To start using DOM Testing Library in your projects, you need to install and set up the appropriate environment. In this topic, we will see how to configure DOM Testing Library step by step, including installation and initial setup.

Prerequisites

Make sure you have Node.js and a package manager like npm or yarn installed. This is necessary to install the dependencies for our tests.

Installing Testing Library

Follow these steps to install DOM Testing Library in your development environment:

1. Initialize your project (if you haven't already):

   bash
   

   or

   bash
   

2. Install DOM Testing Library and its necessary dependencies:

   bash
   

   or

   bash
   

3. Install Jest (or another testing framework). For this course, we will use Jest:

   bash
   

   or

   bash
   

Configuring Jest

To configure Jest, add the following lines to your package.json file:

json

Project Structure

Organize your project as follows:

Complete Configuration Example

Let's write a complete example to verify that our configuration works correctly.

1. Create a test file in the tests folder:

File example.test.js:

javascript

2. Run your tests:

   bash
   

   or

   bash
   

If everything is configured correctly, you should see output indicating that the test passed successfully.

[Placeholder for explanatory image: Screenshot of the terminal showing Jest running the test and successful result]

Common Troubleshooting

1. Problem: "Jest encountered an unexpected token": This usually occurs if your code contains ES6 or JSX syntax that Jest doesn't understand. Make sure to have Babel configured if you need support for these features.

2. Problem: "Cannot find module '@testing-library/dom'": Ensure you have installed DOM Testing Library correctly. Check your package.json and the node_modules folder.

Additional Configuration (Optional)

You can customize Jest's configuration by creating a jest.config.js file at the root of your project:

javascript

This additional configuration is useful for adding extensions and custom configurations to your testing environment.

With this, you have your testing environment configured and ready to start writing and running tests with DOM Testing Library. You are ready to move on to writing your first unit tests.