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

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>
+    <!-- Source-only MTP server-mode client (compiled into CrossPlatEngine), shipped by microsoft/testfx#10085. Restored from the dotnet-tools feed already configured in NuGet.config. -->
+    <MicrosoftTestingPlatformServerModeClientSourcesVersion>2.4.0-preview.26410.1</MicrosoftTestingPlatformServerModeClientSourcesVersion>
     <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 +1,88 @@
+// 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.CoreUtilities.Helpers;
+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 shared connection-timeout knob (VSTEST_CONNECTION_TIMEOUT) rather than
+        // re-reading the environment variable here, so the MTP path honours exactly the same
+        // override, default and diagnostics as every other vstest connection.
+        => TimeSpan.FromSeconds(EnvironmentHelper.GetConnectionTimeout());
+
+    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;
+        }
+    }
+}