feat: replace fixed login rate limit with progressive lockout

Made-with: Cursor

.env.example

@@ -23,8 +23,7 @@ LLM_MAX_RETRIES=1
 LLM_TEMPERATURE=0.7
 LLM_MAX_TOKENS=2048
 
-# Rate limits
+# Rate limits (login uses progressive lockout: 5/10/20 failed attempts -> 15m/1h/24h block)
-RATE_LIMIT_LOGIN=5
 RATE_LIMIT_REGISTER=3
 RATE_LIMIT_FORGOT_PASSWORD=3
 RATE_LIMIT_VERIFY_EMAIL=5

src/app.ts

@@ -8,6 +8,8 @@ import authPlugin from './plugins/auth.js';
 import subscriptionPlugin from './plugins/subscription.js';
 import { authRoutes } from './routes/auth.js';
 import { profileRoutes } from './routes/profile.js';
+import { testsRoutes } from './routes/tests.js';
+import { adminQuestionsRoutes } from './routes/admin/questions.js';
 import { env } from './config/env.js';
 import { randomUUID } from 'node:crypto';
 
@@ -77,6 +79,8 @@ export async function buildApp(): Promise<FastifyInstance> {
   await app.register(subscriptionPlugin);
   await app.register(authRoutes, { prefix: '/auth' });
   await app.register(profileRoutes, { prefix: '/profile' });
+  await app.register(testsRoutes, { prefix: '/tests' });
+  await app.register(adminQuestionsRoutes, { prefix: '/admin' });
 
   app.get('/health', async () => ({ status: 'ok', timestamp: new Date().toISOString() }));
 

src/config/env.ts

@@ -22,7 +22,6 @@ const envSchema = z.object({
   LLM_TEMPERATURE: z.coerce.number().min(0).max(2).default(0.7),
   LLM_MAX_TOKENS: z.coerce.number().default(2048),
 
-  RATE_LIMIT_LOGIN: z.coerce.number().default(5),
   RATE_LIMIT_REGISTER: z.coerce.number().default(3),
   RATE_LIMIT_FORGOT_PASSWORD: z.coerce.number().default(3),
   RATE_LIMIT_VERIFY_EMAIL: z.coerce.number().default(5),

src/plugins/auth.ts

@@ -1,11 +1,14 @@
 import type { FastifyInstance, FastifyRequest, FastifyReply } from 'fastify';
 import fp from 'fastify-plugin';
+import { eq } from 'drizzle-orm';
 import { verifyToken, isAccessPayload } from '../utils/jwt.js';
-import { unauthorized } from '../utils/errors.js';
+import { unauthorized, forbidden } from '../utils/errors.js';
+import { users } from '../db/schema/users.js';
 
 declare module 'fastify' {
   interface FastifyInstance {
     authenticate: (req: FastifyRequest, reply: FastifyReply) => Promise<void>;
+    authenticateAdmin: (req: FastifyRequest, reply: FastifyReply) => Promise<void>;
   }
   interface FastifyRequest {
     user?: { id: string; email: string };
@@ -34,9 +37,22 @@ export async function authenticate(req: FastifyRequest, _reply: FastifyReply): P
   }
 }
 
+export async function authenticateAdmin(req: FastifyRequest, _reply: FastifyReply): Promise<void> {
+  if (!req.user) {
+    throw unauthorized('Authentication required');
+  }
+
+  const [user] = await req.server.db.select({ role: users.role }).from(users).where(eq(users.id, req.user.id));
+
+  if (!user || user.role !== 'admin') {
+    throw forbidden('Admin access required');
+  }
+}
+
 const authPlugin = async (app: FastifyInstance) => {
   app.decorateRequest('user', undefined);
   app.decorate('authenticate', authenticate);
+  app.decorate('authenticateAdmin', authenticateAdmin);
 };
 
-export default fp(authPlugin, { name: 'auth' });
+export default fp(authPlugin, { name: 'auth', dependencies: ['database'] });

src/plugins/rateLimit.ts

@@ -6,7 +6,6 @@ import { env } from '../config/env.js';
 declare module 'fastify' {
   interface FastifyInstance {
     rateLimitOptions: {
-      login: { max: number; timeWindow: string };
       register: { max: number; timeWindow: string };
       forgotPassword: { max: number; timeWindow: string };
       verifyEmail: { max: number; timeWindow: string };
@@ -18,7 +17,6 @@ declare module 'fastify' {
 
 const rateLimitPlugin: FastifyPluginAsync = async (app: FastifyInstance) => {
   const options = {
-    login: { max: env.RATE_LIMIT_LOGIN, timeWindow: '15 minutes' },
     register: { max: env.RATE_LIMIT_REGISTER, timeWindow: '1 hour' },
     forgotPassword: { max: env.RATE_LIMIT_FORGOT_PASSWORD, timeWindow: '1 hour' },
     verifyEmail: { max: env.RATE_LIMIT_VERIFY_EMAIL, timeWindow: '15 minutes' },

src/routes/admin/questions.ts

@@ -0,0 +1,131 @@
+import type { FastifyInstance } from 'fastify';
+import { AdminQuestionService } from '../../services/admin/admin-question.service.js';
+import type { EditQuestionInput } from '../../services/admin/admin-question.service.js';
+
+const STACKS = ['html', 'css', 'js', 'ts', 'react', 'vue', 'nodejs', 'git', 'web_basics'] as const;
+const LEVELS = ['basic', 'beginner', 'intermediate', 'advanced', 'expert'] as const;
+const QUESTION_TYPES = ['single_choice', 'multiple_select', 'true_false', 'short_text'] as const;
+
+const listPendingQuerySchema = {
+  querystring: {
+    type: 'object',
+    properties: {
+      limit: { type: 'integer', minimum: 1, maximum: 100 },
+      offset: { type: 'integer', minimum: 0 },
+    },
+    additionalProperties: false,
+  },
+};
+
+const questionIdParamsSchema = {
+  params: {
+    type: 'object',
+    required: ['questionId'],
+    properties: {
+      questionId: { type: 'string', format: 'uuid' },
+    },
+  },
+};
+
+const editQuestionSchema = {
+  params: {
+    type: 'object',
+    required: ['questionId'],
+    properties: {
+      questionId: { type: 'string', format: 'uuid' },
+    },
+  },
+  body: {
+    type: 'object',
+    properties: {
+      stack: { type: 'string', enum: [...STACKS] },
+      level: { type: 'string', enum: [...LEVELS] },
+      type: { type: 'string', enum: [...QUESTION_TYPES] },
+      questionText: { type: 'string', minLength: 1 },
+      options: {
+        type: 'array',
+        items: {
+          type: 'object',
+          required: ['key', 'text'],
+          properties: {
+            key: { type: 'string' },
+            text: { type: 'string' },
+          },
+        },
+      },
+      correctAnswer: {
+        oneOf: [
+          { type: 'string' },
+          { type: 'array', items: { type: 'string' } },
+        ],
+      },
+      explanation: { type: 'string', minLength: 1 },
+    },
+    additionalProperties: false,
+  },
+};
+
+export async function adminQuestionsRoutes(app: FastifyInstance) {
+  const adminQuestionService = new AdminQuestionService(app.db);
+  const { rateLimitOptions } = app;
+
+  app.get(
+    '/questions/pending',
+    {
+      schema: listPendingQuerySchema,
+      config: { rateLimit: rateLimitOptions.apiAuthed },
+      preHandler: [app.authenticate, app.authenticateAdmin],
+    },
+    async (req, reply) => {
+      const { limit, offset } = (req.query as { limit?: number; offset?: number }) ?? {};
+      const result = await adminQuestionService.listPending(limit, offset);
+      return reply.send(result);
+    },
+  );
+
+  app.post(
+    '/questions/:questionId/approve',
+    {
+      schema: questionIdParamsSchema,
+      config: { rateLimit: rateLimitOptions.apiAuthed },
+      preHandler: [app.authenticate, app.authenticateAdmin],
+    },
+    async (req, reply) => {
+      const adminId = req.user!.id;
+      const { questionId } = req.params as { questionId: string };
+      await adminQuestionService.approve(questionId, adminId);
+      return reply.status(204).send();
+    },
+  );
+
+  app.post(
+    '/questions/:questionId/reject',
+    {
+      schema: questionIdParamsSchema,
+      config: { rateLimit: rateLimitOptions.apiAuthed },
+      preHandler: [app.authenticate, app.authenticateAdmin],
+    },
+    async (req, reply) => {
+      const adminId = req.user!.id;
+      const { questionId } = req.params as { questionId: string };
+      await adminQuestionService.reject(questionId, adminId);
+      return reply.status(204).send();
+    },
+  );
+
+  app.patch(
+    '/questions/:questionId',
+    {
+      schema: editQuestionSchema,
+      config: { rateLimit: rateLimitOptions.apiAuthed },
+      preHandler: [app.authenticate, app.authenticateAdmin],
+    },
+    async (req, reply) => {
+      const adminId = req.user!.id;
+      const { questionId } = req.params as { questionId: string };
+      const body = req.body as EditQuestionInput;
+      const question = await adminQuestionService.edit(questionId, body, adminId);
+      return reply.send(question);
+    },
+  );
+}

src/routes/auth.ts

@@ -1,5 +1,6 @@
 import type { FastifyInstance } from 'fastify';
 import { AuthService } from '../services/auth/auth.service.js';
+import { checkBlocked, clearOnSuccess, recordFailedAttempt } from '../utils/loginLockout.js';
 
 const registerSchema = {
   body: {
@@ -89,20 +90,43 @@ export async function authRoutes(app: FastifyInstance) {
 
   app.post(
     '/login',
-    { schema: loginSchema, config: { rateLimit: rateLimitOptions.login } },
+    {
+      schema: loginSchema,
+      preValidation: async (req, reply) => {
+        const ip = req.ip ?? 'unknown';
+        const { blocked, retryAfter } = await checkBlocked(app.redis, ip);
+        if (blocked) {
+          if (retryAfter !== undefined) {
+            reply.header('Retry-After', String(retryAfter));
+          }
+          return reply.status(429).send({
+            error: {
+              code: 'RATE_LIMIT_EXCEEDED',
+              message: 'Too many failed login attempts. Please try again later.',
+              retryAfter,
+            },
+          });
+        }
+      },
+    },
     async (req, reply) => {
       const body = req.body as { email: string; password: string };
       const userAgent = req.headers['user-agent'];
-      const ipAddress = req.ip;
+      const ip = req.ip ?? 'unknown';
 
-      const result = await authService.login({
+      try {
-        email: body.email,
+        const result = await authService.login({
-        password: body.password,
+          email: body.email,
-        userAgent,
+          password: body.password,
-        ipAddress,
+          userAgent,
-      });
+          ipAddress: ip,
-
+        });
-      return reply.send(result);
+        await clearOnSuccess(app.redis, ip);
+        return reply.send(result);
+      } catch (err) {
+        await recordFailedAttempt(app.redis, ip);
+        throw err;
+      }
     },
   );
 

