content: {-# OPTIONS_GHC -fno-warn-type-defaults #-}
  {-# LANGUAGE RecordWildCards #-}
  
  import Data.Foldable     (for_)
  import Test.Hspec        (Spec, describe, it, shouldBe)
  import Test.Hspec.Runner (configFastFail, defaultConfig, hspecWith)
  
  import Prime (nth)
  
  main :: IO ()
  main = hspecWith defaultConfig {configFastFail = True} specs
  
  specs :: Spec
  specs = describe "nth" $ for_ cases test
    where
  
      test Case{..} = it description assertion
        where
          assertion = nth (fromIntegral input) `shouldBe` expected
  
  data Case = Case { description :: String
                   , input       :: Integer
                   , expected    :: Maybe Integer
                   }
  
  cases :: [Case]
  cases = [ Case { description = "first prime"
                 , input       = 1
                 , expected    = Just 2
                 }
          , Case { description = "second prime"
                 , input       = 2
                 , expected    = Just 3
                 }
          , Case { description = "sixth prime"
                 , input       = 6
                 , expected    = Just 13
                 }
          , Case { description = "big prime"
                 , input       = 10001
                 , expected    = Just 104743
                 }
          , Case { description = "there is no zeroth prime"
                 , input       = 0
                 , expected    = Nothing
                 }
          ]
  