Snapshot Test

Definitions

1. An automated test that captures the serialized output of a component or function (such as rendered HTML or a JSON structure), saves it to a file, and on subsequent runs compares the current output to the stored snapshot — failing if anything has changed unexpectedly. Popularized by Jest for React component testing.

   In plain English: A test that takes a picture of your code's output and alerts you if the output ever changes from what was previously saved.

   Example: "The snapshot test caught that someone accidentally changed the modal's class names — just run jest --updateSnapshot if the change is intentional."

Related Terms

• Feature Flag
• Integration Test
• CI
• Prototype
• Usability Testing
• Snapshot Testing
• Golden File Test
• Puppeteer
• Setup Teardown