close #6295 - set default PoolRouter SupervisorStrategy to Restart (#6366)

* close #6295 - set default PoolRouter SupervisorStrategy to Restart

* use the `SupervisionStrategy.DefaultStrategy`

* Fix unit test

* Change unit test to use RoundRobinPool router

Co-authored-by: Gregorius Soedharmo <arkatufus@yahoo.com>

Author: Aaronontheweb

src/core/Akka.Tests/Routing/RoutingSpec.cs

@@ -11,6 +11,7 @@
 using System.Linq;
 using Akka.Configuration;
 using Akka.Actor;
+using Akka.Actor.Dsl;
 using Akka.Dispatch;
 using Akka.Routing;
 using Akka.TestKit;
@@ -293,27 +294,20 @@ public void Routers_in_general_must_set_supplied_supervisorStrategy_for_FromConf
         }
 
         [Fact]
-        public void Routers_in_general_must_default_to_all_for_one_always_escalate_strategy()
+        public void Routers_in_general_must_default_to_all_for_one_restart_strategy()
         {
-            var restarter = new OneForOneStrategy(e =>
-            {
-                TestActor.Tell(e);
-                return Directive.Restart;
-            });
-
-            var supervisor = Sys.ActorOf(Props.Create(() => new Supervisor(restarter)));
+            var router = Sys.ActorOf(new RoundRobinPool(3).Props(Props.Create(() => new RestartActor(TestActor))));
+            var restarted = new HashSet<string>();
 
-            supervisor.Tell(new RoundRobinPool(3).Props(Props.Create(() => new RestartActor(TestActor))));
-
-            var router = ExpectMsg<IActorRef>();
-            EventFilter.Exception<ArgumentException>("die").ExpectOne(() =>
+            for (var i = 0; i < 3; i++)
             {
                 router.Tell("die");
-            });
-            ExpectMsg<ArgumentException>().Message.Should().Be("die");
-            ExpectMsg("restarted");
-            ExpectMsg("restarted");
-            ExpectMsg("restarted");
+                ExpectMsg("restarted");
+                restarted.Add(LastSender.Path.Name);
+            }
+
+            restarted.Count.Should().Be(3);
+            restarted.Should().BeEquivalentTo(((RoutedActorRef)router).Children.Select(c => c.Path.Name));
         }
 
         [Fact]

src/core/Akka/Routing/RouterConfig.cs

@@ -354,15 +354,9 @@ public override ActorBase CreateRouterActor()
         /// <summary>
         /// TBD
         /// </summary>
-        public static SupervisorStrategy DefaultSupervisorStrategy
-        {
-            get
-            {
-                return new OneForOneStrategy(Decider.From(Directive.Escalate));
-            }
-        }
+        public static SupervisorStrategy DefaultSupervisorStrategy => SupervisorStrategy.DefaultStrategy;
+
 
-        
         public bool Equals(Pool other)
         {
             if (ReferenceEquals(null, other)) return false;