Re: [Haskell-cafe] Type System vs Test Driven Development

On 12 January 2011 21:16, Serge Le Huitouze wrote:

Evan Laforge wrote:

...

QuickCheck seems to fit well when you have small input and output spaces, but complicated stuff in the middle, but still simple relations between the input and output.  I think that's why data structures are so easy to QuickCheck.  I suppose I should look around for more use of QuickCheck for non-data structures... the examples I've seen have been trivial stuff like 'reverse . reverse = id'.

I second this feeling...

For example, I've never seen (I've not looked hard, though) Quickcheck's testing applied on graphs. Generating "interesting" (whatever that means for your particular problem) graphs doesn't seem to be a trivial test, even if it's a mere data structure... Does anyone know of such examples?

I do some graph-based testing in graphviz [1]. It is non-trivial to generate decent Arbitrary instances due to the recursive definitions :s [1]: http://hackage.haskell.org/package/graphviz -- Ivan Lazar Miljenovic Ivan.Miljenovic@gmail.com IvanMiljenovic.wordpress.com