refactor: extract NATS.Server.LeafNodes.Tests project

Move 28 leaf node test files from NATS.Server.Tests into a dedicated
NATS.Server.LeafNodes.Tests project. Update namespaces, add
InternalsVisibleTo, register in solution file. Replace all Task.Delay
polling loops with PollHelper.WaitUntilAsync/YieldForAsync from
TestUtilities. Replace private ReadUntilAsync in LeafProtocolTests
with SocketTestHelper.ReadUntilAsync.

All 281 tests pass.

NatsDotNet.slnx

@@ -9,6 +9,7 @@
     <Project Path="tests/NATS.Server.Transport.Tests/NATS.Server.Transport.Tests.csproj" />
     <Project Path="tests/NATS.Server.Mqtt.Tests/NATS.Server.Mqtt.Tests.csproj" />
     <Project Path="tests/NATS.Server.Gateways.Tests/NATS.Server.Gateways.Tests.csproj" />
+    <Project Path="tests/NATS.Server.LeafNodes.Tests/NATS.Server.LeafNodes.Tests.csproj" />
     <Project Path="tests/NATS.E2E.Tests/NATS.E2E.Tests.csproj" />
   </Folder>
 </Solution>

src/NATS.Server/NATS.Server.csproj

@@ -4,6 +4,7 @@
     <InternalsVisibleTo Include="NATS.Server.Transport.Tests" />
     <InternalsVisibleTo Include="NATS.Server.Mqtt.Tests" />
     <InternalsVisibleTo Include="NATS.Server.Gateways.Tests" />
+    <InternalsVisibleTo Include="NATS.Server.LeafNodes.Tests" />
   </ItemGroup>
   <ItemGroup>
     <FrameworkReference Include="Microsoft.AspNetCore.App" />

tests/NATS.Server.LeafNodes.Tests/LeafAdvancedSemanticsTests.cs

@@ -4,7 +4,7 @@ using System.Text;
 using NATS.Server.LeafNodes;
 using NATS.Server.Subscriptions;
 
-namespace NATS.Server.Tests;
+namespace NATS.Server.LeafNodes.Tests;
 
 public class LeafAdvancedSemanticsTests
 {

tests/NATS.Server.LeafNodes.Tests/LeafNode/LeafNodeGoParityTests.cs

@@ -7,8 +7,9 @@ using NATS.Server.Auth;
 using NATS.Server.Configuration;
 using NATS.Server.LeafNodes;
 using NATS.Server.Subscriptions;
+using NATS.Server.TestUtilities;
 
-namespace NATS.Server.Tests.LeafNode;
+namespace NATS.Server.LeafNodes.Tests.LeafNode;
 
 /// <summary>
 /// Go-parity tests for leaf node functionality.
@@ -330,12 +331,9 @@ public class LeafNodeGoParityTests
 
         // Wait for all three leaf connections to be established.
         // B has TWO leaf connections: one outbound to A, one inbound from C.
-        using var waitTimeout = new CancellationTokenSource(TimeSpan.FromSeconds(10));
+        await PollHelper.WaitUntilAsync(() => serverA.Stats.Leafs > 0
-        while (!waitTimeout.IsCancellationRequested
+            && Interlocked.Read(ref serverB.Stats.Leafs) >= 2
-               && (serverA.Stats.Leafs == 0
+            && serverC.Stats.Leafs > 0, timeoutMs: 10000);
-                   || Interlocked.Read(ref serverB.Stats.Leafs) < 2
-                   || serverC.Stats.Leafs == 0))
-            await Task.Delay(50, waitTimeout.Token).ContinueWith(_ => { }, TaskScheduler.Default);
 
         // Verify the connection counts match the expected topology
         Interlocked.Read(ref serverA.Stats.Leafs).ShouldBe(1);         // A has 1 inbound from B
@@ -542,13 +540,13 @@ public class LeafNodeGoParityTests
             await conn.ConnectAsync();
             var sub = await conn.SubscribeCoreAsync<string>($"concurrent.leaf.{i}");
             await conn.PingAsync();
-            await Task.Delay(30);
+            await PollHelper.YieldForAsync(30);
             await sub.DisposeAsync();
             await conn.PingAsync();
         })).ToList();
 
         await Task.WhenAll(tasks);
-        await Task.Delay(200);
+        await PollHelper.YieldForAsync(200);
 
         // All subs should be gone from hub's perspective
         for (var i = 0; i < 8; i++)
@@ -831,7 +829,7 @@ public class LeafNodeGoParityTests
 
         using var cts = new CancellationTokenSource();
         await manager.StartAsync(cts.Token);
-        await Task.Delay(300);
+        await PollHelper.YieldForAsync(300);
         stats.Leafs.ShouldBe(0);
 
         await cts.CancelAsync();
@@ -857,7 +855,7 @@ public class LeafNodeGoParityTests
 
         using var cts = new CancellationTokenSource();
         await manager.StartAsync(cts.Token);
-        await Task.Delay(150);
+        await PollHelper.YieldForAsync(150);
 
         await cts.CancelAsync();
         await manager.DisposeAsync(); // Must not hang
@@ -1678,14 +1676,7 @@ public class LeafNodeGoParityTests
 
     private static async Task WaitForConditionAsync(Func<bool> predicate, int timeoutMs = 5000)
     {
-        using var cts = new CancellationTokenSource(timeoutMs);
+        await PollHelper.WaitOrThrowAsync(predicate, $"Condition not met within {timeoutMs}ms.", timeoutMs: timeoutMs);
-        while (!cts.IsCancellationRequested)
-        {
-            if (predicate()) return;
-            await Task.Delay(20, cts.Token).ContinueWith(_ => { }, TaskScheduler.Default);
-        }
-
-        throw new TimeoutException($"Condition not met within {timeoutMs}ms.");
     }
 }
 
@@ -1739,36 +1730,19 @@ internal sealed class LeafGoFixture : IAsyncDisposable
         _ = spoke.StartAsync(spokeCts.Token);
         await spoke.WaitForReadyAsync();
 
-        using var timeout = new CancellationTokenSource(TimeSpan.FromSeconds(5));
+        await PollHelper.WaitUntilAsync(() => !((hub.Stats.Leafs == 0 || spoke.Stats.Leafs == 0)), timeoutMs: 5000);
-        while (!timeout.IsCancellationRequested
-               && (hub.Stats.Leafs == 0 || spoke.Stats.Leafs == 0))
-            await Task.Delay(50, timeout.Token).ContinueWith(_ => { }, TaskScheduler.Default);
 
         return new LeafGoFixture(hub, spoke, hubCts, spokeCts);
     }
 
     public async Task WaitForRemoteInterestOnHubAsync(string subject)
     {
-        using var timeout = new CancellationTokenSource(TimeSpan.FromSeconds(5));
+        await PollHelper.WaitOrThrowAsync(() => Hub.HasRemoteInterest(subject), $"Timed out waiting for hub remote interest on '{subject}'.", timeoutMs: 5000);
-        while (!timeout.IsCancellationRequested)
-        {
-            if (Hub.HasRemoteInterest(subject)) return;
-            await Task.Delay(50, timeout.Token).ContinueWith(_ => { }, TaskScheduler.Default);
-        }
-
-        throw new TimeoutException($"Timed out waiting for hub remote interest on '{subject}'.");
     }
 
     public async Task WaitForRemoteInterestOnSpokeAsync(string subject)
     {
-        using var timeout = new CancellationTokenSource(TimeSpan.FromSeconds(5));
+        await PollHelper.WaitOrThrowAsync(() => Spoke.HasRemoteInterest(subject), $"Timed out waiting for spoke remote interest on '{subject}'.", timeoutMs: 5000);
-        while (!timeout.IsCancellationRequested)
-        {
-            if (Spoke.HasRemoteInterest(subject)) return;
-            await Task.Delay(50, timeout.Token).ContinueWith(_ => { }, TaskScheduler.Default);
-        }
-
-        throw new TimeoutException($"Timed out waiting for spoke remote interest on '{subject}'.");
     }
 
     public async ValueTask DisposeAsync()

tests/NATS.Server.LeafNodes.Tests/LeafNodes/LeafAccountScopedDeliveryTests.cs

@@ -2,8 +2,9 @@ using Microsoft.Extensions.Logging.Abstractions;
 using NATS.Client.Core;
 using NATS.Server.Auth;
 using NATS.Server.Configuration;
+using NATS.Server.TestUtilities;
 
