Fix handshaking of dotnet test for MTP (#50513)

Co-authored-by: Copilot <[email protected]>

Author: Youssef1313

src/Cli/dotnet/Commands/Test/Terminal/TerminalTestReporter.cs

@@ -710,7 +710,10 @@ private static void AppendAssemblyLinkTargetFrameworkAndArchitecture(ITerminal t
             if (targetFramework != null)
             {
                 terminal.Append(targetFramework);
-                terminal.Append('|');
+                if (architecture != null)
+                {
+                    terminal.Append('|');
+                }
             }
 
             if (architecture != null)
@@ -822,6 +825,15 @@ internal void AssemblyRunCompleted(string executionId,
 
     internal void HandshakeFailure(string assemblyPath, string targetFramework, int exitCode, string outputData, string errorData)
     {
+        if (_isHelp)
+        {
+            // Ignore handshake failures for help for now.
+            // So far, MTP doesn't handshake on help.
+            // MTP should be updated for that, however, but this workaround will likely need to stay
+            // here for a bit to keep compatibility with older MTP versions. It doesn't have to stay for too long though.
+            return;
+        }
+
         Interlocked.Increment(ref _handshakeFailuresCount);
         _terminalWithProgress.WriteToTerminal(terminal =>
         {

src/Cli/dotnet/Commands/Test/TestApplicationEventHandlers.cs

@@ -17,14 +17,22 @@ internal sealed class TestApplicationsEventHandlers(TerminalTestReporter output)
 
     public void OnHandshakeReceived(object sender, HandshakeArgs args)
     {
+        var testApplication = (TestApplication)sender;
+        // Today, it's 1.0.0 in MTP.
+        // https://github.com/microsoft/testfx/blob/516eebb3c9b7e81eb2677c00b3d0b7867d8acb33/src/Platform/Microsoft.Testing.Platform/ServerMode/DotnetTest/IPC/Constants.cs#L40
+        var supportedProtocolVersions = args.Handshake.Properties[HandshakeMessagePropertyNames.SupportedProtocolVersions];
+        if (supportedProtocolVersions != "1.0.0" && !supportedProtocolVersions.Split(';').Contains("1.0.0"))
+        {
+            _output.HandshakeFailure(testApplication.Module.TargetPath, string.Empty, ExitCode.GenericFailure, $"Supported protocol versions '{supportedProtocolVersions}' doesn't include '1.0.0' which is not supported by the current .NET SDK.", string.Empty);
+        }
+
         var hostType = args.Handshake.Properties[HandshakeMessagePropertyNames.HostType];
         // https://github.com/microsoft/testfx/blob/2a9a353ec2bb4ce403f72e8ba1f29e01e7cf1fd4/src/Platform/Microsoft.Testing.Platform/Hosts/CommonTestHost.cs#L87-L97
         if (hostType == "TestHost")
         {
             // AssemblyRunStarted counts "retry count", and writes to terminal "(Try <number-of-try>) Running tests from <assembly>"
             // So, we want to call it only for test host, and not for test host controller (or orchestrator, if in future it will handshake as well)
             // Calling it for both test host and test host controllers means we will count retries incorrectly, and will messages twice.
-            var testApplication = (TestApplication)sender;
             var executionId = args.Handshake.Properties[HandshakeMessagePropertyNames.ExecutionId];
             var instanceId = args.Handshake.Properties[HandshakeMessagePropertyNames.InstanceId];
             var arch = args.Handshake.Properties[HandshakeMessagePropertyNames.Architecture]?.ToLower();

src/Cli/dotnet/Commands/Test/TestingPlatformCommand.cs

@@ -151,6 +151,7 @@ private void InitializeHelpActionQueue(int degreeOfParallelism, TestOptions test
     {
         _actionQueue = new(degreeOfParallelism, buildOptions, async (TestApplication testApp) =>
         {
+            testApp.HandshakeReceived += _eventHandlers.OnHandshakeReceived;
             testApp.HelpRequested += OnHelpRequested;
             testApp.ErrorReceived += _eventHandlers.OnErrorReceived;
             testApp.TestProcessExited += _eventHandlers.OnTestProcessExited;