https://blog.bitsrc.io/testing-your-react-app-with-puppeteer-and-jest-c72b3dfcde59

End-to-End testing helps us to assure that all the components of our React app work together as we expect, in ways which unit and integration tests can’t.

Puppeteer is an end-to-end testing Node library by Google which provides us with a high-level API that can control Chromium over the dev tools protocol. It can open and run apps and perform the actions it’s given through tests.