diff --git a/test/SplitSpec.hs b/test/SplitSpec.hs
index 8482cb5f8..5cba2a075 100644
--- a/test/SplitSpec.hs
+++ b/test/SplitSpec.hs
@@ -46,6 +46,10 @@ spec = do
           \ source -> splitAnnotatedByLines (source, source) (totalRange source, totalRange source) (mempty, mempty) (Indexed [] :: Syntax String (Diff String Info)) `shouldBe` [
             Row (Line [ Free $ Annotated (Info (totalRange source) mempty) $ Indexed [] ]) (Line [ Free $ Annotated (Info (totalRange source) mempty) $ Indexed [] ]) ]
 
+    prop "preserves line counts in equal sources" $
+      \ source -> let range = totalRange source in
+        length (splitAnnotatedByLines (source, source) (totalRange source, totalRange source) (mempty, mempty) (Indexed . fst $ foldl combineIntoLeaves ([], 0) source)) `shouldBe` length (filter (== '\n') source) + 1
+
   describe "annotatedToRows" $ do
     it "outputs one row for single-line empty unchanged indexed nodes" $
       annotatedToRows (unchanged "[]" "branch" (Indexed [])) "[]" "[]" `shouldBe` [ Row (Line [ Ul (Just "category-branch") [ Text "[]" ] ]) (Line [ Ul (Just "category-branch") [ Text "[]" ] ]) ]
@@ -213,3 +217,5 @@ spec = do
       isClosed (Row _ _) = False
 
       isOnSingleLine (a, _, _) = filter (/= '\n') a == a
+
+      combineIntoLeaves (leaves, start) char = (leaves ++ [ Free $ Annotated (Info (Range start $ start + 1) mempty, Info (Range start $ start + 1) mempty) (Leaf [ char ]) ], start + 1)