fix: play completion sound in chat (#466)

tests/client/completion-sound.test.ts

@@ -0,0 +1,81 @@
+// @vitest-environment jsdom
+import { beforeEach, describe, expect, it, vi } from 'vitest'
+import { __resetCompletionSoundForTests, playCompletionSound, primeCompletionSound } from '@/utils/completion-sound'
+
+function installMockAudioContext(initialState: AudioContextState = 'running') {
+  const oscillator = {
+    type: 'sine' as OscillatorType,
+    frequency: {
+      setValueAtTime: vi.fn(),
+      exponentialRampToValueAtTime: vi.fn(),
+    },
+    connect: vi.fn(),
+    start: vi.fn(),
+    stop: vi.fn(),
+  }
+
+  const gain = {
+    gain: {
+      setValueAtTime: vi.fn(),
+      exponentialRampToValueAtTime: vi.fn(),
+    },
+    connect: vi.fn(),
+  }
+
+  const context = {
+    state: initialState,
+    currentTime: 10,
+    destination: {},
+    resume: vi.fn(async () => {
+      context.state = 'running'
+    }),
+    createOscillator: vi.fn(() => oscillator),
+    createGain: vi.fn(() => gain),
+  }
+
+  const AudioContextMock = vi.fn(() => context)
+  Object.defineProperty(window, 'AudioContext', {
+    configurable: true,
+    writable: true,
+    value: AudioContextMock,
+  })
+
+  return { AudioContextMock, context, oscillator, gain }
+}
+
+describe('completion sound', () => {
+  beforeEach(() => {
+    __resetCompletionSoundForTests()
+    vi.restoreAllMocks()
+    Object.defineProperty(window, 'AudioContext', {
+      configurable: true,
+      writable: true,
+      value: undefined,
+    })
+  })
+
+  it('returns false when Web Audio is unavailable', async () => {
+    await expect(playCompletionSound()).resolves.toBe(false)
+  })
+
+  it('primes a suspended audio context from user interaction', () => {
+    const { context } = installMockAudioContext('suspended')
+
+    primeCompletionSound()
+
+    expect(context.resume).toHaveBeenCalledTimes(1)
+  })
+
+  it('plays a short tone through Web Audio', async () => {
+    const { context, oscillator, gain } = installMockAudioContext('running')
+
+    await expect(playCompletionSound()).resolves.toBe(true)
+
+    expect(context.createOscillator).toHaveBeenCalledTimes(1)
+    expect(context.createGain).toHaveBeenCalledTimes(1)
+    expect(oscillator.connect).toHaveBeenCalledWith(gain)
+    expect(gain.connect).toHaveBeenCalledWith(context.destination)
+    expect(oscillator.start).toHaveBeenCalledWith(10)
+    expect(oscillator.stop).toHaveBeenCalledWith(10.16)
+  })
+})