test(app): add unit tests for usePlayer composable

Tests queue management, state transitions, progress computation,
deduplication, and API shape. 9 test cases.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

packages/app/src/composables/__tests__/usePlayer.test.ts

@@ -0,0 +1,140 @@
+import { describe, it, expect, beforeEach, vi } from 'vitest'
+
+// Mock Plyr before importing usePlayer
+vi.mock('plyr', () => {
+  const MockPlyr = vi.fn().mockImplementation(() => ({
+    on: vi.fn(),
+    play: vi.fn().mockResolvedValue(undefined),
+    pause: vi.fn(),
+    destroy: vi.fn(),
+    currentTime: 0,
+    duration: 120,
+  }))
+  return { default: MockPlyr }
+})
+
+vi.mock('plyr/dist/plyr.css', () => ({}))
+
+import { usePlayer } from '../usePlayer'
+
+function makeSong(id: string, title = `Song ${id}`, artist = `Artist ${id}`) {
+  return {
+    id,
+    title,
+    artist,
+    album: 'Test Album',
+    genres: [],
+  }
+}
+
+describe('usePlayer', () => {
+  beforeEach(() => {
+    const player = usePlayer()
+    player.clearQueue()
+    vi.restoreAllMocks()
+    // Reset fetch mock
+    vi.stubGlobal('fetch', vi.fn().mockResolvedValue({
+      json: () => Promise.resolve({ source: 'test', type: 'stream', url: 'https://example.com/audio.mp3' }),
+    }))
+  })
+
+  it('returns expected API shape', () => {
+    const player = usePlayer()
+    expect(player.currentSong).toBeDefined()
+    expect(player.isPlaying).toBeDefined()
+    expect(player.isLoading).toBeDefined()
+    expect(player.queue).toBeDefined()
+    expect(player.play).toBeTypeOf('function')
+    expect(player.pause).toBeTypeOf('function')
+    expect(player.toggle).toBeTypeOf('function')
+    expect(player.seek).toBeTypeOf('function')
+    expect(player.addToQueue).toBeTypeOf('function')
+    expect(player.playNext).toBeTypeOf('function')
+    expect(player.playPrevious).toBeTypeOf('function')
+    expect(player.clearQueue).toBeTypeOf('function')
+  })
+
+  it('starts with no track', () => {
+    const player = usePlayer()
+    expect(player.hasTrack.value).toBe(false)
+    expect(player.currentSong.value).toBeNull()
+    expect(player.isPlaying.value).toBe(false)
+  })
+
+  it('addToQueue adds songs', () => {
+    const player = usePlayer()
+    const song1 = makeSong('1')
+    const song2 = makeSong('2')
+    player.addToQueue(song1)
+    player.addToQueue(song2)
+    expect(player.queue.value).toHaveLength(2)
+    expect(player.queue.value[0].id).toBe('1')
+    expect(player.queue.value[1].id).toBe('2')
+  })
+
+  it('addToQueue deduplicates by id', () => {
+    const player = usePlayer()
+    const song = makeSong('1')
+    player.addToQueue(song)
+    player.addToQueue(song)
+    expect(player.queue.value).toHaveLength(1)
+  })
+
+  it('removeFromQueue removes by index', () => {
+    const player = usePlayer()
+    player.addToQueue(makeSong('1'))
+    player.addToQueue(makeSong('2'))
+    player.addToQueue(makeSong('3'))
+    player.removeFromQueue(1)
+    expect(player.queue.value).toHaveLength(2)
+    expect(player.queue.value[0].id).toBe('1')
+    expect(player.queue.value[1].id).toBe('3')
+  })
+
+  it('clearQueue resets all state', () => {
+    const player = usePlayer()
+    player.addToQueue(makeSong('1'))
+    player.addToQueue(makeSong('2'))
+    player.clearQueue()
+    expect(player.queue.value).toHaveLength(0)
+    expect(player.currentIndex.value).toBe(-1)
+    expect(player.currentSong.value).toBeNull()
+  })
+
+  it('hasNext and hasPrevious compute correctly', () => {
+    const player = usePlayer()
+    player.addToQueue(makeSong('1'))
+    player.addToQueue(makeSong('2'))
+    player.addToQueue(makeSong('3'))
+
+    // At start, no previous
+    expect(player.hasPrevious.value).toBe(false)
+
+    // Move to middle
+    player.currentIndex.value = 1
+    expect(player.hasNext.value).toBe(true)
+    expect(player.hasPrevious.value).toBe(true)
+
+    // At end
+    player.currentIndex.value = 2
+    expect(player.hasNext.value).toBe(false)
+    expect(player.hasPrevious.value).toBe(true)
+  })
+
+  it('progress computes percentage from currentTime/duration', () => {
+    const player = usePlayer()
+    player.duration.value = 100
+    player.currentTime.value = 50
+    expect(player.progress.value).toBe(50)
+
+    player.currentTime.value = 0
+    expect(player.progress.value).toBe(0)
+  })
+
+  it('progress returns 0 when duration is 0', () => {
+    const player = usePlayer()
+    player.duration.value = 0
+    player.currentTime.value = 10
+    expect(player.progress.value).toBe(0)
+  })
+})