioContext.decodeAudioData(soundAsset.data.buffer)

test/unit/blocks_music.js

@@ -1,5 +1,5 @@
 const test = require('tap').test;
-const Music = require('../../src/blocks/scratch3_music');
+const Music = require('../../src/extensions/scratch3_music/index.js');
 let playedDrum;
 let playedInstrument;
 const runtime = {