feat: add unit tests and CI configuration

lib/utils/__tests__/errorHandler.test.ts

@@ -0,0 +1,95 @@
+import { describe, it, expect, beforeEach, vi } from 'vitest'
+import {
+  getRequestIdFromError,
+  formatErrorMessage,
+  logErrorWithRequestId,
+  getSupportMessage,
+} from '../errorHandler'
+import { setLastRequestId, clearLastRequestId } from '../requestId'
+
+beforeEach(() => {
+  clearLastRequestId()
+})
+
+describe('getRequestIdFromError', () => {
+  it('extracts request ID from error response body', () => {
+    const errorData = { error: { request_id: 'REQ123_abc' } }
+    expect(getRequestIdFromError(errorData)).toBe('REQ123_abc')
+  })
+
+  it('falls back to last stored request ID when not in response', () => {
+    setLastRequestId('REQfallback_xyz')
+    expect(getRequestIdFromError({ error: {} })).toBe('REQfallback_xyz')
+  })
+
+  it('falls back to last stored request ID when no error data', () => {
+    setLastRequestId('REQfallback_xyz')
+    expect(getRequestIdFromError()).toBe('REQfallback_xyz')
+  })
+
+  it('returns null when no ID available anywhere', () => {
+    expect(getRequestIdFromError()).toBeNull()
+  })
+})
+
+describe('formatErrorMessage', () => {
+  it('returns plain message when no request ID available', () => {
+    expect(formatErrorMessage('Something failed')).toBe('Something failed')
+  })
+
+  it('appends request ID in development mode', () => {
+    const original = process.env.NODE_ENV
+    process.env.NODE_ENV = 'development'
+    setLastRequestId('REQ123_abc')
+
+    const msg = formatErrorMessage('Something failed')
+    expect(msg).toContain('Something failed')
+    expect(msg).toContain('REQ123_abc')
+
+    process.env.NODE_ENV = original
+  })
+
+  it('appends request ID when showRequestId option is set', () => {
+    setLastRequestId('REQ123_abc')
+    const msg = formatErrorMessage('Something failed', undefined, { showRequestId: true })
+    expect(msg).toContain('REQ123_abc')
+  })
+})
+
+describe('logErrorWithRequestId', () => {
+  it('logs with request ID when available', () => {
+    const spy = vi.spyOn(console, 'error').mockImplementation(() => {})
+    setLastRequestId('REQ123_abc')
+
+    logErrorWithRequestId('TestContext', new Error('fail'))
+
+    expect(spy).toHaveBeenCalledWith(
+      expect.stringContaining('REQ123_abc'),
+      expect.any(Error)
+    )
+    spy.mockRestore()
+  })
+
+  it('logs without request ID when not available', () => {
+    const spy = vi.spyOn(console, 'error').mockImplementation(() => {})
+
+    logErrorWithRequestId('TestContext', new Error('fail'))
+
+    expect(spy).toHaveBeenCalledWith('[TestContext]', expect.any(Error))
+    spy.mockRestore()
+  })
+})
+
+describe('getSupportMessage', () => {
+  it('includes request ID when available', () => {
+    const errorData = { error: { request_id: 'REQ123_abc' } }
+    const msg = getSupportMessage(errorData)
+    expect(msg).toContain('REQ123_abc')
+    expect(msg).toContain('contact support')
+  })
+
+  it('returns generic message when no request ID', () => {
+    const msg = getSupportMessage()
+    expect(msg).toBe('If this persists, please contact support.')
+  })
+})

lib/utils/__tests__/logger.test.ts

@@ -0,0 +1,29 @@
+import { describe, it, expect, vi, beforeEach } from 'vitest'
+
+describe('logger', () => {
+  beforeEach(() => {
+    vi.resetModules()
+  })
+
+  it('calls console.error in development', async () => {
+    const spy = vi.spyOn(console, 'error').mockImplementation(() => {})
+    process.env.NODE_ENV = 'development'
+
+    const { logger } = await import('../logger')
+    logger.error('test error')
+
+    expect(spy).toHaveBeenCalledWith('test error')
+    spy.mockRestore()
+  })
+
+  it('calls console.warn in development', async () => {
+    const spy = vi.spyOn(console, 'warn').mockImplementation(() => {})
+    process.env.NODE_ENV = 'development'
+
+    const { logger } = await import('../logger')
+    logger.warn('test warning')
+
+    expect(spy).toHaveBeenCalledWith('test warning')
+    spy.mockRestore()
+  })
+})

lib/utils/__tests__/requestId.test.ts

@@ -0,0 +1,61 @@
+import { describe, it, expect, beforeEach } from 'vitest'
+import {
+  generateRequestId,
+  getRequestIdHeader,
+  setLastRequestId,
+  getLastRequestId,
+  clearLastRequestId,
+} from '../requestId'
+
+describe('generateRequestId', () => {
+  it('returns a string starting with REQ', () => {
+    const id = generateRequestId()
+    expect(id).toMatch(/^REQ/)
+  })
+
+  it('contains a timestamp and random segment separated by underscore', () => {
+    const id = generateRequestId()
+    const parts = id.replace('REQ', '').split('_')
+    expect(parts).toHaveLength(2)
+    expect(parts[0].length).toBeGreaterThan(0)
+    expect(parts[1].length).toBeGreaterThan(0)
+  })
+
+  it('generates unique IDs across calls', () => {
+    const ids = new Set(Array.from({ length: 100 }, () => generateRequestId()))
+    expect(ids.size).toBe(100)
+  })
+})
+
+describe('getRequestIdHeader', () => {
+  it('returns X-Request-ID', () => {
+    expect(getRequestIdHeader()).toBe('X-Request-ID')
+  })
+})
+
+describe('lastRequestId storage', () => {
+  beforeEach(() => {
+    clearLastRequestId()
+  })
+
+  it('returns null when no ID has been set', () => {
+    expect(getLastRequestId()).toBeNull()
+  })
+
+  it('stores and retrieves a request ID', () => {
+    setLastRequestId('REQ123_abc')
+    expect(getLastRequestId()).toBe('REQ123_abc')
+  })
+
+  it('overwrites previous ID on set', () => {
+    setLastRequestId('first')
+    setLastRequestId('second')
+    expect(getLastRequestId()).toBe('second')
+  })
+
+  it('clears the stored ID', () => {
+    setLastRequestId('REQ123_abc')
+    clearLastRequestId()
+    expect(getLastRequestId()).toBeNull()
+  })
+})