fix(siteruntime): MV-8 review fixes (construct list inside try; dictionary attr lookup; test hygiene)

tests/ZB.MOM.WW.ScadaBridge.SiteRuntime.Tests/Actors/InstanceActorTests.cs

@@ -583,6 +583,49 @@ public class InstanceActorTests : TestKit, IDisposable
         ExpectNoTerminated(actor, TimeSpan.FromMilliseconds(500));
     }
 
+    /// <summary>
+    /// MV-8 design contract: a failed coercion keeps the PRIOR value. A good
+    /// array is delivered first and stored as a typed list; a subsequent array
+    /// with a non-coercible element must NOT overwrite that value — the stored
+    /// value stays the prior list while the quality flips to <c>Bad</c>.
+    /// </summary>
+    [Fact]
+    public void InstanceActor_DataSourcedListAttribute_BadCoercion_PreservesPriorValue()
+    {
+        const string tag = "ns=3;s=Pump.Keep";
+        var config = new FlattenedConfiguration
+        {
+            InstanceUniqueName = "Pump-ListKeep",
+            Attributes =
+            [
+                new ResolvedAttribute
+                {
+                    CanonicalName = "Counts", Value = null,
+                    DataType = "List", ElementDataType = "Int32",
+                    DataSourceReference = tag, BoundDataConnectionName = "PLC"
+                }
+            ]
+        };
+
+        var dcl = CreateTestProbe();
+        var actor = CreateInstanceActorWithDcl("Pump-ListKeep", config, dcl);
+
+        // (1) A good array establishes the prior value.
+        actor.Tell(new TagValueUpdate("PLC", tag, new[] { 1, 2, 3 }, QualityCode.Good, DateTimeOffset.UtcNow));
+
+        // (2) A second array with a non-coercible element must not overwrite it.
+        actor.Tell(new TagValueUpdate("PLC", tag, new object[] { 4, "not-a-number", 6 }, QualityCode.Good, DateTimeOffset.UtcNow));
+
+        // (3) The stored value is still the prior list; quality is Bad.
+        actor.Tell(new GetAttributeRequest("corr-keep", "Pump-ListKeep", "Counts", DateTimeOffset.UtcNow));
+        var response = ExpectMsg<GetAttributeResponse>(TimeSpan.FromSeconds(5));
+
+        Assert.True(response.Found);
+        Assert.Equal("Bad", response.Quality);
+        var list = Assert.IsType<List<int>>(response.Value);
+        Assert.Equal(new[] { 1, 2, 3 }, list);
+    }
+
     /// <summary>
     /// MV-8 guard: scalar (non-List) data-sourced attributes keep the existing
     /// pass-through behaviour — a scalar value is stored unchanged.
@@ -620,7 +663,7 @@ public class InstanceActorTests : TestKit, IDisposable
     private void ExpectNoTerminated(IActorRef actor, TimeSpan within)
     {
         // The actor is Watch()ed; assert no Terminated arrives in the window.
+        // (Liveness is also proven by the preceding successful GetAttributeResponse.)
         ExpectNoMsg(within);
-        Assert.False(actor.IsNobody());
     }
 }