Search for slnx files when setting solution-relative content root

src/Hosting/TestHost/src/PublicAPI.Unshipped.txt

@@ -1 +1,8 @@
 #nullable enable
+*REMOVED*static Microsoft.AspNetCore.TestHost.WebHostBuilderExtensions.UseSolutionRelativeContentRoot(this Microsoft.AspNetCore.Hosting.IWebHostBuilder! builder, string! solutionRelativePath, string! applicationBasePath, string! solutionName = "*.sln") -> Microsoft.AspNetCore.Hosting.IWebHostBuilder!
+*REMOVED*static Microsoft.AspNetCore.TestHost.WebHostBuilderExtensions.UseSolutionRelativeContentRoot(this Microsoft.AspNetCore.Hosting.IWebHostBuilder! builder, string! solutionRelativePath, string! solutionName = "*.sln") -> Microsoft.AspNetCore.Hosting.IWebHostBuilder!
+static Microsoft.AspNetCore.TestHost.WebHostBuilderExtensions.UseSolutionRelativeContentRoot(this Microsoft.AspNetCore.Hosting.IWebHostBuilder! builder, string! solutionRelativePath) -> Microsoft.AspNetCore.Hosting.IWebHostBuilder!
+static Microsoft.AspNetCore.TestHost.WebHostBuilderExtensions.UseSolutionRelativeContentRoot(this Microsoft.AspNetCore.Hosting.IWebHostBuilder! builder, string! solutionRelativePath, string! applicationBasePath, string! solutionName) -> Microsoft.AspNetCore.Hosting.IWebHostBuilder!
+static Microsoft.AspNetCore.TestHost.WebHostBuilderExtensions.UseSolutionRelativeContentRoot(this Microsoft.AspNetCore.Hosting.IWebHostBuilder! builder, string! solutionRelativePath, string! applicationBasePath, System.ReadOnlySpan<string!> solutionNames = default(System.ReadOnlySpan<string!>)) -> Microsoft.AspNetCore.Hosting.IWebHostBuilder!
+static Microsoft.AspNetCore.TestHost.WebHostBuilderExtensions.UseSolutionRelativeContentRoot(this Microsoft.AspNetCore.Hosting.IWebHostBuilder! builder, string! solutionRelativePath, string! solutionName) -> Microsoft.AspNetCore.Hosting.IWebHostBuilder!
+

src/Hosting/TestHost/src/WebHostBuilderExtensions.cs

@@ -16,6 +16,8 @@ namespace Microsoft.AspNetCore.TestHost;
 /// </summary>
 public static class WebHostBuilderExtensions
 {
+    private static readonly string[] _defaultSolutionNames = ["*.sln", "*.slnx"];
+
     /// <summary>
     /// Enables the <see cref="TestServer" /> service.
     /// </summary>
@@ -115,20 +117,32 @@ public static IWebHostBuilder ConfigureTestContainer<TContainer>(this IWebHostBu
         return webHostBuilder;
     }
 
+    /// <summary>
+    /// Sets the content root of relative to the <paramref name="solutionRelativePath" />.
+    /// </summary>
+    /// <param name="builder">The <see cref="IWebHostBuilder"/>.</param>
+    /// <param name="solutionRelativePath">The directory of the solution file.</param>
+    /// <returns>The <see cref="IWebHostBuilder"/>.</returns>
+    public static IWebHostBuilder UseSolutionRelativeContentRoot(
+        this IWebHostBuilder builder,
+        string solutionRelativePath)
+    {
+        return builder.UseSolutionRelativeContentRoot(solutionRelativePath, AppContext.BaseDirectory, _defaultSolutionNames);
+    }
+
     /// <summary>
     /// Sets the content root of relative to the <paramref name="solutionRelativePath" />.
     /// </summary>
     /// <param name="builder">The <see cref="IWebHostBuilder"/>.</param>
     /// <param name="solutionRelativePath">The directory of the solution file.</param>
     /// <param name="solutionName">The name of the solution file to make the content root relative to.</param>
     /// <returns>The <see cref="IWebHostBuilder"/>.</returns>
-    [SuppressMessage("ApiDesign", "RS0026:Do not add multiple public overloads with optional parameters", Justification = "Required to maintain compatibility")]
     public static IWebHostBuilder UseSolutionRelativeContentRoot(
         this IWebHostBuilder builder,
         string solutionRelativePath,
-        string solutionName = "*.sln")
+        string solutionName)
     {
-        return builder.UseSolutionRelativeContentRoot(solutionRelativePath, AppContext.BaseDirectory, solutionName);
+        return builder.UseSolutionRelativeContentRoot(solutionRelativePath, AppContext.BaseDirectory, [solutionName]);
     }
 
