#28869 - example for setting policies in docs (persistence testkit)

akka-docs/src/main/paradox/typed/persistence-testing.md

@@ -110,7 +110,7 @@ Scala
 :  @@snip [TestKitExamples.scala](/akka-docs/src/test/scala/docs/persistence/testkit/TestKitExamples.scala) { #test }
 
 Java
-:  @@snip [TestKitExamples.java](/akka-docs/src/test/java/jdocs/persistence/testkit/PersistenceTestKitSampleTest.java) { #test }
+:  @@snip [PersistenceTestKitSampleTest.java](/akka-docs/src/test/java/jdocs/persistence/testkit/PersistenceTestKitSampleTest.java) { #test }
 
 You can safely use persistence testkit in combination with main akka testkit.
 
@@ -134,6 +134,12 @@ Implement the @apidoc[ProcessingPolicy[EventStorage.JournalOperation]] @scala[tr
 or @apidoc[ProcessingPolicy[SnapshotStorage.SnapshotOperation]] @scala[trait]@java[interface] for snapshot storage,
 and set it with `withPolicy()` method.
 
+Scala
+:  @@snip [TestKitExamples.scala](/akka-docs/src/test/scala/docs/persistence/testkit/TestKitExamples.scala) { #policy-test }
+
+Java
+:  @@snip [PersistenceTestKitPolicySampleTest.java](/akka-docs/src/test/java/jdocs/persistence/testkit/PersistenceTestKitPolicySampleTest.java) { #policy-test }
+
 `tryProcess()` method of the @apidoc[ProcessingPolicy] has two arguments: persistence id and the storage operation. 
 
 Event storage has the following operations:

akka-docs/src/test/java/jdocs/persistence/testkit/PersistenceTestKitPolicySampleTest.java

@@ -0,0 +1,68 @@
+/*
+ * Copyright (C) 2020 Lightbend Inc. <https://www.lightbend.com>
+ */
+
+package jdocs.persistence.testkit;
+
+import akka.actor.testkit.typed.javadsl.TestKitJunitResource;
+import akka.actor.typed.ActorRef;
+import akka.persistence.testkit.JournalOperation;
+import akka.persistence.testkit.PersistenceTestKitPlugin;
+import akka.persistence.testkit.ProcessingPolicy;
+import akka.persistence.testkit.ProcessingResult;
+import akka.persistence.testkit.ProcessingSuccess;
+import akka.persistence.testkit.StorageFailure;
+import akka.persistence.testkit.WriteEvents;
+import akka.persistence.testkit.javadsl.PersistenceTestKit;
+import akka.persistence.typed.PersistenceId;
+import com.typesafe.config.ConfigFactory;
+import jdocs.AbstractJavaTest;
+import org.junit.Before;
+import org.junit.ClassRule;
+import org.junit.Test;
+
+// #policy-test
+public class PersistenceTestKitPolicySampleTest extends AbstractJavaTest {
+
+  @ClassRule
+  public static final TestKitJunitResource testKit =
+      new TestKitJunitResource(
+          PersistenceTestKitPlugin.getInstance()
+              .config()
+              .withFallback(ConfigFactory.defaultApplication()));
+
+  PersistenceTestKit persistenceTestKit = PersistenceTestKit.create(testKit.system());
+
+  @Before
+  public void beforeEach() {
+    persistenceTestKit.clearAll();
+    persistenceTestKit.returnDefaultPolicy();
+  }
+
+  @Test
+  public void test() {
+    SampleEventStoragePolicy policy = new SampleEventStoragePolicy();
+    persistenceTestKit.withPolicy(policy);
+
+    PersistenceId persistenceId = PersistenceId.ofUniqueId("some-id");
+    ActorRef<YourPersistentBehavior.Cmd> ref =
+        testKit.spawn(YourPersistentBehavior.create(persistenceId));
+
+    YourPersistentBehavior.Cmd cmd = new YourPersistentBehavior.Cmd("data");
+    ref.tell(cmd);
+
+    persistenceTestKit.expectNothingPersisted(persistenceId.id());
+  }
+
+  static class SampleEventStoragePolicy implements ProcessingPolicy<JournalOperation> {
+    @Override
+    public ProcessingResult tryProcess(String persistenceId, JournalOperation processingUnit) {
+      if (processingUnit instanceof WriteEvents) {
+        return StorageFailure.create();
+      } else {
+        return ProcessingSuccess.getInstance();
+      }
+    }
+  }
+}
+// #policy-test

akka-docs/src/test/scala/docs/persistence/testkit/TestKitExamples.scala

@@ -9,7 +9,7 @@ import akka.persistence.typed.scaladsl.Effect
 import akka.persistence.typed.scaladsl.EventSourcedBehavior
 import akka.serialization.jackson.CborSerializable
 import com.typesafe.config.ConfigFactory
-import docs.persistence.testkit.PersistenceTestKitSampleSpec._
+import docs.persistence.testkit.PersistenceTestKitSampleSpec.{ Cmd, Evt, _ }
 import org.scalatest.BeforeAndAfterEach
 import org.scalatest.wordspec.AnyWordSpecLike
 
@@ -117,3 +117,47 @@ class SampleSnapshotStoragePolicy extends SnapshotStorage.SnapshotPolicies.Polic
     }
 }
 //#set-snapshot-storage-policy
+
+//#policy-test
+class PersistenceTestKitSampleSpecWithPolicy
+    extends ScalaTestWithActorTestKit(PersistenceTestKitPlugin.config.withFallback(ConfigFactory.defaultApplication()))
+    with AnyWordSpecLike
+    with BeforeAndAfterEach {
+
+  val persistenceTestKit = PersistenceTestKit(system)
+
+  override def beforeEach(): Unit = {
+    persistenceTestKit.clearAll()
+    persistenceTestKit.returnDefaultPolicy()
+  }
+
+  "Testkit policy" should {
+
+    "fail all operations with custom exception" in {
+      val policy = new EventStorage.JournalPolicies.PolicyType {
+
+        class CustomFailure extends RuntimeException
+
+        override def tryProcess(persistenceId: String, processingUnit: JournalOperation): ProcessingResult =
+          processingUnit match {
+            case WriteEvents(_) => StorageFailure(new CustomFailure)
+            case _              => ProcessingSuccess
+          }
+      }
+      persistenceTestKit.withPolicy(policy)
+
+      val persistenceId = PersistenceId.ofUniqueId("your-persistence-id")
+      val persistentActor = spawn(
+        EventSourcedBehavior[Cmd, Evt, State](
+          persistenceId,
+          emptyState = State.empty,
+          commandHandler = (_, cmd) => Effect.persist(Evt(cmd.data)),
+          eventHandler = (state, evt) => state.updated(evt)))
+
+      persistentActor ! Cmd("data")
+      persistenceTestKit.expectNothingPersisted(persistenceId.id)
+
+    }
+  }
+}
+//#policy-test