hspec test isolation

test_isolation_demonstration.hs

#!/usr/bin/env stack
-- stack --resolver lts-8.0 --install-ghc runghc --package hspec -- -Wall -Werror

import Test.Hspec
import Data.IORef

-- * test should be isolated from other tests - Pass (expected: Pass) ✔

main :: IO ()
main = hspec $ do
  describe "asdf" $ beforeWith (\() -> newIORef False) $ do
    describe "inner" $ beforeWith (\ctx -> writeIORef ctx True >> return ctx) $ do
      it "ctx should be true" $ \ctx -> do
        readIORef ctx >>= shouldBe True
    it "(setting ctx to False)" $ \ctx -> do
      writeIORef ctx False