     /// <summary>
@@ -139,24 +153,49 @@ public static IWebHostBuilder UseSolutionRelativeContentRoot(
     /// <param name="applicationBasePath">The root of the app's directory.</param>
     /// <param name="solutionName">The name of the solution file to make the content root relative to.</param>
     /// <returns>The <see cref="IWebHostBuilder"/>.</returns>
-    [SuppressMessage("ApiDesign", "RS0026:Do not add multiple public overloads with optional parameters", Justification = "Required to maintain compatibility")]
     public static IWebHostBuilder UseSolutionRelativeContentRoot(
         this IWebHostBuilder builder,
         string solutionRelativePath,
         string applicationBasePath,
-        string solutionName = "*.sln")
+        string solutionName)
+    {
+        return builder.UseSolutionRelativeContentRoot(solutionRelativePath, applicationBasePath, [solutionName]);
+    }
+
+    /// <summary>
+    /// Sets the content root of relative to the <paramref name="solutionRelativePath" />.
+    /// </summary>
+    /// <param name="builder">The <see cref="IWebHostBuilder"/>.</param>
+    /// <param name="solutionRelativePath">The directory of the solution file.</param>
+    /// <param name="applicationBasePath">The root of the app's directory.</param>
+    /// <param name="solutionNames">The names of the solution files to make the content root relative to. If empty, defaults to *.sln and *.slnx.</param>
+    /// <returns>The <see cref="IWebHostBuilder"/>.</returns>
+    [SuppressMessage("ApiDesign", "RS0027:Public API with optional parameter(s) should have the most parameters amongst its public overloads", Justification = "Required to maintain compatibility")]
+    public static IWebHostBuilder UseSolutionRelativeContentRoot(
+        this IWebHostBuilder builder,
+        string solutionRelativePath,
+        string applicationBasePath,
+        ReadOnlySpan<string> solutionNames = default)
     {
         ArgumentNullException.ThrowIfNull(solutionRelativePath);
         ArgumentNullException.ThrowIfNull(applicationBasePath);
 
+        if (solutionNames.IsEmpty)
+        {
+            solutionNames = _defaultSolutionNames;
+        }
+
         var directoryInfo = new DirectoryInfo(applicationBasePath);
         do
         {
-            var solutionPath = Directory.EnumerateFiles(directoryInfo.FullName, solutionName).FirstOrDefault();
-            if (solutionPath != null)
+            foreach (var solutionName in solutionNames)
             {
-                builder.UseContentRoot(Path.GetFullPath(Path.Combine(directoryInfo.FullName, solutionRelativePath)));
-                return builder;
+                var solutionPath = Directory.EnumerateFiles(directoryInfo.FullName, solutionName).FirstOrDefault();
+                if (solutionPath != null)
+                {
+                    builder.UseContentRoot(Path.GetFullPath(Path.Combine(directoryInfo.FullName, solutionRelativePath)));
+                    return builder;
+                }
             }
 
             directoryInfo = directoryInfo.Parent;

