pipu-music/apps/web/src/player/audio.test.ts

import { afterEach, describe, expect, it, vi } from 'vitest';

import { AudioAnalysis } from './analysis';
import { AudioEngine } from './engine';

afterEach(() => vi.restoreAllMocks());

function fixture() {
  const sample = vi.fn((data: Uint8Array) => {
    data.fill(0);
    // 48 kHz / 1024: bins 1..4 cover the bass band.
    data.fill(255, 1, 5);
  });
  const analyser = { context: { sampleRate: 48000 }, fftSize: 1024, getByteFrequencyData: sample } as unknown as AnalyserNode;
  const analysis = new AudioAnalysis(() => analyser);
  return { analysis, sample };
}

describe('audio reactivity', () => {
  it('separates bass from the other frequency bands and shares the frame', () => {
    vi.spyOn(performance, 'now').mockReturnValue(100);
    const { analysis, sample } = fixture();
    expect(analysis.read(true)).toEqual({ bass: 1, mid: 0, treble: 0 });
    analysis.read(true);
    expect(sample).toHaveBeenCalledTimes(1);
  });

  it('returns silence after pausing or muting', () => {
    const clock = vi.spyOn(performance, 'now').mockReturnValue(100);
    const { analysis, sample } = fixture();
    analysis.read(true);
    clock.mockReturnValue(120);
    expect(analysis.read(false)).toEqual({ bass: 0, mid: 0, treble: 0 });
    clock.mockReturnValue(140);
    expect(analysis.read(false)).toEqual({ bass: 0, mid: 0, treble: 0 });
    expect(sample).toHaveBeenCalledTimes(1);
  });

  it('works when Web Audio is unavailable', () => {
    const analysis = new AudioAnalysis(() => null);
    expect(analysis.read(false)).toEqual({ bass: 0, mid: 0, treble: 0 });
  });
});

describe('audio engine lifetime', () => {
  it('removes audio listeners on disposal', () => {
    const audio = document.createElement('audio');
    const engine = new AudioEngine(audio);
    const playing = vi.fn();
    engine.on('playing', playing);
    audio.dispatchEvent(new Event('playing'));
    expect(playing).toHaveBeenCalledTimes(1);
    engine.dispose();
    audio.dispatchEvent(new Event('playing'));
    expect(playing).toHaveBeenCalledTimes(1);
  });
});