diff --git a/haskell/Main.hs b/haskell/Main.hs
index 18ab874..bc07fc7 100644
--- a/haskell/Main.hs
+++ b/haskell/Main.hs
@@ -1,7 +1,9 @@
 module Main (main) where
 
+import Data.Bool
 import Data.ByteString.Lazy qualified as BL
 import Data.Functor
+import Data.List.Extra
 import Data.Text.Encoding (encodeUtf8)
 import Data.Text.IO qualified as T
 import Puzzle
@@ -19,7 +21,7 @@ main =
     defaultMain
         . localOption (Always :: UseColor)
         . testGroup "tests"
-        $ ["examples", "real"] <&> \t ->
+        $ enumerate <&> \isRealData@(bool "examples" "real" -> t) ->
             testGroup t $
                 [ Day1.puzzle
                 , Day2.puzzle
@@ -40,4 +42,4 @@ main =
                                         goldenVsString n ("../outputs/" <> t <> "/" <> pt <> "/" <> n) $
                                             BL.fromStrict . encodeUtf8 . pp <$> input
                                     )
-                                        <> [testGroup "extra" extraTests]
+                                        <> [testGroup "extra" $ extraTests isRealData ("../outputs/" <> t <> "/" <> pt <> "/extra/") input]
diff --git a/haskell/Puzzle.hs b/haskell/Puzzle.hs
index 8f252bf..9e5f6a0 100644
--- a/haskell/Puzzle.hs
+++ b/haskell/Puzzle.hs
@@ -9,5 +9,5 @@ data Puzzle = forall input. Puzzle
     { number :: Word
     , parser :: Parsec Void Text input
     , parts :: [input -> Text]
-    , extraTests :: [TestTree]
+    , extraTests :: Bool -> FilePath -> IO input -> [TestTree]
     }
diff --git a/haskell/Puzzles/Day1.hs b/haskell/Puzzles/Day1.hs
index 74883bb..ec27111 100644
--- a/haskell/Puzzles/Day1.hs
+++ b/haskell/Puzzles/Day1.hs
@@ -37,7 +37,7 @@ puzzle =
                                 | p' == 0 -> abs c + 1
                                 | otherwise -> abs c
             ]
-        , extraTests = []
+        , extraTests = mempty
         }
 
 data Direction = L | R
diff --git a/haskell/Puzzles/Day2.hs b/haskell/Puzzles/Day2.hs
index dbda2e1..053aae5 100644
--- a/haskell/Puzzles/Day2.hs
+++ b/haskell/Puzzles/Day2.hs
@@ -25,7 +25,7 @@ puzzle =
                 . concatMap
                     (mapMaybe (\n -> guard (isRepetitionN n) $> n) . uncurry enumFromTo)
             ]
-        , extraTests = []
+        , extraTests = mempty
         }
 
 newtype ID = ID Int
diff --git a/haskell/Puzzles/Day3.hs b/haskell/Puzzles/Day3.hs
index a07967e..90f4bee 100644
--- a/haskell/Puzzles/Day3.hs
+++ b/haskell/Puzzles/Day3.hs
@@ -26,7 +26,7 @@ puzzle =
                 . sum
                 . map (digitsToInt . fromMaybe (error "battery list too short") . maxBatteries 12)
             ]
-        , extraTests = []
+        , extraTests = mempty
         }
 
 newtype Bank = Bank (NonEmpty Battery)
diff --git a/haskell/Puzzles/Day4.hs b/haskell/Puzzles/Day4.hs
index 7685159..87900b4 100644
--- a/haskell/Puzzles/Day4.hs
+++ b/haskell/Puzzles/Day4.hs
@@ -27,7 +27,7 @@ puzzle =
                 . unfoldr ((\r -> guard (fst r /= 0) $> r) . (removeAccessibleRolls <<<<$>>>>) . findAccessible)
                 . addCoords
             ]
-        , extraTests = []
+        , extraTests = mempty
         }
 
 addCoords :: (Num a, Enum a) => [[c]] -> [[(V2 a, c)]]