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Comment by pylua | Hacker News Reader

Unit tests are boiler plate ?

I'm using an expansive definition of boiler plate to be sure. But like boiler plate most unit tests require a little bit of thought and then a good amount of typing, doing things like setting up the data to test, mocking up methods, writing out assertions to test all your edge cases.

I've found sonnet and o1 to be pretty good at this. Better than writing the actual code because while modifying a system requires a lot of context of the overall application and domain, unit testing a method usually doesn't.

Yes. You write a function ApplyFooToBar(), and then unit tests that check that, when supplied with right Foos, the function indeed applies those Foos to the Bar. It's not a very intellectually challenging work.

If anything, the challenge is with all the boilerplate surrounding the test, because you can't just write down what the test checks themselves - you need to assemble data, assemble expected result, which you end up DRY-ing into support modules once you have 20 tests needing similar pre-work, and then there's lots of other bullshit to deal with at the intersection between your programming language, your test framework, and your modularization strategy.

Quite often, yes. That's why I prefer integration tests.

Indeed. To many tests are just testing nothing other than mocks. That goes for my coworkers directly and for their Copilot output. They’re not useful tests, they are thing to catch actual errors, they’re maybe useful as usage documentation. But in general, they’re mostly a waste.

Integration tests, good ones, are harder but far more valuable.

> To many tests are just testing nothing other than mocks

Totally agree, and I find that they don't help with documentation much either, because the person that wrote it doesn't know what they're trying to test. So it only overcomplicates things.

Also harmful because it gives a false sense of security that the code is tested when it really isn't.

This has been my approach in the past that only certain parts of the code are worth unit testing. But given how much easier unit tests are to write now with AI I think the % of code worth unit testing has gone up.

> But given how much easier unit tests are to write now with AI I think the % of code worth unit testing has gone up.

I see the argument, I just disagree with it. Test code is still code and it still has to be maintained, which, sure "the AI will do that" but now theres a lot more that I have to babysit.

The tests that I'm seeing pumped out by my coworkers who are using AI for it just aren't very good tests a lot of the time, and honestly encode too much of the specific implementation details of the module in question into them, making refactoring more of a chore.

The tests I'm talking about simply aren't going to catch any bugs, they weren't used as an isolated execution environment for test driven development, so what use are they? I'm not convinced, not yet anyway.

Just because we can get "9X%" coverage with these tools, doesn't mean we should.

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