Definition

Regression Testing

Regression testing is the practice of re-testing an application after code changes to confirm that previously working features still function correctly and that new changes have not introduced unintended side effects.

Understanding Regression Testing

Every time code changes, there is a risk that the modification breaks something else. Regression testing addresses this risk by verifying that existing functionality still works after updates. In traditional development, regression test suites grow over time as more features are added, creating a safety net that catches unintended breakage.

Regression testing is especially critical for vibecoded applications because AI code generation can have unpredictable ripple effects. When you ask an AI tool to add a new feature or fix a bug, it may modify shared code, change data structures, or alter component behavior in ways that affect other parts of the application. The AI might solve the immediate problem while silently breaking something elsewhere.

For vibecoders who iterate quickly, sending prompts and regenerating code frequently, regression testing can feel burdensome. But skipping it is risky. DidItWork's QA sessions can serve as practical regression checks. After making significant changes to your app, a fresh test session verifies that both the new feature and the existing ones still work correctly.

Example usage

After adding payment processing, our login flow stopped working. A regression test would have caught that before users noticed.

Related terms

Learn more