src/routes/tests.ts

@@ -0,0 +1,185 @@
+import type { FastifyInstance } from 'fastify';
+import { LlmService } from '../services/llm/llm.service.js';
+import { QuestionService } from '../services/questions/question.service.js';
+import { TestsService } from '../services/tests/tests.service.js';
+import { notFound } from '../utils/errors.js';
+import type { CreateTestInput } from '../services/tests/tests.service.js';
+import type { TestSnapshot } from '../services/tests/tests.service.js';
+
+const STACKS = ['html', 'css', 'js', 'ts', 'react', 'vue', 'nodejs', 'git', 'web_basics'] as const;
+const LEVELS = ['basic', 'beginner', 'intermediate', 'advanced', 'expert'] as const;
+
+const createTestSchema = {
+  body: {
+    type: 'object',
+    required: ['stack', 'level', 'questionCount'],
+    properties: {
+      stack: { type: 'string', enum: STACKS },
+      level: { type: 'string', enum: LEVELS },
+      questionCount: { type: 'integer', minimum: 1, maximum: 50 },
+      mode: { type: 'string', enum: ['fixed', 'infinite', 'marathon'] },
+    },
+    additionalProperties: false,
+  },
+};
+
+const testIdParamsSchema = {
+  params: {
+    type: 'object',
+    required: ['testId'],
+    properties: {
+      testId: { type: 'string', format: 'uuid' },
+    },
+  },
+};
+
+const answerSchema = {
+  params: {
+    type: 'object',
+    required: ['testId'],
+    properties: {
+      testId: { type: 'string', format: 'uuid' },
+    },
+  },
+  body: {
+    type: 'object',
+    required: ['questionId', 'answer'],
+    properties: {
+      questionId: { type: 'string', format: 'uuid' },
+      answer: {
+        oneOf: [
+          { type: 'string' },
+          { type: 'array', items: { type: 'string' } },
+        ],
+      },
+    },
+    additionalProperties: false,
+  },
+};
+
+const historyQuerySchema = {
+  querystring: {
+    type: 'object',
+    properties: {
+      limit: { type: 'integer', minimum: 1, maximum: 100 },
+      offset: { type: 'integer', minimum: 0 },
+    },
+    additionalProperties: false,
+  },
+};
+
+function stripAnswersForClient(
+  q: TestSnapshot
+): Omit<TestSnapshot, 'correctAnswer' | 'explanation'> {
+  const { correctAnswer: _, explanation: __, ...rest } = q;
+  return rest;
+}
+
+export async function testsRoutes(app: FastifyInstance) {
+  const llmService = new LlmService();
+  const questionService = new QuestionService(app.db, llmService);
+  const testsService = new TestsService(app.db, questionService);
+  const { rateLimitOptions } = app;
+
+  app.get(
+    '/',
+    {
+      schema: historyQuerySchema,
+      config: { rateLimit: rateLimitOptions.apiAuthed },
+      preHandler: [app.authenticate],
+    },
+    async (req, reply) => {
+      const userId = req.user!.id;
+      const { limit, offset } = (req.query as { limit?: number; offset?: number }) ?? {};
+      const { tests: testList, total } = await testsService.getHistory(
+        userId,
+        { limit, offset }
+      );
+      return reply.send({ tests: testList, total });
+    }
+  );
+
+  app.post(
+    '/',
+    {
+      schema: createTestSchema,
+      config: { rateLimit: rateLimitOptions.apiAuthed },
+      preHandler: [app.authenticate, app.withSubscription],
+    },
+    async (req, reply) => {
+      const userId = req.user!.id;
+      const body = req.body as CreateTestInput;
+      const test = await testsService.createTest(userId, body);
+      const hideAnswers = test.status === 'in_progress';
+      const response = {
+        ...test,
+        questions: hideAnswers
+          ? test.questions.map(stripAnswersForClient)
+          : test.questions,
+      };
+      return reply.status(201).send(response);
+    }
+  );
+
+  app.post(
+    '/:testId/answer',
+    {
+      schema: answerSchema,
+      config: { rateLimit: rateLimitOptions.apiAuthed },
+      preHandler: [app.authenticate],
+    },
+    async (req, reply) => {
+      const userId = req.user!.id;
+      const { testId } = req.params as { testId: string };
+      const { questionId, answer } = req.body as { questionId: string; answer: string | string[] };
+      const snapshot = await testsService.answerQuestion(
+        userId,
+        testId,
+        questionId,
+        answer
+      );
+      return reply.send(snapshot);
+    }
+  );
+
+  app.post(
+    '/:testId/finish',
+    {
+      schema: testIdParamsSchema,
+      config: { rateLimit: rateLimitOptions.apiAuthed },
+      preHandler: [app.authenticate],
+    },
+    async (req, reply) => {
+      const userId = req.user!.id;
+      const { testId } = req.params as { testId: string };
+      const test = await testsService.finishTest(userId, testId);
+      return reply.send(test);
+    }
+  );
+
+  app.get(
+    '/:testId',
+    {
+      schema: testIdParamsSchema,
+      config: { rateLimit: rateLimitOptions.apiAuthed },
+      preHandler: [app.authenticate],
+    },
+    async (req, reply) => {
+      const userId = req.user!.id;
+      const { testId } = req.params as { testId: string };
+      const test = await testsService.getById(userId, testId);
+      if (!test) {
+        throw notFound('Test not found');
+      }
+      const hideAnswers = test.status === 'in_progress';
+      const response = {
+        ...test,
+        questions: hideAnswers
+          ? test.questions.map(stripAnswersForClient)
+          : test.questions,
+      };
+      return reply.send(response);
+    }
+  );
+
+}

src/services/admin/admin-question.service.ts

@@ -0,0 +1,194 @@
+import { eq, asc, count } from 'drizzle-orm';
+import type { NodePgDatabase } from 'drizzle-orm/node-postgres';
+import type * as schema from '../../db/schema/index.js';
+import { questionBank, auditLogs } from '../../db/schema/index.js';
+import { notFound } from '../../utils/errors.js';
+import type { Stack, Level, QuestionType } from '../../db/schema/enums.js';
+
+type Db = NodePgDatabase<typeof schema>;
+
+export type PendingQuestion = {
+  id: string;
+  stack: Stack;
+  level: Level;
+  type: QuestionType;
+  questionText: string;
+  options: Array<{ key: string; text: string }> | null;
+  correctAnswer: string | string[];
+  explanation: string;
+  source: string;
+  createdAt: Date;
+};
+
+export type EditQuestionInput = {
+  stack?: Stack;
+  level?: Level;
+  type?: QuestionType;
+  questionText?: string;
+  options?: Array<{ key: string; text: string }> | null;
+  correctAnswer?: string | string[];
+  explanation?: string;
+};
+
+export type ListPendingResult = {
+  questions: PendingQuestion[];
+  total: number;
+};
+
+export class AdminQuestionService {
+  constructor(private readonly db: Db) {}
+
+  async listPending(limit = 50, offset = 0): Promise<ListPendingResult> {
+    const questions = await this.db
+      .select({
+        id: questionBank.id,
+        stack: questionBank.stack,
+        level: questionBank.level,
+        type: questionBank.type,
+        questionText: questionBank.questionText,
+        options: questionBank.options,
+        correctAnswer: questionBank.correctAnswer,
+        explanation: questionBank.explanation,
+        source: questionBank.source,
+        createdAt: questionBank.createdAt,
+      })
+      .from(questionBank)
+      .where(eq(questionBank.status, 'pending'))
+      .orderBy(asc(questionBank.createdAt))
+      .limit(limit)
+      .offset(offset);
+
+    const [{ count: totalCount }] = await this.db
+      .select({ count: count() })
+      .from(questionBank)
+      .where(eq(questionBank.status, 'pending'));
+
+    return {
+      questions: questions.map((q) => ({
+        id: q.id,
+        stack: q.stack,
+        level: q.level,
+        type: q.type,
+        questionText: q.questionText,
+        options: q.options,
+        correctAnswer: q.correctAnswer,
+        explanation: q.explanation,
+        source: q.source,
+        createdAt: q.createdAt,
+      })),
+      total: totalCount ?? 0,
+    };
+  }
+
+  async approve(questionId: string, adminId: string): Promise<void> {
+    const [updated] = await this.db
+      .update(questionBank)
+      .set({
+        status: 'approved',
+        approvedAt: new Date(),
+      })
+      .where(eq(questionBank.id, questionId))
+      .returning({ id: questionBank.id });
+
+    if (!updated) {
+      throw notFound('Question not found');
+    }
+
+    await this.db.insert(auditLogs).values({
+      adminId,
+      action: 'question_approved',
+      targetType: 'question',
+      targetId: questionId,
+    });
+  }
+
+  async reject(questionId: string, adminId: string): Promise<void> {
+    const [updated] = await this.db
+      .update(questionBank)
+      .set({ status: 'rejected' })
+      .where(eq(questionBank.id, questionId))
+      .returning({ id: questionBank.id });
+
+    if (!updated) {
+      throw notFound('Question not found');
+    }
+
+    await this.db.insert(auditLogs).values({
+      adminId,
+      action: 'question_rejected',
+      targetType: 'question',
+      targetId: questionId,
+    });
+  }
+
+  async edit(questionId: string, input: EditQuestionInput, adminId: string): Promise<PendingQuestion> {
+    const updates: Partial<{
+      stack: Stack;
+      level: Level;
+      type: QuestionType;
+      questionText: string;
+      options: Array<{ key: string; text: string }> | null;
+      correctAnswer: string | string[];
+      explanation: string;
+    }> = {};
+
+    if (input.stack !== undefined) updates.stack = input.stack;
+    if (input.level !== undefined) updates.level = input.level;
+    if (input.type !== undefined) updates.type = input.type;
+    if (input.questionText !== undefined) updates.questionText = input.questionText;
+    if (input.options !== undefined) updates.options = input.options;
+    if (input.correctAnswer !== undefined) updates.correctAnswer = input.correctAnswer;
+    if (input.explanation !== undefined) updates.explanation = input.explanation;
+
+    if (Object.keys(updates).length === 0) {
+      const [existing] = await this.db
+        .select()
+        .from(questionBank)
+        .where(eq(questionBank.id, questionId));
+      if (!existing) throw notFound('Question not found');
+      return {
+        id: existing.id,
+        stack: existing.stack,
+        level: existing.level,
+        type: existing.type,
+        questionText: existing.questionText,
+        options: existing.options,
+        correctAnswer: existing.correctAnswer,
+        explanation: existing.explanation,
+        source: existing.source,
+        createdAt: existing.createdAt,
+      };
+    }
+
+    const [updated] = await this.db
+      .update(questionBank)
+      .set(updates)
+      .where(eq(questionBank.id, questionId))
+      .returning();
+
+    if (!updated) {
+      throw notFound('Question not found');
+    }
+
+    await this.db.insert(auditLogs).values({
+      adminId,
+      action: 'question_edited',
+      targetType: 'question',
+      targetId: questionId,
+      details: updates as Record<string, unknown>,
+    });
+
+    return {
+      id: updated.id,
+      stack: updated.stack,
+      level: updated.level,
+      type: updated.type,
+      questionText: updated.questionText,
+      options: updated.options,
+      correctAnswer: updated.correctAnswer,
+      explanation: updated.explanation,
+      source: updated.source,
+      createdAt: updated.createdAt,
+    };
+  }
+}

src/services/questions/question.service.ts

@@ -0,0 +1,197 @@
+import { eq, and, sql, asc, inArray } from 'drizzle-orm';
+import type { NodePgDatabase } from 'drizzle-orm/node-postgres';
+import type * as schema from '../../db/schema/index.js';
+import {
+  questionBank,
+  questionCacheMeta,
+  userQuestionLog,
+} from '../../db/schema/index.js';
+import { internalError, AppError, ERROR_CODES } from '../../utils/errors.js';
+import type { Stack, Level, QuestionType } from '../../db/schema/enums.js';
+import type {
+  GeneratedQuestion,
+  GenerateQuestionsResult,
+} from '../llm/llm.service.js';
+
+type Db = NodePgDatabase<typeof schema>;
+
+export type QuestionForTest = {
+  questionBankId: string;
+  type: QuestionType;
+  questionText: string;
+  options: Array<{ key: string; text: string }> | null;
+  correctAnswer: string | string[];
+  explanation: string;
+};
+
+export interface LlmServiceInterface {
+  generateQuestions(input: {
+    stack: Stack;
+    level: Level;
+    count: number;
+    types?: QuestionType[];
+  }): Promise<GenerateQuestionsResult>;
+}
+
+function shuffle<T>(arr: T[]): T[] {
+  const result = [...arr];
+  for (let i = result.length - 1; i > 0; i--) {
+    const j = Math.floor(Math.random() * (i + 1));
+    [result[i], result[j]] = [result[j]!, result[i]!];
+  }
+  return result;
+}
+
+export class QuestionService {
+  constructor(
+    private readonly db: Db,
+    private readonly llmService: LlmServiceInterface
+  ) {}
+
+  /**
+   * Get questions for a test. Fetches approved questions from question_bank.
+   * If not enough, generates via LLM, persists to question_bank and question_cache_meta.
+   */
+  async getQuestionsForTest(
+    userId: string,
+    stack: Stack,
+    level: Level,
+    count: number
+  ): Promise<QuestionForTest[]> {
+    const approved = await this.db
+      .select({
+        id: questionBank.id,
+        type: questionBank.type,
+        questionText: questionBank.questionText,
+        options: questionBank.options,
+        correctAnswer: questionBank.correctAnswer,
+        explanation: questionBank.explanation,
+      })
+      .from(questionBank)
+      .where(
+        and(eq(questionBank.stack, stack), eq(questionBank.level, level), eq(questionBank.status, 'approved'))
+      )
+      .orderBy(asc(questionBank.usageCount));
+
+    const seenIds = await this.db
+      .select({ questionBankId: userQuestionLog.questionBankId })
+      .from(userQuestionLog)
+      .where(eq(userQuestionLog.userId, userId));
+
+    const seenSet = new Set(seenIds.map((r) => r.questionBankId));
+    const preferred = approved.filter((q) => !seenSet.has(q.id));
+    const pool = preferred.length >= count ? preferred : approved;
+    const shuffled = shuffle(pool);
+
+    const fromBank: QuestionForTest[] = shuffled.slice(0, count).map((q) => ({
+      questionBankId: q.id,
+      type: q.type,
+      questionText: q.questionText,
+      options: q.options,
+      correctAnswer: q.correctAnswer,
+      explanation: q.explanation,
+    }));
+
+    let result = fromBank;
+
+    if (result.length < count) {
+      const generated = await this.generateAndPersistQuestions(
+        stack,
+        level,
+        count - result.length
+      );
+      result = [...result, ...generated];
+    }
+
+    if (result.length < count) {
+      throw new AppError(
+        ERROR_CODES.QUESTIONS_UNAVAILABLE,
+        'Not enough questions available for this stack and level',
+        422
+      );
+    }
+
+    if (result.length > 0) {
+      await this.db.insert(userQuestionLog).values(
+        result.map((q) => ({
+          userId,
+          questionBankId: q.questionBankId,
+        }))
+      );
+
+      const ids = result.map((q) => q.questionBankId);
+      await this.db
+        .update(questionBank)
+        .set({
+          usageCount: sql`${questionBank.usageCount} + 1`,
+        })
+        .where(inArray(questionBank.id, ids));
+    }
+
+    return result;
+  }
+
+  private async generateAndPersistQuestions(
+    stack: Stack,
+    level: Level,
+    count: number
+  ): Promise<QuestionForTest[]> {
+    let generated: GeneratedQuestion[];
+    let meta: GenerateQuestionsResult['meta'];
+
+    try {
+      const result = await this.llmService.generateQuestions({
+        stack,
+        level,
+        count,
+      });
+      generated = result.questions;
+      meta = result.meta;
+    } catch (err) {
+      throw internalError(
+        'Failed to generate questions',
+        err instanceof Error ? err : undefined
+      );
+    }
+
+    const inserted: QuestionForTest[] = [];
+
+    for (const q of generated) {
+      const [row] = await this.db
+        .insert(questionBank)
+        .values({
+          stack,
+          level,
+          type: q.type as QuestionType,
+          questionText: q.questionText,
+          options: q.options ?? null,
+          correctAnswer: q.correctAnswer,
+          explanation: q.explanation,
+          status: 'approved',
+          source: 'llm_generated',
+        })
+        .returning();
+
+      if (row) {
+        await this.db.insert(questionCacheMeta).values({
+          questionBankId: row.id,
+          llmModel: meta.llmModel,
+          promptHash: meta.promptHash,
+          generationTimeMs: meta.generationTimeMs,
+          rawResponse: meta.rawResponse,
+        });
+
+        inserted.push({
+          questionBankId: row.id,
+          type: row.type,
+          questionText: row.questionText,
+          options: row.options,
+          correctAnswer: row.correctAnswer,
+          explanation: row.explanation,
+        });
+      }
+    }
+
+    return inserted;
+  }
+}

