Haskell unit testing

Question

I\'m new to haskell and working on unit testing, however I find the ecosystem to be very confusing. I\'m confused as to the relationship between HTF and HUnit.

In som

Answer 1

I'm also newbie haskeller and I've found this introduction really helpful: "Getting started with HUnit". To summarize, I'll put here simple testing example of HUnit usage without .cabal project file:

Let's assume that we have module SafePrelude.hs:

module SafePrelude where

safeHead :: [a] -> Maybe a
safeHead []    = Nothing
safeHead (x:_) = Just x

we can put tests into TestSafePrelude.hs as follows:

module TestSafePrelude where

import Test.HUnit
import SafePrelude

testSafeHeadForEmptyList :: Test
testSafeHeadForEmptyList = 
    TestCase $ assertEqual "Should return Nothing for empty list"
                           Nothing (safeHead ([]::[Int]))

testSafeHeadForNonEmptyList :: Test
testSafeHeadForNonEmptyList =
    TestCase $ assertEqual "Should return (Just head) for non empty list" (Just 1)
               (safeHead ([1]::[Int]))

main :: IO Counts
main = runTestTT $ TestList [testSafeHeadForEmptyList, testSafeHeadForNonEmptyList]

Now it's easy to run tests using ghc:

runghc TestSafePrelude.hs

or hugs - in this case TestSafePrelude.hs has to be renamed to Main.hs (as far as I'm familiar with hugs) (don't forget to change module header too):

runhugs Main.hs

or any other haskell compiler ;-)

Of course there is more then that in HUnit, so I really recommend to read suggested tutorial and library User's Guide.