Retarget the MTP client onto Microsoft.Testing.Platform.ServerMode.Client.Sources

.gitignore

@@ -110,6 +110,9 @@ ehthumbs.db
 
 *.dmp
 *.nupkg
+# Exception: the interim committed local feed for the unshipped source-only MTP client package
+# (Microsoft.Testing.Platform.ServerClient.Source). Remove once microsoft/testfx#10085 ships.
+!eng/local-mtp-feed/*.nupkg
 *.zip
 /src/package/sign/sign.nuget.targets
 

NuGet.config

@@ -5,6 +5,10 @@
   </packageRestore>
   <packageSources>
     <clear />
+    <!-- INTERIM committed local feed for the unshipped source-only MTP client package
+         (Microsoft.Testing.Platform.ServerClient.Source). Repo-relative so it resolves on every
+         machine and in CI. Remove once the package ships to a public feed via microsoft/testfx#10085. -->
+    <add key="local-mtp" value="eng/local-mtp-feed" />
     <!--Begin: Package sources managed by Dependency Flow automation. Do not edit the sources below.-->
     <!--  Begin: Package sources from vs-code-coverage -->
     <!--  End: Package sources from vs-code-coverage -->

eng/Versions.props

@@ -84,6 +84,8 @@
     <!-- Name of the elements must be in sync with test\Microsoft.TestPlatform.TestUtilities\IntegrationTestBase.cs -->
     <AwesomeAssertionsVersion>8.1.0</AwesomeAssertionsVersion>
     <MicrosoftTestingPlatformVersion>2.1.0</MicrosoftTestingPlatformVersion>
+    <!-- INTERIM: unshipped source-only MTP server-mode client from microsoft/testfx#10085, served from the committed eng/local-mtp-feed. Pinned to the coordinator's canonical uniquely-named drop to avoid NuGet same-version cache collisions on shared machines. Remove the feed and repin to the published version once #10085 ships to a real feed. -->
+    <MicrosoftTestingPlatformServerClientSourceVersion>2.4.0-dev.numberfix</MicrosoftTestingPlatformServerClientSourceVersion>
     <MoqVersion>4.16.1</MoqVersion>
     <!-- For coverage use our own package on latest stable -->
     <MicrosoftCodeCoverageVersion>18.3.0</MicrosoftCodeCoverageVersion>

src/Microsoft.TestPlatform.CrossPlatEngine/Client/MTP/MtpClientOptionsFactory.cs

@@ -0,0 +1,90 @@
+// Copyright (c) Microsoft Corporation. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+
+using System;
+using System.Collections.Generic;
+
+using Microsoft.Testing.Platform.ServerMode.Client;
+using Microsoft.VisualStudio.TestPlatform.ObjectModel;
+using Microsoft.VisualStudio.TestPlatform.ObjectModel.Logging;
+
+namespace Microsoft.VisualStudio.TestPlatform.CrossPlatEngine.Client.MTP;
+
+/// <summary>
+/// vstest-side glue for the source-only Microsoft.Testing.Platform (MTP) server client: builds the
+/// <see cref="MtpServerClientOptions"/> that identify vstest to the MTP application, bridge the client's
+/// own diagnostics to <see cref="EqtTrace"/>, and map the server's <c>client/log</c> levels onto vstest's
+/// <see cref="TestMessageLevel"/>.
+/// </summary>
+internal static class MtpClientOptionsFactory
+{
+    /// <summary>
+    /// Builds the options used to launch an MTP application: vstest's client identity, a single
+    /// discover-or-run session (not stateful), the vstest connection timeout, the EqtTrace diagnostics
+    /// bridge, and any environment variables to inject into the launched process.
+    /// </summary>
+    public static MtpServerClientOptions CreateOptions(IDictionary<string, string?>? environmentVariables = null)
+    {
+        var options = new MtpServerClientOptions
+        {
+            ClientName = "vstest",
+            ClientVersion = "1.0.0",
+            DebuggerProvider = false,
+            IsStateful = false,
+            ConnectionTimeout = GetConnectionTimeout(),
+            Logger = new DelegateMtpClientLogger(Trace),
+        };
+
+        if (environmentVariables is not null)
+        {
+            foreach (KeyValuePair<string, string?> variable in environmentVariables)
+            {
+                options.EnvironmentVariables[variable.Key] = variable.Value;
+            }
+        }
+
+        return options;
+    }
+
+    /// <summary>
+    /// Maps a server <c>client/log</c> level string onto the vstest <see cref="TestMessageLevel"/>.
+    /// </summary>
+    public static TestMessageLevel MapServerLogLevel(string level)
+        => level switch
+        {
+            "Error" or "Critical" => TestMessageLevel.Error,
+            "Warning" => TestMessageLevel.Warning,
+            _ => TestMessageLevel.Informational,
+        };
+
+    private static TimeSpan GetConnectionTimeout()
+    {
+        // Reuse vstest's connection timeout knob so users can extend it in slow environments.
+        string? value = Environment.GetEnvironmentVariable("VSTEST_CONNECTION_TIMEOUT");
+        return !string.IsNullOrEmpty(value) && int.TryParse(value, out int seconds) && seconds > 0
+            ? TimeSpan.FromSeconds(seconds)
+            : TimeSpan.FromSeconds(90);
+    }
+
+    private static void Trace(MtpClientLogLevel level, string message)
+    {
+        switch (level)
+        {
+            case MtpClientLogLevel.Error:
+                EqtTrace.Error(message);
+                break;
+
+            case MtpClientLogLevel.Warning:
+                EqtTrace.Warning(message);
+                break;
+
+            case MtpClientLogLevel.Information:
+                EqtTrace.Info(message);
+                break;
+
+            default:
+                EqtTrace.Verbose(message);
+                break;
+        }
+    }
+}