Software testing is a critical phase of the SDLC process. Early testing saves a lot of cost and effort — low-quality software can lower customer retention by impacting user engagement negatively. It is therefore essential to build software that is bug-free to increase sales and make the product that much more popular. 

There are different types of testing, such as smoke, sanity, integration, regression, unit testing, and API testing. Regression testing is one of the most important kinds of testing, especially when new features or updates are added to an existing application.