React remains a preferred choice among UI developers, surpassing jQuery in 2021, and is often used alongside Node.js for professional development. This tutorial provides a comprehensive guide to setting up a sample React and Redux application, focusing on testing components and configuring continuous integration (CI) using CircleCI. It begins with the basics of cloning a Redux Async Example app and progresses through setting up a test environment with tools like Jest and Enzyme. The guide highlights the importance of snapshot testing and dives into writing tests for React components, Redux actions, and reducers. It also illustrates the integration of CircleCI with GitHub to automate test execution, ensuring new code does not disrupt existing functionality. The tutorial emphasizes that CI helps catch bugs early by running tests whenever code is pushed to a repository, thereby maintaining a reliable development process.