src/services/tests/tests.service.ts

@@ -0,0 +1,399 @@
+import { eq, and, desc } from 'drizzle-orm';
+import type { NodePgDatabase } from 'drizzle-orm/node-postgres';
+import type * as schema from '../../db/schema/index.js';
+import { tests, testQuestions, userStats } from '../../db/schema/index.js';
+import { notFound, conflict, AppError, ERROR_CODES } from '../../utils/errors.js';
+import type { Stack, Level, TestMode } from '../../db/schema/enums.js';
+import type { QuestionService } from '../questions/question.service.js';
+
+type Db = NodePgDatabase<typeof schema>;
+
+export type CreateTestInput = {
+  stack: Stack;
+  level: Level;
+  questionCount: number;
+  mode?: TestMode;
+};
+
+export type TestSnapshot = {
+  id: string;
+  testId: string;
+  questionBankId: string | null;
+  orderNumber: number;
+  type: string;
+  questionText: string;
+  options: Array<{ key: string; text: string }> | null;
+  correctAnswer: string | string[];
+  explanation: string;
+  userAnswer?: string | string[] | null;
+  isCorrect?: boolean | null;
+  answeredAt?: string | null;
+};
+
+export type TestWithQuestions = {
+  id: string;
+  userId: string;
+  stack: string;
+  level: string;
+  questionCount: number;
+  mode: string;
+  status: string;
+  score: number | null;
+  startedAt: string;
+  finishedAt: string | null;
+  timeLimitSeconds: number | null;
+  questions: TestSnapshot[];
+};
+
+export class TestsService {
+  constructor(
+    private readonly db: Db,
+    private readonly questionService: QuestionService
+  ) {}
+
+  /**
+   * Create a new test: fetch questions, create test record, snapshot questions into test_questions.
+   */
+  async createTest(userId: string, input: CreateTestInput): Promise<TestWithQuestions> {
+    const { stack, level, questionCount, mode = 'fixed' } = input;
+
+    if (questionCount < 1 || questionCount > 50) {
+      throw new AppError(
+        ERROR_CODES.BAD_REQUEST,
+        'questionCount must be between 1 and 50',
+        400
+      );
+    }
+
+    const questions = await this.questionService.getQuestionsForTest(
+      userId,
+      stack,
+      level,
+      questionCount
+    );
+
+    const [test] = await this.db
+      .insert(tests)
+      .values({
+        userId,
+        stack,
+        level,
+        questionCount,
+        mode,
+        status: 'in_progress',
+      })
+      .returning();
+
+    if (!test) {
+      throw new AppError(
+        ERROR_CODES.INTERNAL_ERROR,
+        'Failed to create test',
+        500
+      );
+    }
+
+    const tqValues = questions.map((q, i) => ({
+      testId: test.id,
+      questionBankId: q.questionBankId,
+      orderNumber: i + 1,
+      type: q.type,
+      questionText: q.questionText,
+      options: q.options,
+      correctAnswer: q.correctAnswer,
+      explanation: q.explanation,
+    }));
+
+    await this.db.insert(testQuestions).values(tqValues);
+
+    const questionsRows = await this.db
+      .select()
+      .from(testQuestions)
+      .where(eq(testQuestions.testId, test.id))
+      .orderBy(testQuestions.orderNumber);
+
+    return this.toTestWithQuestions(test, questionsRows);
+  }
+
+  /**
+   * Submit an answer for a question in an in-progress test.
+   */
+  async answerQuestion(
+    userId: string,
+    testId: string,
+    testQuestionId: string,
+    userAnswer: string | string[]
+  ): Promise<TestSnapshot> {
+    const [test] = await this.db
+      .select()
+      .from(tests)
+      .where(and(eq(tests.id, testId), eq(tests.userId, userId)))
+      .limit(1);
+
+    if (!test) {
+      throw notFound('Test not found');
+    }
+    if (test.status !== 'in_progress') {
+      throw conflict(ERROR_CODES.TEST_ALREADY_FINISHED, 'Test is already finished');
+    }
+
+    const [tq] = await this.db
+      .select()
+      .from(testQuestions)
+      .where(
+        and(
+          eq(testQuestions.id, testQuestionId),
+          eq(testQuestions.testId, testId)
+        )
+      )
+      .limit(1);
+
+    if (!tq) {
+      throw conflict(ERROR_CODES.WRONG_QUESTION, 'Question does not belong to this test');
+    }
+    if (tq.userAnswer !== null && tq.userAnswer !== undefined) {
+      throw conflict(ERROR_CODES.QUESTION_ALREADY_ANSWERED, 'Question already answered');
+    }
+
+    const isCorrect = this.checkAnswer(tq.correctAnswer, userAnswer);
+
+    const [updated] = await this.db
+      .update(testQuestions)
+      .set({
+        userAnswer,
+        isCorrect,
+        answeredAt: new Date(),
+      })
+      .where(eq(testQuestions.id, testQuestionId))
+      .returning();
+
+    if (!updated) {
+      throw notFound('Question not found');
+    }
+
+    return {
+      id: updated.id,
+      testId: updated.testId,
+      questionBankId: updated.questionBankId,
+      orderNumber: updated.orderNumber,
+      type: updated.type,
+      questionText: updated.questionText,
+      options: updated.options,
+      correctAnswer: updated.correctAnswer,
+      explanation: updated.explanation,
+      userAnswer: updated.userAnswer,
+      isCorrect: updated.isCorrect,
+      answeredAt: updated.answeredAt?.toISOString() ?? null,
+    };
+  }
+
+  private checkAnswer(
+    correct: string | string[],
+    user: string | string[]
+  ): boolean {
+    if (Array.isArray(correct) && Array.isArray(user)) {
+      if (correct.length !== user.length) return false;
+      const a = [...correct].sort();
+      const b = [...user].sort();
+      return a.every((v, i) => v === b[i]);
+    }
+    if (typeof correct === 'string' && typeof user === 'string') {
+      return correct.trim().toLowerCase() === user.trim().toLowerCase();
+    }
+    return false;
+  }
+
+  /**
+   * Finish a test: calculate score, update user_stats.
+   */
+  async finishTest(userId: string, testId: string): Promise<TestWithQuestions> {
+    const [test] = await this.db
+      .select()
+      .from(tests)
+      .where(and(eq(tests.id, testId), eq(tests.userId, userId)))
+      .limit(1);
+
+    if (!test) {
+      throw notFound('Test not found');
+    }
+    if (test.status !== 'in_progress') {
+      throw conflict(ERROR_CODES.TEST_ALREADY_FINISHED, 'Test is already finished');
+    }
+
+    const questions = await this.db
+      .select()
+      .from(testQuestions)
+      .where(eq(testQuestions.testId, testId));
+
+    const unanswered = questions.filter(
+      (q) => q.userAnswer === null || q.userAnswer === undefined
+    );
+    if (unanswered.length > 0) {
+      throw new AppError(
+        ERROR_CODES.NO_ANSWERS,
+        `Cannot finish: ${unanswered.length} question(s) not answered`,
+        422
+      );
+    }
+
+    const correctCount = questions.filter((q) => q.isCorrect === true).length;
+    const score = Math.round((correctCount / questions.length) * 100);
+
+    const [updatedTest] = await this.db
+      .update(tests)
+      .set({
+        status: 'completed',
+        score,
+        finishedAt: new Date(),
+      })
+      .where(eq(tests.id, testId))
+      .returning();
+
+    if (!updatedTest) {
+      throw notFound('Test not found');
+    }
+
+    await this.upsertUserStats(userId, test.stack as Stack, test.level as Level, {
+      totalQuestions: questions.length,
+      correctAnswers: correctCount,
+      testsTaken: 1,
+    });
+
+    const questionsRows = await this.db
+      .select()
+      .from(testQuestions)
+      .where(eq(testQuestions.testId, testId))
+      .orderBy(testQuestions.orderNumber);
+
+    return this.toTestWithQuestions(updatedTest, questionsRows);
+  }
+
+  private async upsertUserStats(
+    userId: string,
+    stack: Stack,
+    level: Level,
+    delta: { totalQuestions: number; correctAnswers: number; testsTaken: number }
+  ): Promise<void> {
+    const [existing] = await this.db
+      .select()
+      .from(userStats)
+      .where(
+        and(
+          eq(userStats.userId, userId),
+          eq(userStats.stack, stack),
+          eq(userStats.level, level)
+        )
+      )
+      .limit(1);
+
+    const now = new Date();
+
+    if (existing) {
+      await this.db
+        .update(userStats)
+        .set({
+          totalQuestions: existing.totalQuestions + delta.totalQuestions,
+          correctAnswers: existing.correctAnswers + delta.correctAnswers,
+          testsTaken: existing.testsTaken + delta.testsTaken,
+          lastTestAt: now,
+        })
+        .where(eq(userStats.id, existing.id));
+    } else {
+      await this.db.insert(userStats).values({
+        userId,
+        stack,
+        level,
+        totalQuestions: delta.totalQuestions,
+        correctAnswers: delta.correctAnswers,
+        testsTaken: delta.testsTaken,
+        lastTestAt: now,
+      });
+    }
+  }
+
+  /**
+   * Get a single test by ID (must belong to user).
+   */
+  async getById(userId: string, testId: string): Promise<TestWithQuestions | null> {
+    const [test] = await this.db
+      .select()
+      .from(tests)
+      .where(and(eq(tests.id, testId), eq(tests.userId, userId)))
+      .limit(1);
+
+    if (!test) return null;
+
+    const questionsRows = await this.db
+      .select()
+      .from(testQuestions)
+      .where(eq(testQuestions.testId, testId))
+      .orderBy(testQuestions.orderNumber);
+
+    return this.toTestWithQuestions(test, questionsRows);
+  }
+
+  /**
+   * Get test history for a user (most recent first).
+   */
+  async getHistory(
+    userId: string,
+    options?: { limit?: number; offset?: number }
+  ): Promise<{ tests: TestWithQuestions[]; total: number }> {
+    const limit = Math.min(options?.limit ?? 20, 100);
+    const offset = options?.offset ?? 0;
+
+    const all = await this.db
+      .select()
+      .from(tests)
+      .where(eq(tests.userId, userId))
+      .orderBy(desc(tests.startedAt));
+
+    const total = all.length;
+    const page = all.slice(offset, offset + limit);
+
+    const result: TestWithQuestions[] = [];
+
+    for (const test of page) {
+      const questionsRows = await this.db
+        .select()
+        .from(testQuestions)
+        .where(eq(testQuestions.testId, test.id))
+        .orderBy(testQuestions.orderNumber);
+      result.push(this.toTestWithQuestions(test, questionsRows));
+    }
+
+    return { tests: result, total };
+  }
+
+  private toTestWithQuestions(
+    test: (typeof tests.$inferSelect),
+    questionsRows: (typeof testQuestions.$inferSelect)[]
+  ): TestWithQuestions {
+    return {
+      id: test.id,
+      userId: test.userId,
+      stack: test.stack,
+      level: test.level,
+      questionCount: test.questionCount,
+      mode: test.mode,
+      status: test.status,
+      score: test.score,
+      startedAt: test.startedAt.toISOString(),
+      finishedAt: test.finishedAt?.toISOString() ?? null,
+      timeLimitSeconds: test.timeLimitSeconds,
+      questions: questionsRows.map((q) => ({
+        id: q.id,
+        testId: q.testId,
+        questionBankId: q.questionBankId,
+        orderNumber: q.orderNumber,
+        type: q.type,
+        questionText: q.questionText,
+        options: q.options,
+        correctAnswer: q.correctAnswer,
+        explanation: q.explanation,
+        userAnswer: q.userAnswer,
+        isCorrect: q.isCorrect,
+        answeredAt: q.answeredAt?.toISOString() ?? null,
+      })),
+    };
+  }
+}

