From a61a717b3d2f07e9d08737fce0c08c001527eb47 Mon Sep 17 00:00:00 2001
From: Artak Mkrtchyan <artakm@microsoft.com>
Date: Thu, 6 Feb 2025 18:53:00 -0800
Subject: [PATCH 1/3] - Created an ITestServer abstraction to replace the
 TestServer dependency with from in the WebApplicationFactory. - Updated the
 WebApplicationFactory to depend on the ITestServer abstraction

---
 src/Hosting/TestHost/src/ITestServer.cs       | 31 ++++++++++++
 .../TestHost/src/PublicAPI.Unshipped.txt      |  4 ++
 src/Hosting/TestHost/src/TestServer.cs        |  2 +-
 src/Mvc/Mvc.Testing/src/PublicAPI.Shipped.txt |  2 -
 .../Mvc.Testing/src/PublicAPI.Unshipped.txt   |  4 ++
 src/Mvc/Mvc.Testing/src/Resources.resx        |  5 +-
 .../Mvc.Testing/src/WebApplicationFactory.cs  | 47 ++++++++++++++-----
 .../Mvc.FunctionalTests/ApiExplorerTest.cs    |  2 +-
 .../ComponentRenderingFunctionalTests.cs      |  2 +-
 .../Infrastructure/MvcTestFixture.cs          |  2 +-
 .../TestingInfrastructureInheritanceTests.cs  |  2 +-
 11 files changed, 84 insertions(+), 19 deletions(-)
 create mode 100644 src/Hosting/TestHost/src/ITestServer.cs

diff --git a/src/Hosting/TestHost/src/ITestServer.cs b/src/Hosting/TestHost/src/ITestServer.cs
new file mode 100644
index 000000000000..6940074601a7
--- /dev/null
+++ b/src/Hosting/TestHost/src/ITestServer.cs
@@ -0,0 +1,31 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using System.Net.Http;
+using Microsoft.AspNetCore.Hosting;
+using Microsoft.AspNetCore.Hosting.Server;
+
+namespace Microsoft.AspNetCore.TestHost;
+
+/// <summary>
+/// A contract for a test server implementation.
+/// </summary>
+public interface ITestServer : IServer
+{
+    /// <summary>
+    /// Gets the web host associated with the test server.
+    /// </summary>
+    IWebHost Host { get; }
+
+    /// <summary>
+    /// Creates a new <see cref="HttpMessageHandler"/> for processing HTTP requests against the test server.
+    /// </summary>
+    /// <returns>A new <see cref="HttpMessageHandler"/> instance.</returns>
+    HttpMessageHandler CreateHandler();
+
+    /// <summary>
+    /// Creates a new <see cref="HttpClient"/> for processing HTTP requests against the test server.
+    /// </summary>
+    /// <returns></returns>
+    HttpClient CreateClient();
+}
diff --git a/src/Hosting/TestHost/src/PublicAPI.Unshipped.txt b/src/Hosting/TestHost/src/PublicAPI.Unshipped.txt
index 7dc5c58110bf..96a756e2b17a 100644
--- a/src/Hosting/TestHost/src/PublicAPI.Unshipped.txt
+++ b/src/Hosting/TestHost/src/PublicAPI.Unshipped.txt
@@ -1 +1,5 @@
 #nullable enable
+Microsoft.AspNetCore.TestHost.ITestServer
+Microsoft.AspNetCore.TestHost.ITestServer.CreateClient() -> System.Net.Http.HttpClient!
+Microsoft.AspNetCore.TestHost.ITestServer.CreateHandler() -> System.Net.Http.HttpMessageHandler!
+Microsoft.AspNetCore.TestHost.ITestServer.Host.get -> Microsoft.AspNetCore.Hosting.IWebHost!
diff --git a/src/Hosting/TestHost/src/TestServer.cs b/src/Hosting/TestHost/src/TestServer.cs
index 1c9c295406ee..72550e58c6a4 100644
--- a/src/Hosting/TestHost/src/TestServer.cs
+++ b/src/Hosting/TestHost/src/TestServer.cs
@@ -14,7 +14,7 @@ namespace Microsoft.AspNetCore.TestHost;
 /// <summary>
 /// An <see cref="IServer"/> implementation for executing tests.
