Testing Next.js apps with Jest

The tutorial outlines the process of setting up Jest for testing a Next.js application by creating a simple calculator app. It highlights the importance of testing in software development and demonstrates how Jest, now built into Next.js since version 12, simplifies this process. The guide walks through building a calculator app, configuring Jest, writing and running tests to verify functionality, and simulating errors to demonstrate how Jest can catch bugs. Additionally, it covers advanced topics such as mocking external modules and APIs, testing React Hooks, and performing integration testing in Next.js. Throughout, it emphasizes the role of automated testing in ensuring code reliability, with tools like Jest and the React Testing Library being essential for creating effective test suites.