-namespace NATS.Server.Tests.LeafNodes;
+namespace NATS.Server.LeafNodes.Tests.LeafNodes;
 
 public class LeafAccountScopedDeliveryTests
 {
@@ -95,9 +96,7 @@ internal sealed class LeafAccountDeliveryFixture : IAsyncDisposable
         _ = spoke.StartAsync(spokeCts.Token);
         await spoke.WaitForReadyAsync();
 
-        using var timeout = new CancellationTokenSource(TimeSpan.FromSeconds(5));
+        await PollHelper.WaitUntilAsync(() => !((hub.Stats.Leafs == 0 || spoke.Stats.Leafs == 0)), timeoutMs: 5000);
-        while (!timeout.IsCancellationRequested && (hub.Stats.Leafs == 0 || spoke.Stats.Leafs == 0))
-            await Task.Delay(50, timeout.Token).ContinueWith(_ => { }, TaskScheduler.Default);
 
         return new LeafAccountDeliveryFixture(hub, spoke, hubCts, spokeCts);
     }
@@ -114,16 +113,7 @@ internal sealed class LeafAccountDeliveryFixture : IAsyncDisposable
 
     public async Task WaitForRemoteInterestOnHubAsync(string account, string subject)
     {
-        using var timeout = new CancellationTokenSource(TimeSpan.FromSeconds(5));
+        await PollHelper.WaitOrThrowAsync(() => Hub.HasRemoteInterest(account, subject), $"Timed out waiting for remote interest {account}:{subject}.", timeoutMs: 5000);
-        while (!timeout.IsCancellationRequested)
-        {
-            if (Hub.HasRemoteInterest(account, subject))
-                return;
-
-            await Task.Delay(50, timeout.Token).ContinueWith(_ => { }, TaskScheduler.Default);
-        }
-
-        throw new TimeoutException($"Timed out waiting for remote interest {account}:{subject}.");
     }
 
     public async ValueTask DisposeAsync()

tests/NATS.Server.LeafNodes.Tests/LeafNodes/LeafBasicTests.cs

@@ -1,8 +1,9 @@
 using Microsoft.Extensions.Logging.Abstractions;
 using NATS.Client.Core;
 using NATS.Server.Configuration;
+using NATS.Server.TestUtilities;
 
-namespace NATS.Server.Tests.LeafNodes;
+namespace NATS.Server.LeafNodes.Tests.LeafNodes;
 
 /// <summary>
 /// Basic leaf node hub-spoke connectivity tests.
@@ -133,39 +134,19 @@ internal sealed class LeafBasicFixture : IAsyncDisposable
         await spoke.WaitForReadyAsync();
 
         // Wait for the leaf node connection to be established on both sides
-        using var timeout = new CancellationTokenSource(TimeSpan.FromSeconds(5));
+        await PollHelper.WaitUntilAsync(() => !((hub.Stats.Leafs == 0 || spoke.Stats.Leafs == 0)), timeoutMs: 5000);
-        while (!timeout.IsCancellationRequested && (hub.Stats.Leafs == 0 || spoke.Stats.Leafs == 0))
-            await Task.Delay(50, timeout.Token).ContinueWith(_ => { }, TaskScheduler.Default);
 
         return new LeafBasicFixture(hub, spoke, hubCts, spokeCts);
     }
 
     public async Task WaitForRemoteInterestOnHubAsync(string subject)
     {
-        using var timeout = new CancellationTokenSource(TimeSpan.FromSeconds(5));
+        await PollHelper.WaitOrThrowAsync(() => Hub.HasRemoteInterest(subject), $"Timed out waiting for remote interest on hub for '{subject}'.", timeoutMs: 5000);
-        while (!timeout.IsCancellationRequested)
-        {
-            if (Hub.HasRemoteInterest(subject))
-                return;
-
-            await Task.Delay(50, timeout.Token).ContinueWith(_ => { }, TaskScheduler.Default);
-        }
-
-        throw new TimeoutException($"Timed out waiting for remote interest on hub for '{subject}'.");
     }
 
     public async Task WaitForRemoteInterestOnSpokeAsync(string subject)
     {
-        using var timeout = new CancellationTokenSource(TimeSpan.FromSeconds(5));
+        await PollHelper.WaitOrThrowAsync(() => Spoke.HasRemoteInterest(subject), $"Timed out waiting for remote interest on spoke for '{subject}'.", timeoutMs: 5000);
-        while (!timeout.IsCancellationRequested)
-        {
-            if (Spoke.HasRemoteInterest(subject))
-                return;
-
-            await Task.Delay(50, timeout.Token).ContinueWith(_ => { }, TaskScheduler.Default);
-        }
-
-        throw new TimeoutException($"Timed out waiting for remote interest on spoke for '{subject}'.");
     }
 
     public async ValueTask DisposeAsync()

tests/NATS.Server.LeafNodes.Tests/LeafNodes/LeafClusterRegistrationTests.cs

@@ -2,7 +2,7 @@ using Microsoft.Extensions.Logging.Abstractions;
 using NATS.Server.Configuration;
 using NATS.Server.LeafNodes;
 
-namespace NATS.Server.Tests.LeafNodes;
+namespace NATS.Server.LeafNodes.Tests.LeafNodes;
 
 /// <summary>
 /// Unit tests for leaf cluster topology registration (Gap 12.6).

tests/NATS.Server.LeafNodes.Tests/LeafNodes/LeafConnectionAndRemoteConfigParityBatch1Tests.cs

@@ -4,7 +4,7 @@ using Microsoft.Extensions.Logging.Abstractions;
 using NATS.Server.Configuration;
 using NATS.Server.LeafNodes;
 
-namespace NATS.Server.Tests.LeafNodes;
+namespace NATS.Server.LeafNodes.Tests.LeafNodes;
 
 public class LeafConnectionAndRemoteConfigParityBatch1Tests
 {

tests/NATS.Server.LeafNodes.Tests/LeafNodes/LeafConnectionParityBatch3Tests.cs

@@ -5,7 +5,7 @@ using System.Text.Json;
 using NATS.Server.Configuration;
 using NATS.Server.LeafNodes;
 
-namespace NATS.Server.Tests.LeafNodes;
+namespace NATS.Server.LeafNodes.Tests.LeafNodes;
 
 public class LeafConnectionParityBatch3Tests
 {

tests/NATS.Server.LeafNodes.Tests/LeafNodes/LeafConnectionParityBatch4Tests.cs

@@ -4,7 +4,7 @@ using System.Text;
 using NATS.Server.LeafNodes;
 using NATS.Server.Subscriptions;
 
