#2093 - Adding support for setting the sender when using TestActorRef.receive

akka-testkit/src/main/scala/akka/testkit/TestActorRef.scala

@@ -56,7 +56,17 @@ class TestActorRef[T <: Actor](
    * thrown will be available to you, while still being able to use
    * become/unbecome.
    */
-  def receive(o: Any): Unit = underlying.receiveMessage(o)
+  def receive(o: Any): Unit = receive(o, underlying.system.deadLetters)
+
+  /**
+   * Directly inject messages into actor receive behavior. Any exceptions
+   * thrown will be available to you, while still being able to use
+   * become/unbecome.
+   */
+  def receive(o: Any, sender: ActorRef): Unit = try {
+    underlying.currentMessage = Envelope(o, if (sender eq null) underlying.system.deadLetters else sender)(underlying.system)
+    underlying.receiveMessage(o)
+  } finally underlying.currentMessage = null
 
   /**
    * Retrieve reference to the underlying actor, where the static type matches the factory used inside the

akka-testkit/src/test/scala/akka/testkit/TestActorRefSpec.scala

@@ -246,11 +246,18 @@ class TestActorRefSpec extends AkkaSpec("disp1.type=Dispatcher") with BeforeAndA
       a.underlying.dispatcher.getClass must be(classOf[Dispatcher])
     }
 
-    "proxy receive for the underlying actor" in {
+    "proxy receive for the underlying actor without sender" in {
       val ref = TestActorRef[WorkerActor]
       ref.receive("work")
       ref.isTerminated must be(true)
     }
 
+    "proxy receive for the underlying actor with sender" in {
+      val ref = TestActorRef[WorkerActor]
+      ref.receive("work", testActor)
+      ref.isTerminated must be(true)
+      expectMsg("workDone")
+    }
+
   }
 }