quickcheck

FWIW, have a look at https://github.com/leepike/SmartCheck, which claims to derive better shrinks than one can usually do manually.

Writing an instance of Arbitrary for your data type is easy. You just have to implement the arbitrary function, which should return a Gen Cell. The simplest way to do this is to make use of existing Arbitrary instances and also note that Gen is a monad, so we can use do-notation: instance Arbitrary Cell … Read more

I’ve seen one major advancement in QuickCheck 2, I think as important as monadic code testing, if not more : class Arbitrary a where arbitrary :: Gen a shrink :: a -> [a] This, is really awesome. The shrink method is optional, but if you can provide a list of “possibly empty” reduction of your … Read more

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 … Read more