[test] fix running tests when corenlp is already running

We had 'race' previously and so the tests quit immediately, because
corenlp nix couldn't start.

Now I use 'waitBoth' so that even if corenlp fails to start (because
it's already running on dev machine), the tests will continue.

test/Main.hs

@@ -70,7 +70,9 @@ startCoreNLPServer = do
   pure (stdout_hdl, stderr_hdl, hdl)
 
 killProcessTree :: (Handle, Handle, ProcessHandle) -> IO ()
-killProcessTree (_, _, ph) = do
+killProcessTree (_, stderr_hdl, ph) = do
+  errContent <- hGetContents stderr_hdl
+  unless (errContent == "") $ putText $ "CoreNLP ERROR:\n" <> T.pack errContent
   pid <- getPid ph
   case pid of
     Nothing -> putText "Process already terminated"
@@ -105,7 +107,11 @@ waitOrDie (stdout_h, stderr_h, h) = do
 main :: IO ()
 main = do
   hSetBuffering stdout NoBuffering
-  bracket startCoreNLPServer killProcessTree (\h -> race (waitOrDie h) run_tests *> pure())
+  bracket startCoreNLPServer killProcessTree $ \h -> do
+    corenlpP <- async $ waitOrDie h
+    testP <- async run_tests
+    -- race (waitOrDie h) run_tests *> pure()
+    void $ waitBoth corenlpP testP
   where
     run_tests = hspec $ sequential $ do
       API.tests