Add tests for architecture switch feature

scripts/build/TestPlatform.Dependencies.props

@@ -1,4 +1,4 @@
-<?xml version="1.0" encoding="utf-8"?>
+<?xml version="1.0" encoding="utf-8"?>
 <Project ToolsVersion="4.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
   <PropertyGroup>
     <VSSdkBuildToolsVersion>17.0.1600</VSSdkBuildToolsVersion>

scripts/common.lib.ps1

@@ -111,7 +111,9 @@ function Install-DotNetCli
     $dotnetInstallPath = Join-Path $env:TP_TOOLS_DIR "dotnet"
     New-Item -ItemType directory -Path $dotnetInstallPath -Force | Out-Null
     & $dotnetInstallScript -Channel 6.0 -InstallDir $dotnetInstallPath -Version $env:DOTNET_CLI_VERSION
-
+
+    & $dotnetInstallScript -Channel 6.0 -InstallDir "${dotnetInstallPath}_x86" -Version $env:DOTNET_CLI_VERSION -Architecture x86 -NoPath
+
     & $dotnetInstallScript -InstallDir "$dotnetInstallPath" -Runtime 'dotnet' -Version '2.1.30' -Channel '2.1' -Architecture x64 -NoPath
     $env:DOTNET_ROOT= $dotnetInstallPath
 

test/Microsoft.TestPlatform.AcceptanceTests/DotnetArchitectureSwitchTests.Windows.cs

@@ -0,0 +1,94 @@
+// Copyright (c) Microsoft Corporation. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+
+#if !NET451
+
+namespace Microsoft.TestPlatform.AcceptanceTests
+{
+    using Microsoft.TestPlatform.TestUtilities;
+    using Microsoft.VisualStudio.TestTools.UnitTesting;
+    using Newtonsoft.Json.Linq;
+    using System.Collections.Generic;
+    using System.IO;
+    using System.Linq;
+
+    [TestClass]
+    [TestCategory("Windows-Review")]
+    public class DotnetArchitectureSwitchTestsWindowsOnly : AcceptanceTestBase
+    {
+        [TestMethod]
+        [DataRow("X64", "X86")]
+        [DataRow("X86", "X64")]
+        public void Use_EnvironmentVariables(string architectureFrom, string architectureTo)
+        {
+            using (Workspace workSpace = new Workspace(GetResultsDirectory()))
+            {
+                string dotnetPath = GetDownloadedDotnetMuxerFromTools(architectureFrom);
+                string dotnetPathTo = GetDownloadedDotnetMuxerFromTools(architectureTo);
+                var vstestConsolePath = GetDotnetRunnerPath();
+                var dotnetRunnerPath = workSpace.CreateDirectory("dotnetrunner");
+                workSpace.CopyAll(new DirectoryInfo(Path.GetDirectoryName(vstestConsolePath)), dotnetRunnerPath);
+
+                // Patch the runner
+                string sdkVersion = GetLatestSdkVersion(dotnetPath);
+                string runtimeConfigFile = Path.Combine(dotnetRunnerPath.FullName, "vstest.console.runtimeconfig.json");
+                JObject patchRuntimeConfig = JObject.Parse(File.ReadAllText(runtimeConfigFile));
+                patchRuntimeConfig["runtimeOptions"]["framework"]["version"] = sdkVersion;
+                File.WriteAllText(runtimeConfigFile, patchRuntimeConfig.ToString());
+
+                var environmentVariables = new Dictionary<string, string>
+                {
+                    ["DOTNET_MULTILEVEL_LOOKUP"] = "0",
+                    [$"DOTNET_ROOT_{architectureTo}"] = Path.GetDirectoryName(dotnetPathTo),
+                    ["ExpectedArchitecture"] = architectureTo
+                };
+                this.ExecuteApplication(dotnetPath, "new mstest", out string stdOut, out string stdError, out int exitCode, environmentVariables, workSpace.Path);
+
+                // Patch test file
+                File.WriteAllText(Path.Combine(workSpace.Path, "UnitTest1.cs"),
+@"
+using Microsoft.VisualStudio.TestTools.UnitTesting;
+using System;
+
+namespace cfebbc5339cf4c22854e79824e938c74;
+
+[TestClass]
+public class UnitTest1
+{
+    [TestMethod]
+    public void TestMethod1()
+    {
+        Assert.AreEqual(Environment.GetEnvironmentVariable(""ExpectedArchitecture""), System.Runtime.InteropServices.RuntimeInformation.ProcessArchitecture.ToString());
+    }
+}");
+
+                this.ExecuteApplication(dotnetPath, $"test -p:VsTestConsolePath=\"{Path.Combine(dotnetRunnerPath.FullName, Path.GetFileName(vstestConsolePath))}\" --arch {architectureTo.ToLower()} --diag:log.txt", out stdOut, out stdError, out exitCode, environmentVariables, workSpace.Path);
+                Assert.AreEqual(0, exitCode, stdOut);
+
+                environmentVariables = new Dictionary<string, string>
+                {
+                    ["DOTNET_MULTILEVEL_LOOKUP"] = "0",
+                    ["DOTNET_ROOT"] = Path.GetDirectoryName(dotnetPathTo),
+                    ["ExpectedArchitecture"] = architectureTo
+                };
+                this.ExecuteApplication(dotnetPath, $"test -p:VsTestConsolePath=\"{Path.Combine(dotnetRunnerPath.FullName, Path.GetFileName(vstestConsolePath))}\" --arch {architectureTo.ToLower()} --diag:log.txt", out stdOut, out stdError, out exitCode, environmentVariables, workSpace.Path);
+                Assert.AreEqual(0, exitCode, stdOut);
+
+                environmentVariables = new Dictionary<string, string>
+                {
+                    ["DOTNET_MULTILEVEL_LOOKUP"] = "0",
+                    [$"DOTNET_ROOT_{architectureTo}"] = Path.GetDirectoryName(dotnetPathTo),
+                    ["DOTNET_ROOT"] = "WE SHOULD PICK THE ABOVE ONE BEFORE FALLBACK TO DOTNET_ROOT",
+                    ["ExpectedArchitecture"] = architectureTo
+                };
+                this.ExecuteApplication(dotnetPath, $"test -p:VsTestConsolePath=\"{Path.Combine(dotnetRunnerPath.FullName, Path.GetFileName(vstestConsolePath))}\" --arch {architectureTo.ToLower()} --diag:log.txt", out stdOut, out stdError, out exitCode, environmentVariables, workSpace.Path);
+                Assert.AreEqual(0, exitCode, stdOut);
+            }
+        }
+
+        private string GetLatestSdkVersion(string dotnetPath)
+            => Path.GetFileName(Directory.GetDirectories(Path.Combine(Path.GetDirectoryName(dotnetPath), @"shared/Microsoft.NETCore.App")).OrderByDescending(x => x).First());
+    }
+}
+
+#endif