Add 'users/glittershark/xanthous/' from commit '53b56744f4335c038724a1bcffc27a7eb8cf6a6d' r/978

git-subtree-dir: users/glittershark/xanthous
git-subtree-mainline: 91f53f02d8479303910abfd3f3690d3ef27e6c4b
git-subtree-split: 53b56744f4335c038724a1bcffc27a7eb8cf6a6d

1 files changed, 42 insertions, 0 deletions

diff --git a/users/glittershark/xanthous/src/Xanthous/Util/QuickCheck.hs b/users/glittershark/xanthous/src/Xanthous/Util/QuickCheck.hs
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index 000000000000..be12bc294513
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+++ b/users/glittershark/xanthous/src/Xanthous/Util/QuickCheck.hs
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+{-# LANGUAGE UndecidableInstances #-}
+module Xanthous.Util.QuickCheck
+  ( functionShow
+  , FunctionShow(..)
+  , functionJSON
+  , FunctionJSON(..)
+  , genericArbitrary
+  , GenericArbitrary(..)
+  ) where
+--------------------------------------------------------------------------------
+import Xanthous.Prelude
+import Test.QuickCheck
+import Test.QuickCheck.Function
+import Test.QuickCheck.Instances.ByteString ()
+import Test.QuickCheck.Arbitrary.Generic
+import Data.Aeson
+import GHC.Generics (Rep)
+--------------------------------------------------------------------------------
+
+newtype FunctionShow a = FunctionShow a
+  deriving newtype (Show, Read)
+
+instance (Show a, Read a) => Function (FunctionShow a) where
+  function = functionShow
+
+functionJSON :: (ToJSON a, FromJSON a) => (a -> c) -> a :-> c
+functionJSON = functionMap encode (headEx . decode)
+
+newtype FunctionJSON a = FunctionJSON a
+  deriving newtype (ToJSON, FromJSON)
+
+instance (ToJSON a, FromJSON a) => Function (FunctionJSON a) where
+  function = functionJSON
+
+--------------------------------------------------------------------------------
+
+newtype GenericArbitrary a = GenericArbitrary a
+  deriving newtype Generic
+
+instance (Generic a, GArbitrary rep, Rep a ~ rep)
+  => Arbitrary (GenericArbitrary a) where
+  arbitrary = genericArbitrary