-namespace NATS.Server.Tests.LeafNodes;
+namespace NATS.Server.LeafNodes.Tests.LeafNodes;
 
 public class LeafConnectionParityBatch4Tests
 {

tests/NATS.Server.LeafNodes.Tests/LeafNodes/LeafDisableTests.cs

@@ -2,7 +2,7 @@ using Microsoft.Extensions.Logging.Abstractions;
 using NATS.Server.Configuration;
 using NATS.Server.LeafNodes;
 
-namespace NATS.Server.Tests.LeafNodes;
+namespace NATS.Server.LeafNodes.Tests.LeafNodes;
 
 /// <summary>
 /// Unit tests for leaf connection disable flag (Gap 12.7).

tests/NATS.Server.LeafNodes.Tests/LeafNodes/LeafHubSpokeMappingParityTests.cs

@@ -1,6 +1,6 @@
 using NATS.Server.LeafNodes;
 
-namespace NATS.Server.Tests;
+namespace NATS.Server.LeafNodes.Tests.LeafNodes;
 
 public class LeafHubSpokeMappingParityTests
 {

tests/NATS.Server.LeafNodes.Tests/LeafNodes/LeafInterestIdempotencyTests.cs

@@ -3,8 +3,9 @@ using System.Net.Sockets;
 using System.Text;
 using NATS.Server.LeafNodes;
 using NATS.Server.Subscriptions;
+using NATS.Server.TestUtilities;
 
-namespace NATS.Server.Tests.LeafNodes;
+namespace NATS.Server.LeafNodes.Tests.LeafNodes;
 
 public class LeafInterestIdempotencyTests
 {
@@ -45,7 +46,7 @@ public class LeafInterestIdempotencyTests
         await WaitForAsync(() => subList.HasRemoteInterest("A", "orders.created"), timeout.Token);
 
         await WriteLineAsync(remoteSocket, "LS+ A orders.*", timeout.Token);
-        await Task.Delay(100, timeout.Token);
+        await PollHelper.YieldForAsync(100);
 
         subList.MatchRemote("A", "orders.created").Count.ShouldBe(1);
         remoteAdded.ShouldBe(1);
@@ -74,14 +75,6 @@ public class LeafInterestIdempotencyTests
 
     private static async Task WaitForAsync(Func<bool> predicate, CancellationToken ct)
     {
-        while (!ct.IsCancellationRequested)
+        await PollHelper.WaitOrThrowAsync(predicate, "Timed out waiting for condition.");
-        {
-            if (predicate())
-                return;
-
-            await Task.Delay(20, ct);
-        }
-
-        throw new TimeoutException("Timed out waiting for condition.");
     }
 }

tests/NATS.Server.LeafNodes.Tests/LeafNodes/LeafJetStreamMigrationTests.cs

@@ -4,7 +4,7 @@ using Microsoft.Extensions.Logging.Abstractions;
 using NATS.Server.Configuration;
 using NATS.Server.LeafNodes;
 
-namespace NATS.Server.Tests.LeafNodes;
+namespace NATS.Server.LeafNodes.Tests.LeafNodes;
 
 /// <summary>
 /// Unit tests for JetStream migration checks on leaf node connections (Gap 12.4).

tests/NATS.Server.LeafNodes.Tests/LeafNodes/LeafLoopTransparencyRuntimeTests.cs

@@ -1,6 +1,6 @@
 using NATS.Server.LeafNodes;
 
-namespace NATS.Server.Tests.LeafNodes;
+namespace NATS.Server.LeafNodes.Tests.LeafNodes;
 
 public class LeafLoopTransparencyRuntimeTests
 {

tests/NATS.Server.LeafNodes.Tests/LeafNodes/LeafNodeAdvancedTests.cs

@@ -9,7 +9,7 @@ using NATS.Server.LeafNodes;
 using NATS.Server.Subscriptions;
 using NATS.Server.TestUtilities;
 
-namespace NATS.Server.Tests.LeafNodes;
+namespace NATS.Server.LeafNodes.Tests.LeafNodes;
 
 /// <summary>
 /// Advanced leaf node behavior tests: daisy chains, account scoping, concurrency,
@@ -68,10 +68,7 @@ public class LeafNodeAdvancedTests
         await serverC.WaitForReadyAsync();
 
         // Wait for leaf connections
-        using var waitTimeout = new CancellationTokenSource(TimeSpan.FromSeconds(5));
+        await PollHelper.WaitUntilAsync(() => !((serverA.Stats.Leafs == 0 || Interlocked.Read(ref serverB.Stats.Leafs) < 2 || serverC.Stats.Leafs == 0)), timeoutMs: 5000);
-        while (!waitTimeout.IsCancellationRequested
-               && (serverA.Stats.Leafs == 0 || Interlocked.Read(ref serverB.Stats.Leafs) < 2 || serverC.Stats.Leafs == 0))
-            await Task.Delay(50, waitTimeout.Token).ContinueWith(_ => { }, TaskScheduler.Default);
 
         Interlocked.Read(ref serverA.Stats.Leafs).ShouldBe(1);
         Interlocked.Read(ref serverB.Stats.Leafs).ShouldBeGreaterThanOrEqualTo(2);
@@ -171,9 +168,7 @@ public class LeafNodeAdvancedTests
         _ = spoke.StartAsync(spokeCts.Token);
         await spoke.WaitForReadyAsync();
 
-        using var waitTimeout = new CancellationTokenSource(TimeSpan.FromSeconds(5));
+        await PollHelper.WaitUntilAsync(() => !((hub.Stats.Leafs == 0 || spoke.Stats.Leafs == 0)), timeoutMs: 5000);
-        while (!waitTimeout.IsCancellationRequested && (hub.Stats.Leafs == 0 || spoke.Stats.Leafs == 0))
-            await Task.Delay(50, waitTimeout.Token).ContinueWith(_ => { }, TaskScheduler.Default);
 
         // Subscribe with account A on spoke
         await using var connA = new NatsConnection(new NatsOpts
@@ -195,9 +190,7 @@ public class LeafNodeAdvancedTests
         await connB.PingAsync();
 
         // Wait for account A interest to propagate
-        using var interestTimeout = new CancellationTokenSource(TimeSpan.FromSeconds(5));
+        await PollHelper.WaitUntilAsync(() => !(!hub.HasRemoteInterest("ACCT_A", "acct.test")), timeoutMs: 5000);
-        while (!interestTimeout.IsCancellationRequested && !hub.HasRemoteInterest("ACCT_A", "acct.test"))
-            await Task.Delay(50, interestTimeout.Token).ContinueWith(_ => { }, TaskScheduler.Default);
 
         // Publish from account A on hub
         await using var pubA = new NatsConnection(new NatsOpts
@@ -245,7 +238,7 @@ public class LeafNodeAdvancedTests
 
                 var sub = await conn.SubscribeCoreAsync<string>($"concurrent.{index}");
                 await conn.PingAsync();
-                await Task.Delay(50);
+                await PollHelper.YieldForAsync(50);
                 await sub.DisposeAsync();
                 await conn.PingAsync();
             }));
@@ -254,7 +247,7 @@ public class LeafNodeAdvancedTests
         await Task.WhenAll(tasks);
 
