github/semantic
1
1
Fork 0
mirror of https://github.com/github/semantic.git synced 2024-12-29 18:06:14 +03:00
Code Issues Projects Releases Wiki Activity

Validate the relationship between sequenceAlt and merge.

Browse Source
This commit is contained in:
Rob Rix 2016-07-26 04:15:56 -04:00
parent d1bbe1c029
commit a0cf6ce702
1 changed files with 5 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
test/Data/Mergeable/Spec.hs
View File

@ -1,3 +1,4 @@
{-# LANGUAGE ScopedTypeVariables #-}
module Data.Mergeable.Spec where
import Data.Functor.Identity
@ -12,8 +13,11 @@ spec = do
describe "[]" $ sequenceAltLaws (arbitrary :: Gen [Char])
describe "Maybe" $ sequenceAltLaws (arbitrary :: Gen (Maybe Char))
sequenceAltLaws :: (Mergeable f, Eq (f a), Show (f a)) => Gen (f a) -> Spec
sequenceAltLaws :: forall f a. (Arbitrary a, CoArbitrary a, Mergeable f, Eq (f a), Show (f a)) => Gen (f a) -> Spec
sequenceAltLaws gen = do
describe "sequenceAlt" $ do
prop "identity" . forAll gen $
\ a -> sequenceAlt (fmap Just a) `shouldBe` Just a
prop "relationship with merge" . forAll ((,) <$> gen <*> (arbitrary :: Gen (Blind (a -> Maybe a)))) $
\ (a, f) -> sequenceAlt (getBlind f <$> a) `shouldBe` merge (getBlind f) a