src/utils/loginLockout.ts

@@ -0,0 +1,106 @@
+import type { Redis } from 'ioredis';
+
+const WINDOW_15M_SEC = 15 * 60;   // 900
+const WINDOW_1H_SEC = 60 * 60;   // 3600
+const WINDOW_24H_SEC = 24 * 60 * 60; // 86400
+
+const THRESHOLD_15M = 5;
+const THRESHOLD_1H = 10;
+const THRESHOLD_24H = 20;
+
+const BLOCK_15M_SEC = WINDOW_15M_SEC;
+const BLOCK_1H_SEC = WINDOW_1H_SEC;
+const BLOCK_24H_SEC = WINDOW_24H_SEC;
+
+const KEY_PREFIX = 'lockout';
+
+function key15m(ip: string): string {
+  return `${KEY_PREFIX}:15m:${ip}`;
+}
+function key1h(ip: string): string {
+  return `${KEY_PREFIX}:1h:${ip}`;
+}
+function key24h(ip: string): string {
+  return `${KEY_PREFIX}:24h:${ip}`;
+}
+function keyBlocked(ip: string): string {
+  return `${KEY_PREFIX}:blocked:${ip}`;
+}
+
+/**
+ * Check if the IP is currently blocked due to progressive login lockout.
+ * @returns { blocked: true, retryAfter } if blocked, { blocked: false } otherwise
+ */
+export async function checkBlocked(
+  redis: Redis,
+  ip: string
+): Promise<{ blocked: boolean; retryAfter?: number }> {
+  const blockedKey = keyBlocked(ip);
+  const ttl = await redis.ttl(blockedKey);
+  if (ttl > 0) {
+    return { blocked: true, retryAfter: ttl };
+  }
+  return { blocked: false };
+}
+
+const RECORD_SCRIPT = `
+  local c15 = redis.call('INCR', KEYS[1])
+  if redis.call('TTL', KEYS[1]) == -1 then redis.call('EXPIRE', KEYS[1], ARGV[1]) end
+  local c1h = redis.call('INCR', KEYS[2])
+  if redis.call('TTL', KEYS[2]) == -1 then redis.call('EXPIRE', KEYS[2], ARGV[2]) end
+  local c24 = redis.call('INCR', KEYS[3])
+  if redis.call('TTL', KEYS[3]) == -1 then redis.call('EXPIRE', KEYS[3], ARGV[3]) end
+  return {c15, c1h, c24}
+`;
+
+/**
+ * Record a failed login attempt. Increments counters and sets blocked key when thresholds are reached.
+ * Thresholds: 5 in 15m -> 15m block; 10 in 1h -> 1h block; 20 in 24h -> 24h block.
+ */
+export async function recordFailedAttempt(redis: Redis, ip: string): Promise<void> {
+  const k15 = key15m(ip);
+  const k1h = key1h(ip);
+  const k24 = key24h(ip);
+  const kBlocked = keyBlocked(ip);
+
+  const counts = (await redis.eval(
+    RECORD_SCRIPT,
+    3,
+    k15,
+    k1h,
+    k24,
+    String(WINDOW_15M_SEC),
+    String(WINDOW_1H_SEC),
+    String(WINDOW_24H_SEC)
+  )) as number[];
+
+  const count15m = counts[0] ?? 0;
+  const count1h = counts[1] ?? 0;
+  const count24h = counts[2] ?? 0;
+
+  let blockTtl = 0;
+  if (count24h >= THRESHOLD_24H) {
+    blockTtl = BLOCK_24H_SEC;
+  } else if (count1h >= THRESHOLD_1H) {
+    blockTtl = BLOCK_1H_SEC;
+  } else if (count15m >= THRESHOLD_15M) {
+    blockTtl = BLOCK_15M_SEC;
+  }
+
+  if (blockTtl > 0) {
+    await redis.setex(kBlocked, blockTtl, '1');
+  }
+}
+
+/**
+ * Clear all lockout counters and blocked state on successful login.
+ */
+export async function clearOnSuccess(redis: Redis, ip: string): Promise<void> {
+  const keys = [
+    key15m(ip),
+    key1h(ip),
+    key24h(ip),
+    keyBlocked(ip),
+  ];
+  await redis.del(...keys);
+}

tests/helpers/build-admin-test-app.ts

@@ -0,0 +1,51 @@
+import Fastify, { FastifyInstance } from 'fastify';
+import { AppError } from '../../src/utils/errors.js';
+import { adminQuestionsRoutes } from '../../src/routes/admin/questions.js';
+import type { MockDb } from '../test-utils.js';
+import { createMockDb } from '../test-utils.js';
+
+const mockAdminUser = { id: 'admin-1', email: 'admin@test.com' };
+
+/**
+ * Build a minimal Fastify app for admin route integration tests.
+ * Bypasses real auth - preHandlers set req.user to mock admin.
+ */
+export async function buildAdminTestApp(mockDb?: MockDb): Promise<FastifyInstance> {
+  const db = mockDb ?? createMockDb();
+
+  const app = Fastify({
+    logger: false,
+    requestIdHeader: 'x-request-id',
+    requestIdLogLabel: 'requestId',
+  });
+
+  app.setErrorHandler((err: unknown, _request, reply) => {
+    const error = err as Error & { statusCode?: number; validation?: unknown };
+    if (err instanceof AppError) {
+      return reply.status(err.statusCode).send(err.toJSON());
+    }
+    if (error.validation) {
+      return reply.status(422).send({
+        error: { code: 'VALIDATION_ERROR', message: 'Validation failed', details: error.validation },
+      });
+    }
+    return reply.status(500).send({ error: { code: 'INTERNAL_ERROR', message: error.message } });
+  });
+
+  app.decorate('db', db);
+  app.decorate('rateLimitOptions', {
+    apiAuthed: { max: 100, timeWindow: '1 minute' },
+  });
+  app.decorateRequest('user', undefined);
+  app.decorate('authenticate', async (req: { user?: { id: string; email: string } }) => {
+    req.user = mockAdminUser;
+  });
+  app.decorate('authenticateAdmin', async (req: { user?: { id: string; email: string } }) => {
+    if (!req.user) req.user = mockAdminUser;
+    (req.user as { role?: string }).role = 'admin';
+  });
+
+  await app.register(adminQuestionsRoutes, { prefix: '/admin' });
+
+  return app;
+}

tests/helpers/build-test-app.ts

@@ -0,0 +1,46 @@
+import Fastify, { FastifyInstance } from 'fastify';
+import { AppError } from '../../src/utils/errors.js';
+import { authRoutes } from '../../src/routes/auth.js';
+import type { MockDb } from '../test-utils.js';
+import { createMockDb } from '../test-utils.js';
+
+/**
+ * Build a minimal Fastify app for auth route integration tests.
+ * Uses mock db and rate limit options (no actual rate limiting).
+ */
+export async function buildAuthTestApp(mockDb?: MockDb): Promise<FastifyInstance> {
+  const db = mockDb ?? createMockDb();
+
+  const app = Fastify({
+    logger: false,
+    requestIdHeader: 'x-request-id',
+    requestIdLogLabel: 'requestId',
+  });
+
+  app.setErrorHandler((err: unknown, request, reply) => {
+    const error = err as Error & { statusCode?: number; validation?: unknown };
+    if (err instanceof AppError) {
+      return reply.status(err.statusCode).send(err.toJSON());
+    }
+    if (error.validation) {
+      return reply.status(422).send({
+        error: { code: 'VALIDATION_ERROR', message: 'Validation failed', details: error.validation },
+      });
+    }
+    return reply.status(500).send({ error: { code: 'INTERNAL_ERROR', message: error.message } });
+  });
+
+  app.decorate('db', db);
+  app.decorate('rateLimitOptions', {
+    login: { max: 100, timeWindow: '1 minute' },
+    register: { max: 100, timeWindow: '1 hour' },
+    forgotPassword: { max: 100, timeWindow: '1 hour' },
+    verifyEmail: { max: 100, timeWindow: '15 minutes' },
+    apiAuthed: { max: 100, timeWindow: '1 minute' },
+    apiGuest: { max: 100, timeWindow: '1 minute' },
+  });
+
+  await app.register(authRoutes, { prefix: '/auth' });
+
+  return app;
+}

tests/integration/admin.routes.test.ts

@@ -0,0 +1,140 @@
+import { describe, it, expect, vi, beforeEach } from 'vitest';
+import { buildAdminTestApp } from '../helpers/build-admin-test-app.js';
+import {
+  createMockDb,
+  selectChainOrderedLimitOffset,
+  selectChainWhere,
+  updateChainReturning,
+  insertChain,
+} from '../test-utils.js';
+
+describe('Admin routes integration', () => {
+  let app: Awaited<ReturnType<typeof buildAdminTestApp>>;
+  let mockDb: ReturnType<typeof createMockDb>;
+
+  beforeEach(async () => {
+    vi.clearAllMocks();
+    mockDb = createMockDb();
+    app = await buildAdminTestApp(mockDb as never);
+  });
+
+  describe('GET /admin/questions/pending', () => {
+    it('returns pending questions list', async () => {
+      const pendingQuestions = [
+        {
+          id: 'q-1',
+          stack: 'js',
+          level: 'beginner',
+          type: 'single_choice',
+          questionText: 'Test question?',
+          options: [{ key: 'a', text: 'A' }],
+          correctAnswer: 'a',
+          explanation: 'Exp',
+          source: 'manual',
+          createdAt: new Date(),
+        },
+      ];
+      (mockDb.select as ReturnType<typeof vi.fn>)
+        .mockReturnValueOnce(selectChainOrderedLimitOffset(pendingQuestions))
+        .mockReturnValueOnce(selectChainWhere([{ count: 1 }]));
+
+      const res = await app.inject({
+        method: 'GET',
+        url: '/admin/questions/pending',
+        headers: { authorization: 'Bearer any-token' },
+      });
+
+      expect(res.statusCode).toBe(200);
+      const body = JSON.parse(res.body);
+      expect(body.questions).toHaveLength(1);
+      expect(body.questions[0].questionText).toBe('Test question?');
+      expect(body.total).toBe(1);
+    });
+  });
+
+  describe('POST /admin/questions/:questionId/approve', () => {
+    it('returns 204 on success', async () => {
+      (mockDb.update as ReturnType<typeof vi.fn>).mockReturnValueOnce(
+        updateChainReturning([{ id: 'q-1' }])
+      );
+      (mockDb.insert as ReturnType<typeof vi.fn>).mockReturnValueOnce(
+        insertChain([])
+      );
+
+      const res = await app.inject({
+        method: 'POST',
+        url: '/admin/questions/11111111-1111-1111-1111-111111111111/approve',
+        headers: { authorization: 'Bearer any-token' },
+      });
+
+      expect(res.statusCode).toBe(204);
+    });
+
+    it('returns 404 when question not found', async () => {
+      (mockDb.update as ReturnType<typeof vi.fn>).mockReturnValueOnce(
+        updateChainReturning([])
+      );
+
+      const res = await app.inject({
+        method: 'POST',
+        url: '/admin/questions/11111111-1111-1111-1111-111111111111/approve',
+        headers: { authorization: 'Bearer any-token' },
+      });
+
+      expect(res.statusCode).toBe(404);
+    });
+  });
+
+  describe('POST /admin/questions/:questionId/reject', () => {
+    it('returns 204 on success', async () => {
+      (mockDb.update as ReturnType<typeof vi.fn>).mockReturnValueOnce(
+        updateChainReturning([{ id: 'q-1' }])
+      );
+      (mockDb.insert as ReturnType<typeof vi.fn>).mockReturnValueOnce(
+        insertChain([])
+      );
+
+      const res = await app.inject({
+        method: 'POST',
+        url: '/admin/questions/11111111-1111-1111-1111-111111111111/reject',
+        headers: { authorization: 'Bearer any-token' },
+      });
+
+      expect(res.statusCode).toBe(204);
+    });
+  });
+
+  describe('PATCH /admin/questions/:questionId', () => {
+    it('returns updated question', async () => {
+      const updatedQuestion = {
+        id: 'q-1',
+        stack: 'js',
+        level: 'intermediate',
+        type: 'single_choice',
+        questionText: 'Updated?',
+        options: [{ key: 'a', text: 'A' }],
+        correctAnswer: 'a',
+        explanation: 'Updated exp',
+        source: 'manual',
+        createdAt: new Date(),
+      };
+      (mockDb.update as ReturnType<typeof vi.fn>).mockReturnValueOnce(
+        updateChainReturning([updatedQuestion])
+      );
+      (mockDb.insert as ReturnType<typeof vi.fn>).mockReturnValueOnce(
+        insertChain([])
+      );
+
+      const res = await app.inject({
+        method: 'PATCH',
+        url: '/admin/questions/11111111-1111-1111-1111-111111111111',
+        headers: { authorization: 'Bearer any-token' },
+        payload: { questionText: 'Updated?', explanation: 'Updated exp' },
+      });
+
+      expect(res.statusCode).toBe(200);
+      const body = JSON.parse(res.body);
+      expect(body.questionText).toBe('Updated?');
+    });
+  });
+});

