What role does regression testing play in the software development process?

Regression testing is primarily focused on ensuring that any new changes made to the software, such as updates or bug fixes, do not negatively impact the existing functionality. This type of testing is crucial whenever modifications are introduced because it verifies that existing features still work as intended after the changes.

When regression testing is performed, it typically involves re-running previously completed tests to confirm that the software continues to operate correctly following the implementation of new code or enhancements. This helps maintain the integrity of the software and provides confidence that new features or fixes have not inadvertently introduced new issues into parts of the application that were previously functioning correctly.

The other choices, while related to testing, do not accurately describe the primary purpose of regression testing. For instance, identifying new defects pertains more broadly to testing techniques like exploratory or functional testing. Validating against requirements relates more specifically to validation testing, while measuring performance under load is associated with performance testing. Therefore, the essence of regression testing lies in its role of safeguarding existing functionalities amidst ongoing changes.