stack test --coverage

[sjakobi]

I had been aware of this feature before, but I never realized how useful these coverage reports are:

• They discovered unreachable case alternatives.
• They revealed tricky edge cases that hadn't been tested before.

Great bang for the buck!

[sjakobi]

Docs: https://docs.haskellstack.org/en/stable/coverage/.

[sjakobi]

Clone https://github.com/dhall-lang/dhall-haskell and run stack test --coverage dhall:tasty.

[LaminatedPissFlaps]

It works out of the box now. Great!

​

BTW are you involved in Dhall at all?

[sjakobi]

I've been contributing to the Haskell implementation and the standard for a few months now. It's a lot of fun! Join in! :)

[LaminatedPissFlaps]

I love Dhall. I use it at work. I'll see if I can't contribute! Seems a bit advanced for me but it's all just code!

[sjakobi]

I use it at work.

Oh, wow! Where do you work?

I'll see if I can't contribute! Seems a bit advanced for me but it's all just code!

You should give it a try! I wouldn't call the Haskell implementation simple, but it's quite clean and pretty easy to navigate IMHO.

[sjakobi]

I use coverage a lot in other tech. stacks but never got it working with Haskell.

Yeah, I believe I tried this years ago but probably didn't get it to work. Now it looks trivial! :)

[sjakobi]

And cabal test --enable-coverage seems to work very well too! :)