Support runsettings environment variables

src/Adapter/MSTest.TestAdapter/TestingPlatformAdapter/TestApplicationBuilderExtensions.cs

@@ -20,6 +20,7 @@ public static void AddMSTest(this ITestApplicationBuilder testApplicationBuilder
         testApplicationBuilder.AddRunSettingsService(extension);
         testApplicationBuilder.AddTestCaseFilterService(extension);
         testApplicationBuilder.AddTestRunParametersService(extension);
+        testApplicationBuilder.AddEnvironmentVariableProvider(extension);
         testApplicationBuilder.RegisterTestFramework(
             serviceProvider => new TestFrameworkCapabilities(
                 new VSTestBridgeExtensionBaseCapabilities(),

src/Platform/Microsoft.Testing.Extensions.VSTestBridge/Helpers/TestApplicationBuilderExtensions.cs

@@ -3,9 +3,11 @@
 
 using Microsoft.Testing.Extensions.VSTestBridge.CommandLine;
 using Microsoft.Testing.Extensions.VSTestBridge.Configurations;
+using Microsoft.Testing.Extensions.VSTestBridge.TestHostControllers;
 using Microsoft.Testing.Platform.Builder;
 using Microsoft.Testing.Platform.Extensions;
 using Microsoft.Testing.Platform.Helpers;
+using Microsoft.Testing.Platform.Services;
 
 namespace Microsoft.Testing.Extensions.VSTestBridge.Helpers;
 
@@ -44,4 +46,13 @@ public static void AddRunSettingsService(this ITestApplicationBuilder builder, I
     /// <param name="extension">The extension that will be used as the source of registration for this helper service.</param>
     public static void AddTestRunParametersService(this ITestApplicationBuilder builder, IExtension extension)
         => builder.CommandLine.AddProvider(() => new TestRunParametersCommandLineOptionsProvider(extension));
+
+    /// <summary>
+    /// Register the environment variable provider.
+    /// </summary>
+    /// <param name="builder">The test application builder.</param>
+    /// <param name="extension">The extension that will be used as the source of registration for this helper service.</param>
+    public static void AddEnvironmentVariableProvider(this ITestApplicationBuilder builder, IExtension extension)
+        => builder.TestHostControllers.AddEnvironmentVariableProvider(serviceProvider
+            => new VSBridgeEnvironmentVariableProvider(extension, serviceProvider.GetCommandLineOptions(), serviceProvider.GetFileSystem()));
 }

src/Platform/Microsoft.Testing.Extensions.VSTestBridge/PublicAPI.Unshipped.txt

@@ -1 +1,2 @@
 #nullable enable
+static Microsoft.Testing.Extensions.VSTestBridge.Helpers.TestApplicationBuilderExtensions.AddEnvironmentVariableProvider(this Microsoft.Testing.Platform.Builder.ITestApplicationBuilder! builder, Microsoft.Testing.Platform.Extensions.IExtension! extension) -> void

src/Platform/Microsoft.Testing.Extensions.VSTestBridge/TestHostControllers/VSBridgeEnvironmentVariableProvider.cs

@@ -0,0 +1,68 @@
+// 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.Xml.Linq;
+
+using Microsoft.Testing.Extensions.VSTestBridge.CommandLine;
+using Microsoft.Testing.Platform.CommandLine;
+using Microsoft.Testing.Platform.Extensions;
+using Microsoft.Testing.Platform.Extensions.TestHostControllers;
+using Microsoft.Testing.Platform.Helpers;
+
+namespace Microsoft.Testing.Extensions.VSTestBridge.TestHostControllers;
+
+internal class VSBridgeEnvironmentVariableProvider : ITestHostEnvironmentVariableProvider
+{
+    private readonly IExtension _extension;
+    private readonly ICommandLineOptions _commandLineOptions;
+    private readonly IFileSystem _fileSystem;
+    private XDocument? _runSettings;
+
+    public VSBridgeEnvironmentVariableProvider(IExtension extension, ICommandLineOptions commandLineOptions, IFileSystem fileSystem)
+    {
+        _extension = extension;
+        _commandLineOptions = commandLineOptions;
+        _fileSystem = fileSystem;
+    }
+
+    public string Uid => _extension.Uid;
+
+    public string Version => _extension.Version;
+
+    public string DisplayName => _extension.DisplayName;
+
+    public string Description => _extension.Description;
+
+    public async Task<bool> IsEnabledAsync()
+    {
+        if (_commandLineOptions.TryGetOptionArgumentList(RunSettingsCommandLineOptionsProvider.RunSettingsOptionName, out string[]? runsettings))
+        {
+            if (_fileSystem.Exists(runsettings[0]))
+            {
+                using IFileStream fileStream = _fileSystem.NewFileStream(runsettings[0], FileMode.Open);
+#if NETCOREAPP
+                _runSettings = await XDocument.LoadAsync(fileStream.Stream, LoadOptions.None, CancellationToken.None);
+#else
+                using StreamReader streamReader = new(fileStream.Stream);
+                _runSettings = XDocument.Parse(await streamReader.ReadToEndAsync());
+#endif
+                return _runSettings.Element("RunSettings")?.Element("RunConfiguration")?.Element("EnvironmentVariables") is not null;
+            }
+        }
+
+        return false;
+    }
+
+    public Task UpdateAsync(IEnvironmentVariables environmentVariables)
+    {
+        foreach (XElement element in _runSettings!.Element("RunSettings")!.Element("RunConfiguration")!.Element("EnvironmentVariables")!.Elements())
+        {
+            environmentVariables.SetVariable(new(element.Name.ToString(), element.Value, true, true));
+        }
+
+        return Task.CompletedTask;
+    }
+
+    public Task<ValidationResult> ValidateTestHostEnvironmentVariablesAsync(IReadOnlyEnvironmentVariables environmentVariables)
+        => ValidationResult.ValidTask;
+}

