pekko/docs/src/test/java/jdocs/testkit/ParentChildTest.java

/*
 * Copyright (C) 2014-2022 Lightbend Inc. <https://www.lightbend.com>
 */

package jdocs.testkit;

import org.apache.pekko.actor.*;
import org.apache.pekko.japi.Creator;
import org.apache.pekko.japi.Function;
import org.apache.pekko.testkit.PekkoJUnitActorSystemResource;
import org.apache.pekko.testkit.TestProbe;
import org.apache.pekko.testkit.javadsl.TestKit;
import com.typesafe.config.ConfigFactory;
import docs.testkit.MockedChild;
import jdocs.AbstractJavaTest;
import org.junit.ClassRule;
import org.junit.Test;

public class ParentChildTest extends AbstractJavaTest {
  @ClassRule
  public static PekkoJUnitActorSystemResource actorSystemResource =
      new PekkoJUnitActorSystemResource(
          "TestKitDocTest",
          ConfigFactory.parseString(
              "pekko.loggers = [org.apache.pekko.testkit.TestEventListener]"));

  private final ActorSystem system = actorSystemResource.getSystem();

  // #test-example
  static class Parent extends AbstractActor {
    final ActorRef child = getContext().actorOf(Props.create(Child.class), "child");
    boolean ponged = false;

    @Override
    public Receive createReceive() {
      return receiveBuilder()
          .matchEquals("pingit", message -> child.tell("ping", getSelf()))
          .matchEquals("pong", message -> ponged = true)
          .build();
    }
  }

  static class Child extends AbstractActor {
    @Override
    public Receive createReceive() {
      return receiveBuilder()
          .matchEquals(
              "ping",
              message -> {
                getContext().getParent().tell("pong", getSelf());
              })
          .build();
    }
  }
  // #test-example

  static
  // #test-dependentchild
  class DependentChild extends AbstractActor {
    private final ActorRef parent;

    public DependentChild(ActorRef parent) {
      this.parent = parent;
    }

    @Override
    public Receive createReceive() {
      return receiveBuilder()
          .matchEquals("ping", message -> parent.tell("pong", getSelf()))
          .build();
    }
  }
  // #test-dependentchild

  static
  // #test-dependentparent
  class DependentParent extends AbstractActor {
    final ActorRef child;
    final ActorRef probe;

    public DependentParent(Props childProps, ActorRef probe) {
      child = getContext().actorOf(childProps, "child");
      this.probe = probe;
    }

    @Override
    public Receive createReceive() {
      return receiveBuilder()
          .matchEquals("pingit", message -> child.tell("ping", getSelf()))
          .matchEquals("pong", message -> probe.tell("ponged", getSelf()))
          .build();
    }
  }
  // #test-dependentparent

  static
  // #test-dependentparent-generic
  class GenericDependentParent extends AbstractActor {
    final ActorRef child;
    boolean ponged = false;

    public GenericDependentParent(Function<ActorRefFactory, ActorRef> childMaker) throws Exception {
      child = childMaker.apply(getContext());
    }

    @Override
    public Receive createReceive() {
      return receiveBuilder()
          .matchEquals("pingit", message -> child.tell("ping", getSelf()))
          .matchEquals("pong", message -> ponged = true)
          .build();
    }
  }
  // #test-dependentparent-generic

  @Test
  public void testingWithoutParent() {
    TestProbe probe = new TestProbe(system);
    ActorRef child = system.actorOf(Props.create(DependentChild.class, probe.ref()));
    probe.send(child, "ping");
    probe.expectMsg("pong");
  }

  @Test
  public void testingWithCustomProps() {
    final TestProbe probe = new TestProbe(system);
    final Props childProps = Props.create(MockedChild.class);
    final ActorRef parent =
        system.actorOf(Props.create(DependentParent.class, childProps, probe.ref()));

    probe.send(parent, "pingit");

    probe.expectMsg("ponged");
  }

  @Test
  public void testingWithChildProbe() throws Exception {
    final TestProbe probe = new TestProbe(system);
    // #child-maker-test
    Function<ActorRefFactory, ActorRef> maker = param -> probe.ref();
    ActorRef parent = system.actorOf(Props.create(GenericDependentParent.class, maker));
    // #child-maker-test
    probe.send(parent, "pingit");
    probe.expectMsg("ping");
  }

  public void exampleProdActorFactoryFunction() throws Exception {
    // #child-maker-prod
    Function<ActorRefFactory, ActorRef> maker = f -> f.actorOf(Props.create(Child.class));
    ActorRef parent = system.actorOf(Props.create(GenericDependentParent.class, maker));
    // #child-maker-prod
  }

  static
  // #test-fabricated-parent-creator
  class FabricatedParentCreator implements Creator<Actor> {
    private final TestProbe proxy;

    public FabricatedParentCreator(TestProbe proxy) {
      this.proxy = proxy;
    }

    @Override
    public Actor create() throws Exception {
      return new AbstractActor() {
        final ActorRef child = getContext().actorOf(Props.create(Child.class), "child");

        @Override
        public Receive createReceive() {
          return receiveBuilder()
              .matchAny(
                  message -> {
                    if (getSender().equals(child)) {
                      proxy.ref().forward(message, getContext());
                    } else {
                      child.forward(message, getContext());
                    }
                  })
              .build();
        }
      };
    }
  }
  // #test-fabricated-parent-creator

  @Test
  public void testProbeParentTest() throws Exception {
    // #test-TestProbe-parent
    TestKit parent = new TestKit(system);
    ActorRef child = parent.childActorOf(Props.create(Child.class));

    parent.send(child, "ping");
    parent.expectMsgEquals("pong");
    // #test-TestProbe-parent
  }

  @Test
  public void fabricatedParentTestsItsChildResponses() throws Exception {
    // didn't put final on these in order to make the parent fit in one line in the html docs
    // #test-fabricated-parent
    TestProbe proxy = new TestProbe(system);
    ActorRef parent = system.actorOf(Props.create(Actor.class, new FabricatedParentCreator(proxy)));

    proxy.send(parent, "ping");
    proxy.expectMsg("pong");
    // #test-fabricated-parent
  }
}