Kent walks us through the internals of dom-testing-library and react-testing-library. There is a lot of set-up and tear down when testing UI components. These two libraries take away a lot of the work required to test React components well. Jest is commonly used in tandem with react-testing-library to assert results of your components. Jest simulates most browser apis with jsdom. react-testing-library helps you get values out of your components the same way your end users will. Links from the show: - [Testing Library](https://testing-library.com) - [Testing Javascript](https://testingjavascript.com) - [Unit vs Integration vs E2E](https://kentcdodds.com/blog/unit-vs-integration-vs-e2e-tests) - [Why you shouldn't ReactDOM.render to the body](https://medium.com/@dan_abramov/two-weird-tricks-that-fix-react-7cf9bbdef375) - [Effective Snapshot Testing]( https://kentcdodds.com/blog/effective-snapshot-testing/) - [Dev Tips with Kent](https://youtu.be/ttmvAm6esSc) - https://kcd.im/news