deque-blog’s gists

deque-blog / rapid_check_2_testable_class.hs

Created February 4, 2017 18:15

	instance
	(Show a, Arbitrary a,
	Testable testable)
	=> Testable (a -> testable)
	where
	property f = forAll arbitrary f

deque-blog / rapid_check_2_full.hs

Last active February 5, 2017 16:05

	{-# LANGUAGE GeneralizedNewtypeDeriving #-}
	{-# LANGUAGE FlexibleInstances #-}
	module RapidCheck where

	import Control.Monad
	import Data.List
	import System.Random
	import Text.Show.Functions

deque-blog / rapid_check_3_the_need.hs

Last active February 5, 2017 16:56

deque-blog / rapid_check_3_the_goal.hs

Last active February 5, 2017 16:55

deque-blog / rapid_check_3_shrink_in_arbitrary.hs

Last active February 5, 2017 21:13

deque-blog / rapid_check_3_forall_shrink.hs

Last active February 8, 2017 14:10

	forAll :: (Show a, Testable testable)
	=> Gen a -> Shrink a -> (a -> testable) -> Property
	forAll argGen shrink prop =
	Property $ Gen $ \rand -> -- Create a new property that will
	let (rand1, rand2) = split rand -- Split the generator in two
	arg = runGen argGen rand1 -- Use the first generator to produce an arg
	runSub = evalSubProp prop rand2 -- Factorize a runner for the sub-property
	result = runSub arg -- Run the sub-property with value `arg`
	in overFailure result $ \failure -> -- In case of failure,
	shrinking shrink arg runSub -- Attempt to shrink the counter example

deque-blog / rapid_check_3_testable.hs

Created February 5, 2017 20:52

	instance
	(Show a, Arbitrary a, Testable testable)
	=> Testable (a -> testable)
	where
	property = forAll arbitrary shrink

deque-blog / rapid_check_3_shrinking.hs

Last active February 10, 2017 14:56

	shrinking :: (Show a) => Shrink a -> a -> (a -> Result) -> Result
	shrinking shrink arg runSub =
	let children = shrink arg -- Get the children of the current branch
	result = findFailing children runSub -- Look for the first failure
	in case result of
	Nothing -> Success
	Just (shrunk, failure) -> -- In case a failure is found
	shrinking shrink shrunk runSub -- Try to shrink further the child
	<> -- OR (in case it fails)
	addToCounterExample shrunk failure -- Add child to the counter example

deque-blog / rapid_check_3_shrinking_integers.hs

Last active February 9, 2017 18:15

	instance Arbitrary Integer where
	arbitrary = Gen $ \rand -> fromIntegral $ fst (next rand)
	shrink n
	\| n == 0 = []
	\| otherwise = [abs n \| n < 0] ++ 0 : rightDichotomy where
	rightDichotomy =
	takeWhile
	(\m -> abs m < abs n)
	[ n - i \| i <- tail (iterate (`quot` 2) n)]

deque-blog / rapid_check_3_shrinking_integers_ex.hs

Last active February 9, 2017 18:21