         // After all subs are unsubscribed, interest should be gone
-        await Task.Delay(200);
+        await PollHelper.YieldForAsync(200);
         for (var i = 0; i < 10; i++)
             fixture.Hub.HasRemoteInterest($"concurrent.{i}").ShouldBeFalse();
     }
@@ -383,9 +376,7 @@ public class LeafNodeAdvancedTests
         _ = spoke.StartAsync(spokeCts.Token);
         await spoke.WaitForReadyAsync();
 
-        using var waitTimeout = new CancellationTokenSource(TimeSpan.FromSeconds(5));
+        await PollHelper.WaitUntilAsync(() => !(hub.Stats.Leafs == 0), timeoutMs: 5000);
-        while (!waitTimeout.IsCancellationRequested && hub.Stats.Leafs == 0)
-            await Task.Delay(50, waitTimeout.Token).ContinueWith(_ => { }, TaskScheduler.Default);
 
         Interlocked.Read(ref hub.Stats.Leafs).ShouldBe(1);
 
@@ -393,9 +384,7 @@ public class LeafNodeAdvancedTests
         spoke.Dispose();
 
         // After spoke disconnects, wait for count to drop
-        using var disconnTimeout = new CancellationTokenSource(TimeSpan.FromSeconds(5));
+        await PollHelper.WaitUntilAsync(() => !(Interlocked.Read(ref hub.Stats.Leafs) > 0), timeoutMs: 5000);
-        while (!disconnTimeout.IsCancellationRequested && Interlocked.Read(ref hub.Stats.Leafs) > 0)
-            await Task.Delay(50, disconnTimeout.Token).ContinueWith(_ => { }, TaskScheduler.Default);
 
         Interlocked.Read(ref hub.Stats.Leafs).ShouldBe(0);
 
@@ -469,9 +458,7 @@ public class LeafNodeAdvancedTests
         await conn1.PingAsync();
         await conn2.PingAsync();
 
-        using var interestTimeout = new CancellationTokenSource(TimeSpan.FromSeconds(5));
+        await PollHelper.WaitUntilAsync(() => !(!fixture.Hub.HasRemoteInterest("dist.test")), timeoutMs: 5000);
-        while (!interestTimeout.IsCancellationRequested && !fixture.Hub.HasRemoteInterest("dist.test"))
-            await Task.Delay(50, interestTimeout.Token).ContinueWith(_ => { }, TaskScheduler.Default);
 
         // Hub should have remote interest from at least one spoke
         fixture.Hub.HasRemoteInterest("dist.test").ShouldBeTrue();
@@ -643,9 +630,7 @@ public class LeafNodeAdvancedTests
         _ = spoke.StartAsync(spokeCts.Token);
         await spoke.WaitForReadyAsync();
 
-        using var waitTimeout = new CancellationTokenSource(TimeSpan.FromSeconds(5));
+        await PollHelper.WaitUntilAsync(() => !(hub.Stats.Leafs == 0), timeoutMs: 5000);
-        while (!waitTimeout.IsCancellationRequested && hub.Stats.Leafs == 0)
-            await Task.Delay(50, waitTimeout.Token).ContinueWith(_ => { }, TaskScheduler.Default);
 
         Interlocked.Read(ref hub.Stats.Leafs).ShouldBe(1);
 
@@ -653,9 +638,7 @@ public class LeafNodeAdvancedTests
         await spokeCts.CancelAsync();
         spoke.Dispose();
 
-        using var disconnTimeout = new CancellationTokenSource(TimeSpan.FromSeconds(5));
+        await PollHelper.WaitUntilAsync(() => !(Interlocked.Read(ref hub.Stats.Leafs) > 0), timeoutMs: 5000);
-        while (!disconnTimeout.IsCancellationRequested && Interlocked.Read(ref hub.Stats.Leafs) > 0)
-            await Task.Delay(50, disconnTimeout.Token).ContinueWith(_ => { }, TaskScheduler.Default);
 
         Interlocked.Read(ref hub.Stats.Leafs).ShouldBe(0);
 

tests/NATS.Server.LeafNodes.Tests/LeafNodes/LeafNodeConnectionTests.cs

@@ -9,7 +9,7 @@ using NATS.Server.LeafNodes;
 using NATS.Server.Subscriptions;
 using NATS.Server.TestUtilities;
 
-namespace NATS.Server.Tests.LeafNodes;
+namespace NATS.Server.LeafNodes.Tests.LeafNodes;
 
 /// <summary>
 /// Tests for leaf node connection establishment, authentication, and lifecycle.
@@ -60,9 +60,7 @@ public class LeafNodeConnectionTests
         _ = spoke.StartAsync(spokeCts.Token);
         await spoke.WaitForReadyAsync();
 
-        using var timeout = new CancellationTokenSource(TimeSpan.FromSeconds(5));
+        await PollHelper.WaitUntilAsync(() => !((hub.Stats.Leafs == 0 || spoke.Stats.Leafs == 0)), timeoutMs: 5000);
-        while (!timeout.IsCancellationRequested && (hub.Stats.Leafs == 0 || spoke.Stats.Leafs == 0))
-            await Task.Delay(50, timeout.Token).ContinueWith(_ => { }, TaskScheduler.Default);
 
         hub.Stats.Leafs.ShouldBeGreaterThan(0);
         spoke.Stats.Leafs.ShouldBeGreaterThan(0);
@@ -103,9 +101,7 @@ public class LeafNodeConnectionTests
         _ = spoke.StartAsync(spokeCts.Token);
         await spoke.WaitForReadyAsync();
 
-        using var timeout = new CancellationTokenSource(TimeSpan.FromSeconds(5));
+        await PollHelper.WaitUntilAsync(() => !((hub.Stats.Leafs == 0 || spoke.Stats.Leafs == 0)), timeoutMs: 5000);
-        while (!timeout.IsCancellationRequested && (hub.Stats.Leafs == 0 || spoke.Stats.Leafs == 0))
-            await Task.Delay(50, timeout.Token).ContinueWith(_ => { }, TaskScheduler.Default);
 
         hub.Stats.Leafs.ShouldBeGreaterThan(0);
 
@@ -527,12 +523,6 @@ public class LeafNodeConnectionTests
 
     private static async Task WaitForAsync(Func<bool> predicate, CancellationToken ct)
     {
-        while (!ct.IsCancellationRequested)
+        await PollHelper.WaitOrThrowAsync(predicate, "Timed out waiting for condition.");
-        {
-            if (predicate()) return;
-            await Task.Delay(20, ct);
-        }
-
-        throw new TimeoutException("Timed out waiting for condition.");
     }
 }

tests/NATS.Server.LeafNodes.Tests/LeafNodes/LeafNodeForwardingTests.cs

@@ -3,7 +3,7 @@ using NATS.Client.Core;
 using NATS.Server.Configuration;
 using NATS.Server.TestUtilities;
 
-namespace NATS.Server.Tests.LeafNodes;
+namespace NATS.Server.LeafNodes.Tests.LeafNodes;
 
 /// <summary>
 /// Tests for message forwarding through leaf node connections (hub-to-leaf, leaf-to-hub, leaf-to-leaf).
@@ -155,10 +155,7 @@ public class LeafNodeForwardingTests
         await spoke2Conn.PingAsync();
 
