Some more BehaviorIntercept tests

* filter messages
* show how it can be used to implement PoisonPill

akka-actor-typed-tests/src/test/scala/akka/actor/typed/InterceptSpec.scala

@@ -7,20 +7,25 @@ package akka.actor.typed
 import java.util.concurrent.atomic.AtomicBoolean
 
 import akka.testkit.EventFilter
-import akka.actor.testkit.typed.scaladsl.{ ActorTestKit, TestProbe }
+import akka.actor.testkit.typed.scaladsl.TestProbe
 import akka.actor.typed.scaladsl.Behaviors
 import org.scalatest.WordSpecLike
 import scala.concurrent.duration._
 
 import akka.actor.ActorInitializationException
 import akka.actor.testkit.typed.scaladsl.ScalaTestWithActorTestKit
-import com.typesafe.config.ConfigFactory
+
+object InterceptSpec {
+  final case class Msg(hello: String, replyTo: ActorRef[String])
+  case object MyPoisonPill
+}
 
 class InterceptSpec extends ScalaTestWithActorTestKit(
   """
       akka.loggers = [akka.testkit.TestEventListener]
     """) with WordSpecLike {
   import BehaviorInterceptor._
+  import InterceptSpec._
 
   // FIXME eventfilter support in typed testkit
   import scaladsl.adapter._
@@ -268,4 +273,40 @@ class InterceptSpec extends ScalaTestWithActorTestKit(
 
   }
 
+  "be useful for implementing PoisonPill" in {
+
+    def inner(count: Int): Behavior[Msg] = Behaviors.receiveMessage {
+      case Msg(hello, replyTo) ⇒
+        replyTo ! s"$hello-$count"
+        inner(count + 1)
+    }
+
+    val poisonInterceptor = new BehaviorInterceptor[Any, Msg] {
+      override def aroundReceive(ctx: ActorContext[Any], msg: Any, target: ReceiveTarget[Msg]): Behavior[Msg] =
+        msg match {
+          case MyPoisonPill ⇒ Behaviors.stopped
+          case m: Msg       ⇒ target(ctx, m)
+          case _            ⇒ Behaviors.unhandled
+        }
+
+      override def aroundSignal(ctx: ActorContext[Any], signal: Signal, target: SignalTarget[Msg]): Behavior[Msg] =
+        target.apply(ctx, signal)
+
+    }
+
+    val decorated: Behavior[Msg] =
+      Behaviors.intercept(poisonInterceptor)(inner(0)).narrow
+
+    val ref = spawn(decorated)
+    val probe = TestProbe[String]()
+    ref ! Msg("hello", probe.ref)
+    probe.expectMessage("hello-0")
+    ref ! Msg("hello", probe.ref)
+    probe.expectMessage("hello-1")
+
+    ref.upcast[Any] ! MyPoisonPill
+
+    probe.expectTerminated(ref, probe.remainingOrDefault)
+  }
+
 }

akka-actor-typed-tests/src/test/scala/akka/actor/typed/WidenSpec.scala

@@ -13,23 +13,36 @@ import org.scalatest.WordSpecLike
 
 class WidenSpec extends ScalaTestWithActorTestKit with WordSpecLike {
 
+  def intToString(probe: ActorRef[String]): Behavior[Int] = {
+    Behaviors.receiveMessage[String] { msg ⇒
+      probe ! msg
+      Behaviors.same
+    }.widen[Int] {
+      case n if n != 13 ⇒ n.toString
+    }
+  }
+
   "Widen" should {
 
-    "transform messages from an outer type to an inner type" in {
+    "transform from an outer type to an inner type" in {
       val probe = TestProbe[String]()
-      val beh = Behaviors.receiveMessage[String] { msg ⇒
-        probe.ref ! msg
-        Behaviors.same
-      }.widen[Int] {
-        case n ⇒ n.toString
-      }
-      val ref = spawn(beh)
+      val ref = spawn(intToString(probe.ref))
 
       ref ! 42
-
       probe.expectMessage("42")
     }
 
+    "filter messages" in {
+      val probe = TestProbe[String]()
+      val ref = spawn(intToString(probe.ref))
+
+      ref ! 42
+      ref ! 13
+      ref ! 43
+      probe.expectMessage("42")
+      probe.expectMessage("43")
+    }
+
     "not build up when the same widen is used many times (initially)" in {
       val probe = TestProbe[String]()
       val transformCount = new AtomicInteger(0)