When making changes to JavaScript, CSS, or HTML which could change the functionality or layout of a page, it's important to add corresponding [Cypress](https://docs.cypress.io) integration tests.
To learn how to write Cypress tests, or 'specs', please see Cypress' official [documentation](https://docs.cypress.io/guides/getting-started/writing-your-first-test.html).
> Note: When writing tests for freeCodeCamp, remember to add `/* global cy */` to the top of the file to avoid ESLint issues.
- Cypress tests for a curriculum module are in the corresponding curriculum directory, i.e. `cypress/integration/learn/responsive-web-design/basic-css/index.js`.
- [Start the freeCodeCamp client application and API server](/how-to-setup-freecodecamp-locally#step-4-start-the-freecodecamp-client-application-and-api-server)