At one of my previous jobs we did very few unit tests (basically only pure functions) and tons of behavior/integration tests (ie. run the service with a real da

At one of my previous jobs we did very few unit tests (basically only pure functions) and tons of behavior/integration tests (ie. run the service with a real database, real queues, etc. but mock the HTTP dependencies, call its API and check we get the correct result and side effects) and it was the most stable and easy to work with test suite I’ve ever seen. It was extremely reliable too. Not mocking the database and other pipes is the single best improvement everyone can make on their test suites. We also had a test suite that followed the same principle but started all the services together to reduce the mocked surface, it executed every hour and was both incredibly useful and reliable too. The test pyramid is false wisdom.