Jest is a widely used JavaScript testing framework, designed to be fast, reliable, and easy to use. While Angular comes with its own testing tools like Jasmine and Karma, Jest offers several advantages, such as a simpler syntax, better performance, and built-in mocking capabilities. Jest can run tests in parallel, which results in faster test execution, making it an ideal choice for large-scale Angular applications.

Angular components are the building blocks of Angular applications. They encapsulate the HTML, CSS, and JavaScript required to create interactive user interfaces. Ensuring that these components are functioning as expected is crucial for the stability and performance of an Angular application. Angular component testing allows developers to simulate various scenarios, check for edge cases, and validate the functionality of individual components in isolation.