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Next.js 15 Fullstack (App Router + Server Actions) · Aula

Testes de integração de páginas

Realize testes de integração para páginas Next.js e rotas de API, garantindo que diferentes partes da sua aplicação funcionem em conjunto.

Testes de integração de páginas é uma aula grátis de Next.js 15 Fullstack (App Router + Server Actions) no CoddyKit. Esta é a aula 2 de 4. Você pode ler a aula completa abaixo gratuitamente — depois pratica ao vivo no navegador com um editor de código integrado e um tutor de IA 24/7. Faz parte do caminho de aprendizado de Next.js 15 Fullstack (App Router + Server Actions), e seu progresso é sincronizado entre a web e o app CoddyKit. O curso de Next.js 15 Fullstack (App Router + Server Actions) inclui 4 aulas no total.

Partes desta aula ainda não foram traduzidas e aparecem em inglês.

Intro to Integration Tests

Welcome! In this lesson, we'll explore integration testing for your Next.js applications.

Integration tests verify that different parts of your application work correctly together. Instead of isolated units, we check the flow between components, pages, and API routes.

Why Test Pages & Routes?

For Next.js, integration testing is crucial because it ensures:

  • Pages render correctly with their data.
  • User interactions (like form submissions) trigger the right backend logic.
  • API routes respond as expected when called from the frontend or other services.

It helps catch issues that unit tests might miss when components interact.

Tools: Jest, RTL, next/test-utils

We'll primarily use these tools for integration testing:

  • Jest: A popular JavaScript testing framework.
  • React Testing Library (RTL): For rendering React components (like your Next.js pages) and simulating user interactions.
  • @next/test-utils: Provides helpers specifically for testing Next.js features, like API routes.

Testing a Page Component

To test a Next.js page component, we can render it using React Testing Library. This allows us to assert if the correct content is displayed and interact with elements on the page.

You'll typically import the page component directly and render it in your test file.

Code: Simple Page Test

Here's how you might test a simple About page to ensure its heading is rendered.

// pages/about.js
export default function About() {
  return (
    <div>
      <h1>About Us</h1>
      <p>This is the about page.</p>
    </div>
  );
}

// __tests__/about.test.js
import { render, screen } from '@testing-library/react';
import About from '../pages/about';

describe('About Page', () => {
  it('renders the about page heading', () => {
    render(<About />);
    const heading = screen.getByRole('heading', { name: /About Us/i });
    expect(heading).toBeInTheDocument();
  });
});

User Interaction in Tests

Integration tests often involve simulating user behavior. React Testing Library provides utilities like fireEvent (or userEvent for more realistic interactions) to click buttons, type into inputs, and more.

This lets you verify that your page responds correctly to user input, just like a real user would.

// components/Counter.js
import { useState } from 'react';

export default function Counter() {
  const [count, setCount] = useState(0);
  return (
    <div>
      <p>Count: {count}</p>
      <button onClick={() => setCount(count + 1)}>Increment</button>
    </div>
  );
}

// __tests__/counter.test.js
import { render, screen, fireEvent } from '@testing-library/react';
import Counter from '../components/Counter';

describe('Counter Component', () => {
  it('increments count on button click', () => {
    render(<Counter />);
    const button = screen.getByRole('button', { name: /Increment/i });
    fireEvent.click(button);
    expect(screen.getByText(/Count: 1/i)).toBeInTheDocument();
  });
});

Testing Next.js API Routes

Next.js API routes are server-side functions. You can test them by importing their handler function and using createNextApiHandler from @next/test-utils to simulate requests.

This allows you to send mock requests and assert the status code and JSON response.

// pages/api/hello.js
export default function handler(req, res) {
  res.status(200).json({ name: 'John Doe' });
}

// __tests__/api/hello.test.js
import { createNextApiHandler } from '@next/test-utils';
import handler from '../../pages/api/hello';

describe('/api/hello', () => {
  it('returns a name', async () => {
    const testHandler = createNextApiHandler(handler);
    const res = await testHandler({ method: 'GET' });
    expect(res.statusCode).toBe(200);
    expect(await res.json()).toEqual({ name: 'John Doe' });
  });
});

Mocking External Calls in API

API routes often interact with databases or other external services. In integration tests, you should mock these external dependencies to ensure your tests are fast and predictable.

Jest's mocking capabilities are perfect for this, allowing you to control the return values of these external calls.

