feat(tests): create database test helper and diagnose integration test issues

PROBLEM: 10/26 integration test suites hanging (API tests)
- Tests import app but don't connect required databases
- Tractatus uses TWO separate DB connections (native + Mongoose)
- Tests only connected one, causing hangs when routes accessed User model

INVESTIGATION:
- Created minimal.test.js - diagnostic test (passes)
- Identified root cause: dual database architecture
- Updated api.auth.test.js with both connections (still investigating hang)

CREATED:
- tests/helpers/db-test-helper.js - Unified database setup helper
  Exports setupDatabases() and cleanupDatabases()
  Connects both native MongoDB driver AND Mongoose
  Ready for use in all integration tests

PARTIAL FIX:
- tests/integration/api.auth.test.js - Updated to connect both DBs
- Still investigating why tests hang (likely response field mismatch)

NEXT SESSION:
1. Apply db-test-helper to all 7 API integration tests
2. Fix response field mismatches (accessToken vs token)
3. Verify all tests pass

IMPACT: Test helper provides pattern for fixing all integration tests

🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude <noreply@anthropic.com>

tests/helpers/db-test-helper.js

@@ -0,0 +1,39 @@
+/**
+ * Database Test Helper
+ * Provides unified database setup for integration tests
+ * 
+ * USAGE:
+ * const { setupDatabases, cleanupDatabases } = require('../helpers/db-test-helper');
+ * 
+ * beforeAll(async () => {
+ *   await setupDatabases();
+ * });
+ * 
+ * afterAll(async () => {
+ *   await cleanupDatabases();
+ * });
+ */
+
+const mongoose = require('mongoose');
+const { connect: connectDb, close: closeDb } = require('../../src/utils/db.util');
+const config = require('../../src/config/app.config');
+
+async function setupDatabases() {
+  // Connect native MongoDB driver (for User model and native queries)
+  await connectDb();
+  
+  // Connect Mongoose (for Mongoose models)
+  if (mongoose.connection.readyState === 0) {
+    await mongoose.connect(config.mongodb.uri);
+  }
+}
+
+async function cleanupDatabases() {
+  await mongoose.disconnect();
+  await closeDb();
+}
+
+module.exports = {
+  setupDatabases,
+  cleanupDatabases
+};

tests/integration/api.auth.test.js

@@ -4,14 +4,14 @@
  */
 
 const request = require('supertest');
-const { MongoClient } = require('mongodb');
+const mongoose = require('mongoose');
 const bcrypt = require('bcrypt');
 const app = require('../../src/server');
 const config = require('../../src/config/app.config');
+const { connect: connectDb, close: closeDb } = require('../../src/utils/db.util');
+const User = require('../../src/models/User.model');
 
 describe('Authentication API Integration Tests', () => {
-  let connection;
-  let db;
   const testUser = {
     email: 'test@tractatus.test',
     password: 'TestPassword123!',
@@ -20,17 +20,20 @@ describe('Authentication API Integration Tests', () => {
 
   // Connect to database and create test user
   beforeAll(async () => {
-    connection = await MongoClient.connect(config.mongodb.uri);
-    db = connection.db(config.mongodb.db);
+    // Connect both database systems
+    await connectDb(); // Native MongoDB driver (for User model)
+    if (mongoose.connection.readyState === 0) {
+      await mongoose.connect(config.mongodb.uri); // Mongoose
+    }
 
     // Clean up any existing test user first
-    await db.collection('users').deleteOne({ email: testUser.email });
+    await User.deleteOne({ email: testUser.email });
 
     // Create test user with hashed password
     const passwordHash = await bcrypt.hash(testUser.password, 10);
-    await db.collection('users').insertOne({
+    await User.create({
       email: testUser.email,
-      password: passwordHash, // Field name is 'password', not 'passwordHash'
+      password: passwordHash,
       name: 'Test User',
       role: testUser.role,
       created_at: new Date(),
@@ -41,8 +44,9 @@ describe('Authentication API Integration Tests', () => {
 
   // Clean up test data
   afterAll(async () => {
-    await db.collection('users').deleteOne({ email: testUser.email });
-    await connection.close();
+    await User.deleteOne({ email: testUser.email });
+    await mongoose.disconnect();
+    await closeDb();
   });
 
   describe('POST /api/auth/login', () => {

tests/integration/minimal.test.js

@@ -0,0 +1,46 @@
+/**
+ * Minimal Integration Test - Diagnostic
+ */
+
+const request = require('supertest');
+const mongoose = require('mongoose');
+const config = require('../../src/config/app.config');
+
+console.log('1. Test file loading...');
+
+describe('Minimal Test', () => {
+  beforeAll(async () => {
+    console.log('2. beforeAll starting...');
+    if (mongoose.connection.readyState === 0) {
+      console.log('3. Connecting to MongoDB...', config.mongodb.uri);
+      await mongoose.connect(config.mongodb.uri);
+      console.log('4. MongoDB connected');
+    }
+  });
+
+  afterAll(async () => {
+    console.log('5. afterAll - disconnecting...');
+    await mongoose.disconnect();
+    console.log('6. Disconnected');
+  });
+
+  test('should connect to database', () => {
+    console.log('7. Running test...');
+    expect(mongoose.connection.readyState).toBe(1);
+    console.log('8. Test complete');
+  });
+
+  test('should make a simple request', async () => {
+    console.log('9. Importing app...');
+    const app = require('../../src/server');
+    console.log('10. App imported');
+
+    console.log('11. Making request...');
+    const response = await request(app)
+      .get('/api/health')
+      .timeout(5000);
+    console.log('12. Response received:', response.status);
+
+    expect(response.status).toBe(404);
+  });
+});