tests/integration/auth.routes.test.ts

@@ -0,0 +1,265 @@
+import { describe, it, expect, vi, beforeEach } from 'vitest';
+import { buildAuthTestApp } from '../helpers/build-test-app.js';
+import {
+  createMockDb,
+  selectChain,
+  insertChain,
+  updateChain,
+  deleteChain,
+} from '../test-utils.js';
+
+vi.mock('../../src/utils/password.js', () => ({
+  hashPassword: vi.fn().mockResolvedValue('hashed-password'),
+  verifyPassword: vi.fn().mockResolvedValue(true),
+}));
+
+vi.mock('../../src/utils/jwt.js', () => ({
+  signAccessToken: vi.fn().mockResolvedValue('access-token'),
+  signRefreshToken: vi.fn().mockResolvedValue('refresh-token'),
+  verifyToken: vi.fn(),
+  isRefreshPayload: vi.fn(),
+  hashToken: vi.fn((t: string) => `hash-${t}`),
+}));
+
+vi.mock('node:crypto', () => ({
+  randomBytes: vi.fn(() => ({ toString: () => 'abc123' })),
+  randomUUID: vi.fn(() => 'uuid-session-1'),
+}));
+
+import { isRefreshPayload, verifyToken } from '../../src/utils/jwt.js';
+
+describe('Auth routes integration', () => {
+  let app: Awaited<ReturnType<typeof buildAuthTestApp>>;
+  let mockDb: ReturnType<typeof createMockDb>;
+
+  beforeEach(async () => {
+    vi.clearAllMocks();
+    mockDb = createMockDb();
+    app = await buildAuthTestApp(mockDb as never);
+  });
+
+  describe('POST /auth/register', () => {
+    it('returns 201 with userId and verificationCode when registration succeeds', async () => {
+      (mockDb.select as ReturnType<typeof vi.fn>)
+        .mockReturnValueOnce(selectChain([]))
+        .mockReturnValueOnce(selectChain([]));
+      (mockDb.insert as ReturnType<typeof vi.fn>)
+        .mockReturnValueOnce(insertChain([{ id: 'user-123' }]))
+        .mockReturnValueOnce(insertChain([]));
+
+      const res = await app.inject({
+        method: 'POST',
+        url: '/auth/register',
+        payload: {
+          email: 'test@example.com',
+          password: 'password123',
+          nickname: 'tester',
+        },
+      });
+
+      expect(res.statusCode).toBe(201);
+      const body = JSON.parse(res.body);
+      expect(body.userId).toBe('user-123');
+      expect(body.message).toContain('verify your email');
+      expect(body.verificationCode).toBeDefined();
+    });
+
+    it('returns 409 when email is already taken', async () => {
+      (mockDb.select as ReturnType<typeof vi.fn>).mockReturnValueOnce(
+        selectChain([{ id: 'existing', email: 'test@example.com' }])
+      );
+
+      const res = await app.inject({
+        method: 'POST',
+        url: '/auth/register',
+        payload: {
+          email: 'test@example.com',
+          password: 'password123',
+          nickname: 'tester',
+        },
+      });
+
+      expect(res.statusCode).toBe(409);
+      const body = JSON.parse(res.body);
+      expect(body.error?.code).toBe('EMAIL_TAKEN');
+    });
+
+    it('returns 422 when validation fails', async () => {
+      const res = await app.inject({
+        method: 'POST',
+        url: '/auth/register',
+        payload: {
+          email: 'short',
+          password: '123', // too short
+          nickname: 'x', // too short
+        },
+      });
+
+      expect([400, 422]).toContain(res.statusCode);
+      const body = JSON.parse(res.body);
+      expect(body.error?.code ?? body.error).toBeDefined();
+    });
+  });
+
+  describe('POST /auth/login', () => {
+    it('returns tokens when credentials are valid', async () => {
+      const mockUser = {
+        id: 'user-1',
+        email: 'test@example.com',
+        passwordHash: 'hashed',
+      };
+      (mockDb.select as ReturnType<typeof vi.fn>).mockReturnValueOnce(
+        selectChain([mockUser])
+      );
+      (mockDb.insert as ReturnType<typeof vi.fn>).mockReturnValueOnce(
+        insertChain([])
+      );
+
+      const res = await app.inject({
+        method: 'POST',
+        url: '/auth/login',
+        payload: { email: 'test@example.com', password: 'password123' },
+      });
+
+      expect(res.statusCode).toBe(200);
+      const body = JSON.parse(res.body);
+      expect(body.accessToken).toBe('access-token');
+      expect(body.refreshToken).toBe('refresh-token');
+    });
+
+    it('returns 401 when credentials are invalid', async () => {
+      (mockDb.select as ReturnType<typeof vi.fn>).mockReturnValueOnce(
+        selectChain([])
+      );
+
+      const res = await app.inject({
+        method: 'POST',
+        url: '/auth/login',
+        payload: { email: 'unknown@example.com', password: 'wrong' },
+      });
+
+      expect(res.statusCode).toBe(401);
+    });
+  });
+
+  describe('POST /auth/logout', () => {
+    it('returns 204 on success', async () => {
+      (mockDb.delete as ReturnType<typeof vi.fn>).mockReturnValueOnce(
+        deleteChain()
+      );
+
+      const res = await app.inject({
+        method: 'POST',
+        url: '/auth/logout',
+        payload: { refreshToken: 'some-token' },
+      });
+
+      expect(res.statusCode).toBe(204);
+    });
+  });
+
+  describe('POST /auth/refresh', () => {
+    it('returns new tokens when refresh token is valid', async () => {
+      vi.mocked(verifyToken).mockResolvedValueOnce({
+        sub: 'user-1',
+        sid: 'sid-1',
+        type: 'refresh',
+      } as never);
+      vi.mocked(isRefreshPayload).mockReturnValueOnce(true);
+      (mockDb.select as ReturnType<typeof vi.fn>)
+        .mockReturnValueOnce(selectChain([{ id: 'sess-1', userId: 'user-1' }]))
+        .mockReturnValueOnce(selectChain([{ id: 'user-1', email: 'test@example.com' }]));
+      (mockDb.delete as ReturnType<typeof vi.fn>).mockReturnValueOnce(
+        deleteChain()
+      );
+      (mockDb.insert as ReturnType<typeof vi.fn>).mockReturnValueOnce(
+        insertChain([])
+      );
+
+      const res = await app.inject({
+        method: 'POST',
+        url: '/auth/refresh',
+        payload: { refreshToken: 'valid-refresh-token' },
+      });
+
+      expect(res.statusCode).toBe(200);
+      const body = JSON.parse(res.body);
+      expect(body.accessToken).toBe('access-token');
+      expect(body.refreshToken).toBe('refresh-token');
+    });
+  });
+
+  describe('POST /auth/verify-email', () => {
+    it('returns success when code is valid', async () => {
+      const mockCode = {
+        id: 'code-1',
+        userId: 'user-1',
+        code: 'ABC123',
+        expiresAt: new Date(Date.now() + 60000),
+      };
+      (mockDb.select as ReturnType<typeof vi.fn>)
+        .mockReturnValueOnce(selectChain([mockCode]))
+        .mockReturnValueOnce(selectChain([{ id: 'user-1', emailVerifiedAt: null }]));
+      (mockDb.update as ReturnType<typeof vi.fn>).mockReturnValueOnce(
+        updateChain([{ id: 'user-1' }])
+      );
+      (mockDb.delete as ReturnType<typeof vi.fn>).mockReturnValueOnce(
+        deleteChain()
+      );
+
+      const res = await app.inject({
+        method: 'POST',
+        url: '/auth/verify-email',
+        payload: { userId: 'user-1', code: 'ABC123' },
+      });
+
+      expect(res.statusCode).toBe(200);
+    });
+  });
+
+  describe('POST /auth/forgot-password', () => {
+    it('returns 200 with generic message', async () => {
+      (mockDb.select as ReturnType<typeof vi.fn>).mockReturnValueOnce(
+        selectChain([{ id: 'user-1', email: 'test@example.com' }])
+      );
+      (mockDb.insert as ReturnType<typeof vi.fn>).mockReturnValueOnce(
+        insertChain([])
+      );
+
+      const res = await app.inject({
+        method: 'POST',
+        url: '/auth/forgot-password',
+        payload: { email: 'test@example.com' },
+      });
+
+      expect(res.statusCode).toBe(200);
+    });
+  });
+
+  describe('POST /auth/reset-password', () => {
+    it('returns 200 when token is valid', async () => {
+      const mockRecord = {
+        id: 'rec-1',
+        userId: 'user-1',
+        expiresAt: new Date(Date.now() + 60000),
+      };
+      (mockDb.select as ReturnType<typeof vi.fn>).mockReturnValueOnce(
+        selectChain([mockRecord])
+      );
+      (mockDb.update as ReturnType<typeof vi.fn>).mockReturnValueOnce(
+        updateChain([{ id: 'user-1' }])
+      );
+      (mockDb.delete as ReturnType<typeof vi.fn>).mockReturnValueOnce(
+        deleteChain()
+      );
+
+      const res = await app.inject({
+        method: 'POST',
+        url: '/auth/reset-password',
+        payload: { token: 'valid-token', newPassword: 'newPassword123' },
+      });
+
+      expect(res.statusCode).toBe(200);
+    });
+  });
+});

