1 files changed, 28 insertions, 0 deletions
diff --git a/src/Xanthous/Util/QuickCheck.hs b/src/Xanthous/Util/QuickCheck.hs
new file mode 100644
index 0000000000..ac76a4c930
--- /dev/null
+++ b/src/Xanthous/Util/QuickCheck.hs
@@ -0,0 +1,28 @@
+module Xanthous.Util.QuickCheck
+  ( FunctionShow(..)
+  , functionJSON
+  , FunctionJSON(..)
+  ) where
+--------------------------------------------------------------------------------
+import Xanthous.Prelude
+import Test.QuickCheck
+import Test.QuickCheck.Function
+import Test.QuickCheck.Instances.ByteString ()
+import Data.Aeson
+import Data.Coerce
+--------------------------------------------------------------------------------
+
+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