QuickCheck.scala

  property("sorted delete") = forAll { (h: H) =>
    def getSeq(l: List[A], heap: H): List[A] = isEmpty(heap) match {
      case true => l.reverse
      case false => getSeq(findMin(heap) :: l, deleteMin(heap))
    }
    val deleted = getSeq(List(), h)
    deleted == deleted.sorted
  }