mirror of
https://github.com/github/semantic.git
synced 2024-12-29 01:42:43 +03:00
96 lines
3.8 KiB
Haskell
96 lines
3.8 KiB
Haskell
{-# LANGUAGE GADTs, TypeFamilies #-}
|
|
module Test.Hspec.LeanCheck
|
|
( prop
|
|
, forAll
|
|
) where
|
|
|
|
import Control.Exception
|
|
import Data.Bifunctor (first)
|
|
import Data.List (intercalate)
|
|
import Data.Maybe (listToMaybe)
|
|
import Data.Typeable
|
|
import GHC.Show as Show (showsPrec)
|
|
import Test.Hspec
|
|
import Test.Hspec.Core.Spec as Hspec
|
|
import qualified Test.HUnit.Lang as HUnit
|
|
import Test.LeanCheck.Core
|
|
|
|
data Property where
|
|
Property :: IOTestable prop => prop -> Property
|
|
|
|
-- | Perform an enumerative test of a property using LeanCheck.
|
|
--
|
|
-- 'prop' will typically be a function of one or more 'Listable' arguments, returning either 'Bool' or 'IO ()' (in the latter case, typically via 'shouldBe' and friends). For example:
|
|
--
|
|
-- > describe "+" $ do
|
|
-- > prop "associativity" $
|
|
-- > \ a b c -> a + (b + c) `shouldBe` (a + b :: Int) + c
|
|
prop :: (HasCallStack, IOTestable prop) => String -> prop -> Spec
|
|
prop s = it s . Property
|
|
|
|
data ForAll a where
|
|
ForAll :: IOTestable prop => [[a]] -> (a -> prop) -> ForAll a
|
|
|
|
-- | Test a property given by an explicit list of tiers rather than a 'Listable' instance. This can be used to e.g. filter input values for which the property does not hold.
|
|
--
|
|
-- > describe "mean" $ do
|
|
-- > prop "≥ the minimum" . forAll (not . null `filterT` tiers) $
|
|
-- > \ list -> (mean list :: Int) `shouldSatisfy` (>= min list)
|
|
forAll :: IOTestable prop => [[a]] -> (a -> prop) -> ForAll a
|
|
forAll = ForAll
|
|
|
|
instance Example Property where
|
|
type Arg Property = ()
|
|
evaluateExample (Property prop) (Params _ bound) _ _ = do
|
|
result <- try (iocounterExample bound prop)
|
|
case result of
|
|
Left e
|
|
| Just (LeanCheckException messages e') <- fromException e -> throw (addMessages messages e')
|
|
| otherwise -> throw e
|
|
Right (Just messages) -> pure $ Result "" (Failure Nothing (Reason (concat messages)))
|
|
Right Nothing -> pure $ Result "" Success
|
|
where addMessages messages (HUnit.HUnitFailure loc r) = HUnit.HUnitFailure loc $ case r of
|
|
HUnit.Reason s -> HUnit.Reason (intercalate "\n" messages ++ "\n" ++ s)
|
|
HUnit.ExpectedButGot Nothing expected actual -> HUnit.ExpectedButGot (Just (concat messages)) expected actual
|
|
HUnit.ExpectedButGot (Just preface) expected actual -> HUnit.ExpectedButGot (Just (intercalate "\n" messages ++ preface)) expected actual
|
|
|
|
|
|
class IOTestable t where
|
|
-- 'resultiers', lifted into 'IO'.
|
|
ioResultTiers :: t -> [[IO ([String], Bool)]]
|
|
|
|
instance IOTestable (IO ()) where
|
|
ioResultTiers action = [[ (action >> pure ([], True)) `catch` (throw . LeanCheckException []) ]]
|
|
|
|
instance (IOTestable b, Show a, Listable a) => IOTestable (a -> b) where
|
|
ioResultTiers p = concatMapT (resultiersFor p) tiers
|
|
|
|
instance IOTestable Bool where
|
|
ioResultTiers p = [[ pure ([], p) ]]
|
|
|
|
instance Show a => IOTestable (ForAll a) where
|
|
ioResultTiers (ForAll tiers property) = concatMapT (resultiersFor property) tiers
|
|
|
|
resultiersFor :: (IOTestable b, Show a) => (a -> b) -> a -> [[IO ([String], Bool)]]
|
|
resultiersFor p x = fmap (eval x) <$> ioResultTiers (p x)
|
|
|
|
eval :: Show a => a -> IO ([String], Bool) -> IO ([String], Bool)
|
|
eval x action = first (prepend x) <$> action
|
|
`catch` \ (LeanCheckException messages failure) -> throw (LeanCheckException (prepend x messages) failure)
|
|
where prepend x = (showsPrec 11 x "":)
|
|
|
|
|
|
-- | 'counterExamples', lifted into 'IO'.
|
|
iocounterExamples :: IOTestable a => Int -> a -> IO [[String]]
|
|
iocounterExamples n = fmap (fmap fst . filter (not . snd)) . sequenceA . take n . concat . ioResultTiers
|
|
|
|
-- | 'counterExample', lifted into 'IO'.
|
|
iocounterExample :: IOTestable a => Int -> a -> IO (Maybe [String])
|
|
iocounterExample n = fmap listToMaybe . iocounterExamples n
|
|
|
|
|
|
data LeanCheckException = LeanCheckException [String] HUnit.HUnitFailure
|
|
deriving (Show, Typeable)
|
|
|
|
instance Exception LeanCheckException
|