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diff --git a/users/aspen/xanthous/test/Test/Prelude.hs b/users/aspen/xanthous/test/Test/Prelude.hs
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+{-# LANGUAGE AllowAmbiguousTypes #-}
+--------------------------------------------------------------------------------
+module Test.Prelude
+  ( module Xanthous.Prelude
+  , module Test.Tasty
+  , module Test.Tasty.HUnit
+  , module Test.Tasty.QuickCheck
+  , module Test.Tasty.Ingredients.Rerun
+  , module Test.QuickCheck.Classes
+  , testBatch
+  , jsonRoundTrip
+  ) where
+--------------------------------------------------------------------------------
+import           Xanthous.Prelude hiding (assert, elements)
+--------------------------------------------------------------------------------
+import           Test.Tasty
+import           Test.Tasty.QuickCheck
+import           Test.Tasty.HUnit
+import           Test.Tasty.Ingredients.Rerun
+import           Test.QuickCheck.Classes
+import           Test.QuickCheck.Checkers (TestBatch, EqProp ((=-=)))
+import           Test.QuickCheck.Instances.ByteString ()
+--------------------------------------------------------------------------------
+import qualified Data.Aeson as JSON
+import           Data.Aeson (ToJSON, FromJSON)
+--------------------------------------------------------------------------------
+
+testBatch :: TestBatch -> TestTree
+testBatch (name, tests) = testGroup name $ uncurry testProperty <$> tests
+
+jsonRoundTrip
+  :: forall a. (ToJSON a, FromJSON a, EqProp a, Arbitrary a, Show a) => TestTree
+jsonRoundTrip = testProperty "JSON round trip" $ \(x :: a) ->
+  JSON.decode (JSON.encode x) =-= Just x