Baseline

What is Baseline?

A baseline captures a known-good snapshot—a screenshot, a DOM structure, an API response, or a set of expected values—that later test runs are compared against. When a new run diverges from the baseline, the test flags a difference for a human to accept as an intended change or reject as a regression. Baselines are central to visual regression testing and golden-file approaches. Managing them well means updating deliberately when the UI legitimately changes, so that a stale baseline never masks a real defect or drowns the team in false alarms.