Initial commit of 001code-html Scratch frontend project.

Includes scratch-gui, scratch-vm, scratch-blocks, scratch-render, scratch-l10n, and deployment config.

Co-authored-by: Cursor <cursoragent@cursor.com>

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

@@ -0,0 +1,91 @@
+/* global 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', () => {
+    const audioContext = new AudioContext();
+    const audioBuffer = audioContext.createBuffer(1, 400, 44100);
+
+    test('changes buffer length and playback rate for faster effect', () => {
+        const audioEffects = new AudioEffects(audioBuffer, 'faster', 0, 1);
+        expect(audioEffects.audioContext._.length).toBeLessThan(400);
+    });
+
+    test('changes buffer length  and playback rate for slower effect', () => {
+        const audioEffects = new AudioEffects(audioBuffer, 'slower', 0, 1);
+        expect(audioEffects.audioContext._.length).toBeGreaterThan(400);
+    });
+
+    test('changes buffer length for echo effect', () => {
+        const audioEffects = new AudioEffects(audioBuffer, 'echo', 0, 1);
+        expect(audioEffects.audioContext._.length).toBeGreaterThan(400);
+    });
+
+    test('updates the trim positions after an effect has changed the length of selection', () => {
+        const slowerEffect = new AudioEffects(audioBuffer, 'slower', 0.25, 0.75);
+        expect(slowerEffect.adjustedTrimStartSeconds).toEqual(slowerEffect.trimStartSeconds);
+        expect(slowerEffect.adjustedTrimEndSeconds).toBeGreaterThan(slowerEffect.trimEndSeconds);
+
+        const fasterEffect = new AudioEffects(audioBuffer, 'faster', 0.25, 0.75);
+        expect(fasterEffect.adjustedTrimStartSeconds).toEqual(fasterEffect.trimStartSeconds);
+        expect(fasterEffect.adjustedTrimEndSeconds).toBeLessThan(fasterEffect.trimEndSeconds);
+
+        // Some effects do not change the length of the selection
+        const fadeEffect = new AudioEffects(audioBuffer, 'fade in', 0.25, 0.75);
+        expect(fadeEffect.adjustedTrimStartSeconds).toEqual(fadeEffect.trimStartSeconds);
+        // Should be within one millisecond (flooring can change the duration by one sample)
+        expect(fadeEffect.adjustedTrimEndSeconds).toBeCloseTo(fadeEffect.trimEndSeconds, 3);
+    });
+
+    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
+    });
+
+    test('reverse effect strictly reverses the samples', () => {
+        const fakeSound = [1, 2, 3, 4, 5, 6, 7, 8];
+
+        const fakeBuffer = audioContext.createBuffer(1, 8, 44100);
+        const bufferData = fakeBuffer.getChannelData(0);
+        fakeSound.forEach((sample, index) => {
+            bufferData[index] = sample;
+        });
+
+        // Reverse the entire sound
+        const reverseAll = new AudioEffects(fakeBuffer, 'reverse', 0, 1);
+        expect(Array.from(reverseAll.buffer.getChannelData(0))).toEqual(fakeSound.reverse());
+
+        // Reverse part of the sound
+        const reverseSelection = new AudioEffects(fakeBuffer, 'reverse', 0.25, 0.75);
+        const selectionReversed = [1, 2, 6, 5, 4, 3, 7, 8];
+        expect(Array.from(reverseSelection.buffer.getChannelData(0))).toEqual(selectionReversed);
+    });
+});
+
+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, 1);
+        expect(robotEffect.input).toBeInstanceOf(AudioNode);
+        expect(robotEffect.output).toBeInstanceOf(AudioNode);
+
+        const echoEffect = new EchoEffect(audioContext, 0, 1);
+        expect(echoEffect.input).toBeInstanceOf(AudioNode);
+        expect(echoEffect.output).toBeInstanceOf(AudioNode);
+
+        const volumeEffect = new VolumeEffect(audioContext, 0.5, 0, 1);
+        expect(volumeEffect.input).toBeInstanceOf(AudioNode);
+        expect(volumeEffect.output).toBeInstanceOf(AudioNode);
+    });
+});