Some random clean up and improvements (#11095)

These are just some tweaks I've had on my machine awhile.

- Introduce `PlatformInformation` class to remove several
`RuntimeInformation.IsOSPlatform(...)`. These checks are fairly
efficient, but each [requires in a string
comparison](https://github.com/dotnet/runtime/blob/6ed953a000613e5b02e5ac38d35aa4fef6c38660/src/libraries/System.Private.CoreLib/src/System/OperatingSystem.cs#L122-L134)
and it's easy enough to just do those once and remember the result.
- Replace `OSSkipConditionFactAttribute` with
`ConditionalFactAttribute`. This makes it easier to see what conditions
a test will run under. For example, it's much easier to see that a test
will run on Windows if it's marked with `[ConditionalFact(Is.Windows)]`
rather than `[OSSkipConditionFact(["Linux", "OSX"])]`

src/Compiler/Microsoft.AspNetCore.Razor.Language/test/CodeGeneration/DesignTimeNodeWriterTest.cs

@@ -493,7 +493,7 @@ Render Children
             ignoreLineEndingDifferences: true);
     }
 
-    [OSSkipConditionTheory(new[] { "Linux", "OSX" })]
+    [ConditionalTheory(Is.Windows)]
     [InlineData(@"test.cshtml",                     @"test.cshtml")]
     [InlineData(@"pages/test.cshtml",               @"pages\test.cshtml")]
     [InlineData(@"pages\test.cshtml",               @"pages\test.cshtml")]
@@ -540,7 +540,7 @@ public void LinePragma_Is_Adjusted_On_Windows(string fileName, string expectedFi
             ignoreLineEndingDifferences: true);
     }
 
-    [OSSkipConditionTheory(new[] { "Linux", "OSX" })]
+    [ConditionalTheory(Is.Windows)]
     [InlineData(@"test.cshtml",                     @"test.cshtml")]
     [InlineData(@"pages/test.cshtml",               @"pages\test.cshtml")]
     [InlineData(@"pages\test.cshtml",               @"pages\test.cshtml")]

src/Compiler/Microsoft.AspNetCore.Razor.Language/test/DefaultRazorProjectFileSystemTest.cs

@@ -6,7 +6,6 @@
 using System;
 using System.IO;
 using System.Linq;
-using System.Runtime.InteropServices;
 using Xunit;
 
 namespace Microsoft.AspNetCore.Razor.Language;
@@ -261,15 +260,10 @@ public void GetItem_ReturnsFileFromDisk()
         Assert.Equal(Path.Combine("Views", "About", "About.cshtml"), item.RelativePhysicalPath);
     }
 
-    [Fact]
+    // "This test does not makes sense for case sensitive Operating Systems."
+    [ConditionalFact(Is.Windows)]
     public void GetItem_MismatchedCase_ReturnsFileFromDisk()
     {
-        if (!RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
-        {
-            // "This test does not makes sense for case sensitive Operating Systems."
-            return;
-        }
-
         // Arrange
         var filePath = "/Views/About/About.cshtml";
         var lowerCaseTestFolder = TestFolder.ToLowerInvariant();

src/Compiler/Microsoft.AspNetCore.Razor.Language/test/Microsoft.AspNetCore.Razor.Language.Test.csproj

@@ -30,7 +30,6 @@
     <Compile Include="..\..\shared\JsonReaderExtensions.cs" LinkBase="Shared" />
     <Compile Include="..\..\shared\RazorDiagnosticJsonConverter.cs" LinkBase="Shared" />
     <Compile Include="..\..\shared\TagHelperDescriptorJsonConverter.cs" LinkBase="Shared" />
-    <Compile Include="..\..\..\Razor\test\OSSkipConditionFactAttribute.cs" LinkBase="Shared" />
   </ItemGroup>
 
   <ItemGroup>

src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/CSharp/FilePathComparer.cs

@@ -2,7 +2,7 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 
 using System;
-using System.Runtime.InteropServices;
+using Microsoft.AspNetCore.Razor.Utilities;
 
 namespace Microsoft.CodeAnalysis.Razor;
 
