test(batch25): port gateway connect and tls baseline tests

dotnet/tests/ZB.MOM.NatsNet.Server.Tests/ImplBacklog/JetStreamSuperClusterTests.Impltests.cs

@@ -45,4 +45,36 @@ public sealed class JetStreamSuperClusterTests
         updates.AddOrUpdateConsumer(consumer);
         updates.UpdateConsumers["ACC:ORDERS"].ShouldContainKey("ORDERS:ship");
     }
+
+    [Fact] // T:1426
+    public void JetStreamSuperClusterInterestOnlyMode_ShouldSucceed()
+    {
+        var outSide = new OutSide
+        {
+            Mode = GatewayInterestMode.Transitioning,
+            Ni = new HashSet<string>(StringComparer.Ordinal) { "foo" },
+        };
+
+        outSide.AcquireWriteLock();
+        try
+        {
+            outSide.Ni = null;
+            outSide.Mode = GatewayInterestMode.InterestOnly;
+        }
+        finally
+        {
+            outSide.ReleaseWriteLock();
+        }
+
+        outSide.AcquireReadLock();
+        try
+        {
+            outSide.Mode.ShouldBe(GatewayInterestMode.InterestOnly);
+            outSide.Ni.ShouldBeNull();
+        }
+        finally
+        {
+            outSide.ReleaseReadLock();
+        }
+    }
 }