test reproducer for exec/bash tempfile

bar.sh

#!/bin/sh
sleep 1
set -e
cat $1

foo.sh

#!/bin/sh
exec /tmp/bar.sh "$@"

test.hs

{-# LANGUAGE OverloadedStrings #-}                                                                                                                                                                                                                                               
import System.IO.Temp (withSystemTempFile, emptySystemTempFile)                                                                                                                                                                                                                  
import System.IO (hClose)                                                                                                                                                                                                                                                        
import System.Directory (removeFile)                                                                                                                                                                                                                                             
import System.Process.Typed (readProcessInterleaved_, proc)                                                                                                                                                                                                                      
import Control.Monad (void)                                                                                                                                                                                                                                                      
import qualified Data.ByteString as B                                                                                                                                                                                                                                            
                                                                                                                                                                                                                                                                                 
main :: IO ()                                                                                                                                                                                                                                                                    
main = usingWSTF                                                                                                                                                                                                                                                                 
                                                                                                                                                                                                                                                                                 
normal :: IO ()                                                                                                                                                                                                                                                                  
normal = do                                                                                                                                                                                                                                                                      
    fn <- emptySystemTempFile "tmptest"                                                                                                                                                                                                                                          
    B.writeFile fn "<h1>Foo</h1>"                                                                                                                                                                                                                                                
    print ("wrote " <> fn)                                                                                                                                                                                                                                                       
    out <- readProcessInterleaved_ (proc "/tmp/foo.sh" [fn])                                                                                                                                                                                                                     
    print out                                                                                                                                                                                                                                                                    
    removeFile fn                                                                                                                                                                                                                                                                
                                                                                                                                                                                                                                                                                 
usingWSTF :: IO ()                                                                                                                                                                                                                                                               
usingWSTF = void $ withSystemTempFile "tmptest" $ \fn h -> do                                                                                                                                                                                                                    
        B.hPut h "<h1>Foo</h1>"                                                                                                                                                                                                                                                  
        hClose h                                                                                                                                                                                                                                                                 
        print ("wrote " <> fn)                                                                                                                                                                                                                                                   
        out <- readProcessInterleaved_ (proc "/tmp/foo.sh" [fn])                                                                                                                                                                                                                 
        print out