@@ -14,7 +14,7 @@ public static StringComparer Instance
     {
         get
         {
-            return _instance ??= RuntimeInformation.IsOSPlatform(OSPlatform.Linux)
+            return _instance ??= PlatformInformation.IsLinux
                 ? StringComparer.Ordinal
                 : StringComparer.OrdinalIgnoreCase;
         }

src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/CSharp/FilePathComparison.cs

@@ -2,7 +2,7 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 
 using System;
-using System.Runtime.InteropServices;
+using Microsoft.AspNetCore.Razor.Utilities;
 
 namespace Microsoft.CodeAnalysis.Razor;
 
@@ -14,7 +14,7 @@ public static StringComparison Instance
     {
         get
         {
-            return _instance ??= RuntimeInformation.IsOSPlatform(OSPlatform.Linux)
+            return _instance ??= PlatformInformation.IsLinux
                 ? StringComparison.Ordinal
                 : StringComparison.OrdinalIgnoreCase;
         }

src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/CodeGeneration/CodeWriterExtensions.cs

@@ -8,8 +8,8 @@
 using System.Diagnostics;
 using System.Globalization;
 using System.Linq;
-using System.Runtime.InteropServices;
 using Microsoft.AspNetCore.Razor.Language.Intermediate;
+using Microsoft.AspNetCore.Razor.Utilities;
 
 namespace Microsoft.AspNetCore.Razor.Language.CodeGeneration;
 
@@ -661,7 +661,7 @@ public static IDisposable BuildEnhancedLinePragma(this CodeWriter writer, Source
 
     private static SourceSpan RemapFilePathIfNecessary(SourceSpan sourceSpan, CodeRenderingContext context)
     {
-        if (context.Options.RemapLinePragmaPathsOnWindows && RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+        if (context.Options.RemapLinePragmaPathsOnWindows && PlatformInformation.IsWindows)
         {
             // ISSUE: https://github.com/dotnet/razor/issues/9108
             // The razor tooling normalizes paths to be forward slash based, regardless of OS.

src/Razor/src/Microsoft.AspNetCore.Razor.LanguageServer/DefaultLanguageServerFeatureOptions.cs

@@ -1,7 +1,7 @@
 // Copyright (c) .NET Foundation. All rights reserved.
 // Licensed under the MIT license. See License.txt in the project root for license information.
 
-using System.Runtime.InteropServices;
+using Microsoft.AspNetCore.Razor.Utilities;
 using Microsoft.CodeAnalysis.Razor.Workspaces;
 
 namespace Microsoft.AspNetCore.Razor.LanguageServer;
@@ -25,8 +25,7 @@ internal class DefaultLanguageServerFeatureOptions : LanguageServerFeatureOption
 
     // Code action and rename paths in Windows VS Code need to be prefixed with '/':
     // https://github.com/dotnet/razor/issues/8131
-    public override bool ReturnCodeActionAndRenamePathsWithPrefixedSlash
-        => RuntimeInformation.IsOSPlatform(OSPlatform.Windows);
+    public override bool ReturnCodeActionAndRenamePathsWithPrefixedSlash => PlatformInformation.IsWindows;
 
     public override bool ShowAllCSharpCodeActions => false;
 

src/Razor/src/Microsoft.AspNetCore.Razor.LanguageServer/RemoteRazorProjectFileSystem.cs

@@ -4,7 +4,6 @@
 using System;
 using System.Collections.Generic;
 using System.IO;
-using System.Runtime.InteropServices;
 using Microsoft.AspNetCore.Razor.Language;
 using Microsoft.AspNetCore.Razor.Utilities;
 using Microsoft.CodeAnalysis.Razor;
@@ -82,7 +81,7 @@ protected override string NormalizeAndEnsureValidPath(string path)
 
         static bool IsPathRootedForPlatform(string path)
         {
-            if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows) && path == "/")
+            if (PlatformInformation.IsWindows && path == "/")
             {
                 // We have to special case windows and "/" because for some reason Path.IsPathRooted returns true on windows for a single "/" path.
                 return false;

src/Razor/src/Microsoft.AspNetCore.Razor.ProjectEngineHost/Utilities/FilePathNormalizer.cs