         // Both spokes' interests should propagate to the hub
-        using var waitCts = new CancellationTokenSource(TimeSpan.FromSeconds(5));
+        await PollHelper.WaitUntilAsync(() => !((!fixture.Hub.HasRemoteInterest("spoke1.interest") || !fixture.Hub.HasRemoteInterest("spoke2.interest"))), timeoutMs: 5000);
-        while (!waitCts.IsCancellationRequested
-               && (!fixture.Hub.HasRemoteInterest("spoke1.interest") || !fixture.Hub.HasRemoteInterest("spoke2.interest")))
-            await Task.Delay(50, waitCts.Token).ContinueWith(_ => { }, TaskScheduler.Default);
 
         fixture.Hub.HasRemoteInterest("spoke1.interest").ShouldBeTrue();
         fixture.Hub.HasRemoteInterest("spoke2.interest").ShouldBeTrue();
@@ -280,7 +277,7 @@ public class LeafNodeForwardingTests
         await hubConn.ConnectAsync();
 
         await hubConn.PublishAsync("no.subscriber", "lost");
-        await Task.Delay(200);
+        await PollHelper.YieldForAsync(200);
 
         true.ShouldBeTrue(); // No crash = success
     }
@@ -364,12 +361,9 @@ internal sealed class TwoSpokeFixture : IAsyncDisposable
         _ = spoke2.StartAsync(spoke2Cts.Token);
         await spoke2.WaitForReadyAsync();
 
-        using var timeout = new CancellationTokenSource(TimeSpan.FromSeconds(5));
+        await PollHelper.WaitUntilAsync(() => Interlocked.Read(ref hub.Stats.Leafs) >= 2
-        while (!timeout.IsCancellationRequested
+            && spoke1.Stats.Leafs > 0
-               && (Interlocked.Read(ref hub.Stats.Leafs) < 2
+            && spoke2.Stats.Leafs > 0);
-                   || spoke1.Stats.Leafs == 0
-                   || spoke2.Stats.Leafs == 0))
-            await Task.Delay(50, timeout.Token).ContinueWith(_ => { }, TaskScheduler.Default);
 
         return new TwoSpokeFixture(hub, spoke1, spoke2, hubCts, spoke1Cts, spoke2Cts);
     }

tests/NATS.Server.LeafNodes.Tests/LeafNodes/LeafNodeJetStreamTests.cs

@@ -1,8 +1,9 @@
 using Microsoft.Extensions.Logging.Abstractions;
 using NATS.Client.Core;
 using NATS.Server.Configuration;
+using NATS.Server.TestUtilities;
 
-namespace NATS.Server.Tests.LeafNodes;
+namespace NATS.Server.LeafNodes.Tests.LeafNodes;
 
 /// <summary>
 /// Tests for JetStream behavior over leaf node connections.
@@ -44,9 +45,7 @@ public class LeafNodeJetStreamTests
         _ = spoke.StartAsync(spokeCts.Token);
         await spoke.WaitForReadyAsync();
 
-        using var waitTimeout = new CancellationTokenSource(TimeSpan.FromSeconds(5));
+        await PollHelper.WaitUntilAsync(() => !((hub.Stats.Leafs == 0 || spoke.Stats.Leafs == 0)), timeoutMs: 5000);
-        while (!waitTimeout.IsCancellationRequested && (hub.Stats.Leafs == 0 || spoke.Stats.Leafs == 0))
-            await Task.Delay(50, waitTimeout.Token).ContinueWith(_ => { }, TaskScheduler.Default);
 
         hub.Stats.JetStreamEnabled.ShouldBeTrue();
 
@@ -100,9 +99,7 @@ public class LeafNodeJetStreamTests
         _ = spoke.StartAsync(spokeCts.Token);
         await spoke.WaitForReadyAsync();
 
-        using var waitTimeout = new CancellationTokenSource(TimeSpan.FromSeconds(5));
+        await PollHelper.WaitUntilAsync(() => !((hub.Stats.Leafs == 0 || spoke.Stats.Leafs == 0)), timeoutMs: 5000);
-        while (!waitTimeout.IsCancellationRequested && (hub.Stats.Leafs == 0 || spoke.Stats.Leafs == 0))
-            await Task.Delay(50, waitTimeout.Token).ContinueWith(_ => { }, TaskScheduler.Default);
 
         // Subscribe on hub for a subject
         await using var hubConn = new NatsConnection(new NatsOpts
@@ -115,9 +112,7 @@ public class LeafNodeJetStreamTests
         await hubConn.PingAsync();
 
         // Wait for interest propagation
-        using var interestTimeout = new CancellationTokenSource(TimeSpan.FromSeconds(5));
+        await PollHelper.WaitUntilAsync(() => !(!spoke.HasRemoteInterest("js.leaf.test")), timeoutMs: 5000);
-        while (!interestTimeout.IsCancellationRequested && !spoke.HasRemoteInterest("js.leaf.test"))
-            await Task.Delay(50, interestTimeout.Token).ContinueWith(_ => { }, TaskScheduler.Default);
 
         // Publish from spoke
         await using var spokeConn = new NatsConnection(new NatsOpts
@@ -178,9 +173,7 @@ public class LeafNodeJetStreamTests
         _ = spoke.StartAsync(spokeCts.Token);
         await spoke.WaitForReadyAsync();
 
-        using var waitTimeout = new CancellationTokenSource(TimeSpan.FromSeconds(5));
+        await PollHelper.WaitUntilAsync(() => !((hub.Stats.Leafs == 0 || spoke.Stats.Leafs == 0)), timeoutMs: 5000);
-        while (!waitTimeout.IsCancellationRequested && (hub.Stats.Leafs == 0 || spoke.Stats.Leafs == 0))
-            await Task.Delay(50, waitTimeout.Token).ContinueWith(_ => { }, TaskScheduler.Default);
 
         hub.Stats.JetStreamEnabled.ShouldBeTrue();
         spoke.Stats.JetStreamEnabled.ShouldBeFalse();
@@ -191,9 +184,7 @@ public class LeafNodeJetStreamTests
         await using var sub = await hubConn.SubscribeCoreAsync<string>("njs.forward");
         await hubConn.PingAsync();
 
-        using var interestTimeout = new CancellationTokenSource(TimeSpan.FromSeconds(5));
+        await PollHelper.WaitUntilAsync(() => !(!spoke.HasRemoteInterest("njs.forward")), timeoutMs: 5000);
-        while (!interestTimeout.IsCancellationRequested && !spoke.HasRemoteInterest("njs.forward"))
-            await Task.Delay(50, interestTimeout.Token).ContinueWith(_ => { }, TaskScheduler.Default);
 
         // Publish from spoke
         await using var spokeConn = new NatsConnection(new NatsOpts { Url = $"nats://127.0.0.1:{spoke.Port}" });
@@ -253,9 +244,7 @@ public class LeafNodeJetStreamTests
         _ = spoke.StartAsync(spokeCts.Token);
         await spoke.WaitForReadyAsync();
 
-        using var waitTimeout = new CancellationTokenSource(TimeSpan.FromSeconds(5));
+        await PollHelper.WaitUntilAsync(() => !((hub.Stats.Leafs == 0 || spoke.Stats.Leafs == 0)), timeoutMs: 5000);
-        while (!waitTimeout.IsCancellationRequested && (hub.Stats.Leafs == 0 || spoke.Stats.Leafs == 0))
-            await Task.Delay(50, waitTimeout.Token).ContinueWith(_ => { }, TaskScheduler.Default);
 
         hub.Stats.JetStreamEnabled.ShouldBeTrue();
         spoke.Stats.JetStreamEnabled.ShouldBeTrue();
@@ -309,9 +298,7 @@ public class LeafNodeJetStreamTests
         _ = spoke.StartAsync(spokeCts.Token);
         await spoke.WaitForReadyAsync();
 