tests/services/auth.service.test.ts

@@ -0,0 +1,304 @@
+import { describe, it, expect, vi, beforeEach } from 'vitest';
+import { AuthService } from '../../src/services/auth/auth.service.js';
+import {
+  createMockDb,
+  selectChain,
+  insertChain,
+  updateChain,
+  deleteChain,
+} from '../test-utils.js';
+
+vi.mock('../../src/utils/password.js', () => ({
+  hashPassword: vi.fn().mockResolvedValue('hashed-password'),
+  verifyPassword: vi.fn().mockResolvedValue(true),
+}));
+
+vi.mock('../../src/utils/jwt.js', () => ({
+  signAccessToken: vi.fn().mockResolvedValue('access-token'),
+  signRefreshToken: vi.fn().mockResolvedValue('refresh-token'),
+  verifyToken: vi.fn(),
+  isRefreshPayload: vi.fn(),
+  hashToken: vi.fn((t: string) => `hash-${t}`),
+}));
+
+vi.mock('node:crypto', () => ({
+  randomBytes: vi.fn(() => ({
+    toString: () => 'abc123',
+  })),
+  randomUUID: vi.fn(() => 'uuid-session-1'),
+}));
+
+import { hashPassword, verifyPassword } from '../../src/utils/password.js';
+import { signAccessToken, signRefreshToken, verifyToken, isRefreshPayload } from '../../src/utils/jwt.js';
+
+describe('AuthService', () => {
+  let mockDb: ReturnType<typeof createMockDb>;
+  let authService: AuthService;
+
+  beforeEach(() => {
+    vi.clearAllMocks();
+    mockDb = createMockDb();
+    authService = new AuthService(mockDb as never);
+  });
+
+  describe('register', () => {
+    it('registers a new user when email and nickname are available', async () => {
+      (mockDb.select as ReturnType<typeof vi.fn>)
+        .mockReturnValueOnce(selectChain([]))
+        .mockReturnValueOnce(selectChain([]));
+      (mockDb.insert as ReturnType<typeof vi.fn>)
+        .mockReturnValueOnce(insertChain([{ id: 'user-123' }]))
+        .mockReturnValueOnce(insertChain([]));
+
+      const result = await authService.register({
+        email: 'test@example.com',
+        password: 'password123',
+        nickname: 'tester',
+      });
+
+      expect(result.userId).toBe('user-123');
+      expect(result.verificationCode).toBeDefined();
+      expect(hashPassword).toHaveBeenCalledWith('password123');
+    });
+
+    it('throws when email is already taken', async () => {
+      (mockDb.select as ReturnType<typeof vi.fn>).mockReturnValueOnce(
+        selectChain([{ id: 'existing', email: 'test@example.com' }])
+      );
+
+      await expect(
+        authService.register({
+          email: 'test@example.com',
+          password: 'password123',
+          nickname: 'tester',
+        })
+      ).rejects.toMatchObject({ code: 'EMAIL_TAKEN' });
+    });
+
+    it('throws when nickname is already taken', async () => {
+      (mockDb.select as ReturnType<typeof vi.fn>)
+        .mockReturnValueOnce(selectChain([]))
+        .mockReturnValueOnce(selectChain([{ id: 'existing', nickname: 'tester' }]));
+
+      await expect(
+        authService.register({
+          email: 'test@example.com',
+          password: 'password123',
+          nickname: 'tester',
+        })
+      ).rejects.toMatchObject({ code: 'NICKNAME_TAKEN' });
+    });
+  });
+
+  describe('login', () => {
+    it('returns tokens when credentials are valid', async () => {
+      const mockUser = {
+        id: 'user-1',
+        email: 'test@example.com',
+        passwordHash: 'hashed',
+      };
+      (mockDb.select as ReturnType<typeof vi.fn>).mockReturnValueOnce(
+        selectChain([mockUser])
+      );
+      (mockDb.insert as ReturnType<typeof vi.fn>).mockReturnValueOnce(
+        insertChain([])
+      );
+
+      const result = await authService.login({
+        email: 'test@example.com',
+        password: 'password123',
+      });
+
+      expect(result.accessToken).toBe('access-token');
+      expect(result.refreshToken).toBe('refresh-token');
+      expect(verifyPassword).toHaveBeenCalledWith('hashed', 'password123');
+      expect(signAccessToken).toHaveBeenCalled();
+      expect(signRefreshToken).toHaveBeenCalled();
+    });
+
+    it('throws when user not found', async () => {
+      (mockDb.select as ReturnType<typeof vi.fn>).mockReturnValueOnce(
+        selectChain([])
+      );
+
+      await expect(
+        authService.login({ email: 'nonexistent@example.com', password: 'x' })
+      ).rejects.toMatchObject({ code: 'UNAUTHORIZED' });
+    });
+
+    it('throws when password is wrong', async () => {
+      vi.mocked(verifyPassword).mockResolvedValueOnce(false);
+      (mockDb.select as ReturnType<typeof vi.fn>).mockReturnValueOnce(
+        selectChain([{ id: 'user-1', email: 'test@example.com', passwordHash: 'hashed' }])
+      );
+
+      await expect(
+        authService.login({ email: 'test@example.com', password: 'wrong' })
+      ).rejects.toMatchObject({ code: 'UNAUTHORIZED' });
+    });
+  });
+
+  describe('logout', () => {
+    it('deletes session by refresh token hash', async () => {
+      (mockDb.delete as ReturnType<typeof vi.fn>).mockReturnValueOnce(
+        deleteChain()
+      );
+
+      await authService.logout('some-refresh-token');
+
+      expect(mockDb.delete).toHaveBeenCalled();
+    });
+  });
+
+  describe('refresh', () => {
+    it('returns new tokens when refresh token is valid', async () => {
+      vi.mocked(verifyToken).mockResolvedValueOnce({
+        sub: 'user-1',
+        sid: 'sid-1',
+        type: 'refresh',
+      } as never);
+      vi.mocked(isRefreshPayload).mockReturnValueOnce(true);
+      (mockDb.select as ReturnType<typeof vi.fn>).mockReturnValueOnce(
+        selectChain([{ id: 'sess-1', userId: 'user-1' }])
+      );
+      (mockDb.delete as ReturnType<typeof vi.fn>).mockReturnValueOnce(
+        deleteChain()
+      );
+      (mockDb.select as ReturnType<typeof vi.fn>).mockReturnValueOnce(
+        selectChain([{ id: 'user-1', email: 'test@example.com' }])
+      );
+      (mockDb.insert as ReturnType<typeof vi.fn>).mockReturnValueOnce(
+        insertChain([])
+      );
+
+      const result = await authService.refresh({
+        refreshToken: 'valid-refresh-token',
+      });
+
+      expect(result.accessToken).toBe('access-token');
+      expect(result.refreshToken).toBe('refresh-token');
+    });
+
+    it('throws when token is not a refresh payload', async () => {
+      vi.mocked(verifyToken).mockResolvedValueOnce({
+        sub: 'user-1',
+        type: 'access',
+      } as never);
+      vi.mocked(isRefreshPayload).mockReturnValueOnce(false);
+
+      await expect(
+        authService.refresh({ refreshToken: 'access-token' })
+      ).rejects.toMatchObject({ message: expect.stringContaining('Invalid refresh token') });
+    });
+
+    it('throws when session not found', async () => {
+      vi.mocked(verifyToken).mockResolvedValueOnce({
+        sub: 'user-1',
+        sid: 'sid-1',
+        type: 'refresh',
+      } as never);
+      vi.mocked(isRefreshPayload).mockReturnValueOnce(true);
+      (mockDb.select as ReturnType<typeof vi.fn>).mockReturnValueOnce(
+        selectChain([])
+      );
+
+      await expect(
+        authService.refresh({ refreshToken: 'invalid-or-expired' })
+      ).rejects.toMatchObject({ code: 'INVALID_REFRESH_TOKEN' });
+    });
+  });
+
+  describe('verifyEmail', () => {
+    it('throws when verification code is invalid', async () => {
+      (mockDb.select as ReturnType<typeof vi.fn>).mockReturnValueOnce(
+        selectChain([])
+      );
+
+      await expect(
+        authService.verifyEmail('user-1', 'WRONG')
+      ).rejects.toMatchObject({ code: 'INVALID_CODE' });
+    });
+
+    it('updates user and deletes code when valid', async () => {
+      const mockCode = {
+        id: 'code-1',
+        userId: 'user-1',
+        code: 'ABC123',
+        expiresAt: new Date(Date.now() + 60000),
+      };
+      (mockDb.select as ReturnType<typeof vi.fn>)
+        .mockReturnValueOnce(selectChain([mockCode]))
+        .mockReturnValueOnce(selectChain([{ id: 'user-1', emailVerifiedAt: null }]));
+      (mockDb.update as ReturnType<typeof vi.fn>).mockReturnValueOnce(
+        updateChain([{ id: 'user-1' }])
+      );
+      (mockDb.delete as ReturnType<typeof vi.fn>).mockReturnValueOnce(
+        deleteChain()
+      );
+
+      await authService.verifyEmail('user-1', 'ABC123');
+
+      expect(mockDb.update).toHaveBeenCalled();
+      expect(mockDb.delete).toHaveBeenCalled();
+    });
+  });
+
+  describe('forgotPassword', () => {
+    it('returns empty token when user not found', async () => {
+      (mockDb.select as ReturnType<typeof vi.fn>).mockReturnValueOnce(
+        selectChain([])
+      );
+
+      const result = await authService.forgotPassword('unknown@example.com');
+
+      expect(result.token).toBe('');
+      expect(result.expiresAt).toBeInstanceOf(Date);
+    });
+
+    it('returns token when user exists', async () => {
+      (mockDb.select as ReturnType<typeof vi.fn>).mockReturnValueOnce(
+        selectChain([{ id: 'user-1', email: 'test@example.com' }])
+      );
+      (mockDb.insert as ReturnType<typeof vi.fn>).mockReturnValueOnce(
+        insertChain([])
+      );
+
+      const result = await authService.forgotPassword('test@example.com');
+
+      expect(result.token).toBeDefined();
+      expect(result.token).not.toBe('');
+      expect(result.expiresAt).toBeInstanceOf(Date);
+    });
+  });
+
+  describe('resetPassword', () => {
+    it('throws when token is invalid', async () => {
+      (mockDb.select as ReturnType<typeof vi.fn>).mockReturnValueOnce(
+        selectChain([])
+      );
+
+      await expect(
+        authService.resetPassword('invalid-token', 'newPassword123')
+      ).rejects.toMatchObject({ code: 'INVALID_RESET_TOKEN' });
+    });
+
+    it('updates password when token is valid', async () => {
+      const mockRecord = { id: 'rec-1', userId: 'user-1', expiresAt: new Date(Date.now() + 60000) };
+      (mockDb.select as ReturnType<typeof vi.fn>).mockReturnValueOnce(
+        selectChain([mockRecord])
+      );
+      (mockDb.update as ReturnType<typeof vi.fn>).mockReturnValueOnce(
+        updateChain([{ id: 'user-1' }])
+      );
+      (mockDb.delete as ReturnType<typeof vi.fn>).mockReturnValueOnce(
+        deleteChain()
+      );
+
+      await authService.resetPassword('valid-token', 'newPassword123');
+
+      expect(hashPassword).toHaveBeenCalledWith('newPassword123');
+      expect(mockDb.update).toHaveBeenCalled();
+      expect(mockDb.delete).toHaveBeenCalled();
+    });
+  });
+});

