Non-failing test with DejaFu

.gitignore

dist-newstyle/

README.md

A test which I expect to fail (as witnessed by running it in IO) not failing when checked by DejaFu.

dejafu-test.cabal

cabal-version: 3.0
name:          dejafu-test
version:       0.0.0.0
license:       MIT
license-file:  LICENSE
author:        Nicolas Trangez
maintainer:    ikke@nicolast.be
category:      Testing
build-type:    Simple

common warnings
  ghc-options: -Wall

test-suite dejafu-test-test
  import:           warnings
  default-language: Haskell2010
  type:             exitcode-stdio-1.0
  main-is:          Main.hs
  build-depends:
    , base          ^>=4.17.0.0
    , concurrency   ^>=1.11.0.2
    , tasty         ^>=1.4.3
    , tasty-dejafu  ^>=2.1.0.0
    , tasty-hunit   ^>=0.10.0.3

  ghc-options:      -threaded -rtsopts -with-rtsopts=-N2

LICENSE

Copyright (c) 2023 Nicolas Trangez

Permission is hereby granted, free of charge, to any person obtaining
a copy of this software and associated documentation files (the
"Software"), to deal in the Software without restriction, including
without limitation the rights to use, copy, modify, merge, publish,
distribute, sublicense, and/or sell copies of the Software, and to
permit persons to whom the Software is furnished to do so, subject to
the following conditions:

The above copyright notice and this permission notice shall be included
in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

Main.hs

{-# LANGUAGE NoMonomorphismRestriction #-}

module Main (main) where

import Control.Concurrent.Classy.Async (wait, withAsync)
import Control.Concurrent.Classy.MVar (newEmptyMVar, putMVar, readMVar)
import Control.Concurrent.Classy.STM (readTVarConc, writeTVar)
import Control.Monad (forM_)
import Control.Monad.Conc.Class (MonadConc, atomically, newTVarConc)
import Test.Tasty (defaultMain, testGroup)
import Test.Tasty.DejaFu (testAuto)
import Test.Tasty.HUnit (testCase, (@?=))

main :: IO ()
main =
  defaultMain $
    testGroup
      "dejafu-test"
      [ let act = runComputation (pure ()) pure pure
         in testGroup
              "Without MVar"
              [ testCase "IO" $ forM_ [0 :: Int .. 1000] $ \_ -> do
                  v1 <- act
                  v2 <- act

                  v1 @?= v2,
                testAuto "DejaFu" act
              ],
        let act = runComputation newEmptyMVar (`putMVar` ()) readMVar
         in testGroup
              "With MVar"
              [ testCase "IO" $ forM_ [0 :: Int .. 1000] $ \_ -> do
                  v1 <- act
                  v2 <- act
                  v1 @?= v2,
                testAuto "DejaFu" act
              ]
      ]

runComputation :: (MonadConc m) => m a -> (a -> m ()) -> (a -> m ()) -> m Int
runComputation mkLock unLock waitLock = do
  v <- newTVarConc 0

  l <- mkLock

  let act n = do
        waitLock l
        atomically $ writeTVar v n

  withAsync (act 1) $ \a ->
    withAsync (act 2) $ \b -> do
      unLock l
      wait a
      wait b
      readTVarConc v