src/Hosting/TestHost/test/UseSolutionRelativeContentRootTests.cs

@@ -0,0 +1,196 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using Microsoft.AspNetCore.Hosting;
+using Microsoft.Extensions.DependencyInjection;
+
+namespace Microsoft.AspNetCore.TestHost;
+
+public class UseSolutionRelativeContentRootTests : IDisposable
+{
+    private readonly string _tempDirectory;
+    private readonly string _contentDirectory;
+
+    public UseSolutionRelativeContentRootTests()
+    {
+        _tempDirectory = Path.Combine(Path.GetTempPath(), Guid.NewGuid().ToString("N")[..8]);
+        _contentDirectory = Path.Combine(_tempDirectory, "src");
+        Directory.CreateDirectory(_contentDirectory);
+    }
+
+    [Fact]
+    public void UseSolutionRelativeContentRoot_FindsSlnFile()
+    {
+        var solutionFile = Path.Combine(_tempDirectory, "TestApp.sln");
+        File.WriteAllText(solutionFile, "Microsoft Visual Studio Solution File, Format Version 12.00");
+
+        var builder = new WebHostBuilder()
+            .UseTestServer()
+            .Configure(app => { });
+
+        builder.UseSolutionRelativeContentRoot("src", applicationBasePath: _tempDirectory);
+
+        using var host = builder.Build();
+        var environment = host.Services.GetRequiredService<IWebHostEnvironment>();
+
+        Assert.Equal(_contentDirectory, environment.ContentRootPath);
+    }
+
+    [Fact]
+    public void UseSolutionRelativeContentRoot_FindsSlnxFile()
+    {
+        var solutionFile = Path.Combine(_tempDirectory, "TestApp.slnx");
+        File.WriteAllText(solutionFile, """
+            <Solution>
+              <Configurations>
+                <Configuration Name="Debug|Any CPU" />
+                <Configuration Name="Release|Any CPU" />
+              </Configurations>
+            </Solution>
+            """);
+
+        var builder = new WebHostBuilder()
+            .UseTestServer()
+            .Configure(app => { });
+
+        builder.UseSolutionRelativeContentRoot("src", applicationBasePath: _tempDirectory);
+
+        using var host = builder.Build();
+        var environment = host.Services.GetRequiredService<IWebHostEnvironment>();
+
+        Assert.Equal(_contentDirectory, environment.ContentRootPath);
+    }
+
+    [Fact]
+    public void UseSolutionRelativeContentRoot_WithSolutionName_FindsSpecifiedFile()
+    {
+        var subDirectory = Path.Combine(_tempDirectory, "sub");
+        Directory.CreateDirectory(subDirectory);
+
+        var slnFile = Path.Combine(subDirectory, "TestApp.sln");
+        var slnxFile = Path.Combine(_tempDirectory, "TestApp.slnx");
+        File.WriteAllText(slnFile, "Microsoft Visual Studio Solution File, Format Version 12.00");
+        File.WriteAllText(slnxFile, """
+            <Solution>
+              <Configurations>
+                <Configuration Name="Debug|Any CPU" />
+              </Configurations>
+            </Solution>
+            """);
+
+        var builder = new WebHostBuilder()
+            .UseTestServer()
+            .Configure(app => { });
+
+        builder.UseSolutionRelativeContentRoot("src", _tempDirectory, "*.slnx");
+
+        using var host = builder.Build();
+        var environment = host.Services.GetRequiredService<IWebHostEnvironment>();
+
+        Assert.Equal(_contentDirectory, environment.ContentRootPath);
+    }
+
+    [Fact]
+    public void UseSolutionRelativeContentRoot_WithMultipleSolutionNames_FindsInCurrentDirectoryFirst()
+    {
+        var expectedPath = Path.Combine(_contentDirectory, "sub");
+        Directory.CreateDirectory(expectedPath);
+
+        var slnFile = Path.Combine(_tempDirectory, "TestApp.sln");
+        var slnxFile = Path.Combine(_contentDirectory, "TestApp.slnx");
+        File.WriteAllText(slnFile, "Microsoft Visual Studio Solution File, Format Version 12.00");
+        File.WriteAllText(slnxFile, """
+            <Solution>
+              <Configurations>
+                <Configuration Name="Debug|Any CPU" />
+              </Configurations>
+            </Solution>
+            """);
+
+        var builder = new WebHostBuilder()
+            .UseTestServer()
+            .Configure(app => { });
+
+        builder.UseSolutionRelativeContentRoot("sub", _contentDirectory, ["*.sln", "*.slnx"]);
+
+        using var host = builder.Build();
+        var environment = host.Services.GetRequiredService<IWebHostEnvironment>();
+
+        Assert.Equal(expectedPath, environment.ContentRootPath);
+    }
+
+    [Fact]
+    public void UseSolutionRelativeContentRoot_WithMultipleSolutionNames_WorksWithMultipleFiles()
+    {
+        var slnFile = Path.Combine(_tempDirectory, "TestApp.sln");
+        var slnxFile = Path.Combine(_tempDirectory, "TestApp.slnx");
+        File.WriteAllText(slnFile, "Microsoft Visual Studio Solution File, Format Version 12.00");
+        File.WriteAllText(slnxFile, """
+            <Solution>
+              <Configurations>
+                <Configuration Name="Debug|Any CPU" />
+              </Configurations>
+            </Solution>
+            """);
+
+        var builder = new WebHostBuilder()
+            .UseTestServer()
+            .Configure(app => { });
+
+        builder.UseSolutionRelativeContentRoot("src", applicationBasePath: _tempDirectory, solutionNames: ["*.sln", "*.slnx"]);
+
+        using var host = builder.Build();
+        var environment = host.Services.GetRequiredService<IWebHostEnvironment>();
+
+        Assert.Equal(_contentDirectory, environment.ContentRootPath);
+    }
+
+    [Fact]
+    public void UseSolutionRelativeContentRoot_ThrowsWhenSolutionNotFound()
+    {
+        var builder = new WebHostBuilder()
+            .UseTestServer()
+            .Configure(app => { });
+
+        var exception = Assert.Throws<InvalidOperationException>(() =>
+            builder.UseSolutionRelativeContentRoot("src", applicationBasePath: _tempDirectory));
+
+        Assert.Contains("Solution root could not be located", exception.Message);
+        Assert.Contains(_tempDirectory, exception.Message);
+    }
+
+    [Fact]
+    public void UseSolutionRelativeContentRoot_WithSolutionName_SearchesParentDirectories()
+    {
+        var subDirectory = Path.Combine(_tempDirectory, "sub", "folder");
+        Directory.CreateDirectory(subDirectory);
+
+        var solutionFile = Path.Combine(_tempDirectory, "TestApp.slnx");
+        File.WriteAllText(solutionFile, """
+            <Solution>
+              <Configurations>
+                <Configuration Name="Debug|Any CPU" />
+              </Configurations>
+            </Solution>
+            """);
+
+        var builder = new WebHostBuilder()
+            .UseTestServer()
+            .Configure(app => { });
+
+        builder.UseSolutionRelativeContentRoot("src", subDirectory, "*.slnx");
+
+        using var host = builder.Build();
+        var environment = host.Services.GetRequiredService<IWebHostEnvironment>();
+
+        Assert.Equal(_contentDirectory, environment.ContentRootPath);
+    }
+
+    public void Dispose()
+    {
+        if (Directory.Exists(_tempDirectory))
+        {
+            Directory.Delete(_tempDirectory, recursive: true);
+        }
+    }
+}