 /// </summary>
-public class TestServer : IServer
+public class TestServer : ITestServer
 {
     private readonly IWebHost? _hostInstance;
     private bool _disposed;
diff --git a/src/Mvc/Mvc.Testing/src/PublicAPI.Shipped.txt b/src/Mvc/Mvc.Testing/src/PublicAPI.Shipped.txt
index cd734b7284fb..46f1e43e4eac 100644
--- a/src/Mvc/Mvc.Testing/src/PublicAPI.Shipped.txt
+++ b/src/Mvc/Mvc.Testing/src/PublicAPI.Shipped.txt
@@ -16,7 +16,6 @@ Microsoft.AspNetCore.Mvc.Testing.WebApplicationFactory<TEntryPoint>.CreateDefaul
 Microsoft.AspNetCore.Mvc.Testing.WebApplicationFactory<TEntryPoint>.CreateDefaultClient(System.Uri! baseAddress, params System.Net.Http.DelegatingHandler![]! handlers) -> System.Net.Http.HttpClient!
 Microsoft.AspNetCore.Mvc.Testing.WebApplicationFactory<TEntryPoint>.Dispose() -> void
 Microsoft.AspNetCore.Mvc.Testing.WebApplicationFactory<TEntryPoint>.Factories.get -> System.Collections.Generic.IReadOnlyList<Microsoft.AspNetCore.Mvc.Testing.WebApplicationFactory<TEntryPoint!>!>!
-Microsoft.AspNetCore.Mvc.Testing.WebApplicationFactory<TEntryPoint>.Server.get -> Microsoft.AspNetCore.TestHost.TestServer!
 Microsoft.AspNetCore.Mvc.Testing.WebApplicationFactory<TEntryPoint>.WebApplicationFactory() -> void
 Microsoft.AspNetCore.Mvc.Testing.WebApplicationFactory<TEntryPoint>.WithWebHostBuilder(System.Action<Microsoft.AspNetCore.Hosting.IWebHostBuilder!>! configuration) -> Microsoft.AspNetCore.Mvc.Testing.WebApplicationFactory<TEntryPoint!>!
 Microsoft.AspNetCore.Mvc.Testing.WebApplicationFactoryClientOptions
@@ -41,7 +40,6 @@ virtual Microsoft.AspNetCore.Mvc.Testing.WebApplicationFactory<TEntryPoint>.Conf
 virtual Microsoft.AspNetCore.Mvc.Testing.WebApplicationFactory<TEntryPoint>.ConfigureWebHost(Microsoft.AspNetCore.Hosting.IWebHostBuilder! builder) -> void
 virtual Microsoft.AspNetCore.Mvc.Testing.WebApplicationFactory<TEntryPoint>.CreateHost(Microsoft.Extensions.Hosting.IHostBuilder! builder) -> Microsoft.Extensions.Hosting.IHost!
 virtual Microsoft.AspNetCore.Mvc.Testing.WebApplicationFactory<TEntryPoint>.CreateHostBuilder() -> Microsoft.Extensions.Hosting.IHostBuilder?
-virtual Microsoft.AspNetCore.Mvc.Testing.WebApplicationFactory<TEntryPoint>.CreateServer(Microsoft.AspNetCore.Hosting.IWebHostBuilder! builder) -> Microsoft.AspNetCore.TestHost.TestServer!
 virtual Microsoft.AspNetCore.Mvc.Testing.WebApplicationFactory<TEntryPoint>.CreateWebHostBuilder() -> Microsoft.AspNetCore.Hosting.IWebHostBuilder?
 virtual Microsoft.AspNetCore.Mvc.Testing.WebApplicationFactory<TEntryPoint>.Dispose(bool disposing) -> void
 virtual Microsoft.AspNetCore.Mvc.Testing.WebApplicationFactory<TEntryPoint>.DisposeAsync() -> System.Threading.Tasks.ValueTask
diff --git a/src/Mvc/Mvc.Testing/src/PublicAPI.Unshipped.txt b/src/Mvc/Mvc.Testing/src/PublicAPI.Unshipped.txt
index 7dc5c58110bf..68910e215fc2 100644
--- a/src/Mvc/Mvc.Testing/src/PublicAPI.Unshipped.txt
+++ b/src/Mvc/Mvc.Testing/src/PublicAPI.Unshipped.txt
@@ -1 +1,5 @@
 #nullable enable
+Microsoft.AspNetCore.Mvc.Testing.WebApplicationFactory<TEntryPoint>.Initialize() -> void
+Microsoft.AspNetCore.Mvc.Testing.WebApplicationFactory<TEntryPoint>.Server.get -> Microsoft.AspNetCore.TestHost.TestServer?
+Microsoft.AspNetCore.Mvc.Testing.WebApplicationFactory<TEntryPoint>.TestServer.get -> Microsoft.AspNetCore.TestHost.ITestServer?
