Avoid logging to stale ITestOutputHelper in fixture disposal

Author: halter73

tests/ModelContextProtocol.Tests/SseServerIntegrationTestFixture.cs

@@ -11,9 +11,9 @@ public class SseServerIntegrationTestFixture : IAsyncDisposable
 {
     private readonly Task _serverTask;
     private readonly CancellationTokenSource _stopCts = new();
-    private DelegatingTestOutputHelper _delegatingTestOutputHelper = new();
 
-    private ILoggerFactory _redirectingLoggerFactory;
+    private readonly DelegatingTestOutputHelper _delegatingTestOutputHelper = new();
+    private readonly ILoggerFactory _redirectingLoggerFactory;
 
     public McpClientOptions DefaultOptions { get; }
     public McpServerConfig DefaultConfig { get; }
@@ -50,6 +50,7 @@ public void Initialize(ITestOutputHelper output)
 
     public async ValueTask DisposeAsync()
     {
+        _delegatingTestOutputHelper.CurrentTestOutputHelper = null;
         _redirectingLoggerFactory.Dispose();
         _stopCts.Cancel();
         try