tests/services/llm.service.test.ts

@@ -0,0 +1,224 @@
+import { describe, it, expect, vi, beforeEach } from 'vitest';
+
+vi.mock('../../src/config/env.js', () => ({
+  env: {
+    LLM_BASE_URL: 'http://test',
+    LLM_MODEL: 'test-model',
+    LLM_FALLBACK_MODEL: 'fallback-model',
+    LLM_API_KEY: 'key',
+    LLM_TIMEOUT_MS: 5000,
+    LLM_TEMPERATURE: 0.7,
+    LLM_MAX_TOKENS: 2048,
+    LLM_MAX_RETRIES: 1,
+    LLM_RETRY_DELAY_MS: 10,
+  },
+}));
+
+import { LlmService } from '../../src/services/llm/llm.service.js';
+
+const mockConfig = {
+  baseUrl: 'http://llm.test/v1',
+  model: 'test-model',
+  fallbackModel: 'fallback-model',
+  apiKey: 'test-key',
+  timeoutMs: 5000,
+  temperature: 0.7,
+  maxTokens: 2048,
+  maxRetries: 1,
+  retryDelayMs: 10,
+};
+
+const validQuestionsJson = JSON.stringify({
+  questions: [
+    {
+      questionText: 'What is 2+2?',
+      type: 'single_choice',
+      options: [{ key: 'a', text: '4' }, { key: 'b', text: '3' }],
+      correctAnswer: 'a',
+      explanation: 'Basic math',
+    },
+  ],
+});
+
+describe('LlmService', () => {
+  let mockFetch: ReturnType<typeof vi.fn>;
+
+  beforeEach(() => {
+    mockFetch = vi.fn();
+    vi.stubGlobal('fetch', mockFetch);
+  });
+
+  describe('chat', () => {
+    it('returns content from LLM response', async () => {
+      mockFetch.mockResolvedValueOnce({
+        ok: true,
+        json: () => Promise.resolve({
+          choices: [{ message: { content: 'Hello!' } }],
+        }),
+      });
+
+      const service = new LlmService(mockConfig);
+      const result = await service.chat([
+        { role: 'user', content: 'Hi' },
+      ]);
+
+      expect(result).toBe('Hello!');
+      expect(mockFetch).toHaveBeenCalledWith(
+        'http://llm.test/v1/chat/completions',
+        expect.objectContaining({
+          method: 'POST',
+          headers: expect.objectContaining({
+            'Content-Type': 'application/json',
+            'Authorization': 'Bearer test-key',
+          }),
+        })
+      );
+    });
+  });
+
+  describe('chatWithMeta', () => {
+    it('returns content and model name', async () => {
+      mockFetch.mockResolvedValueOnce({
+        ok: true,
+        json: () => Promise.resolve({
+          choices: [{ message: { content: 'Response' } }],
+        }),
+      });
+
+      const service = new LlmService(mockConfig);
+      const result = await service.chatWithMeta([{ role: 'user', content: 'Q' }]);
+
+      expect(result.content).toBe('Response');
+      expect(result.model).toBe('test-model');
+    });
+
+    it('retries on failure then succeeds', async () => {
+      mockFetch
+        .mockRejectedValueOnce(new Error('Network error'))
+        .mockResolvedValueOnce({
+          ok: true,
+          json: () => Promise.resolve({
+            choices: [{ message: { content: 'Retry OK' } }],
+          }),
+        });
+
+      const service = new LlmService({ ...mockConfig, maxRetries: 1 });
+      const result = await service.chatWithMeta([{ role: 'user', content: 'Q' }]);
+
+      expect(result.content).toBe('Retry OK');
+      expect(mockFetch).toHaveBeenCalledTimes(2);
+    });
+
+    it('falls back to fallbackModel when primary fails', async () => {
+      // Primary model: 2 attempts (initial + 1 retry), both fail
+      mockFetch
+        .mockResolvedValueOnce({ ok: false, status: 500, statusText: 'Error', text: () => Promise.resolve('') })
+        .mockResolvedValueOnce({ ok: false, status: 500, statusText: 'Error', text: () => Promise.resolve('') })
+        .mockResolvedValueOnce({
+          ok: true,
+          json: () => Promise.resolve({
+            choices: [{ message: { content: 'Fallback OK' } }],
+          }),
+        });
+
+      const service = new LlmService(mockConfig);
+      const result = await service.chatWithMeta([{ role: 'user', content: 'Q' }]);
+
+      expect(result.content).toBe('Fallback OK');
+      expect(result.model).toBe('fallback-model');
+    });
+
+    it('throws when all attempts fail', async () => {
+      mockFetch.mockRejectedValue(new Error('Network error'));
+
+      const service = new LlmService({ ...mockConfig, maxRetries: 0 });
+      await expect(
+        service.chatWithMeta([{ role: 'user', content: 'Q' }])
+      ).rejects.toThrow();
+    });
+  });
+
+  describe('generateQuestions', () => {
+    it('returns validated questions with meta', async () => {
+      mockFetch.mockResolvedValueOnce({
+        ok: true,
+        json: () => Promise.resolve({
+          choices: [{ message: { content: validQuestionsJson } }],
+        }),
+      });
+
+      const service = new LlmService(mockConfig);
+      const result = await service.generateQuestions({
+        stack: 'js',
+        level: 'beginner',
+        count: 1,
+      });
+
+      expect(result.questions).toHaveLength(1);
+      expect(result.questions[0].questionText).toBe('What is 2+2?');
+      expect(result.questions[0].stack).toBe('js');
+      expect(result.questions[0].level).toBe('beginner');
+      expect(result.meta.llmModel).toBe('test-model');
+      expect(result.meta.promptHash).toBeDefined();
+      expect(result.meta.generationTimeMs).toBeGreaterThanOrEqual(0);
+    });
+
+    it('extracts JSON from markdown code block', async () => {
+      mockFetch.mockResolvedValueOnce({
+        ok: true,
+        json: () => Promise.resolve({
+          choices: [{ message: { content: '```json\n' + validQuestionsJson + '\n```' } }],
+        }),
+      });
+
+      const service = new LlmService(mockConfig);
+      const result = await service.generateQuestions({
+        stack: 'ts',
+        level: 'intermediate',
+        count: 1,
+      });
+
+      expect(result.questions).toHaveLength(1);
+      expect(result.questions[0].type).toBe('single_choice');
+    });
+
+    it('throws when response validation fails', async () => {
+      mockFetch.mockResolvedValueOnce({
+        ok: true,
+        json: () => Promise.resolve({
+          choices: [{ message: { content: '{"invalid": "response"}' } }],
+        }),
+      });
+
+      const service = new LlmService(mockConfig);
+      await expect(
+        service.generateQuestions({ stack: 'js', level: 'beginner', count: 1 })
+      ).rejects.toThrow('LLM response validation failed');
+    });
+
+    it('throws when single_choice has no options', async () => {
+      const invalidJson = JSON.stringify({
+        questions: [
+          {
+            questionText: 'Q?',
+            type: 'single_choice',
+            options: [],
+            correctAnswer: 'a',
+            explanation: 'e',
+          },
+        ],
+      });
+      mockFetch.mockResolvedValueOnce({
+        ok: true,
+        json: () => Promise.resolve({
+          choices: [{ message: { content: invalidJson } }],
+        }),
+      });
+
+      const service = new LlmService(mockConfig);
+      await expect(
+        service.generateQuestions({ stack: 'js', level: 'beginner', count: 1 })
+      ).rejects.toThrow('Question validation failed');
+    });
+  });
+});

tests/services/question.service.test.ts

@@ -0,0 +1,117 @@
+import { describe, it, expect, vi, beforeEach } from 'vitest';
+import { QuestionService } from '../../src/services/questions/question.service.js';
+import {
+  createMockDb,
+  selectChainOrdered,
+  selectChainSimple,
+  insertChain,
+  updateChain,
+} from '../test-utils.js';
+
+const mockLlmQuestions = [
+  {
+    questionBankId: 'qb-new',
+    type: 'single_choice' as const,
+    questionText: 'New question?',
+    options: [{ key: 'a', text: 'A' }, { key: 'b', text: 'B' }],
+    correctAnswer: 'a',
+    explanation: 'Explanation',
+    stack: 'js' as const,
+    level: 'beginner' as const,
+  },
+];
+
+describe('QuestionService', () => {
+  let mockDb: ReturnType<typeof createMockDb>;
+  let mockLlmService: { generateQuestions: ReturnType<typeof vi.fn> };
+  let questionService: QuestionService;
+
+  beforeEach(() => {
+    vi.clearAllMocks();
+    mockDb = createMockDb();
+    mockLlmService = {
+      generateQuestions: vi.fn().mockResolvedValue({
+        questions: mockLlmQuestions,
+        meta: {
+          llmModel: 'test-model',
+          promptHash: 'hash',
+          generationTimeMs: 100,
+          rawResponse: {},
+        },
+      }),
+    };
+    questionService = new QuestionService(mockDb as never, mockLlmService as never);
+  });
+
+  describe('getQuestionsForTest', () => {
+    it('returns questions from bank when enough approved exist', async () => {
+      const approvedRows = [
+        {
+          id: 'qb-1',
+          type: 'single_choice',
+          questionText: 'Q1?',
+          options: [{ key: 'a', text: 'A' }],
+          correctAnswer: 'a',
+          explanation: 'e',
+        },
+      ];
+      (mockDb.select as ReturnType<typeof vi.fn>)
+        .mockReturnValueOnce(selectChainOrdered(approvedRows))
+        .mockReturnValueOnce(selectChainSimple([]));
+      (mockDb.insert as ReturnType<typeof vi.fn>).mockReturnValueOnce(insertChain([]));
+      (mockDb.update as ReturnType<typeof vi.fn>).mockReturnValueOnce(updateChain([]));
+
+      const result = await questionService.getQuestionsForTest(
+        'user-1',
+        'js',
+        'beginner',
+        1
+      );
+
+      expect(result).toHaveLength(1);
+      expect(result[0].questionBankId).toBe('qb-1');
+      expect(mockLlmService.generateQuestions).not.toHaveBeenCalled();
+    });
+
+    it('calls LLM when not enough questions in bank', async () => {
+      const approvedRows: unknown[] = [];
+      const seenIds: unknown[] = [];
+      (mockDb.select as ReturnType<typeof vi.fn>)
+        .mockReturnValueOnce(selectChainOrdered(approvedRows))
+        .mockReturnValueOnce(selectChainSimple(seenIds));
+      (mockDb.insert as ReturnType<typeof vi.fn>)
+        .mockReturnValueOnce(insertChain([{ id: 'qb-new', ...mockLlmQuestions[0] }]))
+        .mockReturnValueOnce(insertChain([]))
+        .mockReturnValueOnce(insertChain([]));
+      (mockDb.update as ReturnType<typeof vi.fn>).mockReturnValueOnce(updateChain([]));
+
+      const result = await questionService.getQuestionsForTest(
+        'user-1',
+        'js',
+        'beginner',
+        1
+      );
+
+      expect(result).toHaveLength(1);
+      expect(mockLlmService.generateQuestions).toHaveBeenCalledWith({
+        stack: 'js',
+        level: 'beginner',
+        count: 1,
+      });
+    });
+
+    it('throws when not enough questions available', async () => {
+      (mockDb.select as ReturnType<typeof vi.fn>)
+        .mockReturnValueOnce(selectChainOrdered([]))
+        .mockReturnValueOnce(selectChainSimple([]));
+      mockLlmService.generateQuestions.mockResolvedValueOnce({
+        questions: [],
+        meta: { llmModel: 'x', promptHash: 'y', generationTimeMs: 0, rawResponse: {} },
+      });
+
+      await expect(
+        questionService.getQuestionsForTest('user-1', 'js', 'beginner', 5)
+      ).rejects.toMatchObject({ code: 'QUESTIONS_UNAVAILABLE' });
+    });
+  });
+});

