Snapshot Testing
In plain terms
Comparing output against a saved reference snapshot.
Going deeper
Snapshot testing captures a component's or function's output and flags any future changes against the saved version. It catches unintended changes.
Under the hood
Great for UI regression but snapshots can become stale or rubber-stamped if not reviewed carefully.
Examples
React component testing, Jest snapshots, UI regression, output comparison.
Think of it like...
Like keeping a 'before' photo and getting alerted whenever the 'after' differs.