Technology

zealous application of DRY is not a good idea with tests

I absolutely agree. My point is that if you need complex setup, there's a good chance you can reuse it and replace only the data that's relevant for your test instead of constructing it every time.

But yes, there's a limit here. We currently have a veritable mess because we populate the database with fixture data so we have enough data to not need setup logic for each test. Changing that fixture data causes a dozen tests to fail across suites. Since I started at this org, I've been pushing against that and introduced the repository pattern so we can easily mock db calls.

IMO, reused logic/structures should be limited to one test suite. But even then, rules are meant to be broken, just make sure you justify it.

also a place where an LLM can save you some time.

I'm still not convinced that's the case though. A typical mock takes a minute or two to write, most of the time is spent thinking about which cases to hit or refactoring code to make testing easier. Working with the LLM takes at least that long, esp if you count reviewing the generated code and whatnot.

LLMs are like the junior dev

Right, and I don't want a junior dev writing my tests. Junior devs are there to be trained with the expectation that they'll learn from mistakes. LLMs don't learn, they're perennially junior.

That's why I don't use them for code gen and instead use them for research. Writing code is the easy part of my job, knowing what to write is what takes time, so I outsource as much of the latter as I can.