Visual regression testing catches what functional tests miss: layout shifts, font changes, and styling regressions. But false positives can make it noisy. Use component-level screenshots for stability and full-page screenshots for key user journeys only.
Strong answers cover: screenshot comparison tools (Percy, Chromatic, BackstopJS), managing baseline images, handling acceptable visual changes versus bugs, reducing false positives (stable test data, consistent rendering), and integrating visual tests into CI. Best candidates discuss when visual regression testing is worth the maintenance cost and when it is not.
Modern testing technique. Candidates with visual testing experience are thinking beyond functional correctness. Ask about their false positive rate and how they manage it.