From b59f03fa34208d49ae2317b511cc694d52601f77 Mon Sep 17 00:00:00 2001
From: Patrik Nordwall <patrik.nordwall@gmail.com>
Date: Mon, 5 Sep 2016 14:03:52 +0200
Subject: [PATCH] fix failing SystemMessageDeliverySpec, #21331

---
 .../src/test/scala/akka/remote/artery/TestContext.scala       | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/akka-remote/src/test/scala/akka/remote/artery/TestContext.scala b/akka-remote/src/test/scala/akka/remote/artery/TestContext.scala
index 5ae7d99c58..9a350984ef 100644
--- a/akka-remote/src/test/scala/akka/remote/artery/TestContext.scala
+++ b/akka-remote/src/test/scala/akka/remote/artery/TestContext.scala
@@ -126,12 +126,12 @@ private[remote] class ManualReplyInboundContext(
 
   private var lastReply: Option[(Address, ControlMessage)] = None
 
-  override def sendControl(to: Address, message: ControlMessage) = {
+  override def sendControl(to: Address, message: ControlMessage): Unit = synchronized {
     lastReply = Some((to, message))
     replyProbe ! message
   }
 
-  def deliverLastReply(): Unit = {
+  def deliverLastReply(): Unit = synchronized {
     lastReply.foreach { case (to, message) ⇒ super.sendControl(to, message) }
     lastReply = None
   }