quickcheck

I have a cabal package that exports a type NBT which might be useful for other developers. I've gone through the trouble of defining an Arbitrary instance for my type, and it would be a shame to not offer it to other developers for testing their code that integrates my work. However, I want to avoid situations where my instance might get in the way. Perhaps the other developer has a different idea for what the Arbitrary instance should be. Perhaps my package's dependency on a particular version of QuickCheck might interfere with or be unwanted in the dependencies of the client project. My

I'm learning the ropes of QuickCheck >= 2.6 but I don't understand what a shrink is. From looking at the type signature shrink looks more like expand! Please illuminate me :) When QuickCheck finds an input that violates a property, it will first try to find smaller inputs that also violate the property, in order to give the developer a better message about the nature of the failure. What it means to be „small“ of course depends on the datatype in question; to QuickCheck it is anything that comes out from from the shrink function. It is best explained in a QuickCheck session: Prelude Test

When i google for how to integrate unit tests with cabal files, i either find http://www.haskell.org/haskellwiki/How_to_write_a_Haskell_program which does not seem to describe the integration of HUnit/QuickCheck with the Cabal file or i see messages like "wait for Cabal x.y which will support cabal test" but i can not find any documentation for this either How would you run all unit test using cabal (for example everytime i do a "cabal build") today? tibbe Make sure you have the latest version of Cabal and cabal-install installed. Have a test-suite section in your .cabal file. See this section

I have a function arbExample to generate a random Example data type which depends on a numbers of functions. I am trying to do some property testing by doing quickCheck prop_example , the problem is I don't know how to define an Arbitrary instance for Example which uses arbExample . I like to be able run quickCheck prop_example while specifying the Gens data structure which arbExample uses. data Example = Example { myInt :: Int , myList :: [String] } deriving (Show) data Gens = Gens { gen1 :: Gen Int , gen2 :: Gen String } arbExample :: Gens -> Gen Example arbExample gens = do i <- gen1 gens