-        using var waitTimeout = new CancellationTokenSource(TimeSpan.FromSeconds(5));
+        await PollHelper.WaitUntilAsync(() => !((hub.Stats.Leafs == 0 || spoke.Stats.Leafs == 0)), timeoutMs: 5000);
-        while (!waitTimeout.IsCancellationRequested && (hub.Stats.Leafs == 0 || spoke.Stats.Leafs == 0))
-            await Task.Delay(50, waitTimeout.Token).ContinueWith(_ => { }, TaskScheduler.Default);
 
         // Regular pub/sub should still work alongside JS
         await using var leafConn = new NatsConnection(new NatsOpts { Url = $"nats://127.0.0.1:{spoke.Port}" });
@@ -322,9 +309,7 @@ public class LeafNodeJetStreamTests
         await using var sub = await leafConn.SubscribeCoreAsync<string>("combo.test");
         await leafConn.PingAsync();
 
-        using var interestTimeout = new CancellationTokenSource(TimeSpan.FromSeconds(5));
+        await PollHelper.WaitUntilAsync(() => !(!hub.HasRemoteInterest("combo.test")), timeoutMs: 5000);
-        while (!interestTimeout.IsCancellationRequested && !hub.HasRemoteInterest("combo.test"))
-            await Task.Delay(50, interestTimeout.Token).ContinueWith(_ => { }, TaskScheduler.Default);
 
         await hubConn.PublishAsync("combo.test", "js-combo");
 

tests/NATS.Server.LeafNodes.Tests/LeafNodes/LeafNodeLoopDetectionTests.cs

@@ -1,6 +1,6 @@
 using NATS.Server.LeafNodes;
 
-namespace NATS.Server.Tests.LeafNodes;
+namespace NATS.Server.LeafNodes.Tests.LeafNodes;
 
 /// <summary>
 /// Tests for leaf node loop detection via $LDS. prefix.

tests/NATS.Server.LeafNodes.Tests/LeafNodes/LeafNodeManagerParityBatch5Tests.cs

@@ -5,7 +5,7 @@ using Microsoft.Extensions.Logging.Abstractions;
 using NATS.Server.Configuration;
 using NATS.Server.LeafNodes;
 
-namespace NATS.Server.Tests.LeafNodes;
+namespace NATS.Server.LeafNodes.Tests.LeafNodes;
 
 public class LeafNodeManagerParityBatch5Tests
 {

tests/NATS.Server.LeafNodes.Tests/LeafNodes/LeafNodeSubjectFilterTests.cs

@@ -1,7 +1,7 @@
 using NATS.Client.Core;
 using NATS.Server.TestUtilities;
 
-namespace NATS.Server.Tests.LeafNodes;
+namespace NATS.Server.LeafNodes.Tests.LeafNodes;
 
 /// <summary>
 /// Tests for subject filter propagation through leaf nodes.
@@ -105,9 +105,7 @@ public class LeafNodeSubjectFilterTests
         await sub.DisposeAsync();
         await leafConn.PingAsync();
 
-        using var timeout = new CancellationTokenSource(TimeSpan.FromSeconds(5));
+        await PollHelper.WaitUntilAsync(() => !(fixture.Hub.HasRemoteInterest("unsub.test")), timeoutMs: 5000);
-        while (!timeout.IsCancellationRequested && fixture.Hub.HasRemoteInterest("unsub.test"))
-            await Task.Delay(50, timeout.Token).ContinueWith(_ => { }, TaskScheduler.Default);
 
         fixture.Hub.HasRemoteInterest("unsub.test").ShouldBeFalse();
     }

tests/NATS.Server.LeafNodes.Tests/LeafNodes/LeafPermissionSyncTests.cs

@@ -5,7 +5,7 @@ using Microsoft.Extensions.Logging.Abstractions;
 using NATS.Server.Configuration;
 using NATS.Server.LeafNodes;
 
-namespace NATS.Server.Tests.LeafNodes;
+namespace NATS.Server.LeafNodes.Tests.LeafNodes;
 
 /// <summary>
 /// Unit tests for leaf node permission and account syncing (Gap 12.2).

tests/NATS.Server.LeafNodes.Tests/LeafNodes/LeafSolicitedConnectionTests.cs

@@ -5,8 +5,9 @@ using Microsoft.Extensions.Logging.Abstractions;
 using NATS.Server.Configuration;
 using NATS.Server.LeafNodes;
 using NATS.Server.Subscriptions;
+using NATS.Server.TestUtilities;
 
-namespace NATS.Server.Tests.LeafNodes;
+namespace NATS.Server.LeafNodes.Tests.LeafNodes;
 
 /// <summary>
 /// Tests for solicited (outbound) leaf node connections with retry logic,
@@ -55,9 +56,7 @@ public class LeafSolicitedConnectionTests
         await spoke.WaitForReadyAsync();
 
         // Wait for leaf connections to establish
-        using var timeout = new CancellationTokenSource(TimeSpan.FromSeconds(5));
+        await PollHelper.WaitUntilAsync(() => !((hub.Stats.Leafs == 0 || spoke.Stats.Leafs == 0)), timeoutMs: 5000);
-        while (!timeout.IsCancellationRequested && (hub.Stats.Leafs == 0 || spoke.Stats.Leafs == 0))
-            await Task.Delay(50, timeout.Token).ContinueWith(_ => { }, TaskScheduler.Default);
 
         hub.Stats.Leafs.ShouldBeGreaterThan(0);
         spoke.Stats.Leafs.ShouldBeGreaterThan(0);
@@ -93,7 +92,7 @@ public class LeafSolicitedConnectionTests
         await manager.StartAsync(cts.Token);
 
         // Give it some time to attempt connections
-        await Task.Delay(500);
+        await PollHelper.YieldForAsync(500);
 
         // No connections should have succeeded
         stats.Leafs.ShouldBe(0);
@@ -185,7 +184,7 @@ public class LeafSolicitedConnectionTests
         await manager.StartAsync(cts.Token);
 
         // Let it attempt at least one retry
-        await Task.Delay(200);
+        await PollHelper.YieldForAsync(200);
 
         // Cancel — the retry loop should stop promptly
         await cts.CancelAsync();

tests/NATS.Server.LeafNodes.Tests/LeafNodes/LeafSubKeyParityBatch2Tests.cs

@@ -1,7 +1,7 @@
 using NATS.Server.LeafNodes;
 using NATS.Server.Subscriptions;
 
-namespace NATS.Server.Tests.LeafNodes;
+namespace NATS.Server.LeafNodes.Tests.LeafNodes;
 
 public class LeafSubKeyParityBatch2Tests
 {

tests/NATS.Server.LeafNodes.Tests/LeafNodes/LeafSubjectFilterTests.cs

@@ -6,8 +6,9 @@ using NATS.Client.Core;
 using NATS.Server.Configuration;
 using NATS.Server.LeafNodes;
 using NATS.Server.Subscriptions;
+using NATS.Server.TestUtilities;
 
-namespace NATS.Server.Tests.LeafNodes;
+namespace NATS.Server.LeafNodes.Tests.LeafNodes;
 