@@ -12,7 +12,7 @@ namespace Microsoft.AspNetCore.Razor.Utilities;
 
 internal static class FilePathNormalizer
 {
-    private static readonly Func<char, char> s_charConverter = RuntimeInformation.IsOSPlatform(OSPlatform.Linux)
+    private static readonly Func<char, char> s_charConverter = PlatformInformation.IsLinux
         ? c => c
         : char.ToLowerInvariant;
 
@@ -223,7 +223,7 @@ private static (int start, int length) NormalizeCore(ReadOnlySpan<char> source,
         // Replace slashes in our normalized span.
         NormalizeAndDedupeSlashes(destination, ref charsWritten);
 
-        if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows) &&
+        if (PlatformInformation.IsWindows &&
             charsWritten > 1 &&
             destination is ['/', ..] and not ['/', '/', ..])
         {

src/Razor/src/Microsoft.AspNetCore.Razor.ProjectEngineHost/Utilities/RazorProjectInfoFactory.cs

@@ -5,7 +5,6 @@
 using System.Collections.Immutable;
 using System.Diagnostics.CodeAnalysis;
 using System.IO;
-using System.Runtime.InteropServices;
 using System.Threading;
 using System.Threading.Tasks;
 using Microsoft.AspNetCore.Razor.Language;
@@ -29,7 +28,7 @@ internal static class RazorProjectInfoFactory
 
     static RazorProjectInfoFactory()
     {
-        s_stringComparison = RuntimeInformation.IsOSPlatform(OSPlatform.Linux)
+        s_stringComparison = PlatformInformation.IsLinux
             ? StringComparison.Ordinal
             : StringComparison.OrdinalIgnoreCase;
     }

src/Razor/src/Microsoft.VisualStudio.LanguageServices.Razor/DynamicFiles/RazorDynamicFileInfoProvider.cs

@@ -6,13 +6,13 @@
 using System.Collections.Generic;
 using System.ComponentModel.Composition;
 using System.Diagnostics;
-using System.Runtime.InteropServices;
 using System.Text;
 using System.Threading;
 using System.Threading.Tasks;
 using Microsoft.AspNetCore.Razor;
 using Microsoft.AspNetCore.Razor.ProjectSystem;
 using Microsoft.AspNetCore.Razor.Threading;
+using Microsoft.AspNetCore.Razor.Utilities;
 using Microsoft.CodeAnalysis;
 using Microsoft.CodeAnalysis.ExternalAccess.Razor;
 using Microsoft.CodeAnalysis.Razor;
@@ -305,7 +305,7 @@ public static string GetProjectSystemFilePath(Uri uri)
         // however, it's the only way to get the correct file path for a document to map to a corresponding project
         // system.
 
-        if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+        if (PlatformInformation.IsWindows)
         {
             // VSWin
             return uri.GetAbsoluteOrUNCPath().Replace('/', '\\');

src/Razor/src/rzls/Program.cs

@@ -4,12 +4,12 @@
 using System;
 using System.Diagnostics;
 using System.Linq;
-using System.Runtime.InteropServices;
 using System.Threading;
 using System.Threading.Tasks;
 using Microsoft.AspNetCore.Razor.LanguageServer.Extensions;
 using Microsoft.AspNetCore.Razor.LanguageServer.Hosting;
 using Microsoft.AspNetCore.Razor.Telemetry;
+using Microsoft.AspNetCore.Razor.Utilities;
 using Microsoft.CodeAnalysis.Razor.Logging;
 using Microsoft.CodeAnalysis.Razor.ProjectSystem;
 using Microsoft.Extensions.DependencyInjection;
@@ -30,10 +30,10 @@ public static async Task Main(string[] args)
             if (args[i].Contains("debug", StringComparison.OrdinalIgnoreCase))
             {
                 await Console.Error.WriteLineAsync($"Server started with process ID {Environment.ProcessId}").ConfigureAwait(true);
-                if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+                if (PlatformInformation.IsWindows)
                 {
                     // Debugger.Launch() only works on Windows.
-                    _ = Debugger.Launch();
+                    Debugger.Launch();
                 }
                 else
                 {

src/Razor/test/Microsoft.AspNetCore.Razor.ExternalAccess.LegacyEditor.Test/Microsoft.AspNetCore.Razor.ExternalAccess.LegacyEditor.Test.csproj

