{-# LANGUAGE MultiParamTypeClasses #-}
{-# LANGUAGE ScopedTypeVariables #-}

-- | Standard tests involving validity
module Test.Syd.Validity.Functions.Idempotence
    ( idempotentOnGen
    , idempotentOnValid
    , idempotent
    , idempotentOnArbitrary
    ) where

import Data.GenValidity

import Test.Syd
import Test.QuickCheck

idempotentOnGen :: (Show a, Eq a) => (a -> a) -> Gen a -> (a -> [a]) -> Property
idempotentOnGen :: (a -> a) -> Gen a -> (a -> [a]) -> Property
idempotentOnGen a -> a
f Gen a
gen a -> [a]
s = Gen a -> (a -> [a]) -> (a -> IO ()) -> Property
forall a prop.
(Show a, Testable prop) =>
Gen a -> (a -> [a]) -> (a -> prop) -> Property
forAllShrink Gen a
gen a -> [a]
s ((a -> IO ()) -> Property) -> (a -> IO ()) -> Property
forall a b. (a -> b) -> a -> b
$ \a
a -> a -> a
f (a -> a
f a
a) a -> a -> IO ()
forall a. (HasCallStack, Show a, Eq a) => a -> a -> IO ()
`shouldBe` a -> a
f a
a

idempotentOnValid :: (Show a, Eq a, GenValid a) => (a -> a) -> Property
idempotentOnValid :: (a -> a) -> Property
idempotentOnValid a -> a
func = (a -> a) -> Gen a -> (a -> [a]) -> Property
forall a.
(Show a, Eq a) =>
(a -> a) -> Gen a -> (a -> [a]) -> Property
idempotentOnGen a -> a
func Gen a
forall a. GenValid a => Gen a
genValid a -> [a]
forall a. GenValid a => a -> [a]
shrinkValid

idempotent :: (Show a, Eq a, GenUnchecked a) => (a -> a) -> Property
idempotent :: (a -> a) -> Property
idempotent a -> a
func = (a -> a) -> Gen a -> (a -> [a]) -> Property
forall a.
(Show a, Eq a) =>
(a -> a) -> Gen a -> (a -> [a]) -> Property
idempotentOnGen a -> a
func Gen a
forall a. GenUnchecked a => Gen a
genUnchecked a -> [a]
forall a. GenUnchecked a => a -> [a]
shrinkUnchecked

-- |
--
-- 'id' is idempotent for any type:
--
-- prop> idempotentOnArbitrary (id :: Int -> Int)
--
-- 'const', given any input, is idempotent for any type as well:
--
-- prop> \int -> idempotentOnArbitrary (const int :: Int -> Int)
idempotentOnArbitrary :: (Show a, Eq a, Arbitrary a) => (a -> a) -> Property
idempotentOnArbitrary :: (a -> a) -> Property
idempotentOnArbitrary a -> a
func = (a -> a) -> Gen a -> (a -> [a]) -> Property
forall a.
(Show a, Eq a) =>
(a -> a) -> Gen a -> (a -> [a]) -> Property
idempotentOnGen a -> a
func Gen a
forall a. Arbitrary a => Gen a
arbitrary a -> [a]
forall a. Arbitrary a => a -> [a]
shrink