Testing Akka Actors

Question

I have the following actor definition:

class MyActor extends Actor {
    override def preStart(): Unit = {
        super.preStart()
        self ! M1("from M1")
    }

    def receive = initial("initial state")

    def initial(str: String): Receive = {
        case m1: M1 =>
            self ! M3("from M3")
            context.become(active(str))
        case m2: M2 => println(m2.str)

    }

    def active(str: String): Receive = {
        case m1: M1 => println(m1.str)
        case m3: M3 => println(m3.str)
        case str: String => println(s"string in active is ${str}")
    }
}

I was under the impression that I could just use sbt to test my actor and I went ahead and did the following in my sbt console:

val f = Await.result(myActor ? M1("hello world"), 10 seconds)

I was left with a Timeout Exception. How can I test this actor? I mean, I just want to see what gets printed out to the console!