Test Framework ‐ Jest React Testing Framework

The project follows the industry standards with Jest for component testing which is paired with React Testing Library for nice UI selectors that work with React. The tests are run on the CI before merge, and it's a good idea to have new tests for any new functionality we add.

NewEPubModal.test.js is a good example to look at if you're starting with test cases. It has an example of mocking, varying props, selectors and checking for UI components. Originally introduced in PR #802.

Here are a few helpful links for learn more:

• https://jestjs.io/docs/using-matchers - jest basics
• https://blog.logrocket.com/testing-react-apps-jest-react-testing-library/ - intro tutorial on jest + react
• https://stackoverflow.com/a/62765143 - where to keep test files
• https://testing-library.com/docs/queries/about/ - different types of queries within react testing library
• https://kentcdodds.com/blog/common-mistakes-with-react-testing-library#using-get-variants-as-assertions - tips from the library creator
• https://testing-library.com/docs/dom-testing-library/api-accessibility - tests for accessibility features
• https://robertmarshall.dev/blog/react-component-props-passed-to-child-jest-unit-test/ - how to mock child components (only if needed, but sometimes it can get quite complicated to test child components)
• https://jestjs.io/docs/asynchronous - async tests