tests/services/tests.service.test.ts

@@ -0,0 +1,230 @@
+import { describe, it, expect, vi, beforeEach } from 'vitest';
+import { TestsService } from '../../src/services/tests/tests.service.js';
+import {
+  createMockDb,
+  selectChain,
+  selectChainOrdered,
+  selectChainWhere,
+  insertChain,
+  updateChain,
+  updateChainReturning,
+} from '../test-utils.js';
+
+const mockQuestions = [
+  {
+    questionBankId: 'qb-1',
+    type: 'single_choice' as const,
+    questionText: 'What is 2+2?',
+    options: [{ key: 'a', text: '4' }, { key: 'b', text: '3' }],
+    correctAnswer: 'a',
+    explanation: 'Basic math',
+  },
+];
+
+describe('TestsService', () => {
+  let mockDb: ReturnType<typeof createMockDb>;
+  let mockQuestionService: { getQuestionsForTest: ReturnType<typeof vi.fn> };
+  let testsService: TestsService;
+
+  beforeEach(() => {
+    vi.clearAllMocks();
+    mockDb = createMockDb();
+    mockQuestionService = {
+      getQuestionsForTest: vi.fn().mockResolvedValue(mockQuestions),
+    };
+    testsService = new TestsService(mockDb as never, mockQuestionService as never);
+  });
+
+  describe('createTest', () => {
+    it('creates a test with questions from QuestionService', async () => {
+      const mockTest = {
+        id: 'test-1',
+        userId: 'user-1',
+        stack: 'js',
+        level: 'beginner',
+        questionCount: 1,
+        mode: 'fixed',
+        status: 'in_progress',
+        score: null,
+        startedAt: new Date(),
+        finishedAt: null,
+        timeLimitSeconds: null,
+      };
+      const mockTqRows = [
+        {
+          id: 'tq-1',
+          testId: 'test-1',
+          questionBankId: 'qb-1',
+          orderNumber: 1,
+          type: 'single_choice',
+          questionText: 'What is 2+2?',
+          options: [{ key: 'a', text: '4' }],
+          correctAnswer: 'a',
+          explanation: 'Basic math',
+          userAnswer: null,
+          isCorrect: null,
+          answeredAt: null,
+        },
+      ];
+      (mockDb.insert as ReturnType<typeof vi.fn>)
+        .mockReturnValueOnce(insertChain([mockTest]))
+        .mockReturnValueOnce(insertChain([]));
+      (mockDb.select as ReturnType<typeof vi.fn>).mockReturnValueOnce(
+        selectChainOrdered(mockTqRows)
+      );
+
+      const result = await testsService.createTest('user-1', {
+        stack: 'js',
+        level: 'beginner',
+        questionCount: 1,
+      });
+
+      expect(result.id).toBe('test-1');
+      expect(result.questions).toHaveLength(1);
+      expect(mockQuestionService.getQuestionsForTest).toHaveBeenCalledWith(
+        'user-1',
+        'js',
+        'beginner',
+        1
+      );
+    });
+
+    it('throws when questionCount is out of range', async () => {
+      await expect(
+        testsService.createTest('user-1', {
+          stack: 'js',
+          level: 'beginner',
+          questionCount: 0,
+        })
+      ).rejects.toMatchObject({ code: 'BAD_REQUEST' });
+
+      await expect(
+        testsService.createTest('user-1', {
+          stack: 'js',
+          level: 'beginner',
+          questionCount: 51,
+        })
+      ).rejects.toMatchObject({ code: 'BAD_REQUEST' });
+    });
+  });
+
+  describe('answerQuestion', () => {
+    it('returns updated question snapshot when answer is correct', async () => {
+      const mockTest = { id: 't-1', userId: 'user-1', status: 'in_progress' };
+      const mockTq = {
+        id: 'tq-1',
+        testId: 't-1',
+        correctAnswer: 'a',
+        userAnswer: null,
+        questionBankId: 'qb-1',
+        orderNumber: 1,
+        type: 'single_choice',
+        questionText: 'Q?',
+        options: [{ key: 'a', text: 'A' }],
+        explanation: 'exp',
+      };
+      const updatedTq = { ...mockTq, userAnswer: 'a', isCorrect: true, answeredAt: new Date() };
+      (mockDb.select as ReturnType<typeof vi.fn>)
+        .mockReturnValueOnce(selectChain([mockTest]))
+        .mockReturnValueOnce(selectChain([mockTq]));
+      (mockDb.update as ReturnType<typeof vi.fn>).mockReturnValueOnce(
+        updateChainReturning([updatedTq])
+      );
+
+      const result = await testsService.answerQuestion('user-1', 't-1', 'tq-1', 'a');
+
+      expect(result.isCorrect).toBe(true);
+      expect(result.userAnswer).toBe('a');
+    });
+
+    it('throws when test not found', async () => {
+      (mockDb.select as ReturnType<typeof vi.fn>).mockReturnValueOnce(selectChain([]));
+
+      await expect(
+        testsService.answerQuestion('user-1', 'bad-id', 'tq-1', 'a')
+      ).rejects.toMatchObject({ code: 'NOT_FOUND' });
+    });
+
+    it('throws when test is already finished', async () => {
+      (mockDb.select as ReturnType<typeof vi.fn>).mockReturnValueOnce(
+        selectChain([{ id: 't-1', userId: 'user-1', status: 'completed' }])
+      );
+
+      await expect(
+        testsService.answerQuestion('user-1', 't-1', 'tq-1', 'a')
+      ).rejects.toMatchObject({ code: 'TEST_ALREADY_FINISHED' });
+    });
+  });
+
+  describe('finishTest', () => {
+    it('throws when there are unanswered questions', async () => {
+      const mockTest = { id: 't-1', userId: 'user-1', status: 'in_progress', stack: 'js', level: 'beginner' };
+      const mockQuestionsWithUnanswered = [
+        { id: 'tq-1', testId: 't-1', userAnswer: 'a', isCorrect: true },
+        { id: 'tq-2', testId: 't-1', userAnswer: null, isCorrect: null },
+      ];
+      (mockDb.select as ReturnType<typeof vi.fn>)
+        .mockReturnValueOnce(selectChain([mockTest]))
+        .mockReturnValueOnce(selectChainWhere(mockQuestionsWithUnanswered));
+
+      await expect(
+        testsService.finishTest('user-1', 't-1')
+      ).rejects.toMatchObject({ code: 'NO_ANSWERS' });
+    });
+  });
+
+  describe('getById', () => {
+    it('returns null when test not found', async () => {
+      (mockDb.select as ReturnType<typeof vi.fn>).mockReturnValueOnce(selectChain([]));
+
+      const result = await testsService.getById('user-1', 'bad-id');
+
+      expect(result).toBeNull();
+    });
+
+    it('returns test with questions when found', async () => {
+      const mockTest = {
+        id: 't-1',
+        userId: 'user-1',
+        stack: 'js',
+        level: 'beginner',
+        questionCount: 2,
+        mode: 'fixed',
+        status: 'in_progress',
+        score: null,
+        startedAt: new Date(),
+        finishedAt: null,
+        timeLimitSeconds: null,
+      };
+      const mockTqRows = [
+        { id: 'tq-1', testId: 't-1', orderNumber: 1, questionBankId: 'qb-1', type: 'single_choice', questionText: 'Q1', options: [], correctAnswer: 'a', explanation: 'e', userAnswer: null, isCorrect: null, answeredAt: null },
+      ];
+      (mockDb.select as ReturnType<typeof vi.fn>)
+        .mockReturnValueOnce(selectChain([mockTest]))
+        .mockReturnValueOnce(selectChainOrdered(mockTqRows));
+
+      const result = await testsService.getById('user-1', 't-1');
+
+      expect(result).not.toBeNull();
+      expect(result!.id).toBe('t-1');
+      expect(result!.questions).toHaveLength(1);
+    });
+  });
+
+  describe('getHistory', () => {
+    it('returns paginated test history', async () => {
+      const mockTests = [
+        { id: 't-1', userId: 'user-1', stack: 'js', level: 'beginner', questionCount: 1, mode: 'fixed', status: 'completed', score: 100, startedAt: new Date(), finishedAt: new Date(), timeLimitSeconds: null },
+      ];
+      const mockTqRows = [];
+      (mockDb.select as ReturnType<typeof vi.fn>)
+        .mockReturnValueOnce(selectChainOrdered(mockTests))
+        .mockReturnValueOnce(selectChainOrdered(mockTqRows));
+
+      const result = await testsService.getHistory('user-1', { limit: 10, offset: 0 });
+
+      expect(result.tests).toHaveLength(1);
+      expect(result.total).toBe(1);
+    });
+  });
+});

tests/setup.ts

@@ -0,0 +1,11 @@
+import { beforeAll, vi } from 'vitest';
+
+beforeAll(() => {
+  vi.stubEnv('NODE_ENV', 'test');
+  if (!process.env.DATABASE_URL) {
+    process.env.DATABASE_URL = 'postgresql://test:test@localhost:5432/test';
+  }
+  if (!process.env.JWT_SECRET) {
+    process.env.JWT_SECRET = 'test-secret-min-32-chars-long-for-validation';
+  }
+});

tests/smoke.test.ts

@@ -0,0 +1,12 @@
+import { describe, it, expect } from 'vitest';
+import { createMockDb } from './test-utils.js';
+
+describe('test-utils', () => {
+  it('createMockDb returns mock with select, insert, update, delete', () => {
+    const db = createMockDb();
+    expect(db.select).toBeDefined();
+    expect(db.insert).toBeDefined();
+    expect(db.update).toBeDefined();
+    expect(db.delete).toBeDefined();
+  });
+});

tests/test-utils.ts

@@ -0,0 +1,165 @@
+import { vi } from 'vitest';
+import type { FastifyInstance } from 'fastify';
+import type { NodePgDatabase } from 'drizzle-orm/node-postgres';
+import type * as schema from '../src/db/schema/index.js';
+
+export type MockDb = {
+  select: ReturnType<NodePgDatabase<typeof schema>['select']>;
+  insert: ReturnType<NodePgDatabase<typeof schema>['insert']>;
+  update: ReturnType<NodePgDatabase<typeof schema>['update']>;
+  delete: ReturnType<NodePgDatabase<typeof schema>['delete']>;
+};
+
+/** Build a select chain that resolves to the given rows at .limit(n) */
+export function selectChain(resolveAtLimit: unknown[] = []) {
+  const limitFn = vi.fn().mockResolvedValue(resolveAtLimit);
+  return {
+    from: vi.fn().mockReturnValue({
+      where: vi.fn().mockReturnValue({
+        limit: limitFn,
+        orderBy: vi.fn().mockReturnValue({ limit: limitFn }),
+      }),
+      limit: limitFn,
+    }),
+  };
+}
+
+/** Build a select chain for .from().where().orderBy() - orderBy is terminal */
+export function selectChainOrdered(resolveAtOrderBy: unknown[] = []) {
+  const orderByThenable = {
+    then: (resolve: (v: unknown) => void) => resolve(resolveAtOrderBy),
+  };
+  return {
+    from: vi.fn().mockReturnValue({
+      where: vi.fn().mockReturnValue({
+        orderBy: vi.fn().mockReturnValue(orderByThenable),
+      }),
+    }),
+  };
+}
+
+/** Build a select chain for .from().where() with no orderBy - used by select({...}).from() */
+export function selectChainSimple(resolveRows: unknown[] = []) {
+  const thenable = { then: (resolve: (v: unknown) => void) => resolve(resolveRows) };
+  return {
+    from: vi.fn().mockReturnValue({
+      where: vi.fn().mockReturnValue(thenable),
+    }),
+  };
+}
+
+/** Build a select chain for .from().where() - where is terminal (no orderBy/limit) */
+export function selectChainWhere(resolveAtWhere: unknown[] = []) {
+  const thenable = { then: (resolve: (v: unknown) => void) => resolve(resolveAtWhere) };
+  return {
+    from: vi.fn().mockReturnValue({
+      where: vi.fn().mockReturnValue(thenable),
+    }),
+  };
+}
+
+/** Build a select chain for .from().where().orderBy().limit().offset() */
+export function selectChainOrderedLimitOffset(resolveRows: unknown[] = []) {
+  const offsetFn = vi.fn().mockResolvedValue(resolveRows);
+  return {
+    from: vi.fn().mockReturnValue({
+      where: vi.fn().mockReturnValue({
+        orderBy: vi.fn().mockReturnValue({
+          limit: vi.fn().mockReturnValue({
+            offset: offsetFn,
+          }),
+        }),
+      }),
+    }),
+  };
+}
+
+/** Build an insert chain that resolves at .returning() or .values() */
+export function insertChain(resolveAtReturning: unknown[] = []) {
+  const returningFn = vi.fn().mockResolvedValue(resolveAtReturning);
+  const chainFromValues = {
+    returning: returningFn,
+    then: (resolve: (v?: unknown) => void) => resolve(undefined),
+  };
+  return {
+    values: vi.fn().mockReturnValue(chainFromValues),
+    returning: returningFn,
+  };
+}
+
+/** Build an update chain that resolves at .where() */
+export function updateChain(resolveAtWhere: unknown[] = []) {
+  return {
+    set: vi.fn().mockReturnValue({
+      where: vi.fn().mockResolvedValue(resolveAtWhere),
+    }),
+  };
+}
+
+/** Build an update chain with .where().returning() */
+export function updateChainReturning(resolveAtReturning: unknown[] = []) {
+  const returningFn = vi.fn().mockResolvedValue(resolveAtReturning);
+  return {
+    set: vi.fn().mockReturnValue({
+      where: vi.fn().mockReturnValue({
+        returning: returningFn,
+      }),
+    }),
+  };
+}
+
+/** Build a delete chain that resolves at .where() */
+export function deleteChain() {
+  return {
+    where: vi.fn().mockResolvedValue(undefined),
+  };
+}
+
+/**
+ * Create a chainable mock for Drizzle DB operations.
+ * Use mockReturnValue with selectChain/insertChain/updateChain/deleteChain.
+ */
+export function createMockDb(): MockDb {
+  const chain = {
+    from: vi.fn().mockReturnThis(),
+    where: vi.fn().mockReturnThis(),
+    values: vi.fn().mockReturnThis(),
+    set: vi.fn().mockReturnThis(),
+    orderBy: vi.fn().mockReturnThis(),
+    limit: vi.fn().mockReturnThis(),
+    returning: vi.fn().mockReturnThis(),
+  };
+
+  return {
+    select: vi.fn().mockReturnValue(chain),
+    insert: vi.fn().mockReturnValue(chain),
+    update: vi.fn().mockReturnValue(chain),
+    delete: vi.fn().mockReturnValue(chain),
+  } as unknown as MockDb;
+}
+
+/**
+ * Create a minimal mock Fastify app with db for route/integration tests.
+ * Use buildApp() from app.ts for full integration tests.
+ */
+export function createMockApp(): FastifyInstance & { db: MockDb } {
+  return {
+    db: createMockDb(),
+    log: {
+      child: () => ({
+        debug: () => {},
+        info: () => {},
+        warn: () => {},
+        error: () => {},
+        trace: () => {},
+        fatal: () => {},
+      }),
+      debug: () => {},
+      info: () => {},
+      warn: () => {},
+      error: () => {},
+      trace: () => {},
+      fatal: () => {},
+    },
+  } as FastifyInstance & { db: MockDb };
+}

vitest.config.ts

@@ -0,0 +1,40 @@
+import { defineConfig } from 'vitest/config';
+import { resolve } from 'path';
+
+export default defineConfig({
+  test: {
+    globals: true,
+    environment: 'node',
+    include: ['tests/**/*.test.ts', 'tests/**/*.spec.ts'],
+    coverage: {
+      provider: 'v8',
+      reporter: ['text', 'json', 'lcov'],
+      include: [
+        'src/services/auth/**/*.ts',
+        'src/services/llm/**/*.ts',
+        'src/services/questions/**/*.ts',
+        'src/services/tests/**/*.ts',
+        'src/services/admin/**/*.ts',
+      ],
+      exclude: [
+        'src/services/**/*.d.ts',
+        '**/*.test.ts',
+        '**/*.spec.ts',
+        '**/index.ts',
+      ],
+      thresholds: {
+        lines: 70,
+        functions: 70,
+        branches: 68,
+        statements: 70,
+      },
+    },
+    setupFiles: ['tests/setup.ts'],
+    testTimeout: 10000,
+  },
+  resolve: {
+    alias: {
+      '@': resolve(__dirname, 'src'),
+    },
+  },
+});