From 719eade5e0817d643167a6913582dec9b96dc4a5 Mon Sep 17 00:00:00 2001 From: Tarek Mahmoud Sayed <10833894+tarekgh@users.noreply.github.com> Date: Thu, 4 Jun 2026 15:06:16 -0700 Subject: [PATCH] Fix flaky AddIncomingMessageFilter_Multiple_Filters_Execute_In_Order test (#1627) Co-authored-by: Tarek Mahmoud Sayed --- ...cpServerBuilderExtensionsMessageFilterTests.cs | 15 +++++++++++++++ 1 file changed, 15 insertions(+) diff --git a/tests/ModelContextProtocol.Tests/Configuration/McpServerBuilderExtensionsMessageFilterTests.cs b/tests/ModelContextProtocol.Tests/Configuration/McpServerBuilderExtensionsMessageFilterTests.cs index a39d489..c59c6a0 100644 --- a/tests/ModelContextProtocol.Tests/Configuration/McpServerBuilderExtensionsMessageFilterTests.cs +++ b/tests/ModelContextProtocol.Tests/Configuration/McpServerBuilderExtensionsMessageFilterTests.cs @@ -100,6 +100,12 @@ public class McpServerBuilderExtensionsMessageFilterTests(ITestOutputHelper test [Fact] public async Task AddIncomingMessageFilter_Multiple_Filters_Execute_In_Order() { + // The client sends notifications/initialized fire-and-forget, so unlike the initialize and + // tools/list request/response exchanges it has no synchronization point the test can await. + // Signal once the outermost filter finishes processing it so the strict counts below observe a + // complete, stable log instead of racing the still-in-flight notification. + var initializedNotificationProcessed = new TaskCompletionSource(TaskCreationOptions.RunContinuationsAsynchronously); + McpServerBuilder .WithMessageFilters(filters => { @@ -109,6 +115,11 @@ public class McpServerBuilderExtensionsMessageFilterTests(ITestOutputHelper test logger.LogInformation("MessageFilter1 before"); await next(context, cancellationToken); logger.LogInformation("MessageFilter1 after"); + + if (context.JsonRpcMessage is JsonRpcNotification { Method: NotificationMethods.InitializedNotification }) + { + initializedNotificationProcessed.TrySetResult(true); + } }); filters.AddIncomingFilter((next) => async (context, cancellationToken) => @@ -127,6 +138,10 @@ public class McpServerBuilderExtensionsMessageFilterTests(ITestOutputHelper test await client.ListToolsAsync(cancellationToken: TestContext.Current.CancellationToken); + // Wait for the fire-and-forget initialized notification to flow through the filter pipeline + // before snapshotting the log; otherwise the strict counts below can race the notification. + await initializedNotificationProcessed.Task.WaitAsync(TestConstants.DefaultTimeout, TestContext.Current.CancellationToken); + var logMessages = MockLoggerProvider.LogMessages .Where(m => m.Category.StartsWith("MessageFilter")) .Select(m => m.Message)