BinaryTreeSuite.scala

  test("proper inserts and lookups and remove") {
    val topNode = system.actorOf(Props[BinaryTreeSet])

    topNode ! Contains(testActor, id = 1, 1)
    expectMsg(ContainsResult(1, false))

    topNode ! Insert(testActor, id = 2, 1)
    expectMsg(OperationFinished(2))
    
    topNode ! Remove(testActor, id = 4, 1)
    expectMsg(OperationFinished(4))    
    
    topNode ! Contains(testActor, id = 5, 1)
    expectMsg(ContainsResult(5, false))
  }