diff --git a/semantic-diff.cabal b/semantic-diff.cabal
index 6a11e6424..3742bc5d6 100644
--- a/semantic-diff.cabal
+++ b/semantic-diff.cabal
@@ -72,7 +72,6 @@ test-suite semantic-diff-test
   other-modules:       AlignmentSpec
                      , ArbitraryTerm
                      , CorpusSpec
-                     , Data.Adjoined.Spec
                      , InterpreterSpec
                      , OrderedMapSpec
                      , PatchOutputSpec
diff --git a/test/Data/Adjoined/Spec.hs b/test/Data/Adjoined/Spec.hs
deleted file mode 100644
index 8b77d0168..000000000
--- a/test/Data/Adjoined/Spec.hs
+++ /dev/null
@@ -1,94 +0,0 @@
-module Data.Adjoined.Spec (spec) where
-
-import ArbitraryTerm ()
-import Control.Applicative
-import Data.Adjoined
-import Data.Coalescent
-import Data.Foldable
-import Data.Functor.Both
-import Data.Typeable
-import Line
-import Test.Hspec
-import Test.Hspec.QuickCheck
-import Test.QuickCheck
-
-spec :: Spec
-spec = do
-  prop "equality is reflexive" $
-    \ a -> a `shouldBe` (a :: Adjoined (Uncoalesced Char))
-
-  monoid (arbitrary :: Gen (Adjoined (Coalesced String)))
-  monoid (arbitrary :: Gen (Adjoined (Uncoalesced String)))
-  monoid (arbitrary :: Gen (Adjoined (Semicoalesced String)))
-  monoid (arbitrary :: Gen (Adjoined (Line Char)))
-  -- monoid (arbitrary :: Gen (Adjoined (Both (Line Char))))
-
-monoid :: (Arbitrary a, Coalescent a, Eq a, Show a, Typeable a) => Gen (Adjoined a) -> Spec
-monoid gen =
-  describe ("Monoid (" ++ showTypeOf (`asGeneratedTypeOf` gen) ++ ")") $ do
-    describe "mempty" $ do
-      prop "left identity" $ forAll gen $
-        \ a -> mempty `mappend` a `shouldBe` a
-
-      prop "right identity" $ forAll gen $
-        \ a -> a `mappend` mempty `shouldBe` a
-
-    describe "mappend" $ do
-      prop "associativity" $ forAll gen $
-        \ a b c -> (a `mappend` b) `mappend` c `shouldBe` a `mappend` (b `mappend` c)
-
-
-instance Arbitrary a => Arbitrary (Adjoined a) where
-  arbitrary = fromList <$> arbitrary
-  shrink arbitrary = fromList <$> shrinkList shrink (toList arbitrary)
-
-
--- | A wrapper which never coalesces values.
-newtype Uncoalesced a = Uncoalesced { runUncoalesced :: a }
-  deriving (Eq, Show)
-
-instance Arbitrary a => Arbitrary (Uncoalesced a) where
-  arbitrary = Uncoalesced <$> arbitrary
-
-instance Coalescent (Uncoalesced a) where
-  coalesce a b = pure a <|> pure b
-
-
--- | A wrapper which always coalesces values.
-newtype Coalesced a = Coalesced { runCoalesced :: a }
-  deriving (Eq, Show)
-
-instance Arbitrary a => Arbitrary (Coalesced a) where
-  arbitrary = Coalesced <$> arbitrary
-
-instance Monoid a => Coalescent (Coalesced a) where
-  coalesce a b = pure (Coalesced (runCoalesced a `mappend` runCoalesced b))
-
-
--- | A wrapper which coalesces asymmetrically.
--- |
--- | Specifically, it coalesces only when the value at the left has `True` set.
-newtype Semicoalesced a = Semicoalesced { runSemicoalesced :: (Bool, a) }
-  deriving (Eq, Show)
-
-instance Arbitrary a => Arbitrary (Semicoalesced a) where
-  arbitrary = Semicoalesced <$> arbitrary
-
-instance Monoid a => Coalescent (Semicoalesced a) where
-  Semicoalesced (True, a) `coalesce` Semicoalesced (flag, b) = pure (Semicoalesced (flag, a `mappend` b))
-  a `coalesce` b = pure a <|> pure b
-
-
--- | Returns a string with the name of a type.
--- |
--- | Use with `asTypeOf` or `asGeneratedTypeOf` to show type names for parameters without fighting type variable scoping:
--- |
--- |   showTypeOf (`asTypeOf` someTypeParametricValue)
-showTypeOf :: Typeable a => (a -> a) -> String
-showTypeOf f = show (typeRep (proxyOf f))
-  where proxyOf :: (a -> a) -> Proxy a
-        proxyOf _ = Proxy
-
--- | Type-restricted `const`, usually written infix or as an operator section with `showTypeOf`.
-asGeneratedTypeOf :: a -> Gen a -> a
-asGeneratedTypeOf = const
diff --git a/test/Spec.hs b/test/Spec.hs
index ba2c9bd74..ab58ba320 100644
--- a/test/Spec.hs
+++ b/test/Spec.hs
@@ -2,7 +2,6 @@ module Main where
 
 import qualified AlignmentSpec
 import qualified CorpusSpec
-import qualified Data.Adjoined.Spec
 import qualified InterpreterSpec
 import qualified OrderedMapSpec
 import qualified PatchOutputSpec
@@ -13,7 +12,6 @@ main :: IO ()
 main = hspec $ parallel $ do
   describe "Alignment" AlignmentSpec.spec
   describe "Corpus" CorpusSpec.spec
-  describe "Data.Adjoined" Data.Adjoined.Spec.spec
   describe "Interpreter" InterpreterSpec.spec
   describe "OrderedMap" OrderedMapSpec.spec
   describe "PatchOutput" PatchOutputSpec.spec