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

Pengujian Integrasi Halaman

Lakukan pengujian integrasi untuk halaman Next.js dan rute API guna memastikan berbagai bagian aplikasi Anda bekerja bersama.

Pengujian Integrasi Halaman adalah pelajaran Next.js 15 Fullstack (App Router + Server Actions) gratis di CoddyKit. Ini adalah pelajaran 2 dari 4. Kamu bisa membaca pelajaran lengkapnya di bawah secara gratis — lalu praktikkan langsung di browser dengan editor kode bawaan dan tutor AI 24/7. Ini adalah bagian dari jalur belajar Next.js 15 Fullstack (App Router + Server Actions), dan progresmu tersinkronisasi di web dan aplikasi CoddyKit. Kursus Next.js 15 Fullstack (App Router + Server Actions) mencakup 4 pelajaran total.

Bagian dari pelajaran ini belum diterjemahkan dan ditampilkan dalam bahasa Inggris.

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!

Pertanyaan yang Sering Diajukan

Apakah pelajaran “Pengujian Integrasi Halaman” gratis?

Ya — teks lengkap “Pengujian Integrasi Halaman” gratis dibaca di sini di web. Untuk praktiknya secara interaktif (editor kode bawaan dan tutor AI 24/7) dan buka sisa kursus Next.js 15 Fullstack (App Router + Server Actions), upgrade ke CoddyKit PRO. Kursus Next.js 15 Fullstack (App Router + Server Actions) mencakup 4 pelajaran total.

Apa yang akan aku pelajari di “Pengujian Integrasi Halaman”?

Lakukan pengujian integrasi untuk halaman Next.js dan rute API guna memastikan berbagai bagian aplikasi Anda bekerja bersama. Kamu berlatih Next.js 15 Fullstack (App Router + Server Actions) dengan kode praktik yang langsung kamu jalankan di browser, dan tutor AI 24/7 menjawab pertanyaanmu saat kamu mengerjakan pelajaran ini.

Apakah aku perlu pengalaman untuk memulai Next.js 15 Fullstack (App Router + Server Actions)?

Tidak diperlukan pengalaman sebelumnya. Next.js 15 Fullstack (App Router + Server Actions) di CoddyKit dirancang untuk pemula hingga pelajar tingkat lanjut, jadi kamu bisa memulai di sini atau dari awal dan belajar sesuai kecepatan kamu sendiri. Ini adalah pelajaran 2 dari 4.

Berapa lama pelajaran “Pengujian Integrasi Halaman” memakan waktu?

Sebagian besar pelajaran CoddyKit memakan waktu sekitar 5–10 menit. Setiap pelajaran ringkas dan interaktif, jadi kamu membuat kemajuan stabil dan melanjutkan dari tempat kamu tinggalkan di web dan aplikasi.

Bisakah aku menulis dan menjalankan kode dalam pelajaran Next.js 15 Fullstack (App Router + Server Actions) ini?

Ya. Setiap pelajaran Next.js 15 Fullstack (App Router + Server Actions) menyertakan editor kode bawaan, jadi kamu menulis dan menjalankan kode nyata langsung di browser dan mendapatkan umpan balik AI instan — tidak diperlukan penyiapan lokal.

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