Re: [Haskell-cafe] ANN: quickcheck-properties
On 11-05-30 05:05 AM, Alexey Khudyakov wrote: On 30.05.2011 12:26, Bas van Dijk wrote: On 30 May 2011 00:14, Alexey Khudyakov wrote: It always puzzled me why there are no packages for for testing general type classes laws. (Monoid laws, monad laws etc). It looks like ideal case for quickcheck and smallcheck. How about 'checkers' by Conal Elliott: http://hackage.haskell.org/package/checkers We really need better search on hackage than C-f in browser. I didn't find them. Thank you for pointers. When I needed the very same thing a few months ago, I discovered checkers by using the reverse dependencies list for QuickCheck: http://bifunctor.homelinux.net/~roel/cgi-bin/hackage-scripts/revdeps/QuickCheck-2.4.1.1#direct That helped a lot, though finding checkers in the list still wasn't a breeze. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] ANN: quickcheck-properties
On 30.05.2011 14:45, Henning Thielemann wrote: Alexey Khudyakov schrieb: On 30.05.2011 12:26, Bas van Dijk wrote: How about 'checkers' by Conal Elliott: http://hackage.haskell.org/package/checkers We really need better search on hackage than C-f in browser. I didn't find them. Thank you for pointers. google with site:hackage.haskell.org option might help It's do not offer much help. It finds too many pages for module descriptions packages get lost here. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] ANN: quickcheck-properties
Alexey Khudyakov schrieb: > On 30.05.2011 12:26, Bas van Dijk wrote: >> >> How about 'checkers' by Conal Elliott: >> http://hackage.haskell.org/package/checkers >> > We really need better search on hackage than C-f in browser. I didn't > find them. Thank you for pointers. google with site:hackage.haskell.org option might help ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] ANN: quickcheck-properties
On 30.05.2011 12:26, Bas van Dijk wrote: On 30 May 2011 00:14, Alexey Khudyakov wrote: It always puzzled me why there are no packages for for testing general type classes laws. (Monoid laws, monad laws etc). It looks like ideal case for quickcheck and smallcheck. How about 'checkers' by Conal Elliott: http://hackage.haskell.org/package/checkers We really need better search on hackage than C-f in browser. I didn't find them. Thank you for pointers. Nice work by the way! Bas ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] ANN: quickcheck-properties
On 30 May 2011 00:14, Alexey Khudyakov wrote: > It always puzzled me why there are no packages for for testing general > type classes laws. (Monoid laws, monad laws etc). It looks like ideal > case for quickcheck and smallcheck. How about 'checkers' by Conal Elliott: http://hackage.haskell.org/package/checkers Nice work by the way! Bas ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] ANN: quickcheck-properties
Hello It always puzzled me why there are no packages for for testing general type classes laws. (Monoid laws, monad laws etc). It looks like ideal case for quickcheck and smallcheck. I'm glad to present package quickcheck-properties[1]. It containt set of generic properties for semiroups, monoids, groups and unsatisfactory imlementatation of functor's properties. Despite its name package do not depend on quickcheck and could be used with smallcheck as well. Examples Here are few examples: >>> quickCheck $ eq $ prop_Monoid (T :: T [Int]) +++ OK, passed 100 tests. >>> quickCheck $ eq $ prop_Monoid (T :: T (Maybe [Int])) +++ OK, passed 100 tests. prop_Monoid tests all monoid properties: associativity, left and right identity. T is used to fix type of monoid to test. It could be done with type signature for prop_Monoid but writing signature for three parameter function is just too cumbersome. eq compares expression in properties using == operator. Many (most?) of properties have form > expression = another expression Easiest solution is to compare them with ==. But is's not satisfactory. Data type may not have Eq instance. Eq instance may provide structural equality but some form of equivalince is needed. etc. It's left to library user to decide how to compare values. In this contrived example lists are compared by length. > eqOn length $ prop_Monoid (T :: T [Int]) Problems There are unsolved problems. So it's announcement with question. Functor/Applicative/Monads laws involve arbitrary functions. It would be natural to generate them using quickcheck but I don't know how to generate random functions. Any suggestions? [1] http://hackage.haskell.org/package/quickcheck-properties -- Aleksey Khudyakov ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
