Make InternalTestActor override its SupervisionStrategy

src/core/Akka.TestKit.Tests/TestActorRefTests/TestProbeSpec.cs

@@ -7,6 +7,7 @@
 
 using System;
 using System.Collections.Generic;
+using System.Threading.Tasks;
 using Akka.Actor;
 using Akka.TestKit.TestActors;
 using Akka.Util.Internal;
@@ -89,6 +90,17 @@ public void TestProbe_restart_a_failing_child_if_the_given_supervisor_says_so()
             });
         }
 
+        [Fact]
+        public async Task TestProbe_kill_a_failing_child_if_the_given_supervisor_says_so()
+        {
+            var restarts = new AtomicCounter(0);
+            var probe = CreateTestProbe();
+            var child = await probe.ChildActorOfAsync(Props.Create(() => new FailingActor(restarts)), new FailOnExceptionStrategy());
+            await WatchAsync(child);
+            child.Tell("hello");
+            await ExpectTerminatedAsync(child);
+        }
+
         class FailingActor : ActorBase
         {
             private AtomicCounter Restarts { get; }
@@ -108,5 +120,13 @@ protected override void PostRestart(Exception reason)
                 Restarts.IncrementAndGet();
             }
         }
+
+        private class FailOnExceptionStrategy: OneForOneStrategy
+        {
+            protected override Directive Handle(IActorRef child, Exception exception)
+            {
+                return Directive.Stop;
+            }
+        }
     }
 }

src/core/Akka.TestKit/DelegatingSupervisorStrategy.cs

@@ -7,6 +7,7 @@
 
 using System;
 using System.Collections.Generic;
+using System.Reflection;
 using Akka.Actor;
 using Akka.Actor.Internal;
 using Akka.Util;
@@ -21,7 +22,15 @@ public class DelegatingSupervisorStrategy : SupervisorStrategy
 
         protected override Directive Handle(IActorRef child, Exception exception)
         {
-            throw new NotImplementedException();
+            var childDelegate = Delegates[child];
+            var handleMethod = typeof(SupervisorStrategy).GetMethod(
+                name: "Handle", 
+                bindingAttr: BindingFlags.Instance | BindingFlags.NonPublic, 
+                binder: Type.DefaultBinder,
+                types: new[] {typeof(IActorRef), typeof(Exception)}, 
+                modifiers: null);
+            var result = (Directive) handleMethod.Invoke(childDelegate, new object[]{ child, exception });
+            return result;
         }
 
         public override void ProcessFailure(IActorContext context, bool restart, IActorRef child, Exception cause, ChildRestartStats stats,

src/core/Akka.TestKit/Internal/InternalTestActor.cs

@@ -102,5 +102,7 @@ protected override void OnReceive(object message)
                 }
             }
         }
+
+        protected override SupervisorStrategy SupervisorStrategy() => _supervisorStrategy;
     }
 }