Show cumulative times for tests with dependents

haskell/Pre.hs

@@ -107,6 +107,7 @@ import Control.Monad.Writer
 import Data.Bifunctor
 import Data.Bool
 import Data.Char
+import Data.Either.Extra
 import Data.Finite
 import Data.Fixed (Fixed (MkFixed))
 import Data.Foldable hiding (foldl1, foldr1, maximum, maximumBy, minimum, minimumBy)
@@ -433,8 +434,10 @@ runTests opts r0 (TestTree name tc ts) =
                     pure $ Left e
                 Right (Left e) ->
                     pure $ Left $ ExceptionFailure e
-                Right (Right (r, dt)) ->
-                    Right . (dt,) <$> for ts (runTests opts r)
+                Right (Right (r, dt)) -> do
+                    rs <- for ts $ runTests opts r
+                    let childTimes = fromMaybe 0 $ eitherToMaybe $ fmap (sum . map fst) $ traverse (.result) rs
+                    pure $ Right (dt + childTimes, rs)
   where
     runTest = \case
         TestCase f -> timed (liftIO . evaluate . DeepSeq.force) $ f r0