Merge pull request #18214 from ktoso/wip-18061-testactorref-dislikes-persistentactor-ktoso

=per,doc #18061 doc that Persistence won't work with TestActorRef

akka-docs/rst/java/lambda-persistence.rst

@@ -853,6 +853,14 @@ or
 
 in your Akka configuration. The LevelDB Java port is for testing purposes only.
 
+.. warning::
+  It is not possible to test persistence provided classes (i.e. :ref:`PersistentActor <event-sourcing-java>`
+  and :ref:`AtLeastOnceDelivery <at-least-once-delivery-java>`) using ``TestActorRef`` due to its *synchronous* nature.
+  These traits need to be able to perform asynchronous tasks in the background in order to handle internal persistence
+  related events.
+
+  When testing Persistence based projects always rely on :ref:`asynchronous messaging using the TestKit <async-integration-testing-java>`.
+
 Multiple persistence plugin configurations
 ==========================================
 

akka-docs/rst/java/persistence.rst

@@ -844,6 +844,14 @@ or
 
 in your Akka configuration. The LevelDB Java port is for testing purposes only.
 
+.. warning::
+  It is not possible to test persistence provided classes (i.e. :ref:`PersistentActor <event-sourcing-java>`
+  and :ref:`AtLeastOnceDelivery <at-least-once-delivery-java>`) using ``TestActorRef`` due to its *synchronous* nature.
+  These traits need to be able to perform asynchronous tasks in the background in order to handle internal persistence
+  related events.
+
+  When testing Persistence based projects always rely on :ref:`asynchronous messaging using the TestKit <async-integration-testing-java>`.
+
 Configuration
 =============
 

akka-docs/rst/java/testing.rst

@@ -70,6 +70,7 @@ section below.
   to ask the Actor to reply with the state you want to run assertions against),
   instead of using ``TestActorRef`` whenever possible.
 
+.. warning::
   Due to the synchronous nature of ``TestActorRef`` it will **not** work with some support
   traits that Akka provides as they require asynchronous behaviours to function properly.
   Examples of traits that do not mix well with test actor refs are :ref:`PersistentActor <event-sourcing-java>`
@@ -151,6 +152,8 @@ Feel free to experiment with the possibilities, and if you find useful
 patterns, don't hesitate to let the Akka forums know about them! Who knows,
 common operations might even be worked into nice DSLs.
 
+.. _async-integration-testing-java:
+
 Asynchronous Integration Testing with :class:`JavaTestKit`
 ==========================================================
 

akka-docs/rst/scala/persistence.rst

@@ -897,6 +897,14 @@ or
 
 in your Akka configuration. The LevelDB Java port is for testing purposes only.
 
+.. warning::
+  It is not possible to test persistence provided classes (i.e. :ref:`PersistentActor <event-sourcing-scala>`
+  and :ref:`AtLeastOnceDelivery <at-least-once-delivery-scala>`) using ``TestActorRef`` due to its *synchronous* nature.
+  These traits need to be able to perform asynchronous tasks in the background in order to handle internal persistence
+  related events.
+
+  When testing Persistence based projects always rely on :ref:`asynchronous messaging using the TestKit <async-integration-testing-scala>`.
+
 Configuration
 =============
 

akka-docs/rst/scala/testing.rst

@@ -59,6 +59,7 @@ section below.
   to ask the Actor to reply with the state you want to run assertions against),
   instead of using ``TestActorRef`` whenever possible.
 
+.. warning::
   Due to the synchronous nature of ``TestActorRef`` it will **not** work with some support
   traits that Akka provides as they require asynchronous behaviours to function properly.
   Examples of traits that do not mix well with test actor refs are :ref:`PersistentActor <event-sourcing>`
@@ -160,6 +161,8 @@ Feel free to experiment with the possibilities, and if you find useful
 patterns, don't hesitate to let the Akka forums know about them! Who knows,
 common operations might even be worked into nice DSLs.
 
+.. _async-integration-testing-scala:
+
 Asynchronous Integration Testing with :class:`TestKit`
 ======================================================
 

akka-persistence/src/test/scala/akka/persistence/fsm/PersistentFSMSpec.scala

@@ -5,7 +5,7 @@
 package akka.persistence.fsm
 
 import akka.actor._
-import akka.persistence.{PersistentActor, RecoveryCompleted, PersistenceSpec}
+import akka.persistence.{ PersistentActor, RecoveryCompleted, PersistenceSpec }
 import akka.persistence.fsm.PersistentFSM._
 import akka.testkit._
 import com.typesafe.config.Config
@@ -266,13 +266,13 @@ abstract class PersistentFSMSpec(config: Config) extends PersistenceSpec(config)
       val persistentEventsStreamer = system.actorOf(PersistentEventsStreamer.props(persistenceId, testActor))
 
       expectMsg(ItemAdded(Item("1", "Shirt", 59.99F)))
-      expectMsgType[StateChangeEvent]   //because a timeout is defined, State Change is persisted
+      expectMsgType[StateChangeEvent] //because a timeout is defined, State Change is persisted
 
       expectMsg(ItemAdded(Item("2", "Shoes", 89.99F)))
-      expectMsgType[StateChangeEvent]   //because a timeout is defined, State Change is persisted
+      expectMsgType[StateChangeEvent] //because a timeout is defined, State Change is persisted
 
       expectMsg(ItemAdded(Item("3", "Coat", 119.99F)))
-      expectMsgType[StateChangeEvent]   //because a timeout is defined, State Change is persisted
+      expectMsgType[StateChangeEvent] //because a timeout is defined, State Change is persisted
 
       expectMsg(OrderExecuted)
       expectMsgType[StateChangeEvent]
@@ -431,13 +431,13 @@ object PersistentFSMSpec {
     def props(persistenceId: String, reportActor: ActorRef) =
       Props(new WebStoreCustomerFSM(persistenceId, reportActor))
   }
-  
+
   class PersistentEventsStreamer(id: String, client: ActorRef) extends PersistentActor {
     override val persistenceId: String = id
 
     def receiveRecover = {
-      case RecoveryCompleted  ⇒ // do nothing
-      case persistentEvent    ⇒ client ! persistentEvent
+      case RecoveryCompleted ⇒ // do nothing
+      case persistentEvent   ⇒ client ! persistentEvent
     }
 
     def receiveCommand = {