FitSpec provides automated assistance in the task of refining test properties
for Haskell functions.
FitSpec tests mutant variations of functions under test against a given
property set, recording any surviving mutants that pass all tests. FitSpec
then reports:
surviving mutants: indicating incompleteness of properties,
prompting the user to amend a property or to add a new one;
conjectures: indicating redundancy in the property set,
prompting the user to remove properties so to reduce the cost of testing.