What is regression testing?
For the founder whose fix for one thing broke another. Here is the practice that stops it happening twice.
In short
Regression testing is re-running a suite of existing tests after every change to confirm that features which already worked still work. A regression is something that used to work and broke. Automated regression tests run in the CI pipeline on each change, so a fix in one place cannot silently break another before it reaches users.
Also called: Regression tests, Visual regression testing
Why it matters when your prototype goes to production
Prompting an AI builder to fix one thing can change code far from where you were looking, and nobody checks the rest. That is how an app slowly gets worse while every individual change looked fine. Regression tests are the memory of everything that is supposed to keep working.
Kinds worth knowing
- Functional regression: automated tests of behaviour, run on every change.
- Visual regression: screenshots compared before and after, to catch layout breaks.
- Bug regression: every fixed bug gets a test, so it cannot come back.
In our process, every version you send from Lovable passes AI and human testing, including regression and visual regression, before it ships. On Looph the automated suite grew from 1,152 tests at handover to 10,387 passing in CI.
Common questions
Can regression testing be automated?
Mostly, and it should be. Automated suites run on every change in minutes; people then test what is new rather than re-checking what is old.
What is the difference between regression testing and smoke testing?
A smoke test is a quick check that the most important paths work at all. Regression testing is the broader suite that checks everything that worked before still does.
Related terms
Read next
More on this: Production architecture & security · All glossary terms
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