Safe Haskell	None
Language	Haskell98

Test.Feat.Access

Contents

Accessing functions
A simple property tester
Compatibility
- QuickCheck
- SmallCheck
Non-class versions of the access functions

Description

Functions for accessing the values of enumerations including compatibility with the property based testing frameworks QuickCheck and SmallCheck.

Synopsis

Accessing functions

index :: Enumerable a => Integer -> a #

Mainly as a proof of concept we define a function to index into an enumeration. (If this is repeated multiple times it might be very inefficient, depending on whether the dictionary for the Enumerable is shared or not.)

select :: Enumerable a => Int -> Index -> a #

A more fine grained version of index that takes a size and an index into the values of that size. select p i is only defined for i

values :: Enumerable a => [(Integer, [a])] #

All values of the enumeration by increasing cost (which is the number of constructors for most types). Also contains the cardinality of each list.

striped :: Enumerable a => Index -> Integer -> [(Integer, [a])] #

A generalisation of values that enumerates every nth value of the enumeration from a given starting point. As a special case values = striped 0 1.

Useful for running enumerations in parallel since e.g. striped 0 2 is disjoint from striped 0 1 2 and the union of the two cover all values.

bounded :: Enumerable a => Integer -> [(Integer, [a])] #

A version of values with a limited number of values in each inner list. If the list corresponds to a Part which is larger than the bound it evenly distributes the values across the enumeration of the Part.

A simple property tester

featCheck :: (Enumerable a, Show a) => Int -> (a -> Bool) -> IO () #

Check a property for all values up to a given size. featCheck p prop = ioAll p (inputRep prop)

ioFeat :: [(Integer, [a])] -> Report a -> IO () #

A rather simple but general property testing driver. The property is an (funcurried) IO function that both tests and reports the error. The driver goes on forever or until the list is exhausted, reporting its progress and the number of tests before each new part.

ioAll :: Enumerable a => Int -> Report a -> IO () #

Defined as ioAll p = ioFeat (take p values)

ioBounded :: Enumerable a => Integer -> Int -> Report a -> IO () #

Defined as ioBounded n p = ioFeat (take p $ bounded n)

type Report a = a -> IO () #

Functions that test a property and reports the result.

inputRep :: Show a => (a -> Bool) -> Report a #

Reports counterexamples to the given predicate by printing them

prePostRep :: (Show a, Show b) => (a -> b) -> (a -> b -> Bool) -> Report a #

Takes a function and a predicate on its input/output pairs. Reports counterexamples by printing the failing input/output pair.