How does testing fit into CI/CD?

In CI/CD, automated tests run as gates in the pipeline - typically after build and before deploy to staging or production. Fast unit and static checks run on every commit; heavier integration and UI suites often run on merge or on a schedule to protect pipeline speed. Failed tests should block promotion to the next environment unless an explicit override policy exists. Test results and artifacts (logs, screenshots, videos) feed developers the same way build errors do. CD only delivers value if tests are trusted; flaky or skipped gates undermine the whole flow. Treat test infrastructure - browsers, databases, secrets - as first-class pipeline dependencies. Testing is not a phase after development; it is part of the delivery path.