feat(sitecallaudit): central→site Retry/Discard relay for parked operations

tests/ScadaLink.Communication.Tests/CommunicationServiceTests.cs

@@ -382,6 +382,64 @@ public class CommunicationServiceTests : TestKit
         Assert.Equal("plant-a", result.Sites[0].SourceSite);
     }
 
+    [Fact]
+    public async Task RetrySiteCallAsync_BeforeSiteCallAuditSet_Throws()
+    {
+        var service = new CommunicationService(
+            Options.Create(new CommunicationOptions()),
+            NullLogger<CommunicationService>.Instance);
+
+        await Assert.ThrowsAsync<InvalidOperationException>(() =>
+            service.RetrySiteCallAsync(new RetrySiteCallRequest("corr-1", Guid.NewGuid(), "plant-a")));
+    }
+
+    [Fact]
+    public async Task RetrySiteCallAsync_AsksSiteCallAuditProxyDirectly()
+    {
+        // The relay is initiated by Asking the central-local Site Call Audit
+        // proxy directly (no SiteEnvelope wrapping at this layer — the actor
+        // does the site routing itself).
+        var service = new CommunicationService(
+            Options.Create(new CommunicationOptions()),
+            NullLogger<CommunicationService>.Instance);
+        var probe = CreateTestProbe();
+        service.SetSiteCallAudit(probe.Ref);
+
+        var request = new RetrySiteCallRequest("corr-r", Guid.NewGuid(), "plant-a");
+        var task = service.RetrySiteCallAsync(request);
+
+        var received = probe.ExpectMsg<RetrySiteCallRequest>();
+        Assert.Same(request, received);
+        var reply = new RetrySiteCallResponse(
+            "corr-r", SiteCallRelayOutcome.Applied, true, true, null);
+        probe.Reply(reply);
+
+        Assert.Same(reply, await task);
+    }
+
+    [Fact]
+    public async Task DiscardSiteCallAsync_AsksSiteCallAuditProxyDirectly()
+    {
+        var service = new CommunicationService(
+            Options.Create(new CommunicationOptions()),
+            NullLogger<CommunicationService>.Instance);
+        var probe = CreateTestProbe();
+        service.SetSiteCallAudit(probe.Ref);
+
+        var request = new DiscardSiteCallRequest("corr-d", Guid.NewGuid(), "plant-a");
+        var task = service.DiscardSiteCallAsync(request);
+
+        var received = probe.ExpectMsg<DiscardSiteCallRequest>();
+        Assert.Same(request, received);
+        var reply = new DiscardSiteCallResponse(
+            "corr-d", SiteCallRelayOutcome.SiteUnreachable, false, false, "unreachable");
+        probe.Reply(reply);
+
+        var result = await task;
+        Assert.Same(reply, result);
+        Assert.False(result.SiteReachable);
+    }
+
     /// <summary>
     /// Stand-in for CentralCommunicationActor: verifies the message is wrapped
     /// in a SiteEnvelope targeting the requested site and replies with a typed

tests/ScadaLink.Communication.Tests/SiteCommunicationActorTests.cs

@@ -214,4 +214,72 @@ public class SiteCommunicationActorTests : TestKit
 
         ExpectMsg<EventLogQueryResponse>(msg => !msg.Success);
     }
+
+    // ── Task 5 (#22): central→site Retry/Discard relay for parked cached calls ──
+
+    [Fact]
+    public void RetryParkedOperation_WithHandler_ForwardedToParkedMessageHandler()
+    {
+        var dmProbe = CreateTestProbe();
+        var handlerProbe = CreateTestProbe();
+        var siteActor = Sys.ActorOf(Props.Create(() =>
+            new SiteCommunicationActor("site1", _options, dmProbe.Ref)));
+
+        siteActor.Tell(new RegisterLocalHandler(LocalHandlerType.ParkedMessages, handlerProbe.Ref));
+
+        var id = Commons.Types.TrackedOperationId.New();
+        siteActor.Tell(new RetryParkedOperation("corr-rp", id));
+
+        handlerProbe.ExpectMsg<RetryParkedOperation>(msg =>
+            msg.CorrelationId == "corr-rp" && msg.TrackedOperationId.Equals(id));
+    }
+
+    [Fact]
+    public void DiscardParkedOperation_WithHandler_ForwardedToParkedMessageHandler()
+    {
+        var dmProbe = CreateTestProbe();
+        var handlerProbe = CreateTestProbe();
+        var siteActor = Sys.ActorOf(Props.Create(() =>
+            new SiteCommunicationActor("site1", _options, dmProbe.Ref)));
+
+        siteActor.Tell(new RegisterLocalHandler(LocalHandlerType.ParkedMessages, handlerProbe.Ref));
+
+        var id = Commons.Types.TrackedOperationId.New();
+        siteActor.Tell(new DiscardParkedOperation("corr-dp", id));
+
+        handlerProbe.ExpectMsg<DiscardParkedOperation>(msg =>
+            msg.CorrelationId == "corr-dp" && msg.TrackedOperationId.Equals(id));
+    }
+
+    [Fact]
+    public void RetryParkedOperation_WithoutHandler_RepliesNotAppliedAck()
+    {
+        // No parked-message handler registered — the relay must get a definitive
+        // non-applied ack, not silence (the SiteCallAuditActor's Ask must not
+        // hang and then mis-report site-unreachable when the site IS reachable).
+        var dmProbe = CreateTestProbe();
+        var siteActor = Sys.ActorOf(Props.Create(() =>
+            new SiteCommunicationActor("site1", _options, dmProbe.Ref)));
+
+        siteActor.Tell(new RetryParkedOperation("corr-no-handler", Commons.Types.TrackedOperationId.New()));
+
+        var ack = ExpectMsg<ParkedOperationActionAck>();
+        Assert.Equal("corr-no-handler", ack.CorrelationId);
+        Assert.False(ack.Applied);
+        Assert.NotNull(ack.ErrorMessage);
+    }
+
+    [Fact]
+    public void DiscardParkedOperation_WithoutHandler_RepliesNotAppliedAck()
+    {
+        var dmProbe = CreateTestProbe();
+        var siteActor = Sys.ActorOf(Props.Create(() =>
+            new SiteCommunicationActor("site1", _options, dmProbe.Ref)));
+
+        siteActor.Tell(new DiscardParkedOperation("corr-no-handler", Commons.Types.TrackedOperationId.New()));
+
+        var ack = ExpectMsg<ParkedOperationActionAck>();
+        Assert.False(ack.Applied);
+        Assert.NotNull(ack.ErrorMessage);
+    }
 }