Which type of testing ensures that the code works as planned without affecting existing functionality?

Non-regression testing is specifically designed to verify that recent changes to the code have not adversely affected existing functionality. This type of testing assesses updates or modifications to ensure that previously working features remain intact after the new changes are applied.

The primary goal of non-regression testing is to detect any unintended side effects caused by modifications, thus providing confidence in the overall stability and reliability of the software. This is crucial in maintaining software quality, ensuring new features or fixes don’t introduce bugs elsewhere in the system.

Other testing methods, while valuable, do not specifically focus on preserving existing functionality as their primary aim. Static testing involves reviewing code without executing it, primarily for identifying potential errors and ensuring adherence to standards. Dynamic testing executes the program to find defects but does not focus specifically on verifying existing functionalities. Whitebox testing examines the internal structures or workings of an application rather than testing its overall functionality from an end-user perspective.