Avoid timing sensitivity in test

Author: alanz

src/Haskell/Ide/Engine/Transport/JsonStdio.hs

@@ -37,8 +37,8 @@ jsonStdioTransport cin = do
   P.runEffect (parseFrames PB.stdin P.>-> parseToJsonPipe cin cout 1 P.>-> jsonConsumer)
 
 parseToJsonPipe
-  :: Chan ChannelRequest
-  -> Chan ChannelResponse
+  :: TChan ChannelRequest
+  -> TChan ChannelResponse
   -> Int
   -> P.Pipe (Either PAe.DecodingError WireRequest) A.Value IO ()
 parseToJsonPipe cin cout cid =
@@ -53,8 +53,8 @@ parseToJsonPipe cin cout cid =
               T.pack $ "jsonStdioTransport:parse error:" ++ show decodeErr
             P.yield $ A.toJSON $ channelToWire rsp
        Right req ->
-         do liftIO $ writeChan cin (wireToChannel cout cid req)
-            rsp <- liftIO $ readChan cout
+         do liftIO $ atomically $ writeTChan cin (wireToChannel cout cid req)
+            rsp <- liftIO $ atomically $ readTChan cout
             P.yield $ A.toJSON $ channelToWire rsp
      parseToJsonPipe cin
                      cout

test/DispatcherSpec.hs

@@ -232,16 +232,14 @@ dispatcherSpec = do
       r2 <- withStdoutLogging $ runIdeM (IdeState Map.empty) (doDispatch (testPlugins chSync) cr2)
       r1 `shouldBe` Nothing
       r2 `shouldBe` Nothing
-      yield
-      rc1 <- atomically $ tryReadTChan chan
-      yield
-      rc2 <- atomically $ tryReadTChan chan
-      rc1 `shouldBe` Just (CResp { couPlugin = "test"
-                                 , coutReqId = 2
-                                 , coutResp = IdeResponseOk (HM.fromList [("response",String "asyncCmd2 sent strobe")])})
-      rc2 `shouldBe` Just (CResp { couPlugin = "test"
-                                 , coutReqId = 1
-                                 , coutResp = IdeResponseOk (HM.fromList [("response",String "asyncCmd1 got strobe")])})
+      rc1 <- atomically $ readTChan chan
+      rc2 <- atomically $ readTChan chan
+      rc1 `shouldBe` (CResp { couPlugin = "test"
+                            , coutReqId = 2
+                            , coutResp = IdeResponseOk (HM.fromList [("response",String "asyncCmd2 sent strobe")])})
+      rc2 `shouldBe` (CResp { couPlugin = "test"
+                            , coutReqId = 1
+                            , coutResp = IdeResponseOk (HM.fromList [("response",String "asyncCmd1 got strobe")])})
 
 -- ---------------------------------------------------------------------