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semantic/test/Data/Mergeable/Spec.hs
2016-07-26 15:27:32 -04:00

54 lines
2.5 KiB
Haskell

{-# LANGUAGE RankNTypes, ScopedTypeVariables #-}
module Data.Mergeable.Spec where
import Data.Functor.Identity
import Data.Mergeable
import Prologue
import Syntax
import Test.Hspec
import Test.Hspec.QuickCheck
import Test.QuickCheck
spec :: Spec
spec = parallel $ do
describe "[]" $ do
let gen = scale (`div` 25) arbitrary :: Gen [Char]
withAlternativeInstances sequenceAltLaws gen
withAlternativeInstances mergeLaws gen
describe "Maybe" $ do
withAlternativeInstances sequenceAltLaws (arbitrary :: Gen (Maybe Char))
withAlternativeInstances mergeLaws (arbitrary :: Gen (Maybe Char))
describe "Identity" $ do
withAlternativeInstances sequenceAltLaws (Identity <$> arbitrary :: Gen (Identity Char))
withAlternativeInstances mergeLaws (Identity <$> arbitrary :: Gen (Identity Char))
describe "Syntax" $ do
withAlternativeInstances sequenceAltLaws (sized (syntaxOfSize (const arbitrary)) :: Gen (Syntax Char Char))
withAlternativeInstances mergeLaws (sized (syntaxOfSize (const arbitrary)) :: Gen (Syntax Char Char))
prop "subsumes catMaybes/Just" $ do
\ a -> sequenceAlt a `shouldBe` pure (catMaybes (a :: [Maybe Char]))
mergeLaws :: forall f g a. (Mergeable f, Alternative g, Eq (g (f a)), Show (f a), Show (g (f a))) => Gen (f a) -> Gen (Blind (a -> g a)) -> Spec
mergeLaws value function = describe "merge" $ do
prop "identity" . forAll value $
\ a -> merge pure a `shouldNotBe` (empty :: g (f a))
let pair = (,) <$> value <*> function
prop "relationship with sequenceAlt" . forAll pair $
\ (a, f) -> merge (getBlind f) a `shouldBe` sequenceAlt (fmap (getBlind f) a)
sequenceAltLaws :: forall f g a. (Mergeable f, Alternative g, Eq (g (f a)), Show (f a), Show (g (f a))) => Gen (f a) -> Gen (Blind (a -> g a)) -> Spec
sequenceAltLaws value function = do
describe "sequenceAlt" $ do
prop "identity" . forAll value $
\ a -> sequenceAlt (pure <$> a) `shouldNotBe` (empty :: g (f a))
prop "relationship with merge" . forAll (Blind <$> (fmap . getBlind <$> function <*> value) :: Gen (Blind (f (g a)))) $
\ a -> sequenceAlt (getBlind a) `shouldBe` merge identity (getBlind a)
withAlternativeInstances :: forall f a. (Arbitrary a, CoArbitrary a, Eq (f a), Show (f a)) => (forall g. (Alternative g, Eq (g (f a)), Show (g (f a))) => Gen (f a) -> Gen (Blind (a -> g a)) -> Spec) -> Gen (f a) -> Spec
withAlternativeInstances laws gen = do
describe "[]" $ laws gen (scale (`div` 25) (arbitrary :: Gen (Blind (a -> [a]))))
describe "Maybe" $ laws gen (arbitrary :: Gen (Blind (a -> Maybe a)))