Move the Arbitrary instances for Join (,) and Join These into semantic-diff proper.

bench/Main.hs

@@ -5,6 +5,7 @@ module Main where
 import Alignment
 import Criterion.Main
 import Data.Bifunctor.Join
+import Data.Bifunctor.Join.Arbitrary ()
 import Data.Functor.Foldable
 import qualified Data.List as List
 import qualified Data.OrderedMap as Map
@@ -51,10 +52,6 @@ toDiff = fmap (fmap toTerm) . unfold unArbitraryDiff
 deriving instance (NFData a, NFData b) => NFData (These a b)
 deriving instance NFData a => NFData (Join These a)
 
-instance Arbitrary a => Arbitrary (Join These a) where
-  arbitrary = Join <$> arbitrary
-  shrink (Join a) = Join <$> shrink a
-
 instance (Eq leaf, Eq annotation, Arbitrary leaf, Arbitrary annotation) => Arbitrary (ArbitraryDiff leaf annotation) where
   arbitrary = scale (`div` 2) $ sized (\ x -> boundedTerm x x) -- first indicates the cube of the max length of lists, second indicates the cube of the max depth of the tree
     where boundedTerm maxLength maxDepth = oneof [ (ArbitraryDiff .) . (Free .) . (:<) <$> (pure <$> arbitrary) <*> boundedSyntax maxLength maxDepth

semantic-diff.cabal

@@ -16,6 +16,7 @@ library
   exposed-modules:     Algorithm
                      , Alignment
                      , Category
+                     , Data.Bifunctor.Join.Arbitrary
                      , Data.Functor.Both
                      , Data.OrderedMap
                      , Data.These.Arbitrary

src/Data/Bifunctor/Join/Arbitrary.hs

@@ -0,0 +1,17 @@
+{-# OPTIONS_GHC -fno-warn-orphans #-}
+module Data.Bifunctor.Join.Arbitrary where
+
+import Data.Bifunctor.Join
+import Data.Functor.Both as Both
+import Data.These
+import Data.These.Arbitrary ()
+import Prologue
+import Test.QuickCheck
+
+instance Arbitrary a => Arbitrary (Join These a) where
+  arbitrary = Join <$> arbitrary
+  shrink (Join a) = Join <$> shrink a
+
+instance Arbitrary a => Arbitrary (Join (,) a) where
+  arbitrary = both <$> arbitrary <*> arbitrary
+  shrink b = both <$> shrink (Both.fst b) <*> shrink (Both.snd b)

test/AlignmentSpec.hs

@@ -7,6 +7,7 @@ import Control.Monad.State
 import Data.Align hiding (align)
 import Data.Bifunctor
 import Data.Bifunctor.Join
+import Data.Bifunctor.Join.Arbitrary ()
 import Data.Functor.Both as Both
 import Data.List (nub)
 import Data.Monoid

test/ArbitraryTerm.hs

@@ -2,10 +2,7 @@
 module ArbitraryTerm where
 
 import Category
-import Data.Bifunctor.Join
-import Data.Functor.Both
 import Data.Text.Arbitrary ()
-import Data.These
 import Data.These.Arbitrary ()
 import Info
 import Prologue hiding (fst, snd)
@@ -19,14 +16,6 @@ data CategorySet = A | B | C | D deriving (Eq, Show)
 instance Arbitrary CategorySet where
   arbitrary = elements [ A, B, C, D ]
 
-instance Arbitrary a => Arbitrary (Join (,) a) where
-  arbitrary = both <$> arbitrary <*> arbitrary
-  shrink b = both <$> shrink (fst b) <*> shrink (snd b)
-
-instance Arbitrary a => Arbitrary (Join These a) where
-  arbitrary = Join <$> arbitrary
-  shrink (Join a) = Join <$> shrink a
-
 instance Arbitrary a => Arbitrary (Source a) where
   arbitrary = Source.fromList <$> arbitrary