-- {-# LANGUAGE GHC2021 #-}

module HCatSpec (spec) where

import HCat.Internal (chunksOf, parseArgs)

import Test.Hspec
import Test.Hspec.QuickCheck (prop)
import Test.QuickCheck (Positive (getPositive))

spec :: Spec
spec = do
  describe "parseArgs" do
    it "returns the filename if given a single argument" do
      parseArgs ["foo"] `shouldBe` Right "foo"
      parseArgs [] `shouldBe` Left "No filename given!"
      parseArgs ["foo", "bar"] `shouldBe` Left "Only a single file is supported"
  describe "chunksOf" $ do
    prop "each chunk contains at most N items" $ \n xs ->
      let chunkLengths = length <$> chunksOf n (xs :: [Int])
       in case chunkLengths of
            [] -> pure ()
            ns -> maximum ns `shouldSatisfy` (<= n)

    prop "the sum of all lengths is equal to the length of the input" $ \n xs ->
      let chunkLengths = length <$> chunksOf (getPositive n) (xs :: [Int])
       in sum chunkLengths `shouldBe` length xs