GenValiditySpec.hs

module Data.GenValiditySpec (spec) where

import           Test.Hspec
import           Test.QuickCheck

import           Data.GenValidity

spec :: Spec
spec = do
    describe "upTo" $ do
        it "returns only positive integers" $ do
            forAll arbitrary $ \n ->
                forAll (upTo n) (`shouldSatisfy` (>= 0))

    describe "genSplit" $ do
        it "returns positive integers" $ do
            forAll arbitrary $ \i ->
                forAll (genSplit i) $ \(a, b) -> do
                    a `shouldSatisfy` (>= 0)
                    b `shouldSatisfy` (>= 0)

        it "returns two integers such that the sum is the original integer" $ do
            forAll (arbitrary `suchThat` (>= 0)) $ \i ->
                forAll (genSplit i) $ \(a, b) ->
                    a + b `shouldBe` i

    describe "arbPartition" $ do
        it "returns an empty list upon strictly negative input" $ do
            forAll (arbitrary `suchThat` (< 0)) $ \n ->
                forAll (arbPartition n) (`shouldBe` [])

        it "returns a list of strictly positive integers" $ do
            forAll arbitrary $ \n ->
                forAll (arbPartition n) $ \p ->
                    p `shouldSatisfy` all (> 0)

        it "returns a list of integers that sum to the original positive integer" $ do
            forAll (arbitrary `suchThat` (>= 0)) $ \n ->
                forAll (arbPartition n) $ \p ->
                    sum p `shouldBe` n