How to unit test Akka Agents? - scala

Question

I'm trying to write a scala class which periodically retrieves data from an external location. I don't care when the data is retrieved, just that it happens every hour. Akka agents are a perfect solution for this but I have no idea how to test them. Here's an example to illustrate my problem:
import akka.actor.ActorSystem
import akka.agent.Agent
import scala.concurrent.duration._
abstract class Fetcher(implicit actorSystem: ActorSystem) {
import actorSystem.dispatcher
private val data: Agent[String] = Agent("")
def current: String = data.get()
protected def retrieveData(): String
actorSystem.scheduler.schedule(0.seconds, 1.hour) {
data send retrieveData()
}
}
import akka.actor.ActorSystem
import bbc.scala.whitelist.dynamic.Fetcher
import org.specs2._
class FetcherSpec extends mutable.Specification {
implicit val actorSystem = ActorSystem("TestActorSystem")
class TestFetcher extends Fetcher {
override protected def retrieveData(): String = "data!"
}
"The Fetcher" should {
"contain the empty string initially" in {
val fetcher = new TestFetcher
fetcher.current must be equalTo ""
}
"contain data after the first scheduled update" in {
val fetcher = new TestFetcher
Thread.sleep(100)
fetcher.current must be equalTo "data!"
}
}
}
That second unit test currently passes but I do not like the Thread.sleep at all! How can I force the scheduled task to happen before making my assertion? Any help would be much appreciated. Thank you very much.