cabal sandbox example

install-test.cabal

name:                install-test
version:             0.1
license:             AllRightsReserved
build-type:          Simple
cabal-version:       >=1.8

executable install-test
  hs-source-dirs:    .
  main-is:           Test.hs
  build-depends:     base >= 4.5 && < 5
                   , text

Test.hs

import qualified Data.Text as T

main :: IO ()
main = putStrLn (T.unpack . T.pack $ "hello")