As a programmer, I have bought whole-heartedly into the TDD philosophy and take the effort to make extensive unit tests for any nontrivial code I write. Sometimes this road can be painful (behavioral changes causing cascading multiple unit test changes; high amounts of scaffolding necessary), but on the whole I refuse to program without ...
I have a type class Atomic, which defines functions for converting certain types to/from a wrapper value (Atom). I'd like to define a QuickCheck property which states: "for all instances of Atomic, any value may be stored and retrieved safely". The property looks like this: class Atomic a where toAtom :: a -> Atom fromAtom :: At...
I'm working through Real World Haskell one of the exercises of chapter 4 is to implement an foldr based version of concat. I thought this would be a great candidate for testing with QuickCheck since there is an existing implementation to validate my results. This however requires me to define an instance of the Arbitrary typeclass that c...
I am trying to write a prop that changes a Sudoku and then checks if it's still valid. However, I am not sure how to use the "oneof"-function properly. Can you give me some hints, please? prop_candidates :: Sudoku -> Bool prop_candidates su = isSudoku newSu && isOkay newSu where newSu = update su aBlank aCandidate aCandi...
What are the major differences between QuickCheck 1 and QuickCheck 2? From looking at Haddock docs I can see that it is split across more modules, coarbitrary has been replaced by the new Fun type and FunArbitrary class (which seems easier to understand to me), and testing monadic code is now supported. What else should I be aware of? ...
The function verboseCheck from QuickCheck 1 seems to be absent in QuickCheck 2 (or at least, I can't find it). Is there any other way to show which values are used during testing? ...
I have a set of Happstack.State MACID methods that I want to test using QuickCheck, but I'm having trouble figuring out the most elegant way to accomplish that. The problems I'm running into are: The only way to evaluate an Ev monad computation is in the IO monad via query or update. There's no way to create a purely in-memory MACID s...