Add regression test for putEnv wrt #68

Author: hasufell

tests/PutEnv001.hs

@@ -0,0 +1,32 @@
+{-# LANGUAGE OverloadedStrings #-}
+{-# OPTIONS_GHC -O0 -Wno-name-shadowing #-}
+
+module Main (main) where
+
+import Data.String ( fromString )
+import System.Mem
+import System.Posix.Env.ByteString
+import Test.Tasty
+import Test.Tasty.HUnit
+
+-- test regression of incorrect 'free': https://github.com/haskell/unix/issues/68#issue-170072591
+main :: IO ()
+main = do
+  putEnv "foo=bar"
+  defaultMain $ testGroup "All" [ test ]
+
+test :: TestTree
+test = testCase "putEnv" $ do
+  performMinorGC
+  env <- System.Posix.Env.ByteString.getEnv (fromString "foo")
+  performMinorGC
+  print env
+  env <- System.Posix.Env.ByteString.getEnv (fromString "foo")
+  performMinorGC
+  print env
+  env <- System.Posix.Env.ByteString.getEnv (fromString "foo")
+  performMinorGC
+  print env
+  env <- System.Posix.Env.ByteString.getEnv (fromString "foo")
+  print env
+  env @?= Just (fromString "bar")

unix.cabal

@@ -242,3 +242,11 @@ test-suite Terminal
     default-language: Haskell2010
     build-depends: base, unix, tasty-hunit
     ghc-options: -Wall
+
+test-suite PutEnv001
+    hs-source-dirs: tests
+    main-is: PutEnv001.hs
+    type: exitcode-stdio-1.0
+    default-language: Haskell2010
+    build-depends: base, unix, tasty, tasty-hunit
+    ghc-options: -Wall -with-rtsopts=-V0 -O0