diff --git a/source/test-suite/Main.hs b/source/test-suite/Main.hs
index ecc3042..e48ec56 100644
--- a/source/test-suite/Main.hs
+++ b/source/test-suite/Main.hs
@@ -1,14 +1,12 @@
-import qualified Control.Exception as Exception
 import qualified Control.Monad as Monad
 import qualified Data.List as List
 import qualified Language.Haskell.Brittany.Main as Brittany
 import qualified System.Directory as Directory
 import qualified System.FilePath as FilePath
-import qualified System.IO as IO
 import qualified Test.Hspec as Hspec
 
 main :: IO ()
-main = Hspec.hspec $ do
+main = Hspec.hspec . Hspec.parallel $ do
   let directory = "data"
   entries <- Hspec.runIO $ Directory.listDirectory directory
   Monad.forM_ (List.sort entries) $ \entry ->
@@ -17,31 +15,20 @@ main = Hspec.hspec $ do
       Just slug -> Hspec.it slug $ do
         let input = FilePath.combine directory entry
         expected <- readFile input
-        actual <- withTemporaryFile $ \output handle -> do
-          IO.hClose handle
-          Directory.copyFile input output
-          Brittany.mainWith
-            "brittany"
-            [ "--config-file"
-            , FilePath.combine directory "brittany.yaml"
-            , "--no-user-config"
-            , "--write-mode"
-            , "inplace"
-            , output
-            ]
-          readFile output
+        let output = FilePath.combine "output" entry
+        Directory.copyFile input output
+        Brittany.mainWith
+          "brittany"
+          [ "--config-file"
+          , FilePath.combine directory "brittany.yaml"
+          , "--no-user-config"
+          , "--write-mode"
+          , "inplace"
+          , output
+          ]
+        actual <- readFile output
         Literal actual `Hspec.shouldBe` Literal expected
 
-withTemporaryFile :: (FilePath -> IO.Handle -> IO a) -> IO a
-withTemporaryFile callback = do
-  directory <- Directory.getTemporaryDirectory
-  let
-    acquire = IO.openTempFile directory "brittany-.hs"
-    release filePath handle = do
-      IO.hClose handle
-      Directory.removeFile filePath
-  Exception.bracket acquire (uncurry release) (uncurry callback)
-
 newtype Literal
   = Literal String
   deriving Eq