test: add unit tests for lib/ (validate, auth, storage, email, rate-limit)

49 tests for all 10 Zod schemas in validate.ts, 26 tests for auth (hashPassword,
verifyPassword, createSession, getSession, getCurrentUser, deleteSession), 11 for
storage (magic-byte validation, saveImage, deleteImageFile), 9 for email (sendMail
scenarios), and 6 for rate limiting logic.

test/unit/lib/rate-limit.test.ts

@@ -0,0 +1,71 @@
+import { describe, it, expect, vi, beforeEach } from 'vitest'
+import '../../../test/__mocks__/prisma'
+
+import { checkRateLimit, recordAttempt } from '@/lib/rate-limit'
+import { prisma } from '@/lib/prisma'
+
+beforeEach(() => {
+  vi.clearAllMocks()
+})
+
+describe('checkRateLimit', () => {
+  it('returns not limited when attempts < 10', async () => {
+    vi.mocked(prisma.loginAttempt.count).mockResolvedValue(5)
+    const result = await checkRateLimit('1.2.3.4')
+    expect(result.limited).toBe(false)
+    expect(result.remaining).toBe(5)
+  })
+
+  it('returns limited when attempts >= 10', async () => {
+    vi.mocked(prisma.loginAttempt.count).mockResolvedValue(10)
+    const result = await checkRateLimit('1.2.3.4')
+    expect(result.limited).toBe(true)
+    expect(result.remaining).toBe(0)
+  })
+
+  it('returns limited when attempts > 10', async () => {
+    vi.mocked(prisma.loginAttempt.count).mockResolvedValue(15)
+    const result = await checkRateLimit('1.2.3.4')
+    expect(result.limited).toBe(true)
+  })
+
+  it('returns remaining = 1 when attempts = 9', async () => {
+    vi.mocked(prisma.loginAttempt.count).mockResolvedValue(9)
+    const result = await checkRateLimit('1.2.3.4')
+    expect(result.limited).toBe(false)
+    expect(result.remaining).toBe(1)
+  })
+
+  it('queries with a windowStart within the last 15 minutes', async () => {
+    vi.mocked(prisma.loginAttempt.count).mockResolvedValue(0)
+    const before = new Date(Date.now() - 15 * 60 * 1000 - 100)
+
+    await checkRateLimit('1.2.3.4')
+
+    const callArg = vi.mocked(prisma.loginAttempt.count).mock.calls[0][0]
+    const windowStart = callArg?.where?.createdAt?.gte as Date
+    expect(windowStart.getTime()).toBeGreaterThan(before.getTime())
+  })
+})
+
+describe('recordAttempt', () => {
+  it('creates a login attempt record', async () => {
+    vi.mocked(prisma.loginAttempt.create).mockResolvedValue({ id: '1', key: '1.2.3.4', createdAt: new Date() })
+    vi.mocked(prisma.loginAttempt.deleteMany).mockResolvedValue({ count: 0 })
+
+    await recordAttempt('1.2.3.4')
+
+    expect(prisma.loginAttempt.create).toHaveBeenCalledWith({ data: { key: '1.2.3.4' } })
+  })
+
+  it('cleans up old records after creating', async () => {
+    vi.mocked(prisma.loginAttempt.create).mockResolvedValue({ id: '1', key: '1.2.3.4', createdAt: new Date() })
+    vi.mocked(prisma.loginAttempt.deleteMany).mockResolvedValue({ count: 0 })
+
+    await recordAttempt('1.2.3.4')
+
+    expect(prisma.loginAttempt.deleteMany).toHaveBeenCalledWith(
+      expect.objectContaining({ where: expect.objectContaining({ createdAt: expect.anything() }) })
+    )
+  })
+})