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import collection.immutable._
import org.scalacheck._
import Prop._
import Gen._
import Arbitrary._
import util._
import Buildable._
object Test extends Properties("TreeMap") {
implicit def arbTreeMap[A : Arbitrary : Ordering, B : Arbitrary]: Arbitrary[TreeMap[A, B]] =
Arbitrary(for {
keys <- listOf(arbitrary[A])
values <- listOfN(keys.size, arbitrary[B])
} yield TreeMap(keys zip values: _*))
property("foreach/iterator consistency") = forAll { (subject: TreeMap[Int, String]) =>
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 = TreeMap(values zip values: _*)
val it = subject.iterator
try { while (it.hasNext) it.next; true } catch { case _ => false }
}
property("sorted") = forAll { (subject: TreeMap[Int, String]) => (subject.size >= 3) ==> {
subject.zip(subject.tail).forall { case (x, y) => x._1 < y._1 }
}}
property("contains all") = forAll { (arr: List[(Int, String)]) =>
val subject = TreeMap(arr: _*)
arr.map(_._1).forall(subject.contains(_))
}
property("size") = forAll { (elements: List[(Int, Int)]) =>
val subject = TreeMap(elements: _*)
elements.map(_._1).distinct.size == subject.size
}
property("toSeq") = forAll { (elements: List[(Int, Int)]) =>
val subject = TreeMap(elements: _*)
elements.map(_._1).distinct.sorted == subject.toSeq.map(_._1)
}
property("head") = forAll { (elements: List[Int]) => elements.nonEmpty ==> {
val subject = TreeMap(elements zip elements: _*)
elements.min == subject.head._1
}}
property("last") = forAll { (elements: List[Int]) => elements.nonEmpty ==> {
val subject = TreeMap(elements zip elements: _*)
elements.max == subject.last._1
}}
property("head/tail identity") = forAll { (subject: TreeMap[Int, String]) => subject.nonEmpty ==> {
subject == (subject.tail + subject.head)
}}
property("init/last identity") = forAll { (subject: TreeMap[Int, String]) => subject.nonEmpty ==> {
subject == (subject.init + subject.last)
}}
property("take") = forAll { (subject: TreeMap[Int, String]) =>
val n = choose(0, subject.size).sample.get
n == subject.take(n).size && subject.take(n).forall(elt => subject.get(elt._1) == Some(elt._2))
}
property("drop") = forAll { (subject: TreeMap[Int, String]) =>
val n = choose(0, subject.size).sample.get
(subject.size - n) == subject.drop(n).size && subject.drop(n).forall(elt => subject.get(elt._1) == Some(elt._2))
}
property("take/drop identity") = forAll { (subject: TreeMap[Int, String]) =>
val n = choose(-1, subject.size + 1).sample.get
subject == subject.take(n) ++ subject.drop(n)
}
property("splitAt") = forAll { (subject: TreeMap[Int, String]) =>
val n = choose(-1, subject.size + 1).sample.get
val (prefix, suffix) = subject.splitAt(n)
prefix == subject.take(n) && suffix == subject.drop(n)
}
property("remove single") = forAll { (subject: TreeMap[Int, String]) => subject.nonEmpty ==> {
val key = oneOf(subject.keys.toSeq).sample.get
val removed = subject - key
subject.contains(key) && !removed.contains(key) && subject.size - 1 == removed.size
}}
property("remove all") = forAll { (subject: TreeMap[Int, String]) =>
val result = subject.foldLeft(subject)((acc, elt) => acc - elt._1)
result.isEmpty
}
}
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