 /// <summary>
 /// Tests for leaf node subject filtering via DenyExports/DenyImports (deny-lists) and
@@ -196,9 +197,7 @@ public class LeafSubjectFilterTests
             try
             {
                 // Wait for leaf connection
-                using var timeout = new CancellationTokenSource(TimeSpan.FromSeconds(5));
+                await PollHelper.WaitUntilAsync(() => !((hub.Stats.Leafs == 0 || spoke.Stats.Leafs == 0)), timeoutMs: 5000);
-                while (!timeout.IsCancellationRequested && (hub.Stats.Leafs == 0 || spoke.Stats.Leafs == 0))
-                    await Task.Delay(50, timeout.Token).ContinueWith(_ => { }, TaskScheduler.Default);
 
                 await using var leafConn = new NatsConnection(new NatsOpts { Url = $"nats://127.0.0.1:{spoke.Port}" });
                 await leafConn.ConnectAsync();
@@ -211,7 +210,7 @@ public class LeafSubjectFilterTests
                 await leafConn.PingAsync();
 
                 // Wait for interest propagation
-                await Task.Delay(500);
+                await PollHelper.YieldForAsync(500);
 
                 // Publish from hub
                 await hubConn.PublishAsync("public.data", "allowed-msg");
@@ -285,9 +284,7 @@ public class LeafSubjectFilterTests
             try
             {
                 // Wait for leaf connection
-                using var timeout = new CancellationTokenSource(TimeSpan.FromSeconds(5));
+                await PollHelper.WaitUntilAsync(() => !((hub.Stats.Leafs == 0 || spoke.Stats.Leafs == 0)), timeoutMs: 5000);
-                while (!timeout.IsCancellationRequested && (hub.Stats.Leafs == 0 || spoke.Stats.Leafs == 0))
-                    await Task.Delay(50, timeout.Token).ContinueWith(_ => { }, TaskScheduler.Default);
 
                 await using var hubConn = new NatsConnection(new NatsOpts { Url = $"nats://127.0.0.1:{hub.Port}" });
                 await hubConn.ConnectAsync();
@@ -300,7 +297,7 @@ public class LeafSubjectFilterTests
                 await hubConn.PingAsync();
 
                 // Wait for interest propagation
-                await Task.Delay(500);
+                await PollHelper.YieldForAsync(500);
 
                 // Publish from spoke (leaf)
                 await leafConn.PublishAsync("public.data", "allowed-msg");
@@ -372,9 +369,7 @@ public class LeafSubjectFilterTests
 
             try
             {
-                using var timeout = new CancellationTokenSource(TimeSpan.FromSeconds(5));
+                await PollHelper.WaitUntilAsync(() => !((hub.Stats.Leafs == 0 || spoke.Stats.Leafs == 0)), timeoutMs: 5000);
-                while (!timeout.IsCancellationRequested && (hub.Stats.Leafs == 0 || spoke.Stats.Leafs == 0))
-                    await Task.Delay(50, timeout.Token).ContinueWith(_ => { }, TaskScheduler.Default);
 
                 await using var leafConn = new NatsConnection(new NatsOpts { Url = $"nats://127.0.0.1:{spoke.Port}" });
                 await leafConn.ConnectAsync();
@@ -385,7 +380,7 @@ public class LeafSubjectFilterTests
                 await using var blockedSub = await leafConn.SubscribeCoreAsync<string>("admin.users");
                 await using var allowedSub = await leafConn.SubscribeCoreAsync<string>("admin.deep.nested");
                 await leafConn.PingAsync();
-                await Task.Delay(500);
+                await PollHelper.YieldForAsync(500);
 
                 await hubConn.PublishAsync("admin.users", "blocked");
                 await hubConn.PublishAsync("admin.deep.nested", "allowed");
@@ -451,11 +446,11 @@ public class LeafSubjectFilterTests
             var line = await ReadLineAsync(remoteSocket, cts.Token);
             line.ShouldStartWith("LEAF ");
 
-            await Task.Delay(200);
+            await PollHelper.YieldForAsync(200);
 
             // Propagate allowed subscription
             manager.PropagateLocalSubscription("$G", "public.data", null);
-            await Task.Delay(100);
+            await PollHelper.YieldForAsync(100);
             var lsLine = await ReadLineAsync(remoteSocket, cts.Token);
             lsLine.ShouldBe("LS+ $G public.data");
 
@@ -464,7 +459,7 @@ public class LeafSubjectFilterTests
 
             // Send a PING to verify nothing else was sent
             manager.PropagateLocalSubscription("$G", "allowed.check", null);
-            await Task.Delay(100);
+            await PollHelper.YieldForAsync(100);
             var nextLine = await ReadLineAsync(remoteSocket, cts.Token);
             nextLine.ShouldBe("LS+ $G allowed.check");
         }
@@ -687,9 +682,7 @@ public class LeafSubjectFilterTests
 
             try
             {
-                using var timeout = new CancellationTokenSource(TimeSpan.FromSeconds(5));
+                await PollHelper.WaitUntilAsync(() => !((hub.Stats.Leafs == 0 || spoke.Stats.Leafs == 0)), timeoutMs: 5000);
-                while (!timeout.IsCancellationRequested && (hub.Stats.Leafs == 0 || spoke.Stats.Leafs == 0))
-                    await Task.Delay(50, timeout.Token).ContinueWith(_ => { }, TaskScheduler.Default);
 
                 await using var leafConn = new NatsConnection(new NatsOpts { Url = $"nats://127.0.0.1:{spoke.Port}" });
                 await leafConn.ConnectAsync();
@@ -699,7 +692,7 @@ public class LeafSubjectFilterTests
                 await using var allowedSub = await leafConn.SubscribeCoreAsync<string>("allowed.data");
                 await using var blockedSub = await leafConn.SubscribeCoreAsync<string>("blocked.data");
                 await leafConn.PingAsync();
-                await Task.Delay(500);
+                await PollHelper.YieldForAsync(500);
 
                 await hubConn.PublishAsync("allowed.data", "yes");
                 await hubConn.PublishAsync("blocked.data", "no");
@@ -768,9 +761,7 @@ public class LeafSubjectFilterTests
 
             try
             {
-                using var timeout = new CancellationTokenSource(TimeSpan.FromSeconds(5));
+                await PollHelper.WaitUntilAsync(() => !((hub.Stats.Leafs == 0 || spoke.Stats.Leafs == 0)), timeoutMs: 5000);
-                while (!timeout.IsCancellationRequested && (hub.Stats.Leafs == 0 || spoke.Stats.Leafs == 0))
-                    await Task.Delay(50, timeout.Token).ContinueWith(_ => { }, TaskScheduler.Default);
 
                 await using var hubConn = new NatsConnection(new NatsOpts { Url = $"nats://127.0.0.1:{hub.Port}" });
                 await hubConn.ConnectAsync();
@@ -780,7 +771,7 @@ public class LeafSubjectFilterTests
                 await using var allowedSub = await hubConn.SubscribeCoreAsync<string>("allowed.data");
                 await using var blockedSub = await hubConn.SubscribeCoreAsync<string>("blocked.data");
                 await hubConn.PingAsync();
-                await Task.Delay(500);
+                await PollHelper.YieldForAsync(500);
 
                 await leafConn.PublishAsync("allowed.data", "yes");
                 await leafConn.PublishAsync("blocked.data", "no");
@@ -839,11 +830,11 @@ public class LeafSubjectFilterTests
             var line = await ReadLineAsync(remoteSocket, cts.Token);
             line.ShouldStartWith("LEAF ");
 
