From cec0744bb2d5421c41f85facccad55e56fd79b5e Mon Sep 17 00:00:00 2001
From: Tom Longhurst <30480171+thomhurst@users.noreply.github.com>
Date: Mon, 12 Jan 2026 00:37:18 +0000
Subject: [PATCH] perf: skip Discovered messages during test execution

- Remove Discovered message loop from HandleRunRequestAsync
- Only send Discovered messages during discovery requests
- Change DynamicTestQueue.EnqueueAsync to sync Enqueue
- Dynamic tests created at runtime don't need discovery notifications

This saves time and allocations when running tests since Discovered
messages are only needed for test explorer discovery, not execution.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
---
 TUnit.Engine/Framework/TestRequestHandler.cs | 7 ++-----
 TUnit.Engine/Interfaces/IDynamicTestQueue.cs | 5 ++---
 TUnit.Engine/Services/DynamicTestQueue.cs    | 5 +++--
 TUnit.Engine/Services/TestRegistry.cs        | 2 +-
 4 files changed, 8 insertions(+), 11 deletions(-)

diff --git a/TUnit.Engine/Framework/TestRequestHandler.cs b/TUnit.Engine/Framework/TestRequestHandler.cs
index b431468cd7..6ca42cf218 100644
--- a/TUnit.Engine/Framework/TestRequestHandler.cs
+++ b/TUnit.Engine/Framework/TestRequestHandler.cs
@@ -65,11 +65,8 @@ private async Task HandleRunRequestAsync(
 
         var allTests = discoveryResult.Tests.ToArray();
 
-        foreach (var test in allTests)
-        {
-            context.CancellationToken.ThrowIfCancellationRequested();
-            await serviceProvider.MessageBus.Discovered(test.Context);
-        }
+        // Skip sending Discovered messages during execution - they're only needed for discovery requests
+        // This saves significant time and allocations when running tests
 
         await serviceProvider.TestSessionCoordinator.ExecuteTests(
             allTests,
diff --git a/TUnit.Engine/Interfaces/IDynamicTestQueue.cs b/TUnit.Engine/Interfaces/IDynamicTestQueue.cs
index 4dfc42f872..501336a0c2 100644
--- a/TUnit.Engine/Interfaces/IDynamicTestQueue.cs
+++ b/TUnit.Engine/Interfaces/IDynamicTestQueue.cs
@@ -10,11 +10,10 @@ namespace TUnit.Engine.Interfaces;
 internal interface IDynamicTestQueue
 {
     /// <summary>
-    /// Enqueues a test for execution and notifies the message bus. Thread-safe.
+    /// Enqueues a test for execution. Thread-safe.
     /// </summary>
     /// <param name="test">The test to enqueue</param>
-    /// <returns>Task that completes when the test is enqueued and discovery is notified</returns>
-    Task EnqueueAsync(AbstractExecutableTest test);
+    void Enqueue(AbstractExecutableTest test);
 
     /// <summary>
     /// Attempts to dequeue the next test. Thread-safe.
diff --git a/TUnit.Engine/Services/DynamicTestQueue.cs b/TUnit.Engine/Services/DynamicTestQueue.cs
index 16d157365c..714a1d309c 100644
--- a/TUnit.Engine/Services/DynamicTestQueue.cs
+++ b/TUnit.Engine/Services/DynamicTestQueue.cs
@@ -29,7 +29,7 @@ public DynamicTestQueue(ITUnitMessageBus messageBus)
         });
     }
 
-    public async Task EnqueueAsync(AbstractExecutableTest test)
+    public void Enqueue(AbstractExecutableTest test)
     {
         Interlocked.Increment(ref _pendingCount);
 
@@ -39,7 +39,8 @@ public async Task EnqueueAsync(AbstractExecutableTest test)
             throw new InvalidOperationException("Failed to enqueue test to dynamic test queue.");
         }
 
-        await _messageBus.Discovered(test.Context);
+        // Skip sending Discovered message - dynamic tests are created during execution,
+        // and Discovered messages are only needed for discovery requests
     }
 
     public bool TryDequeue(out AbstractExecutableTest? test)
diff --git a/TUnit.Engine/Services/TestRegistry.cs b/TUnit.Engine/Services/TestRegistry.cs
index 4e75f2d07b..0fd6ee844f 100644
--- a/TUnit.Engine/Services/TestRegistry.cs
+++ b/TUnit.Engine/Services/TestRegistry.cs
@@ -101,7 +101,7 @@ private async Task ProcessPendingDynamicTests()
 
         foreach (var test in builtTests)
         {
-            await _dynamicTestQueue.EnqueueAsync(test);
+            _dynamicTestQueue.Enqueue(test);
         }
     }