@@ -6,7 +6,6 @@
 
   <ItemGroup>
     <None Include="xunit.runner.json" CopyToOutputDirectory="PreserveNewest" />
-    <Compile Include="..\OSSkipConditionFactAttribute.cs" LinkBase="Shared" />
   </ItemGroup>
 
   <ItemGroup>

src/Razor/test/Microsoft.AspNetCore.Razor.ExternalAccess.RoslynWorkspace.Test/Microsoft.AspNetCore.Razor.ExternalAccess.RoslynWorkspace.Test.csproj

@@ -6,7 +6,6 @@
 
   <ItemGroup>
     <None Include="xunit.runner.json" CopyToOutputDirectory="PreserveNewest" />
-    <Compile Include="..\OSSkipConditionFactAttribute.cs" LinkBase="Shared" />
   </ItemGroup>
 
   <ItemGroup>

src/Razor/test/Microsoft.AspNetCore.Razor.LanguageServer.Test/DocumentPresentation/TextDocumentUriPresentationEndpointTests.cs

@@ -23,7 +23,7 @@ namespace Microsoft.AspNetCore.Razor.LanguageServer.DocumentPresentation;
 
 public class TextDocumentUriPresentationEndpointTests(ITestOutputHelper testOutput) : LanguageServerTestBase(testOutput)
 {
-    [OSSkipConditionFact(["OSX", "Linux"])]
+    [ConditionalFact(Is.Windows)]
     public async Task Handle_SimpleComponent_ReturnsResult()
     {
         // Arrange
@@ -83,7 +83,7 @@ await projectManager.UpdateAsync(updater =>
         Assert.Equal("<MyTagHelper />", documentEdits[0].Edits[0].NewText);
     }
 
-    [OSSkipConditionFact(["OSX", "Linux"])]
+    [ConditionalFact(Is.Windows)]
     public async Task Handle_SimpleComponentWithChildFile_ReturnsResult()
     {
         // Arrange
@@ -148,7 +148,7 @@ await projectManager.UpdateAsync(updater =>
         Assert.Equal("<MyTagHelper />", documentEdits[0].Edits[0].NewText);
     }
 
-    [OSSkipConditionFact(["OSX", "Linux"])]
+    [ConditionalFact(Is.Windows)]
     public async Task Handle_ComponentWithRequiredAttribute_ReturnsResult()
     {
         // Arrange
@@ -308,7 +308,7 @@ public async Task Handle_NotComponent_ReturnsNull()
         Assert.Null(result);
     }
 
-    [OSSkipConditionFact(["OSX", "Linux"])]
+    [ConditionalFact(Is.Windows)]
     public async Task Handle_ComponentWithNestedFiles_ReturnsResult()
     {
         // Arrange

src/Razor/test/Microsoft.AspNetCore.Razor.LanguageServer.Test/FindNodeTests.cs

@@ -1,10 +1,10 @@
 // Copyright (c) .NET Foundation. All rights reserved.
 // Licensed under the MIT license. See License.txt in the project root for license information.
 
-using System.Runtime.InteropServices;
 using Microsoft.AspNetCore.Razor.Language;
 using Microsoft.AspNetCore.Razor.Language.Syntax;
 using Microsoft.AspNetCore.Razor.Test.Common;
+using Microsoft.AspNetCore.Razor.Utilities;
 using Microsoft.CodeAnalysis.Text;
 using Xunit;
 using Xunit.Abstractions;
@@ -63,7 +63,7 @@ protected override async Task OnInitializedAsync()
             }
             """;
 
