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Discussion on: Unit Testing is Overrated

tyrrrz profile image
Alexey Golub Author

This was shown in the article. Unfortunately, separating pure from impure code will be able to get you so far and you will still have to mock quite a few things. For example, think of a case where you need to query a small portion of a very big dataset, then perform some transformation on it, then use the result to query another portion, transform that one, and finally post the resulting data to some web service. Your pure code is interleaved with impure code and your best option is to test those parts separately, but that breaks the flow in which the code is executed and you won't have confidence that you tested the pure parts exhaustively, or in the fact that the side-effects are executed correctly. This approach works out for simple transformations that follow the [data in] -> [data out] principle, but unfortunately that's not always the case.

mirichan profile image

Wow. Look, I don't doubt that this has been true for you, but you can't speak in absolutes like that and not expect opposition.

You're speaking from an experience informed by the codebases you've worked in. I assure you that there are other codebases out there for which your statements are categorically untrue.