worker(alarms): synthetic GUID + degraded/source_provider on emitted transitions

src/ZB.MOM.WW.MxGateway.Worker.Tests/MxAccess/AlarmDispatcherTests.cs

@@ -64,6 +64,41 @@ public sealed class AlarmDispatcherTests
         Assert.Equal(ts, body.TransitionTimestamp.ToDateTime());
     }
 
+    /// <summary>
+    ///     Verifies that a transition enqueued via the subtag fallback
+    ///     (<c>degraded: true</c>) is marked <see cref="OnAlarmTransitionEvent.Degraded"/>
+    ///     with <see cref="AlarmProviderMode.Subtag"/>, while the default path
+    ///     stays on the alarmmgr parity contract.
+    /// </summary>
+    [Fact]
+    public void EnqueueTransition_WhenDegraded_MarksDegradedAndSubtagProvider()
+    {
+        MxAccessEventQueue queue = new MxAccessEventQueue();
+        MxAccessAlarmEventSink sink = new MxAccessAlarmEventSink(queue, new MxAccessEventMapper());
+        sink.Attach(new object(), SessionId);
+
+        DateTime ts = new DateTime(2026, 5, 1, 17, 26, 14, 709, DateTimeKind.Utc);
+        sink.EnqueueTransition(
+            alarmFullReference: "Galaxy!TestArea.TestMachine_001.TestAlarm001",
+            sourceObjectReference: "TestMachine_001.TestAlarm001",
+            alarmTypeName: "DSC",
+            transitionKind: AlarmTransitionKind.Raise,
+            severity: 500,
+            originalRaiseTimestampUtc: null,
+            transitionTimestampUtc: ts,
+            operatorUser: string.Empty,
+            operatorComment: string.Empty,
+            category: "TestArea",
+            description: string.Empty,
+            degraded: true);
+
+        Assert.Equal(1, queue.Count);
+        Assert.True(queue.TryDequeue(out WorkerEvent? workerEvent));
+        OnAlarmTransitionEvent body = workerEvent!.Event.OnAlarmTransition;
+        Assert.True(body.Degraded);
+        Assert.Equal(AlarmProviderMode.Subtag, body.SourceProvider);
+    }
+
     /// <summary>Verifies that unchanged alarm states do not emit transitions.</summary>
     [Fact]
     public void OnTransition_WithConsecutiveUnchangedState_DoesNotEmitTransition()

src/ZB.MOM.WW.MxGateway.Worker.Tests/MxAccess/SyntheticAlarmGuidTests.cs

@@ -0,0 +1,27 @@
+using System;
+using ZB.MOM.WW.MxGateway.Worker.MxAccess;
+
+namespace ZB.MOM.WW.MxGateway.Worker.Tests.MxAccess;
+
+/// <summary>
+///     Unit tests for <see cref="SyntheticAlarmGuid"/>: the subtag-fallback
+///     path derives a deterministic GUID from the alarm reference, so identical
+///     references must collide and distinct references must not.
+/// </summary>
+public sealed class SyntheticAlarmGuidTests
+{
+    /// <summary>Verifies the same reference yields the same GUID.</summary>
+    [Fact]
+    public void SameReference_SameGuid() =>
+        Assert.Equal(SyntheticAlarmGuid.ForReference("A.B.C"), SyntheticAlarmGuid.ForReference("A.B.C"));
+
+    /// <summary>Verifies distinct references yield distinct GUIDs.</summary>
+    [Fact]
+    public void DifferentReference_DifferentGuid() =>
+        Assert.NotEqual(SyntheticAlarmGuid.ForReference("A.B.C"), SyntheticAlarmGuid.ForReference("A.B.D"));
+
+    /// <summary>Verifies a reference produces a non-empty GUID.</summary>
+    [Fact]
+    public void Reference_ProducesNonEmptyGuid() =>
+        Assert.NotEqual(Guid.Empty, SyntheticAlarmGuid.ForReference("A.B.C"));
+}