Comment by mvdtnz
11 days ago
That engineer may have spent a couple of dozen hours on their mock. But the engineers who spent time on a test framework that uses real databases will soak up thousands of developer hours in CI time over the next decade.
Spinning up DB instances is a lot faster now than it used to be in the past. There are even modules for in-memory instances of certain databases. The speed of a unit test vs. that of one that uses an actual database is small enough for it to be a real consideration.
That being said, of course, "it depends" on your use case. But I've found setting up this sort of test environment quite a bit easier now than writing database mocks, a lot less time-and-maintenance intensive, and relatively quick to run in any environment.
(Also, in a decade, I'm pretty confident this gap will get even smaller, while the time to maintain mocks will stay constant)
Each mock needs to be maintained, sanity checking against the latest behavior of the actual dependency. And CI costs hardware, not developer time if he has anything else to work on.