Introducing Jest
Jest is an open source, robust, well-documented, fast, and safe JavaScript testing framework. Jest provides the tools and resources that you need to have absolute confidence in your JavaScript code base. Testing is fundamental to quality code writing, and Jest with almost zero configuration delightfully handles test implementation.
Jest is very popular in the JavaScript community. You can write tests in Jest leveraging its feature-rich set of APIs, such as matchers, mocked functions, code coverage, and snapshot testing. Jest can be used to test React components, and the React team actually recommends Jest to test React projects.
Jest is a Node.js test runner, which means that the tests always run in a Node environment. Jest is built with performance in mind. You can run a suite of tests in parallel effectively. The Jest toolkit comes with code coverage that enables you to have information about tested and untested files in your project. And when your tests fail...