QA Foundations
Regression testing
Also known as: regression suite
Regression testing re-runs existing tests to confirm that a change has not broken behaviour that previously worked — the reason most automated suites exist at all.
A regression suite grows monotonically, which creates its own problem: it gets slower every release while the value of any individual test decays. The two standard responses are to run fewer tests per change through impact analysis, and to run the remainder concurrently through sharding.
The suite is only worth its runtime if failures are trusted. A regression suite with a high flake rate is worse than a smaller reliable one, because engineers learn to re-run rather than investigate — and a real regression then arrives looking exactly like the noise they have been trained to dismiss.
- Protects working behaviour rather than verifying new behaviour.
- Grows monotonically, so it gets slower every release without active management.
- Only valuable if failures are trusted — flakiness destroys the signal it exists to provide.
Related terms
See it in your own test results
Qualflare detects flaky tests, clusters failures by root cause, and scores release risk from the test results you already produce in CI. Start free.
Start free with Qualflare← Back to the testing & observability glossary.
Last reviewed September 9, 2026