To preserve code quality over time, you may want to add testing to your Gatsby site. Several of the more popular testing use-cases with Gatsby are JavaScript unit tests (Jest), React component tests (react-testing-library), and end-to-end tests (Cypress).
Unit testing protects against unexpected behavior in your code. Walk through a few extra steps you'll need to set up Jest, a popular Javascript testing framework, with Gatsby.
Install and use react-testing-library, the most popular framework for testing the behavior of React components.
Automated checks of specific user flows through one or many pages.