=doc #13043 Adding section on testing parent-child relationships

akka-docs/rst/scala/code/docs/testkit/ParentChildSpec.scala

@@ -0,0 +1,135 @@
+package docs.testkit
+
+import org.scalatest.WordSpec
+import org.scalatest.Matchers
+import akka.testkit.TestKitBase
+import akka.actor.ActorSystem
+import akka.actor.Props
+import akka.actor.Actor
+import akka.actor.ActorRef
+import akka.testkit.ImplicitSender
+import akka.testkit.TestProbe
+import akka.testkit.TestActorRef
+import akka.actor.ActorRefFactory
+
+/**
+ * Parent-Child examples
+ */
+
+//#test-example
+class Parent extends Actor {
+  val child = context.actorOf(Props[Child], "child")
+  var ponged = false
+
+  def receive = {
+    case "pingit" => child ! "ping"
+    case "pong"   => ponged = true
+  }
+}
+
+class Child extends Actor {
+  def receive = {
+    case "ping" => context.parent ! "pong"
+  }
+}
+//#test-example
+
+//#test-dependentchild
+class DependentChild(parent: ActorRef) extends Actor {
+  def receive = {
+    case "ping" => parent ! "pong"
+  }
+}
+//#test-dependentchild
+
+//#test-dependentparent
+class DependentParent(childProps: Props) extends Actor {
+  val child = context.actorOf(childProps, "child")
+  var ponged = false
+
+  def receive = {
+    case "pingit" => child ! "ping"
+    case "pong"   => ponged = true
+  }
+}
+
+class GenericDependentParent(childMaker: ActorRefFactory => ActorRef) extends Actor {
+  val child = childMaker(context)
+  var ponged = false
+
+  def receive = {
+    case "pingit" => child ! "ping"
+    case "pong"   => ponged = true
+  }
+}
+//#test-dependentparent
+
+/**
+ * Test specification
+ */
+
+class MockedChild extends Actor {
+  def receive = {
+    case "ping" => sender ! "pong"
+  }
+}
+
+class ParentChildSpec extends WordSpec with Matchers with TestKitBase {
+  implicit lazy val system = ActorSystem()
+
+  "A DependentChild" should {
+    "be tested without its parent" in {
+      val probe = TestProbe()
+      val child = system.actorOf(Props(classOf[DependentChild], probe.ref))
+      probe.send(child, "ping")
+      probe.expectMsg("pong")
+    }
+  }
+
+  "A DependentParent" should {
+    "be tested with custom props" in {
+      val probe = TestProbe()
+      val parent = TestActorRef(new DependentParent(Props[MockedChild]))
+      probe.send(parent, "pingit")
+      // test some parent state change
+      parent.underlyingActor.ponged should (be(true) or be(false))
+    }
+  }
+
+  "A GenericDependentParent" should {
+    "be tested with a child probe" in {
+      val probe = TestProbe()
+      //#child-maker-test
+      val maker = (_: ActorRefFactory) => probe.ref
+      val parent = system.actorOf(Props(classOf[GenericDependentParent], maker))
+      //#child-maker-test
+      probe.send(parent, "pingit")
+      probe.expectMsg("ping")
+    }
+
+    "demonstrate production version of child creator" in {
+      //#child-maker-prod
+      val maker = (f: ActorRefFactory) => f.actorOf(Props[Child])
+      val parent = system.actorOf(Props(classOf[GenericDependentParent], maker))
+      //#child-maker-prod
+    }
+  }
+
+  //#test-fabricated-parent
+  "A fabricated parent" should {
+    "test its child responses" in {
+      val proxy = TestProbe()
+      val parent = system.actorOf(Props(new Actor {
+        val child = context.actorOf(Props[Child], "child")
+        def receive = {
+          case x if sender == child => proxy.ref forward x
+          case x                    => child forward x
+        }
+      }))
+
+      proxy.send(parent, "ping")
+      proxy.expectMsg("pong")
+    }
+  }
+  //#test-fabricated-parent
+}