-- | A compatibility module to use "Faker" data in your "Hedgehog" tests. module Hedgehog.Gen.Faker where import System.IO.Unsafe (unsafePerformIO) import qualified Faker import Faker (Fake) import System.Random (mkStdGen) import Hedgehog (Gen) import qualified Hedgehog.Gen as Gen import qualified Hedgehog.Range as Range import qualified Hedgehog.Internal.Gen as InternalGen import qualified Hedgehog.Internal.Seed as InternalSeed -- | Select a value 'Fake' program in 'Gen'. -- -- @since 0.0.1.0 fake :: Fake a -> Gen a fake f = do randomGen <- mkStdGen <$> Gen.integral Range.linearBounded pure $! unsafePerformIO $ -- (parsonsmatt): OK so `unsafePerformIO` is bad, unless you know exactly -- what you're doing, so do I know exactly what I am doing? Perhaps I can -- convince you. -- -- The Faker library doesn't keep the data as Haskell values, but stores it -- in `data-files`. The code that generates this fake data loads the values -- from the `data-files` for the library. That's what happens in IO. It is -- possible that the data-file is missing, and an exception will be thrown. -- However, no mutating actions are performed. I believe this is a safe use -- of 'unsafePerformIO'. -- -- The alternative would be to lift it into `GenT IO a`, which is -- undesirable, as it would harm composition with basically any other -- generator. Faker.generateWithSettings (Faker.setRandomGen randomGen Faker.defaultFakerSettings ) f