-    private static readonly string s_fetchDataContents = RuntimeInformation.IsOSPlatform(OSPlatform.Windows)
+    private static readonly string s_fetchDataContents = PlatformInformation.IsWindows
         ? FetchDataContents
         : FetchDataContents.Replace("\n", "\r\n");
 

src/Razor/test/Microsoft.AspNetCore.Razor.LanguageServer.Test/Microsoft.AspNetCore.Razor.LanguageServer.Test.csproj

@@ -10,7 +10,6 @@
 
   <ItemGroup>
     <None Include="xunit.runner.json" CopyToOutputDirectory="PreserveNewest" />
-    <Compile Include="..\OSSkipConditionFactAttribute.cs" LinkBase="Shared" />
   </ItemGroup>
 
   <ItemGroup>

src/Razor/test/Microsoft.AspNetCore.Razor.LanguageServer.Test/ProjectSystem/IProjectSnapshotManagerExtensionsTest.cs

@@ -177,7 +177,7 @@ public async Task TryResolveAllProjects_MiscellaneousOwnerProjectWithOthers_Retu
         AssertSnapshotsEqual(miscProject, project);
     }
 
-    [OSSkipConditionFact(["OSX", "Linux"])]
+    [ConditionalFact(Is.Windows)]
     public async Task TryResolveAllProjects_OwnerProjectDifferentCasing_ReturnsTrue()
     {
         // Arrange

src/Razor/test/Microsoft.AspNetCore.Razor.LanguageServer.Test/RemoteRazorProjectFileSystemTest.cs

@@ -3,8 +3,8 @@
 
 #nullable disable
 
-using System.Runtime.InteropServices;
 using Microsoft.AspNetCore.Razor.Test.Common;
+using Microsoft.AspNetCore.Razor.Utilities;
 using Xunit;
 using Xunit.Abstractions;
 
@@ -54,7 +54,7 @@ public void GetItem_RootedFilePath_DoesNotBelongToProject()
         RemoteRazorProjectFileSystem fileSystem;
         string documentFilePath;
 
-        if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+        if (PlatformInformation.IsWindows)
         {
             fileSystem = new RemoteRazorProjectFileSystem(@"C:\path\to");
             documentFilePath = @"C:\otherpath\to\file.cshtml";

src/Razor/test/Microsoft.AspNetCore.Razor.LanguageServer.Test/Semantic/SemanticTokensTest.cs

@@ -8,7 +8,6 @@
 using System.Linq;
 using System.Reflection;
 using System.Runtime.CompilerServices;
-using System.Runtime.InteropServices;
 using System.Text;
 using System.Text.RegularExpressions;
 using System.Threading;
@@ -19,6 +18,7 @@
 using Microsoft.AspNetCore.Razor.PooledObjects;
 using Microsoft.AspNetCore.Razor.Test.Common;
 using Microsoft.AspNetCore.Razor.Test.Common.LanguageServer;
+using Microsoft.AspNetCore.Razor.Utilities;
 using Microsoft.CodeAnalysis;
 using Microsoft.CodeAnalysis.Razor.ProjectSystem;
 using Microsoft.CodeAnalysis.Razor.Protocol;
@@ -903,7 +903,7 @@ public void GetMappedCSharpRanges_MinimalRangeVsSmallDisjointRanges_DisjointRang
         else
         {
             // Note that the expected lengths are different on Windows vs. Unix.
-            var expectedCsharpRangeLength = RuntimeInformation.IsOSPlatform(OSPlatform.Windows) ? 945 : 911;
+            var expectedCsharpRangeLength = PlatformInformation.IsWindows ? 945 : 911;
             Assert.True(codeDocument.TryGetMinimalCSharpRange(razorRange, out var csharpRange));
             var textSpan = csharpSourceText.GetTextSpan(csharpRange);
             Assert.Equal(expectedCsharpRangeLength, textSpan.Length);
@@ -1120,7 +1120,7 @@ private string GetBaselineFileContents(string baselineFileName)
 
         var baselineContents = semanticFile.ReadAllText();
 
-        if (!RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+        if (!PlatformInformation.IsWindows)
         {
             baselineContents = s_matchNewLines.Replace(baselineContents, "\n");
         }