import collection.immutable._ import org.scalacheck._ import Prop._ import Gen._ import Arbitrary._ import util._ object TreeSetTest extends Properties("TreeSet") { def genTreeSet[A: Arbitrary: Ordering]: Gen[TreeSet[A]] = for { elements <- listOf(arbitrary[A]) } yield TreeSet(elements: _*) implicit def arbTreeSet[A : Arbitrary : Ordering]: Arbitrary[TreeSet[A]] = Arbitrary(genTreeSet) property("foreach/iterator consistency") = forAll { (subject: TreeSet[Int]) => val it = subject.iterator var consistent = true subject.foreach { element => consistent &&= it.hasNext && element == it.next } consistent } property("worst-case tree height is iterable") = forAll(choose(0, 10), arbitrary[Boolean]) { (n: Int, even: Boolean) => /* * According to "Ralf Hinze. Constructing red-black trees" [http://www.cs.ox.ac.uk/ralf.hinze/publications/#P5] * you can construct a skinny tree of height 2n by inserting the elements [1 .. 2^(n+1) - 2] and a tree of height * 2n+1 by inserting the elements [1 .. 3 * 2^n - 2], both in reverse order. * * Since we allocate a fixed size buffer in the iterator (based on the tree size) we need to ensure * it is big enough for these worst-case trees. */ val highest = if (even) (1 << (n+1)) - 2 else 3*(1 << n) - 2 val values = (1 to highest).reverse val subject = TreeSet(values: _*) val it = subject.iterator try { while (it.hasNext) it.next; true } catch { case _: Throwable => false } } property("sorted") = forAll { (subject: TreeSet[Int]) => (subject.size >= 3) ==> { subject.zip(subject.tail).forall { case (x, y) => x < y } }} property("contains all") = forAll { (elements: List[Int]) => val subject = TreeSet(elements: _*) elements.forall(subject.contains) } property("size") = forAll { (elements: List[Int]) => val subject = TreeSet(elements: _*) elements.distinct.size == subject.size } property("toSeq") = forAll { (elements: List[Int]) => val subject = TreeSet(elements: _*) elements.distinct.sorted == subject.toSeq } property("head") = forAll { (elements: List[Int]) => elements.nonEmpty ==> { val subject = TreeSet(elements: _*) elements.min == subject.head }} property("last") = forAll { (elements: List[Int]) => elements.nonEmpty ==> { val subject = TreeSet(elements: _*) elements.max == subject.last }} property("head/tail identity") = forAll { (subject: TreeSet[Int]) => subject.nonEmpty ==> { subject == (subject.tail + subject.head) }} property("init/last identity") = forAll { (subject: TreeSet[Int]) => subject.nonEmpty ==> { subject == (subject.init + subject.last) }} property("take") = forAll { (subject: TreeSet[Int]) => val n = choose(0, subject.size).sample.get n == subject.take(n).size && subject.take(n).forall(subject.contains) } property("drop") = forAll { (subject: TreeSet[Int]) => val n = choose(0, subject.size).sample.get (subject.size - n) == subject.drop(n).size && subject.drop(n).forall(subject.contains) } property("take/drop identity") = forAll { (subject: TreeSet[Int]) => val n = choose(-1, subject.size + 1).sample.get subject == subject.take(n) ++ subject.drop(n) } property("splitAt") = forAll { (subject: TreeSet[Int]) => val n = choose(-1, subject.size + 1).sample.get val (prefix, suffix) = subject.splitAt(n) prefix == subject.take(n) && suffix == subject.drop(n) } def genSliceParms = for { tree <- genTreeSet[Int] from <- choose(0, tree.size) until <- choose(from, tree.size) } yield (tree, from, until) property("slice") = forAll(genSliceParms) { case (subject, from, until) => val slice = subject.slice(from, until) slice.size == until - from && subject.toSeq == subject.take(from).toSeq ++ slice ++ subject.drop(until) } property("takeWhile") = forAll { (subject: TreeSet[Int]) => val result = subject.takeWhile(_ < 0) result.forall(_ < 0) && result == subject.take(result.size) } property("dropWhile") = forAll { (subject: TreeSet[Int]) => val result = subject.dropWhile(_ < 0) result.forall(_ >= 0) && result == subject.takeRight(result.size) } property("span identity") = forAll { (subject: TreeSet[Int]) => val (prefix, suffix) = subject.span(_ < 0) prefix.forall(_ < 0) && suffix.forall(_ >= 0) && subject == prefix ++ suffix } property("from is inclusive") = forAll { (subject: TreeSet[Int]) => subject.nonEmpty ==> { val n = choose(0, subject.size - 1).sample.get val from = subject.drop(n).firstKey subject.from(from).firstKey == from && subject.from(from).forall(_ >= from) }} property("to is inclusive") = forAll { (subject: TreeSet[Int]) => subject.nonEmpty ==> { val n = choose(0, subject.size - 1).sample.get val to = subject.drop(n).firstKey subject.to(to).lastKey == to && subject.to(to).forall(_ <= to) }} property("until is exclusive") = forAll { (subject: TreeSet[Int]) => subject.size > 1 ==> { val n = choose(1, subject.size - 1).sample.get val until = subject.drop(n).firstKey subject.until(until).lastKey == subject.take(n).lastKey && subject.until(until).forall(_ <= until) }} property("remove single") = forAll { (subject: TreeSet[Int]) => subject.nonEmpty ==> { val element = oneOf(subject.toSeq).sample.get val removed = subject - element subject.contains(element) && !removed.contains(element) && subject.size - 1 == removed.size }} property("remove all") = forAll { (subject: TreeSet[Int]) => val result = subject.foldLeft(subject)((acc, elt) => acc - elt) result.isEmpty } property("ordering must not be null") = throws(classOf[NullPointerException])(TreeSet.empty[Int](null)) }