running a cabal test

Main.hs

module Main(main, a) where

a = "foo"

main = putStrLn a

MainSpec.hs

module MainSpec where

import Main (a)

main :: IO ()
main = putStrLn a

Thing.cabal

name:                Thing
version:             0.1.0.0
license:             BSD3
license-file:        LICENSE
author:              Leif Warner
maintainer:          [email protected]
build-type:          Simple
extra-source-files:  ChangeLog.md
cabal-version:       >=1.10

executable Thing
  main-is:             Main.hs
  build-depends:       base >=4.11 && <4.12
  default-language:    Haskell2010


test-suite spec
  type: exitcode-stdio-1.0
  main-is: MainSpec.hs
  build-depends:       base >=4.11 && <4.12
  default-language:    Haskell2010