test(sampling-master): test the sampling master

With help from the "web-audio-test-api" project. Many thanks!

package.json

@@ -72,6 +72,7 @@
     "through2": "^0.6.3",
     "url-loader": "^0.5.5",
     "val-loader": "^0.5.0",
+    "web-audio-test-api": "^0.2.1",
     "webpack": "^1.4.13",
     "webpack-dev-server": "^1.6.6"
   },

spec/sampling-master/sampling-master_spec.js

@@ -0,0 +1,98 @@
+
+import SamplingMaster from 'bemuse/sampling-master'
+import 'web-audio-test-api'
+
+describe('SamplingMaster', function() {
+
+  let context
+  let master
+  before(() => { WebAudioTestAPI.use() })
+  beforeEach(() => {
+    context = new AudioContext()
+    master  = new SamplingMaster(context)
+  })
+
+  describe('#unmute', function() {
+    it('unmutes the audio', function() {
+      let gain = context.createGain()
+      sinon.stub(context, 'createGain').returns(gain)
+      sinon.spy(gain, 'connect')
+      sinon.spy(gain, 'disconnect')
+      master.unmute()
+      void expect(context.createGain).to.have.been.called
+      void expect(gain.connect).to.have.been.called
+      void expect(gain.disconnect).to.have.been.called
+    })
+  })
+
+  describe('#sample', function() {
+    it('should coerce blob', function() {
+      return master.sample(new Blob([]))
+    })
+    it('should coerce array buffer', function() {
+      return master.sample(new ArrayBuffer(0))
+    })
+    it('should reject when decoding failed', function() {
+      context.DECODE_AUDIO_DATA_FAILED = true
+      return expect(master.sample(new ArrayBuffer(0))
+        .finally(() => context.DECODE_AUDIO_DATA_FAILED = false))
+          .to.be.rejected
+    })
+    describe('#play', function() {
+      let sample
+      let bufferSource
+      beforeEach(function() {
+        bufferSource = context.createBufferSource()
+        sinon.stub(context, 'createBufferSource').returns(bufferSource)
+        sinon.spy(bufferSource, 'start')
+        return master.sample(new Blob([])).then(s => sample = s)
+      })
+      it('should play a buffer source', function() {
+        sample.play()
+        void expect(context.createBufferSource).to.have.been.called
+        expect(bufferSource.start).to.have.been.calledWith(0)
+      })
+      it('should play a buffer source with delay', function() {
+        context.$processTo(1)
+        sample.play(20)
+        void expect(context.createBufferSource).to.have.been.called
+        expect(bufferSource.start).to.have.been.calledWith(21)
+      })
+      describe('#stop', function() {
+        it('should stop the buffer source', function() {
+          let instance = sample.play()
+          sinon.spy(bufferSource, 'stop')
+          instance.stop()
+          void expect(bufferSource.stop).to.have.been.called
+        })
+      })
+    })
+  })
+
+  describe('#destroy', function() {
+    let sample
+    beforeEach(function() {
+      return master.sample(new Blob([])).then(s => sample = s)
+    })
+    it('should stop all samples', function() {
+      let a = sample.play()
+      let b = sample.play()
+      let c = sample.play()
+      sinon.spy(a, 'stop')
+      sinon.spy(b, 'stop')
+      sinon.spy(c, 'stop')
+      master.destroy()
+      void expect(a.stop).to.have.been.called
+      void expect(b.stop).to.have.been.called
+      void expect(c.stop).to.have.been.called
+    })
+    it('can no longer create samples', function() {
+      master.destroy()
+      return expect(master.sample(new Blob([]))).to.be.rejected
+    })
+  })
+
+  after(() => { WebAudioTestAPI.unuse() })
+
+})
+

src/sampling-master/index.js

@@ -106,7 +106,7 @@ class PlayInstance {
     gain.connect(node || context.destination)
     this._source = source
     this._gain = gain
-    source.start(delay === 0 ? 0 : Math.max(0, context.currentTime + delay))
+    source.start(!delay ? 0 : Math.max(0, context.currentTime + delay))
     setTimeout(() => this.stop(), (delay + buffer.duration + 0.01) * 1000)
     this._master._startPlaying(this)
   }