Too Long; Didn't Read
This article is intended to who just start to learn React and wonder how to write some simple tests with React applications. Jest and React Testing Library are the tools chain behind the test, they both are ship with create-react-app by default. The default test is written by Jest using Jest, and it put.test.js suffix after App component name as its.name. It is the default conventions suggested by team (link here) Jest is importing from a global setup file if you wonder.