setting-up-react-testing-library.md

Setting up React Testing Library

It's useful to customize React Testing Library's render method to include things like global context providers, data stores, etc. that are used in your app. This enables tests to run in an environment closer to your real app. In addition, this approach avoids repeating wrappers in every test. To make this render method available globally, define a utility file that re-exports everything from React Testing Library while customizing the render method with your app-specific wrappers. Here's an example: test-utils.tsx.

Start importing test-utils.tsx

Once you have a custom render method in test-utils, replace React Testing Library imports in your tests with this file. For example, replace

import { render } from '@testing-library/react';

with

import { render } from '../../test/test-utils';

Import userEvent from test-utils.tsx

Note that test-utils re-exports userEvent. This allows us to reduce the number of imports in our tests. For example, we can replace

import { render, screen } from '@testing-library/react';
import userEvent from '@testing-library/user-event';

with

import { render, screen, userEvent } from '../../test/test-utils';

Easily set initial route using the custom render method

If your test needs to start on a specific route, use the initalRoute option provided by the custom render method. For example:

render(<App />, { initialRoute: '/signin' });