Implement testing framework with Vitest, add unit tests for API routes and utility functions, and configure CI workflow for automated testing. Update package dependencies for testing libraries and add test scripts to package.json.

app/api/download/route.test.ts

@@ -0,0 +1,149 @@
+import { describe, it, expect, vi, beforeEach } from 'vitest'
+import { POST } from './route'
+import { NextRequest } from 'next/server'
+
+vi.mock('@/lib/youtube', () => ({
+  downloadVideo: vi.fn(),
+}))
+
+import { downloadVideo } from '@/lib/youtube'
+
+const mockDownloadVideo = vi.mocked(downloadVideo)
+
+function createRequest(body: object): NextRequest {
+  return new NextRequest('http://localhost:3000/api/download', {
+    method: 'POST',
+    body: JSON.stringify(body),
+    headers: { 'Content-Type': 'application/json' },
+  })
+}
+
+describe('POST /api/download', () => {
+  beforeEach(() => {
+    vi.clearAllMocks()
+  })
+
+  it('returns 400 when url is missing', async () => {
+    const request = createRequest({ format: 'mp4', formatType: 'video' })
+    const response = await POST(request)
+    const data = await response.json()
+
+    expect(response.status).toBe(400)
+    expect(data.success).toBe(false)
+    expect(data.error).toBe('Missing required fields')
+  })
+
+  it('returns 400 when format is missing', async () => {
+    const request = createRequest({ url: 'https://youtube.com/watch?v=abc', formatType: 'video' })
+    const response = await POST(request)
+    const data = await response.json()
+
+    expect(response.status).toBe(400)
+    expect(data.success).toBe(false)
+    expect(data.error).toBe('Missing required fields')
+  })
+
+  it('returns 400 when formatType is missing', async () => {
+    const request = createRequest({ url: 'https://youtube.com/watch?v=abc', format: 'mp4' })
+    const response = await POST(request)
+    const data = await response.json()
+
+    expect(response.status).toBe(400)
+    expect(data.success).toBe(false)
+    expect(data.error).toBe('Missing required fields')
+  })
+
+  it('returns 400 for invalid YouTube URL', async () => {
+    const request = createRequest({
+      url: 'https://vimeo.com/123',
+      format: 'mp4',
+      formatType: 'video',
+    })
+    const response = await POST(request)
+    const data = await response.json()
+
+    expect(response.status).toBe(400)
+    expect(data.success).toBe(false)
+    expect(data.error).toBe('Invalid YouTube URL')
+  })
+
+  it('returns 500 when download fails', async () => {
+    mockDownloadVideo.mockResolvedValue({
+      success: false,
+      error: 'Download failed',
+    })
+
+    const request = createRequest({
+      url: 'https://youtube.com/watch?v=dQw4w9WgXcQ',
+      format: 'mp4',
+      formatType: 'video',
+    })
+    const response = await POST(request)
+    const data = await response.json()
+
+    expect(response.status).toBe(500)
+    expect(data.success).toBe(false)
+    expect(data.error).toBe('Download failed')
+  })
+
+  it('returns download result on success', async () => {
+    const mockResult = {
+      success: true,
+      downloadUrl: '/downloads/123.mp4',
+      filename: 'video.mp4',
+    }
+    mockDownloadVideo.mockResolvedValue(mockResult)
+
+    const request = createRequest({
+      url: 'https://youtube.com/watch?v=dQw4w9WgXcQ',
+      format: 'mp4',
+      formatType: 'video',
+    })
+    const response = await POST(request)
+    const data = await response.json()
+
+    expect(response.status).toBe(200)
+    expect(data.success).toBe(true)
+    expect(data.downloadUrl).toBe('/downloads/123.mp4')
+    expect(data.filename).toBe('video.mp4')
+  })
+
+  it('passes correct parameters to downloadVideo', async () => {
+    mockDownloadVideo.mockResolvedValue({
+      success: true,
+      downloadUrl: '/downloads/123.mp3',
+      filename: 'audio.mp3',
+    })
+
+    const request = createRequest({
+      url: 'https://youtube.com/watch?v=dQw4w9WgXcQ',
+      format: 'mp3',
+      formatType: 'audio',
+    })
+    await POST(request)
+
+    expect(mockDownloadVideo).toHaveBeenCalledWith({
+      url: 'https://youtube.com/watch?v=dQw4w9WgXcQ',
+      format: 'mp3',
+      formatType: 'audio',
+    })
+  })
+
+  it('handles exceptions gracefully', async () => {
+    const consoleSpy = vi.spyOn(console, 'error').mockImplementation(() => {})
+    mockDownloadVideo.mockRejectedValue(new Error('Unexpected error'))
+
+    const request = createRequest({
+      url: 'https://youtube.com/watch?v=dQw4w9WgXcQ',
+      format: 'mp4',
+      formatType: 'video',
+    })
+    const response = await POST(request)
+    const data = await response.json()
+
+    expect(response.status).toBe(500)
+    expect(data.success).toBe(false)
+    expect(data.error).toBe('Unexpected error')
+    consoleSpy.mockRestore()
+  })
+})