test/IntegrationTests/MSTest.Acceptance.IntegrationTests/RunsettingsTests.cs

@@ -1,6 +1,8 @@
 // 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.Runtime.InteropServices;
+
 using Microsoft.Testing.Platform.Acceptance.IntegrationTests;
 using Microsoft.Testing.Platform.Acceptance.IntegrationTests.Helpers;
 
@@ -14,9 +16,21 @@ public sealed class RunSettingsTests : AcceptanceTestBase
     public RunSettingsTests(ITestExecutionContext testExecutionContext, TestAssetFixture testAssetFixture)
         : base(testExecutionContext) => _testAssetFixture = testAssetFixture;
 
-    public async Task UnsupportedRunSettingsEntriesAreFlagged()
+    internal static IEnumerable<TestArgumentsEntry<string>> TfmList()
+    {
+        yield return TargetFrameworks.NetCurrent;
+        yield return TargetFrameworks.NetFramework.First();
+    }
+
+    [ArgumentsProvider(nameof(TfmList))]
+    public async Task UnsupportedRunSettingsEntriesAreFlagged(string tfm)
     {
-        var testHost = TestHost.LocateFrom(_testAssetFixture.ProjectPath, TestAssetFixture.ProjectName, TargetFrameworks.NetCurrent.Arguments);
+        if (!RuntimeInformation.IsOSPlatform(OSPlatform.Windows) && tfm == TargetFrameworks.NetFramework.First().Arguments)
+        {
+            return;
+        }
+
+        var testHost = TestHost.LocateFrom(_testAssetFixture.ProjectPath, TestAssetFixture.ProjectName, tfm);
         TestHostResult testHostResult = await testHost.ExecuteAsync("--settings my.runsettings");
 
         // Assert
@@ -45,7 +59,7 @@ public sealed class TestAssetFixture(AcceptanceFixture acceptanceFixture) : Test
         {
             yield return (ProjectName, ProjectName,
                 SourceCode
-                .PatchTargetFrameworks(TargetFrameworks.NetCurrent)
+                .PatchTargetFrameworks(TargetFrameworks.NetCurrent, TargetFrameworks.NetFramework.First())
                 .PatchCodeWithReplace("$MSTestVersion$", MSTestVersion));
         }
 
@@ -57,6 +71,7 @@ public sealed class TestAssetFixture(AcceptanceFixture acceptanceFixture) : Test
     <OutputType>Exe</OutputType>
     <EnableMSTestRunner>true</EnableMSTestRunner>
     <TargetFrameworks>$TargetFrameworks$</TargetFrameworks>
+    <LangVersion>Preview</LangVersion>
   </PropertyGroup>
 
   <ItemGroup>
@@ -105,6 +120,11 @@ public sealed class TestAssetFixture(AcceptanceFixture acceptanceFixture) : Test
     <!-- true or false -->
     <!-- Value that specifies the exit code when no tests are discovered -->
     <TreatNoTestsAsError>true</TreatNoTestsAsError>
+
+    <!-- List of environment variables we want to set-->
+    <EnvironmentVariables>
+        <SAMPLEKEY>SAMPLEVALUE</SAMPLEKEY>
+    </EnvironmentVariables>
   </RunConfiguration>
 
   <!-- Configurations for data collectors -->
@@ -200,6 +220,7 @@ public class UnitTest1
     [TestMethod]
     public void TestMethod()
     {
+        Assert.AreEqual("SAMPLEVALUE", System.Environment.GetEnvironmentVariable("SAMPLEKEY")!);
     }
 }
 """;