src/Mvc/test/Mvc.FunctionalTests/WebApplicationFactorySlnxTests.cs

@@ -0,0 +1,74 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using Microsoft.AspNetCore.Hosting;
+using Microsoft.AspNetCore.Mvc.Testing;
+using Microsoft.AspNetCore.TestHost;
+using Microsoft.Extensions.DependencyInjection;
+using BasicWebSite;
+
+namespace Microsoft.AspNetCore.Mvc.FunctionalTests;
+
+public class WebApplicationFactorySlnxTests : IClassFixture<WebApplicationFactory<BasicWebSite.Startup>>, IDisposable
+{
+    private readonly string _tempDirectory;
+    private readonly string _contentDirectory;
+
+    public WebApplicationFactorySlnxTests(WebApplicationFactory<BasicWebSite.Startup> factory)
+    {
+        Factory = factory;
+        _tempDirectory = Path.Combine(Path.GetTempPath(), Guid.NewGuid().ToString("N")[..8]);
+        _contentDirectory = Path.Combine(_tempDirectory, "BasicWebSite");
+
+        Directory.CreateDirectory(_tempDirectory);
+        Directory.CreateDirectory(_contentDirectory);
+
+        // Create a minimal wwwroot directory to satisfy content root expectations
+        var wwwrootDir = Path.Combine(_contentDirectory, "wwwroot");
+        Directory.CreateDirectory(wwwrootDir);
+    }
+
+    public WebApplicationFactory<BasicWebSite.Startup> Factory { get; }
+
+    [Fact]
+    public async Task WebApplicationFactory_UsesSlnxForSolutionRelativeContentRoot()
+    {
+        // Create .slnx file in temp directory
+        var slnxFile = Path.Combine(_tempDirectory, "TestSolution.slnx");
+        File.WriteAllText(slnxFile, """
+            <Solution>
+              <Configurations>
+                <Configuration Name="Debug|Any CPU" />
+                <Configuration Name="Release|Any CPU" />
+              </Configurations>
+              <Folder Name="/BasicWebSite/">
+                <Project Path="BasicWebSite/BasicWebSite.csproj" />
+              </Folder>
+            </Solution>
+            """);
+
+        var factory = Factory.WithWebHostBuilder(builder =>
+        {
+            builder.UseSolutionRelativeContentRoot("BasicWebSite", _tempDirectory, "TestSolution.slnx");
+        });
+
+        using var client = factory.CreateClient();
+
+        // Verify that the content root was set correctly by accessing the environment
+        var environment = factory.Services.GetRequiredService<IWebHostEnvironment>();
+        Assert.Equal(_contentDirectory, environment.ContentRootPath);
+        Assert.True(Directory.Exists(environment.ContentRootPath));
+
+        // Verify the factory is functional with the .slnx-resolved content root
+        var response = await client.GetAsync("/");
+        Assert.True(response.IsSuccessStatusCode);
+    }
+
+    public void Dispose()
+    {
+        if (Directory.Exists(_tempDirectory))
+        {
+            Directory.Delete(_tempDirectory, recursive: true);
+        }
+    }
+}