diff --git a/System/FileLock.hs b/System/FileLock.hs
--- a/System/FileLock.hs
+++ b/System/FileLock.hs
@@ -27,6 +27,7 @@
   , tryLockFile
   , unlockFile
   , withFileLock
+  , withTryFileLock
   ) where
 
 import Control.Applicative
@@ -35,6 +36,7 @@
 import Data.IORef
 import Data.Traversable (traverse)
 import Data.Typeable
+import Prelude
 
 #ifdef USE_FLOCK
 import qualified System.FileLock.Internal.Flock as I
@@ -77,6 +79,10 @@
   wasAlive <- atomicModifyIORef ref $ \old -> (False, old)
   when wasAlive $ I.unlock l
 
--- | Perform some action with a lock held.
+-- | Perform some action with a lock held. Blocks until the lock is available.
 withFileLock :: FilePath -> SharedExclusive -> (FileLock -> IO a) -> IO a
 withFileLock path mode = E.bracket (lockFile path mode) unlockFile
+
+-- | Perform sme action with a lock held. Non-blocking.
+withTryFileLock :: FilePath -> SharedExclusive -> (FileLock -> IO a) -> IO (Maybe a)
+withTryFileLock path mode f = E.bracket (tryLockFile path mode) (traverse unlockFile) (traverse f)
diff --git a/System/FileLock/Internal/Flock.hsc b/System/FileLock/Internal/Flock.hsc
--- a/System/FileLock/Internal/Flock.hsc
+++ b/System/FileLock/Internal/Flock.hsc
@@ -14,6 +14,7 @@
 import System.Posix.Files
 import System.Posix.IO (openFd, closeFd, defaultFileFlags, OpenMode(..))
 import System.Posix.Types
+import Prelude
 
 type Lock = Fd
 
diff --git a/filelock.cabal b/filelock.cabal
--- a/filelock.cabal
+++ b/filelock.cabal
@@ -2,7 +2,7 @@
 -- documentation, see http://haskell.org/cabal/users-guide/
 
 name:                filelock
-version:             0.1.0.1
+version:             0.1.1.1
 synopsis:            Portable interface to file locking (flock / LockFileEx)
 description:         This package provides an interface to Windows and Unix
                      file locking functionalities.
@@ -33,3 +33,11 @@
   else
     cpp-options:      -DUSE_FLOCK
     build-depends:    unix
+
+test-suite test
+  type:               exitcode-stdio-1.0
+  hs-source-dirs:     tests
+  main-is:            test.hs
+  build-depends:      filelock, process, async, base
+  ghc-options:        -threaded
+  default-language:   Haskell2010
diff --git a/tests/test.hs b/tests/test.hs
new file mode 100644
--- /dev/null
+++ b/tests/test.hs
@@ -0,0 +1,87 @@
+{-# LANGUAGE ViewPatterns #-}
+
+import Control.Monad
+import Control.Concurrent
+import Control.Concurrent.Async
+import System.Environment
+import System.Exit
+import System.Process
+import System.IO
+
+import System.FileLock
+
+main :: IO ()
+main = do
+  hSetBuffering stdout LineBuffering
+  args <- getArgs
+  case args of
+    ["shared", read -> duration]
+      -> holdLock "shared" Shared duration
+    ["exclusive", read -> duration]
+      -> holdLock "exclusive" Exclusive duration
+    ["try"]
+      -> tryTakingLock
+    ["tryshared", read -> duration]
+      -> tryHoldLock "shared" Shared duration
+    ["tryexclusive", read -> duration]
+      -> tryHoldLock "exclusive" Exclusive duration
+    _ -> do
+      withFile "lock.log" WriteMode $ \h ->
+        void $ mapConcurrently id
+          [ callSelf h ["shared", "300"]
+          , callSelf h ["shared", "200"]
+          , msleep 10 >> callSelf h ["exclusive", "500"]
+          , msleep 20 >> callSelf h ["try"]
+          , msleep 50 >> callSelf h ["shared", "500"]
+          , msleep 700 >> callSelf h ["shared", "10"]
+          , msleep 1500 >> callSelf h ["try"]
+          ]
+      msleep 2000
+      log <- readFile "lock.log"
+      expected <- readFile "tests/lock.log.expected"
+      when (log /= expected) $ do
+        putStrLn "log mismatch!"
+        exitFailure
+
+callSelf :: Handle -> [String] -> IO ()
+callSelf out args = do
+  self <- getExecutablePath
+  (_hin, _hout, _herr, ph) <- createProcess_ "callSelf"
+    (proc self args) { std_out = UseHandle out }
+  ExitSuccess <- waitForProcess ph
+  return ()
+
+msleep :: Int -> IO ()
+msleep = threadDelay . (*1000)
+
+holdLock :: String -> SharedExclusive -> Int -> IO ()
+holdLock ty sex duration = do
+  withFileLock lockfile sex $ \_ -> do
+    putStrLn $ "took " ++ desc
+    msleep duration
+  putStrLn $ "released " ++ desc
+  where
+    desc = ty ++ " lock"
+
+tryTakingLock :: IO ()
+tryTakingLock = do
+  ml <- tryLockFile lockfile Exclusive
+  case ml of
+    Nothing -> putStrLn "lock not available"
+    Just l -> do
+      putStrLn "lock was available"
+      unlockFile l
+
+tryHoldLock :: String -> SharedExclusive -> Int -> IO ()
+tryHoldLock ty sex duration = do
+  res <- withTryFileLock lockfile sex $ \_ -> do
+    putStrLn $ "took " ++ desc
+    msleep duration
+  case res of
+    Nothing -> putStrLn "lock not available"
+    Just _  -> putStrLn $ "released " ++ desc
+  where
+    desc = ty ++ " lock"
+
+lockfile :: String
+lockfile = "lock"