// lib/db.js (simplified)
export const getUser = async (id) => ({ id, name: 'Mock User' });

// pages/api/user/[id].js
import { getUser } from '../../../lib/db';

export default async function handler(req, res) {
  const { id } = req.query;
  const user = await getUser(id);
  res.status(200).json(user);
}

// __tests__/api/user.test.js
import { createNextApiHandler } from '@next/test-utils';
import handler from '../../pages/api/user/[id]';
import * as db from '../../lib/db';

describe('/api/user/[id]', () => {
  it('returns a user with mocked DB', async () => {
    jest.spyOn(db, 'getUser').mockResolvedValue({ id: '1', name: 'Test User' });

    const testHandler = createNextApiHandler(handler);
    const res = await testHandler({ method: 'GET', query: { id: '1' } });
    expect(res.statusCode).toBe(200);
    expect(await res.json()).toEqual({ id: '1', name: 'Test User' });

    jest.restoreAllMocks();
  });
});

Pages & Server Actions Integration

Testing pages that use Server Actions involves rendering the page, simulating a form submission, and asserting that the Server Action was called with the correct data.

You can mock the Server Action function itself to control its return value and verify it was invoked.

// app/actions.js
'use server';
export async function submitForm(formData) {
  const name = formData.get('name');
  return { success: true, message: `Hello, ${name}!` };
}

// app/page.js
import { submitForm } from './actions';

export default function Page() {
  return (
    <form action={submitForm}>
      <input type="text" name="name" defaultValue="Guest" />
      <button type="submit">Say Hello</button>
    </form>
  );
}

// __tests__/page.test.js
import { render, screen, fireEvent } from '@testing-library/react';
import Page from '../app/page';
import * as actions from '../app/actions';

describe('Home Page with Server Action', () => {
  it('submits form and calls server action', async () => {
    const mockSubmitForm = jest.spyOn(actions, 'submitForm')
      .mockResolvedValue({ success: true, message: 'Hello, Test User!' });

    render(<Page />);

    const input = screen.getByRole('textbox', { name: /name/i });
    fireEvent.change(input, { target: { value: 'Test User' } });

    const button = screen.getByRole('button', { name: /Say Hello/i });
    fireEvent.click(button);

    expect(mockSubmitForm).toHaveBeenCalledWith(
      expect.any(FormData)
    );
    mockSubmitForm.mockRestore();
  });
});

Test Your Knowledge

Time for a quick check on integration testing!

Recap: Building Robust Apps

Great job! You've learned the fundamentals of integration testing in Next.js.

  • We covered how to test pages and API routes.
  • You saw how to simulate user interactions and mock external dependencies.
  • Tools like Jest, React Testing Library, and @next/test-utils are essential.

By writing integration tests, you build more robust applications and catch bugs earlier in the development process!

Perguntas Frequentes

A aula “Testes de integração de páginas” é grátis?

Sim — o texto completo de “Testes de integração de páginas” é grátis para ler aqui na web. Para praticá-la interativamente (um editor de código integrado e um tutor de IA 24/7) e desbloquear o restante do curso de Next.js 15 Fullstack (App Router + Server Actions), atualize para CoddyKit PRO. O curso de Next.js 15 Fullstack (App Router + Server Actions) inclui 4 aulas no total.

O que vou aprender em “Testes de integração de páginas”?

Realize testes de integração para páginas Next.js e rotas de API, garantindo que diferentes partes da sua aplicação funcionem em conjunto. Você pratica Next.js 15 Fullstack (App Router + Server Actions) com código prático que executa diretamente no navegador, e um tutor de IA 24/7 responde suas dúvidas enquanto trabalha na aula.

Preciso ter experiência prévia para começar Next.js 15 Fullstack (App Router + Server Actions)?

Nenhuma experiência prévia é necessária. Next.js 15 Fullstack (App Router + Server Actions) no CoddyKit é estruturado para alunos iniciantes até avançados, então você pode começar aqui ou desde o início e aprender no seu ritmo. Esta é a aula 2 de 4.

Quanto tempo leva a aula “Testes de integração de páginas”?

A maioria das aulas CoddyKit leva cerca de 5–10 minutos. Cada uma é compacta e interativa, então você faz progresso constante e retoma exatamente de onde parou entre web e app.

Posso escrever e executar código nesta aula de Next.js 15 Fullstack (App Router + Server Actions)?

Sim. Cada aula de Next.js 15 Fullstack (App Router + Server Actions) inclui um editor de código integrado, então você escreve e executa código real direto no navegador e recebe feedback de IA instantaneamente — nenhuma configuração local necessária.

Todas as aulas deste curso

  1. Testes unitários de componentes
  2. Testes de integração de páginas
  3. Testes de ponta a ponta com Playwright/Cypress
  4. Simulação e Testes de Rotas de API
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