Add tests for the audio effects

test/unit/util/audio-effects.test.js

+/* eslint-env jest */
+/* global AudioNode AudioContext WebAudioTestAPI */
+import 'web-audio-test-api';
+WebAudioTestAPI.setState({
+    'OfflineAudioContext#startRendering': 'promise'
+});
+
+import AudioEffects from '../../../src/lib/audio/audio-effects';
+import RobotEffect from '../../../src/lib/audio/effects/robot-effect';
+import EchoEffect from '../../../src/lib/audio/effects/echo-effect';
+import VolumeEffect from '../../../src/lib/audio/effects/volume-effect';
+
+describe('Audio Effects manager', () => {
+    let audioContext = new AudioContext();
+    let audioBuffer = audioContext.createBuffer(1, 400, 44100);
+
+    test('changes buffer length and playback rate for faster effect', () => {
+        const audioEffects = new AudioEffects(audioBuffer, 'faster');
+        expect(audioEffects.audioContext._.length).toEqual(Math.floor(400 / 1.5));
+        expect(audioEffects.source.playbackRate.value).toEqual(1.5);
+    });
+
+    test('changes buffer length  and playback rate for slower effect', () => {
+        const audioEffects = new AudioEffects(audioBuffer, 'slower');
+        expect(audioEffects.audioContext._.length).toEqual(Math.floor(400 / 0.5));
+        expect(audioEffects.source.playbackRate.value).toEqual(0.5);
+    });
+
+    test('changes buffer length for echo effect', () => {
+        const audioEffects = new AudioEffects(audioBuffer, 'echo');
+        expect(audioEffects.audioContext._.length).toBeGreaterThan(400);
+    });
+
+    test.skip('process starts the offline rendering context and returns a promise', () => {
+        // @todo haven't been able to get web audio test api to actually run render
+    });
+});
+
+describe('Effects', () => {
+    let audioContext;
+
+    beforeEach(() => {
+        audioContext = new AudioContext();
+    });
+
+    test('all effects provide an input and output that are connected', () => {
+        const robotEffect = new RobotEffect(audioContext, 0.5);
+        expect(robotEffect.input).toBeInstanceOf(AudioNode);
+        expect(robotEffect.output).toBeInstanceOf(AudioNode);
+
+        const echoEffect = new EchoEffect(audioContext, 0.5);
+        expect(echoEffect.input).toBeInstanceOf(AudioNode);
+        expect(echoEffect.output).toBeInstanceOf(AudioNode);
+
+        const volumeEffect = new VolumeEffect(audioContext, 0.5);
+        expect(volumeEffect.input).toBeInstanceOf(AudioNode);
+        expect(volumeEffect.output).toBeInstanceOf(AudioNode);
+    });
+});