How do I test my MERN stack application?

How do I test my MERN stack application?

To test your MERN stack application, you can use tools like Jest for unit testing and Supertest for API testing.

Can you give me an example of a unit test for a React component?

Sure! Here's a simple example using Jest:

import { render, screen } from '@testing-library/react';
import MyComponent from './MyComponent';

test('renders learn react link', () => {
  render(<MyComponent />);
  const linkElement = screen.getByText(/learn react/i);
  expect(linkElement).toBeInTheDocument();
});

What about testing the Express backend?

For testing your Express backend, you can use Supertest. Here's a basic example:

const request = require('supertest');
const app = require('../app');

describe('GET /api/items', () => {
  it('responds with json', async () => {
    const response = await request(app).get('/api/items');
    expect(response.statusCode).toBe(200);
    expect(response.body).toBeInstanceOf(Array);
  });
});