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()

tests/ZB.MOM.WW.ScadaBridge.HealthMonitoring.Tests/CentralHealthAggregatorTests.cs

@@ -473,6 +473,27 @@ public class CentralHealthAggregatorTests
         Assert.False(aggregator.GetSiteState("site-a")!.IsMetricsStale);
     }
 
+    /// <summary>
+    /// Review 01 [Low]: <c>_siteStates</c> only ever grew — a site deleted from
+    /// configuration remained a permanently-offline dashboard tile (and a KPI
+    /// sample source) forever. Pruning against the known-site set evicts it; the
+    /// synthetic central id is always retained.
+    /// </summary>
+    [Fact]
+    public void PruneUnknownSites_RemovesDeletedSites_KeepsKnownAndCentral()
+    {
+        var (aggregator, _) = NewAggregator();
+        aggregator.ProcessReport(MakeReport("site-a", 1));
+        aggregator.ProcessReport(MakeReport("site-b", 1));
+        aggregator.ProcessReport(MakeReport(CentralHealthReportLoop.CentralSiteId, 1));
+
+        aggregator.PruneUnknownSites(new[] { "site-a" });
+
+        Assert.NotNull(aggregator.GetSiteState("site-a"));
+        Assert.Null(aggregator.GetSiteState("site-b"));
+        Assert.NotNull(aggregator.GetSiteState(CentralHealthReportLoop.CentralSiteId)); // synthetic id always kept
+    }
+
     /// <summary>
     /// Review 01 underdeveloped #7: "when did the site drop" was unanswerable.
     /// Every online↔offline flip stamps <see cref="SiteHealthState.LastStatusChangeAt"/>.

tests/ZB.MOM.WW.ScadaBridge.HealthMonitoring.Tests/CentralHealthReportLoopTests.cs

@@ -27,6 +27,7 @@ public class CentralHealthReportLoopTests
         public IReadOnlyDictionary<string, SiteHealthState> GetAllSiteStates() =>
             new Dictionary<string, SiteHealthState>();
         public SiteHealthState? GetSiteState(string siteId) => null;
+        public void PruneUnknownSites(IReadOnlyCollection<string> knownSiteIds) { }
     }
 
     /// <summary>
@@ -256,6 +257,7 @@ public class CentralHealthReportLoopTests
         public IReadOnlyDictionary<string, SiteHealthState> GetAllSiteStates() =>
             new Dictionary<string, SiteHealthState>();
         public SiteHealthState? GetSiteState(string siteId) => null;
+        public void PruneUnknownSites(IReadOnlyCollection<string> knownSiteIds) { }
     }
 
     [Fact]

tests/ZB.MOM.WW.ScadaBridge.HealthMonitoring.Tests/Kpi/SiteHealthKpiSampleSourceTests.cs

@@ -166,5 +166,8 @@ public class SiteHealthKpiSampleSourceTests
 
         public void MarkHeartbeat(string siteId, DateTimeOffset receivedAt) =>
             throw new NotSupportedException();
+
+        public void PruneUnknownSites(IReadOnlyCollection<string> knownSiteIds) =>
+            throw new NotSupportedException();
     }
 }