Backend Testing

🧪 Backend Testing Skill — LuxCode AI

Stack de testing recomendado

Estructura de carpetas

src/
├── __tests__/
│   ├── unit/           # Tests de funciones puras, servicios
│   ├── integration/    # Tests de endpoints con Supertest
│   └── e2e/            # Tests de flujo completo
├── __fixtures__/       # Datos de prueba reutilizables
└── __mocks__/          # Mocks globales (DB, servicios externos)

Patrones obligatorios

Unit test (Vitest)

import { describe, it, expect, vi, beforeEach } from 'vitest';
import { UserService } from '../services/UserService';

describe('UserService', () => {
  beforeEach(() => { vi.clearAllMocks(); });

  it('should return user by id', async () => {
    const mockUser = { id: '1', name: 'Luis', email: 'luis@test.com' };
    vi.spyOn(UserService, 'findById').mockResolvedValue(mockUser);
    const result = await UserService.findById('1');
    expect(result).toEqual(mockUser);
    expect(result.email).toMatch(/@/);
  });

  it('should throw when user not found', async () => {
    vi.spyOn(UserService, 'findById').mockResolvedValue(null);
    await expect(UserService.findById('999')).rejects.toThrow('User not found');
  });
});

Integration test con Supertest

import { describe, it, expect, beforeAll, afterAll } from 'vitest';
import request from 'supertest';
import { app } from '../app';
import { db } from '../db';

beforeAll(async () => { await db.connect(); });
afterAll(async () => { await db.disconnect(); });

describe('POST /api/users', () => {
  it('creates user with valid data', async () => {
    const res = await request(app)
      .post('/api/users')
      .send({ name: 'Luis', email: 'luis@test.com' })
      .expect(201);
    expect(res.body).toMatchObject({ id: expect.any(String), name: 'Luis' });
  });

  it('returns 400 with invalid email', async () => {
    const res = await request(app)
      .post('/api/users')
      .send({ name: 'Luis', email: 'not-an-email' })
      .expect(400);
    expect(res.body.error).toBeDefined();
  });

  it('returns 401 without auth token', async () => {
    await request(app).get('/api/users/me').expect(401);
  });
});

Reglas de calidad

Fixture pattern

// src/__fixtures__/user.fixture.ts
export const userFixture = {
  valid: { id: 'u1', name: 'Luis', email: 'luis@test.com', role: 'admin' },
  noEmail: { id: 'u2', name: 'Ana' },
  expired: { id: 'u3', name: 'Bob', tokenExpiry: new Date('2020-01-01') },
};

vitest.config.ts generado por LuxCode

import { defineConfig } from 'vitest/config';

export default defineConfig({
  test: {
    globals: true,
    environment: 'node',
    coverage: {
      provider: 'v8',
      reporter: ['text', 'lcov'],
      thresholds: { statements: 80, branches: 70, functions: 80, lines: 80 }
    },
    setupFiles: ['./src/__tests__/setup.ts'],
  },
});

Checklist

• Happy path test por endpoint
• Error test (4xx, 5xx) por endpoint
• Auth tests (sin token, token expirado)
• Input validation tests (vacío, nulo, muy largo)
• Mocks de servicios externos
• beforeEach(vi.clearAllMocks) en cada describe
• Coverage >= 80% statements
• Fixtures en __fixtures__/ (no datos inline)

Source: luisitoys12/luxcode-ai — distributed by TomeVault.