getopt-generics-0.11: test/WithCliSpec.hs

module WithCliSpec where

import           System.Environment
import           System.Exit
import           System.IO
import           System.IO.Silently
import           Test.Hspec

import           WithCli

spec :: Spec
spec = do
  describe "withCli" $ do
    context "no arguments" $ do
      it "executes the operation in case of no command line arguments" $ do
        let main :: IO ()
            main = putStrLn "success"
        (capture_ $ withArgs [] $ withCli main)
          `shouldReturn` "success\n"

      it "produces nice error messages" $ do
        let main :: IO ()
            main = putStrLn "success"
        output <- hCapture_ [stderr] (withArgs ["foo"] (withCli main) `shouldThrow` (== ExitFailure 1))
        output `shouldBe` "unknown argument: foo\n"

    context "1 argument" $ do
      it "parses Ints" $ do
        let main :: Int -> IO ()
            main n = putStrLn ("success: " ++ show n)
        (capture_ $ withArgs ["12"] $ withCli main)
          `shouldReturn` "success: 12\n"

      it "error parsing" $ do
        let main :: Int -> IO ()
            main n = putStrLn ("error: " ++ show n)
        output <- hCapture_ [stderr] (withArgs (words "12 foo") (withCli main) `shouldThrow` (== ExitFailure 1))
        output `shouldBe` "unknown argument: foo\n"

      it "handle Maybes as positional arguments with a proper error message" $ do
        let main :: Maybe Int -> IO ()
            main = error "main"
        output <- hCapture_ [stderr] (withCli main `shouldThrow` (== ExitFailure 1))
        output `shouldBe` "cannot use Maybes for positional arguments\n"