{-# LANGUAGE ScopedTypeVariables #-}

module DiscoverTest where

import Data.List
import Test.Tasty
import Test.Tasty.Hspec
import Test.Tasty.HUnit
import Test.Tasty.QuickCheck

import qualified Hedgehog       as H
import qualified Hedgehog.Gen   as G
import qualified Hedgehog.Range as R

unit_listCompare :: IO ()
unit_listCompare = [1 :: Int, 2, 3] `compare` [1,2] @?= GT

prop_additionCommutative :: Int -> Int -> Bool
prop_additionCommutative a b = a + b == b + a

scprop_sortReverse :: [Int] -> Bool
scprop_sortReverse list = sort list == sort (reverse list)

spec_prelude :: Spec
spec_prelude = describe "Prelude.head" $ do
  it "returns the first element of a list" $ do
    head [23 ..] `shouldBe` (23 :: Int)

test_addition :: TestTree
test_addition = testProperty "Addition commutes" $ \(a :: Int) (b :: Int) -> a + b == b + a

test_multiplication :: [TestTree]
test_multiplication =
  [ testProperty "Multiplication commutes" $ \(a :: Int) (b :: Int) -> a * b == b * a
  , testProperty "One is identity" $ \(a :: Int) -> a == a
  ]

test_generateTree :: IO TestTree
test_generateTree = do
  let input = "Some input"
  pure $ testCase input $ pure ()

test_generateTrees :: IO [TestTree]
test_generateTrees = pure (map (\s -> testCase s $ pure ()) ["First input", "Second input"])

{-# ANN hprop_reverse "HLint: ignore Avoid reverse" #-}
hprop_reverse :: H.Property
hprop_reverse = H.property $ do
  xs <- H.forAll $ G.list (R.linear 0 100) G.alpha
  reverse (reverse xs) H.=== xs