Add TestEventSource and use it in TestInvoker (#2884)

src/xunit.v3.core/Sdk/v3/EventSources/TestEventSource.cs

@@ -0,0 +1,30 @@
+using System.Diagnostics.Tracing;
+
+namespace Xunit.v3;
+
+[EventSource(Name = sourceName, Guid = "ae399e80-45fc-4219-aacc-b73a458ad7e1")]
+internal sealed class TestEventSource : EventSource
+{
+	const string sourceName = "xUnit.TestEventSource";
+
+	internal static readonly TestEventSource Log = new();
+
+	TestEventSource() { }
+
+	[Event(Events.TestStart, Level = EventLevel.Informational, Task = Tasks.Test, Opcode = EventOpcode.Start)]
+	internal void TestStart(string testName) => WriteEvent(Events.TestStart, testName);
+
+	[Event(Events.TestStop, Level = EventLevel.Informational, Task = Tasks.Test, Opcode = EventOpcode.Stop)]
+	internal void TestStop(string testName) => WriteEvent(Events.TestStop, testName);
+
+	class Events
+	{
+		internal const int TestStart = 1;
+		internal const int TestStop = 2;
+	}
+
+	class Tasks
+	{
+		internal const EventTask Test = (EventTask)1;
+	}
+}

src/xunit.v3.core/Sdk/v3/Runners/TestInvoker.cs

@@ -185,15 +185,28 @@ public abstract class TestInvoker<TContext>
 						}
 						else
 						{
-							var result = CallTestMethod(ctxt, testClassInstance);
-							var valueTask = AsyncUtility.TryConvertToValueTask(result);
-							if (valueTask.HasValue)
-								await valueTask.Value;
-							else if (asyncSyncContext is not null)
+							var logEnabled = TestEventSource.Log.IsEnabled();
+
+							if (logEnabled)
+								TestEventSource.Log.TestStart(ctxt.Test.TestDisplayName);
+
+							try
+							{
+								var result = CallTestMethod(ctxt, testClassInstance);
+								var valueTask = AsyncUtility.TryConvertToValueTask(result);
+								if (valueTask.HasValue)
+									await valueTask.Value;
+								else if (asyncSyncContext is not null)
+								{
+									var ex = await asyncSyncContext.WaitForCompletionAsync();
+									if (ex is not null)
+										ctxt.Aggregator.Add(ex);
+								}
+							}
+							finally
 							{
-								var ex = await asyncSyncContext.WaitForCompletionAsync();
-								if (ex is not null)
-									ctxt.Aggregator.Add(ex);
+								if (logEnabled)
+									TestEventSource.Log.TestStop(ctxt.Test.TestDisplayName);
 							}
 						}
 					}