Stop modifying current working directory from test.

This commit fixes the ToolPackageInstaller tests so that they no longer modify
the current working directory.  The directory being set is now being properly
passed in as an argument to override the default of the current working
directory.

Additionally, this commit also changes the package root to a temp location
rather than based off of the current working directory.

src/dotnet/ToolPackage/IToolPackageInstaller.cs

@@ -15,6 +15,7 @@ namespace Microsoft.DotNet.ToolPackage
             VersionRange versionRange = null,
             string targetFramework = null,
             FilePath? nugetConfig = null,
+            DirectoryPath? rootConfigDirectory = null,
             string source = null,
             string verbosity = null);
     }

src/dotnet/ToolPackage/ToolPackageInstaller.cs

@@ -35,6 +35,7 @@ namespace Microsoft.DotNet.ToolPackage
             VersionRange versionRange = null,
             string targetFramework = null,
             FilePath? nugetConfig = null,
+            DirectoryPath? rootConfigDirectory = null,
             string source = null,
             string verbosity = null)
         {
@@ -53,7 +54,8 @@ namespace Microsoft.DotNet.ToolPackage
                             packageId: packageId,
                             versionRange: versionRange,
                             targetFramework: targetFramework ?? BundledTargetFramework.GetTargetFrameworkMoniker(),
-                            restoreDirectory: stageDirectory);
+                            restoreDirectory: stageDirectory,
+                            rootConfigDirectory: rootConfigDirectory);
 
                         try
                         {
@@ -115,7 +117,8 @@ namespace Microsoft.DotNet.ToolPackage
             PackageId packageId,
             VersionRange versionRange,
             string targetFramework,
-            DirectoryPath restoreDirectory)
+            DirectoryPath restoreDirectory,
+            DirectoryPath? rootConfigDirectory)
         {
             var tempProject = _tempProject ?? new DirectoryPath(Path.GetTempPath())
                 .WithSubDirectories(Path.GetRandomFileName())
@@ -135,7 +138,7 @@ namespace Microsoft.DotNet.ToolPackage
                         new XElement("TargetFramework", targetFramework),
                         new XElement("RestorePackagesPath", restoreDirectory.Value),
                         new XElement("RestoreProjectStyle", "DotnetToolReference"), // without it, project cannot reference tool package
-                        new XElement("RestoreRootConfigDirectory", Directory.GetCurrentDirectory()), // config file probing start directory
+                        new XElement("RestoreRootConfigDirectory", rootConfigDirectory?.Value ?? Directory.GetCurrentDirectory()), // config file probing start directory
                         new XElement("DisableImplicitFrameworkReferences", "true"), // no Microsoft.NETCore.App in tool folder
                         new XElement("RestoreFallbackFolders", "clear"), // do not use fallbackfolder, tool package need to be copied to tool folder
                         new XElement("RestoreAdditionalProjectSources", // use fallbackfolder as feed to enable offline

test/Microsoft.DotNet.ToolPackage.Tests/ToolPackageInstallerTests.cs

@@ -154,21 +154,17 @@ namespace Microsoft.DotNet.ToolPackage.Tests
         }
 
         [Fact]
-        public void GivenAConfigFileInCurrentDirectoryPackageInstallSucceeds()
+        public void GivenAConfigFileRootDirectoryPackageInstallSucceeds()
         {
             var nugetConfigPath = WriteNugetConfigFileToPointToTheFeed();
 
             var (store, installer, reporter, fileSystem) = Setup(useMock: false);
 
-            /*
-             * In test, we don't want NuGet to keep look up, so we point current directory to nugetconfig.
-             */
-            Directory.SetCurrentDirectory(nugetConfigPath.GetDirectoryPath().Value);
-
             var package = installer.InstallPackage(
                 packageId: TestPackageId,
                 versionRange: VersionRange.Parse(TestPackageVersion),
-                targetFramework: _testTargetframework);
+                targetFramework: _testTargetframework,
+                rootConfigDirectory: nugetConfigPath.GetDirectoryPath());
 
             AssertPackageInstall(reporter, fileSystem, package, store);
 
@@ -641,7 +637,7 @@ namespace Microsoft.DotNet.ToolPackage.Tests
             FilePath? tempProject = null,
             DirectoryPath? offlineFeed = null)
         {
-            var root = new DirectoryPath(Path.Combine(Directory.GetCurrentDirectory(), Path.GetRandomFileName()));
+            var root = new DirectoryPath(Path.Combine(Path.GetFullPath(TempRoot.Root), Path.GetRandomFileName()));
             var reporter = new BufferedReporter();
 
             IFileSystem fileSystem;

test/Microsoft.DotNet.Tools.Tests.ComponentMocks/ToolPackageInstallerMock.cs

@@ -40,6 +40,7 @@ namespace Microsoft.DotNet.Tools.Tests.ComponentMocks
             VersionRange versionRange = null,
             string targetFramework = null,
             FilePath? nugetConfig = null,
+            DirectoryPath? rootConfigDirectory = null,
             string source = null,
             string verbosity = null)
         {