-            await Task.Delay(200);
+            await PollHelper.YieldForAsync(200);
 
             // Propagate allowed subscription
             manager.PropagateLocalSubscription("$G", "allowed.data", null);
-            await Task.Delay(100);
+            await PollHelper.YieldForAsync(100);
             var lsLine = await ReadLineAsync(remoteSocket, cts.Token);
             lsLine.ShouldBe("LS+ $G allowed.data");
 
@@ -852,7 +843,7 @@ public class LeafSubjectFilterTests
 
             // Verify by sending another allowed subscription
             manager.PropagateLocalSubscription("$G", "allowed.check", null);
-            await Task.Delay(100);
+            await PollHelper.YieldForAsync(100);
             var nextLine = await ReadLineAsync(remoteSocket, cts.Token);
             nextLine.ShouldBe("LS+ $G allowed.check");
         }

tests/NATS.Server.LeafNodes.Tests/LeafNodes/LeafTlsReloadTests.cs

@@ -2,7 +2,7 @@ using Microsoft.Extensions.Logging.Abstractions;
 using NATS.Server.Configuration;
 using NATS.Server.LeafNodes;
 
-namespace NATS.Server.Tests.LeafNodes;
+namespace NATS.Server.LeafNodes.Tests.LeafNodes;
 
 /// <summary>
 /// Unit tests for leaf node TLS certificate hot-reload (Gap 12.1).

tests/NATS.Server.LeafNodes.Tests/LeafNodes/LeafValidationTests.cs

@@ -4,7 +4,7 @@ using Microsoft.Extensions.Logging.Abstractions;
 using NATS.Server.Configuration;
 using NATS.Server.LeafNodes;
 
-namespace NATS.Server.Tests.LeafNodes;
+namespace NATS.Server.LeafNodes.Tests.LeafNodes;
 
 /// <summary>
 /// Unit tests for leaf node reconnect state validation (Gap 12.3).

tests/NATS.Server.LeafNodes.Tests/LeafNodes/LeafWebSocketTests.cs

@@ -3,7 +3,7 @@ using System.Net.WebSockets;
 using NSubstitute;
 using NATS.Server.LeafNodes;
 
-namespace NATS.Server.Tests.LeafNodes;
+namespace NATS.Server.LeafNodes.Tests.LeafNodes;
 
 /// <summary>
 /// Unit tests for <see cref="WebSocketStreamAdapter"/> (Gap 12.5).

tests/NATS.Server.LeafNodes.Tests/LeafProtocolTests.cs

@@ -3,8 +3,9 @@ using System.Net.Sockets;
 using System.Text;
 using Microsoft.Extensions.Logging.Abstractions;
 using NATS.Server.Configuration;
+using NATS.Server.TestUtilities;
 
-namespace NATS.Server.Tests;
+namespace NATS.Server.LeafNodes.Tests;
 
 public class LeafProtocolTests
 {
@@ -70,9 +71,7 @@ internal sealed class LeafProtocolTestFixture : IAsyncDisposable
         _ = spoke.StartAsync(spokeCts.Token);
         await spoke.WaitForReadyAsync();
 
-        using var timeout = new CancellationTokenSource(TimeSpan.FromSeconds(5));
+        await PollHelper.WaitUntilAsync(() => hub.Stats.Leafs > 0 && spoke.Stats.Leafs > 0);
-        while (!timeout.IsCancellationRequested && (hub.Stats.Leafs == 0 || spoke.Stats.Leafs == 0))
-            await Task.Delay(50, timeout.Token).ContinueWith(_ => { }, TaskScheduler.Default);
 
         return new LeafProtocolTestFixture(hub, spoke, hubCts, spokeCts);
     }
@@ -85,7 +84,7 @@ internal sealed class LeafProtocolTestFixture : IAsyncDisposable
 
         _ = await ReadLineAsync(sock); // INFO
         await sock.SendAsync(Encoding.ASCII.GetBytes($"CONNECT {{}}\r\nSUB {subject} 1\r\nPING\r\n"));
-        await ReadUntilAsync(sock, "PONG");
+        await SocketTestHelper.ReadUntilAsync(sock, "PONG");
     }
 
     public async Task PublishHubAsync(string subject, string payload)
@@ -98,11 +97,11 @@ internal sealed class LeafProtocolTestFixture : IAsyncDisposable
             _hubPublisher = sock;
             _ = await ReadLineAsync(sock); // INFO
             await sock.SendAsync(Encoding.ASCII.GetBytes("CONNECT {}\r\nPING\r\n"));
-            await ReadUntilAsync(sock, "PONG");
+            await SocketTestHelper.ReadUntilAsync(sock, "PONG");
         }
 
         await sock.SendAsync(Encoding.ASCII.GetBytes($"PUB {subject} {payload.Length}\r\n{payload}\r\nPING\r\n"));
-        await ReadUntilAsync(sock, "PONG");
+        await SocketTestHelper.ReadUntilAsync(sock, "PONG");
     }
 
     public Task<string> ReadSpokeMessageAsync()
@@ -110,7 +109,7 @@ internal sealed class LeafProtocolTestFixture : IAsyncDisposable
         if (_spokeSubscriber == null)
             throw new InvalidOperationException("Spoke subscriber was not initialized.");
 
-        return ReadUntilAsync(_spokeSubscriber, "MSG ");
+        return SocketTestHelper.ReadUntilAsync(_spokeSubscriber, "MSG ");
     }
 
     public async ValueTask DisposeAsync()
@@ -132,20 +131,5 @@ internal sealed class LeafProtocolTestFixture : IAsyncDisposable
         return Encoding.ASCII.GetString(buf, 0, n);
     }
 
-    private static async Task<string> ReadUntilAsync(Socket sock, string expected)
-    {
-        var sb = new StringBuilder();
-        var buf = new byte[4096];
-        using var cts = new CancellationTokenSource(TimeSpan.FromSeconds(5));
 
-        while (!sb.ToString().Contains(expected, StringComparison.Ordinal))
-        {
-            var n = await sock.ReceiveAsync(buf, SocketFlags.None, cts.Token);
-            if (n == 0)
-                break;
-            sb.Append(Encoding.ASCII.GetString(buf, 0, n));
-        }
-
-        return sb.ToString();
-    }
 }

tests/NATS.Server.LeafNodes.Tests/NATS.Server.LeafNodes.Tests.csproj

@@ -0,0 +1,25 @@
+<Project Sdk="Microsoft.NET.Sdk">
+  <PropertyGroup>
+    <IsPackable>false</IsPackable>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="coverlet.collector" />
+    <PackageReference Include="Microsoft.NET.Test.Sdk" />
+    <PackageReference Include="NATS.Client.Core" />
+    <PackageReference Include="NSubstitute" />
+    <PackageReference Include="Shouldly" />
+    <PackageReference Include="xunit" />
+    <PackageReference Include="xunit.runner.visualstudio" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <Using Include="Xunit" />
+    <Using Include="Shouldly" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\..\src\NATS.Server\NATS.Server.csproj" />
+    <ProjectReference Include="..\NATS.Server.TestUtilities\NATS.Server.TestUtilities.csproj" />
+  </ItemGroup>
+</Project>