QuickCheck Scala Reactive programming class submission.

QuickCheck.scala

package quickcheck

import common._

import org.scalacheck._
import Arbitrary._
import Gen._
import Prop._
import Math._

abstract class QuickCheckHeap extends Properties("Heap") with IntHeap {
  lazy val genHeap: Gen[H] = for {
    n <- arbitrary[A]
    h <- frequency((1, value(empty)), (9, genHeap))
  }
  yield insert(n, h)

  property("h1") = forAll {
    (a: A, b: A) => findMin(insert(a, insert(b, empty))) == min(a, b)
  }

  property("h2") = forAll { 
    (a: A) => isEmpty(deleteMin(insert(a, empty)))
  }

  property("h3") = forAll { 
    (h: H) =>
    def isSorted(h: H): Boolean =
      if (isEmpty(h)) true
    else {
      val h2 = deleteMin(h)
      isEmpty(h2) || (findMin(h) <= findMin(h2) && isSorted(h2))
    }
    isSorted(h)
  }

  property("h4") = forAll { 
    (h1: H, h2: H) => findMin(meld(h1, h2)) == min(findMin(h1), findMin(h2))
  }

  property("meld") = forAll { 
    (h1: H, h2: H) =>
    def heapEqual(h1: H, h2: H): Boolean = 
      if (isEmpty(h1) && isEmpty(h2)) true
    else findMin(h1) == findMin(h2) && heapEqual(deleteMin(h1), deleteMin(h2))
    heapEqual(meld(h1, h2), meld(deleteMin(h1), insert(findMin(h1), h2)))
  }

  implicit lazy val arbHeap: Arbitrary[H] = Arbitrary(genHeap)
}