Choosing the Right Testing Philosophy for React Projects

As more developers start working on a medium-sized production React application, it's important to figure out the right testing philosophy for it going forward. Currently, the project has two types of tests: unit tests and a suite of end-to-end (e2e) tests involving playwright and spinning up the backend service and database that the React app talks to.

While both types of tests have their pros and cons, e2e testing with playwright guarantees better correctness because it involves user communication. However, they have to be run sequentially to avoid data collision between tests, which makes them slower to execute in CI.

On the other hand, unit tests provide more flexibility by allowing developers to mock all modules, including error handling cases. However, they are slower to write and require developers to come up with the right mocks instead of having the backend return them.

There is no one-size-fits-all answer to the question of which testing philosophy is correct or widely accepted. It ultimately depends on the project's specific needs and goals. However, a combination of both unit and e2e testing is often recommended to ensure maximum test coverage and accuracy.

For React projects, Jest is a popular testing framework that supports both unit and e2e testing. It provides a built-in mocking system and supports snapshot testing, making it easier to write and maintain tests. Additionally, Cypress is a popular e2e testing framework that offers a simple and intuitive API for writing tests.

In conclusion, choosing the right testing philosophy for React projects requires careful consideration of the project's specific needs and goals. A combination of both unit and e2e testing is often recommended, and popular testing frameworks like Jest and Cypress can help streamline the testing process.