This is ... not even basic test engineering 101. This is remedial: understand the testing pyramid. If you can take a 5ms unit test and verify with 80% confiden

This is ... not even basic test engineering 101. This is remedial: understand the testing pyramid. If you can take a 5ms unit test and verify with 80% confidence for a given feature, run that first before running at 5s system integration test that verifies it with 100% confidence. You run both, because you run unit tests with a build/linting stage (something that can run synchronously with every commit, or close to it) and you run the integration test less frequently because of time/cost constraints (stable branch merges). Even though they test they same thing, they serve different needs.