Invoke GHC to check that files compile in a cabal test suite

test.hs

module Main where

import           System.Exit
import           System.Process

main :: IO ()
main = do
    (c1, o1, e1) <- readProcessWithExitCode "ghc" ["-ilib", "-o", "/tmp/failure", "test/fail.hs"] ""
    (c2, o2, e2) <- readProcessWithExitCode "ghc" ["-ilib", "-o", "/tmp/passure", "test/pass.hs"] ""

    case (c1, c2) of
        (ExitFailure _, ExitSuccess  ) -> exitSuccess
        (ExitSuccess  , ExitSuccess  ) -> putStrLn "Fail did not fail" >> exitFailure
        (ExitSuccess  , ExitFailure _) -> putStrLn "Pass did not pass" >> putStrLn "Fail did not fail" >> exitFailure
        (ExitFailure _, ExitFailure _) -> putStrLn "Pass did not pass" >> exitFailure