WiP

test/dotnet.Tests/GivenThatIWantToManageMulticoreJIT.cs

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+// Copyright (c) .NET Foundation and contributors. All rights reserved. 
+// Licensed under the MIT license. See LICENSE file in the project root for full license information. 
+
+using Microsoft.DotNet.Cli.Utils;
+using Microsoft.DotNet.Tools.Test.Utilities;
+using Microsoft.Extensions.PlatformAbstractions;
+using System;
+using System.IO;
+using System.Runtime.InteropServices;
+using Xunit;
+using Xunit.Abstractions;
+using FluentAssertions;
+
+namespace Microsoft.DotNet.Tests
+{
+    public class GivenThatIWantToManageMulticoreJIT : TestBase
+    {
+        ITestOutputHelper _output;
+        private const string OptimizationProfileFileName = "dotnet.";
+        private readonly string _optimizationProfileFilePath;
+        
+        public GivenThatIWantToManageMulticoreJIT(ITestOutputHelper output)
+        {
+            _output = output;
+            _optimizationProfileFilePath = GetOptimizationProfileFilePath();
+        }
+
+        [Fact]
+        public void When_invoked_it_writes_optimization_data_to_the_profile_root()
+        {
+            var testStartTime = DateTime.UtcNow;
+
+            new TestCommand("dotnet")
+                .Execute("--version");
+
+            File.Exists(_optimizationProfileFilePath)
+                .Should().BeTrue("Because dotnet CLI creates it after each run");
+
+            File.GetLastWriteTimeUtc(_optimizationProfileFilePath)
+                .Should().BeOnOrAfter(testStartTime, "Because dotnet CLI was executed after that time.");
+        }
+
+        private static string GetOptimizationProfileFilePath()
+        {
+            Console.WriteLine(GetOptimizationRootPath(GetDotnetVersion()));
+            return Path.Combine(GetOptimizationRootPath(GetDotnetVersion()),
+                OptimizationProfileFileName);
+        }
+
+        private static string GetOptimizationRootPath(string version)
+        {
+            return RuntimeInformation.IsOSPlatform(OSPlatform.Windows)
+                ? GetWindowsProfileRoot(version)
+                : GetNonWindowsProfileRoot(version);
+        }
+
+        private static string GetWindowsProfileRoot(string version)
+        {
+            return $@"{(Environment.GetEnvironmentVariable("LocalAppData"))}\Microsoft\dotnet\sdk\{version}\optimizationdata";
+        }
+
+        private static string GetNonWindowsProfileRoot(string version)
+        {
+            return $"{(Environment.GetEnvironmentVariable("HOME"))}/.dotnet/sdk/{version}/optimizationdata";
+        }
+
+        private static string GetDotnetVersion()
+        {
+            return Command.Create("dotnet", new[] { "--version" })
+                .CaptureStdOut()
+                .Execute()
+                .StdOut
+                .Trim();
+        }
+    }
+}