{-# LANGUAGE AllowAmbiguousTypes #-}
{-# LANGUAGE MultiParamTypeClasses #-}
{-# LANGUAGE ScopedTypeVariables #-}
{-# LANGUAGE TypeApplications #-}

-- | Tests for Arbitrary instances involving Validity
--
-- You will need @TypeApplications@ to use these.
module Test.Validity.Arbitrary
  ( arbitrarySpec,
    arbitraryGeneratesOnlyValid,
  )
where

import Data.Data
import Data.GenValidity
import Test.Hspec
import Test.QuickCheck
import Test.Validity.GenValidity
import Test.Validity.Utils

-- | A @Spec@ that specifies that @arbitrary@ only generates data that
-- satisfy @isValid@
--
-- Example usage:
--
-- > arbitrarySpec @Int
arbitrarySpec ::
  forall a.
  (Typeable a, Show a, Validity a, Arbitrary a) =>
  Spec
arbitrarySpec :: forall a. (Typeable a, Show a, Validity a, Arbitrary a) => Spec
arbitrarySpec = do
  let name :: String
name = forall {k} (a :: k). Typeable a => String
nameOf @a
  forall a. HasCallStack => String -> SpecWith a -> SpecWith a
describe (String
"Arbitrary " forall a. [a] -> [a] -> [a]
++ String
name) forall a b. (a -> b) -> a -> b
$
    forall a. HasCallStack => String -> SpecWith a -> SpecWith a
describe (String
"arbitrary :: Gen " forall a. [a] -> [a] -> [a]
++ String
name) forall a b. (a -> b) -> a -> b
$
      forall a.
(HasCallStack, Example a) =>
String -> a -> SpecWith (Arg a)
it String
"only generates valid values" forall a b. (a -> b) -> a -> b
$ forall a. (Show a, Validity a, Arbitrary a) => Property
arbitraryGeneratesOnlyValid @a

-- | @arbitrary@ only generates valid data
--
-- prop> arbitraryGeneratesOnlyValid @Int
arbitraryGeneratesOnlyValid ::
  forall a.
  (Show a, Validity a, Arbitrary a) =>
  Property
arbitraryGeneratesOnlyValid :: forall a. (Show a, Validity a, Arbitrary a) => Property
arbitraryGeneratesOnlyValid = forall a. (Show a, Validity a) => Gen a -> Property
genGeneratesValid @a forall a. Arbitrary a => Gen a
arbitrary