1 files changed, 96 insertions, 0 deletions
diff --git a/testsuite/tests/lib/Concurrent/QSemN001.hs b/testsuite/tests/lib/Concurrent/QSemN001.hs
new file mode 100644
index 0000000000..c31d6a6964
--- /dev/null
+++ b/testsuite/tests/lib/Concurrent/QSemN001.hs
@@ -0,0 +1,96 @@
+import Debug.QuickCheck
+import System.IO.Unsafe
+import Control.Concurrent.QSemN
+import Control.Concurrent
+import Control.Monad
+
+
+main = do 
+  t <- myThreadId
+  forkIO (threadDelay 1000000 >> killThread t)
+	-- just in case we deadlock
+  testQSemN
+
+data Action = NewQSemN Int | SignalQSemN Int | WaitQSemN Int
+  deriving (Eq,Show)
+
+
+testQSemN :: IO ()
+testQSemN = do
+  quietCheck prop_SignalWait
+  quietCheck prop_WaitSignal
+
+quietCheck = check defaultConfig{configEvery = \n args -> ""}
+
+
+prop_SignalWait l m n = l+m>=n ==> 
+  [NewQSemN l,SignalQSemN m,WaitQSemN n] =^ [NewQSemN (l+m-n)]
+
+prop_WaitSignal l m n = l>=m ==> 
+  [NewQSemN l,WaitQSemN m,SignalQSemN n] =^ [NewQSemN (l-m+n)]
+
+
+perform :: [Action] -> IO [Int]
+perform [] = return []
+
+perform (a:as) =
+  case a of
+    NewQSemN n   -> newQSemN n >>= \qs -> perform' qs as
+    _		 -> error $ "Please use NewQSemN as first action" ++ show a
+
+
+perform' :: QSemN -> [Action] -> IO [Int]
+perform' _ [] = return []
+
+perform' qs (a:as) =
+  case a of
+    SignalQSemN n    -> signalQSemN qs n >> perform' qs as
+    WaitQSemN n      -> waitQSemN qs n >> perform' qs as
+    _		     -> error $ "If you want to use " ++ show a 
+			        ++ " please use the =^ operator"
+   
+
+actions :: Gen [Action]
+actions = do
+  i <- arbitrary
+  liftM (NewQSemN i:) (actions' i) 
+
+
+actions' :: Int -> Gen [Action]
+actions' quantity =
+  oneof ([return [],
+	  do i<- choose (0,maxBound)
+	     liftM (SignalQSemN i:) (actions' (quantity+i))] ++
+	  if quantity<=0
+	     then []
+	     else [do i<- choose (0,quantity)
+		      liftM (WaitQSemN i:) (actions' (quantity-i))])  
+
+
+(=^) :: [Action] -> [Action] -> Property
+c =^ c' =
+  forAll (actions' (delta 0 c))
+	 (\suff -> observe c suff == observe c' suff)
+  where observe x suff = unsafePerformIO (perform (x++suff))
+
+
+(^=^) :: [Action] -> [Action] -> Property
+c ^=^ c' =
+  forAll actions
+	 (\pref -> forAll (actions' (delta 0 (pref++c)))
+			  (\suff -> observe c pref suff == 
+				      observe c' pref suff))
+  where observe x pref suff = unsafePerformIO (perform (pref++x++suff))
+
+
+delta :: Int -> [Action] -> Int
+delta i [] = i
+
+delta _ (NewQSemN i:as) = delta i as
+
+delta i (SignalQSemN n:as) = delta (i+n) as
+
+delta i (WaitQSemN n:as) = delta (if i<n
+				  then error "wait on 'empty' QSemN"
+				  else i-n) as
+