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)
    topNode ! Contains(testActor, id = 3, 1)
    topNode ! Remove(testActor, id = 4, 1)
    topNode ! Contains(testActor, id = 5, 1)

    expectMsg(OperationFinished(2))
    expectMsg(ContainsResult(3, true))
    expectMsg(OperationFinished(id=4))
    expectMsg(ContainsResult(5, false))
  }