fix(health): evict deleted sites from the aggregator on the periodic site refresh

tests/ZB.MOM.WW.ScadaBridge.Communication.Tests/CentralCommunicationActorClientLifecycleTests.cs

@@ -10,6 +10,7 @@ using ZB.MOM.WW.ScadaBridge.Commons.Entities.Sites;
 using ZB.MOM.WW.ScadaBridge.Commons.Interfaces.Repositories;
 using ZB.MOM.WW.ScadaBridge.Communication;
 using ZB.MOM.WW.ScadaBridge.Communication.Actors;
+using ZB.MOM.WW.ScadaBridge.HealthMonitoring;
 
 namespace ZB.MOM.WW.ScadaBridge.Communication.Tests;
 
@@ -37,7 +38,37 @@ public class CentralCommunicationActorClientLifecycleTests : TestKit
 
     private static SiteAddressCacheLoaded Load(string siteId, params string[] addrs) =>
         new(new Dictionary<string, IReadOnlyList<string>>
-            { [siteId] = addrs.ToList().AsReadOnly() });
+            { [siteId] = addrs.ToList().AsReadOnly() },
+            new[] { siteId });
+
+    [Fact]
+    public void PeriodicRefresh_PrunesDeletedSites_FromHealthAggregator()
+    {
+        // PLAN-01 Task 18: the periodic site refresh feeds the currently-configured
+        // site ids to the aggregator so a deleted site is evicted within one
+        // refresh interval. Repo returns only "site-a".
+        var siteRepo = Substitute.For<ISiteRepository>();
+        siteRepo.GetAllSitesAsync(Arg.Any<CancellationToken>())
+            .Returns(new List<Site> { new("Site A", "site-a") });
+        var aggregator = Substitute.For<ICentralHealthAggregator>();
+        var services = new ServiceCollection();
+        services.AddScoped(_ => siteRepo);
+        services.AddSingleton(aggregator);
+        var provider = services.BuildServiceProvider();
+
+        var actor = Sys.ActorOf(Props.Create(() => new CentralCommunicationActor(
+            provider, new DefaultSiteClientFactory(), null)));
+
+        // Trigger the refresh (also fires at PreStart, but drive it explicitly so
+        // the assertion is deterministic). The load runs on a detached task and
+        // pipes SiteAddressCacheLoaded back to the actor, which then prunes.
+        actor.Tell(new RefreshSiteAddresses());
+
+        AwaitAssert(
+            () => aggregator.Received().PruneUnknownSites(
+                Arg.Is<IReadOnlyCollection<string>>(ids => ids.Contains("site-a"))),
+            TimeSpan.FromSeconds(3));
+    }
 
     [Fact]
     public void AddressEdit_RecreatesClient_WithoutRestartLoop()