CPP the Arbitrary instance for the 7.8 users

bloodhound.cabal

@@ -67,7 +67,7 @@ test-suite tests
                        time,
                        aeson,
                        semigroups,
-                       QuickCheck >= 2.8,
+                       QuickCheck,
                        vector,
                        unordered-containers >= 0.2.5.0 && <0.3,
                        mtl,

stack-7.8.yaml

@@ -9,7 +9,6 @@ extra-deps:
 - http-types-0.9
 - http-client-0.5.0
 - attoparsec-0.13.0.1
-- QuickCheck-2.8.2
 - doctest-0.10.1
 - doctest-prop-0.2.0.1
 - quickcheck-properties-0.1

tests/tests.hs

@@ -1,3 +1,4 @@
+{-# LANGUAGE CPP                        #-}
 {-# LANGUAGE DefaultSignatures          #-}
 {-# LANGUAGE DeriveGeneric              #-}
 {-# LANGUAGE FlexibleContexts           #-}
@@ -585,6 +586,11 @@ noDuplicates xs = nub xs == xs
 instance Arbitrary NominalDiffTime where
   arbitrary = fromInteger <$> arbitrary
 
+#if !MIN_VERSION_QuickCheck(2,8,0)
+instance (Arbitrary k, Ord k, Arbitrary v) => Arbitrary (M.Map k v) where
+  arbitrary = M.fromList <$> arbitrary
+#endif
+
 instance Arbitrary Text where
   arbitrary = T.pack <$> arbitrary