Choose the installation info of your platform from here.
For mac I recommend using ghcup to install to install ghc and cabal-install.
Install HSpec with
cabal update && cabal install --lib hspecNavigate to the directory where the CodeKataSpec.hs test file is and run:
$ runhaskell CodeKataSpec.hsIt will fail with the following error message:
$ runhaskell CodeKataSpec.hs
Loaded package environment from {#your_environment}
Example Tests
  should work with example tests FAILED [1]
Failures:
  CodeKataSpec.hs:8:7: 
  1) Example Tests should work with example tests
       expected: True
        but got: False
  To rerun use: --match "/Example Tests/should work with example tests/"
Randomized with seed 752281758
Finished in 0.0013 seconds
1 example, 1 failureIf you insert the following code block to CodeKata.hs:
module CodeKata (test) where
test :: String -> Bool
test string = True
It will pass with:
$ runhaskell CodeKataSpec.hs
Loaded package environment from {#your_environment}
Example Tests
  should work with example tests
Finished in 0.0003 seconds
1 example, 0 failures