A company wants to ensure its existing functionalities are not compromised by the addition of...

 Regression testing is the best testing technique to ensure that the existing functionalities are not compromised by the addition of a new functionality. Regression testing is the type of testing performed to ensure that a code change in software does not affect the product’s existing functionality. This ensures that the product functions correctly with new functionality, bug fixes, or changes to existing features. To validate the impact of the shift, previously executed test cases are re-executed1. Regression testing can be done manually or by using automated tools. Some of the most commonly used tools for regression testing are Selenium, WATIR, QTP, RFT, Winrunner, and Silktest2.