test: lock SubList remote-key and match behavior

tests/NATS.Server.Clustering.Tests/Routes/RouteRemoteSubCleanupParityBatch2Tests.cs

@@ -47,6 +47,23 @@ public class RouteRemoteSubCleanupParityBatch2Tests
         sl.HasRemoteInterest("B", "orders.created").ShouldBeTrue();
     }
 
+    [Fact]
+    public void Applying_same_remote_subscription_twice_is_idempotent_for_interest_tracking()
+    {
+        using var sl = new SubList();
+        var changes = new List<InterestChange>();
+        sl.InterestChanged += changes.Add;
+
+        var sub = new RemoteSubscription("orders.*", "workers", "r1", "A");
+
+        sl.ApplyRemoteSub(sub);
+        sl.ApplyRemoteSub(sub);
+
+        sl.HasRemoteInterest("A", "orders.created").ShouldBeTrue();
+        sl.MatchRemote("A", "orders.created").Count.ShouldBe(1);
+        changes.Count(change => change.Kind == InterestChangeKind.RemoteAdded).ShouldBe(1);
+    }
+
     [Fact]
     public async Task Route_disconnect_cleans_remote_interest_without_explicit_rs_minus()
     {

tests/NATS.Server.Core.Tests/Subscriptions/SubListAllocationGuardTests.cs

@@ -0,0 +1,48 @@
+using System.Reflection;
+using NATS.Server.Subscriptions;
+
+namespace NATS.Server.Core.Tests;
+
+public class SubListAllocationGuardTests
+{
+    [Fact]
+    public void Remote_subscription_dictionary_uses_dedicated_routed_sub_key_type()
+    {
+        var field = typeof(SubList).GetField("_remoteSubs", BindingFlags.Instance | BindingFlags.NonPublic);
+
+        field.ShouldNotBeNull();
+        field.FieldType.IsGenericType.ShouldBeTrue();
+        field.FieldType.GetGenericArguments()[0].Name.ShouldBe("RoutedSubKey");
+    }
+
+    [Fact]
+    public void Has_remote_interest_supports_exact_and_wildcard_subjects_per_account()
+    {
+        using var sl = new SubList();
+        sl.ApplyRemoteSub(new RemoteSubscription("orders.created", null, "r1", "A"));
+        sl.ApplyRemoteSub(new RemoteSubscription("orders.*", null, "r2", "A"));
+        sl.ApplyRemoteSub(new RemoteSubscription("payments.*", null, "r3", "B"));
+
+        sl.HasRemoteInterest("A", "orders.created").ShouldBeTrue();
+        sl.HasRemoteInterest("A", "orders.updated").ShouldBeTrue();
+        sl.HasRemoteInterest("A", "payments.created").ShouldBeFalse();
+        sl.HasRemoteInterest("B", "payments.posted").ShouldBeTrue();
+        sl.HasRemoteInterest("B", "orders.created").ShouldBeFalse();
+    }
+
+    [Fact]
+    public void Match_remote_reflects_queue_weight_updates_for_existing_remote_queue_sub()
+    {
+        using var sl = new SubList();
+        var sub = new RemoteSubscription("orders.*", "workers", "r1", "A", QueueWeight: 1);
+        sl.ApplyRemoteSub(sub);
+
+        sl.MatchRemote("A", "orders.created").Count.ShouldBe(1);
+
+        sl.UpdateRemoteQSub(sub with { QueueWeight = 4 });
+
+        var matches = sl.MatchRemote("A", "orders.created");
+        matches.Count.ShouldBe(4);
+        matches.ShouldAllBe(match => match.Queue == "workers");
+    }
+}

tests/NATS.Server.Core.Tests/Subscriptions/SubListGoParityTests.cs

@@ -199,6 +199,33 @@ public class SubListGoParityTests
         sl.Match("foo.bar").PlainSubs.Length.ShouldBe(3);
     }
 
+    [Fact]
+    public void Cache_generation_bump_rebuilds_match_result_after_insert_and_remove()
+    {
+        var sl = new SubList();
+        var exact = MakeSub("foo.bar", sid: "1");
+        var wildcard = MakeSub("foo.*", sid: "2");
+
+        sl.Insert(exact);
+
+        var first = sl.Match("foo.bar");
+        var second = sl.Match("foo.bar");
+        ReferenceEquals(first, second).ShouldBeTrue();
+        first.PlainSubs.Select(sub => sub.Sid).ShouldBe(["1"]);
+
+        sl.Insert(wildcard);
+
+        var afterInsert = sl.Match("foo.bar");
+        ReferenceEquals(afterInsert, first).ShouldBeFalse();
+        afterInsert.PlainSubs.Select(sub => sub.Sid).OrderBy(x => x).ToArray().ShouldBe(["1", "2"]);
+
+        sl.Remove(wildcard);
+
+        var afterRemove = sl.Match("foo.bar");
+        ReferenceEquals(afterRemove, afterInsert).ShouldBeFalse();
+        afterRemove.PlainSubs.Select(sub => sub.Sid).ShouldBe(["1"]);
+    }
+
     /// <summary>
     /// Empty result is a shared singleton — two calls that yield no matches return
     /// the same object reference.