+virtual Microsoft.AspNetCore.Mvc.Testing.WebApplicationFactory<TEntryPoint>.CreateServer(Microsoft.AspNetCore.Hosting.IWebHostBuilder! builder) -> Microsoft.AspNetCore.TestHost.ITestServer!
diff --git a/src/Mvc/Mvc.Testing/src/Resources.resx b/src/Mvc/Mvc.Testing/src/Resources.resx
index 84ce491ca5ed..1c1ec82845da 100644
--- a/src/Mvc/Mvc.Testing/src/Resources.resx
+++ b/src/Mvc/Mvc.Testing/src/Resources.resx
@@ -1,4 +1,4 @@
-<?xml version="1.0" encoding="utf-8"?>
+<?xml version="1.0" encoding="utf-8"?>
 <root>
   <!-- 
     Microsoft ResX Schema 
@@ -120,6 +120,9 @@
   <data name="InvalidAssemblyEntryPoint" xml:space="preserve">
     <value>The provided Type '{0}' does not belong to an assembly with an entry point. A common cause for this error is providing a Type from a class library.</value>
   </data>
+  <data name="InvalidTestServerConfiguration" xml:space="preserve">
+    <value>The host doesn't contain a valid ITestServer configuration.</value>
+  </data>
   <data name="MissingBuilderMethod" xml:space="preserve">
     <value>No method 'public static {0} CreateHostBuilder(string[] args)' or 'public static {1} CreateWebHostBuilder(string[] args)' found on '{2}'. Alternatively, {3} can be extended and '{4}' or '{5}' can be overridden to provide your own instance.</value>
   </data>
diff --git a/src/Mvc/Mvc.Testing/src/WebApplicationFactory.cs b/src/Mvc/Mvc.Testing/src/WebApplicationFactory.cs
index dd43bdac2e7c..b2aae99e95eb 100644
--- a/src/Mvc/Mvc.Testing/src/WebApplicationFactory.cs
+++ b/src/Mvc/Mvc.Testing/src/WebApplicationFactory.cs
@@ -22,11 +22,16 @@ namespace Microsoft.AspNetCore.Mvc.Testing;
 /// </summary>
 /// <typeparam name="TEntryPoint">A type in the entry point assembly of the application.
 /// Typically the Startup or Program classes can be used.</typeparam>
+/// <remarks>The default behavior of the <see cref="CreateServer(IWebHostBuilder)"/> implementation
+/// creates a new <see cref="TestHost.TestServer"/> instance as an in-memory server to utilize for testing.
+/// If the developers wants, they can override the <see cref="CreateServer(IWebHostBuilder)"/> method to return a customer <see cref="ITestServer"/> implementation,
+/// and provide an adapter over a real web server, if needed. If done so, the <see cref="CreateClient()"/> and similar methods will
+/// create <see cref="HttpClient"/> instances configured to interact with the provided test server instead.</remarks>
 public partial class WebApplicationFactory<TEntryPoint> : IDisposable, IAsyncDisposable where TEntryPoint : class
 {
     private bool _disposed;
     private bool _disposedAsync;
-    private TestServer? _server;
+    private ITestServer? _server;
     private IHost? _host;
     private Action<IWebHostBuilder> _configuration;
     private readonly List<HttpClient> _clients = new();
@@ -71,11 +76,23 @@ public WebApplicationFactory()
     /// <summary>
     /// Gets the <see cref="TestServer"/> created by this <see cref="WebApplicationFactory{TEntryPoint}"/>.
     /// </summary>
-    public TestServer Server
+    [Obsolete("This property is obsolete. Consider utilizing the TestServer property instead.")]
+    public TestServer? Server
     {
         get
         {
-            EnsureServer();
+            return TestServer as TestServer;
+        }
+    }
+
+    /// <summary>
+    /// Gets the <see cref="ITestServer"/> instance created by the underyling <see cref="CreateServer(IWebHostBuilder)"/> call.
+    /// </summary>
+    public ITestServer? TestServer
+    {
+        get
+        {
+            Initialize();
             return _server;
         }
     }
@@ -87,7 +104,7 @@ public virtual IServiceProvider Services
     {
         get
         {
-            EnsureServer();
+            Initialize();
             return _host?.Services ?? _server.Host.Services;
         }
     }
@@ -136,8 +153,12 @@ internal virtual WebApplicationFactory<TEntryPoint> WithWebHostBuilderCore(Actio
         return factory;
     }
 
+    /// <summary>
+    /// Initializes the instance by configurating the host builder.
+    /// </summary>
+    /// <exception cref="InvalidOperationException">Thrown if the provided <typeparamref name="TEntryPoint"/> type has no factory method.</exception>
     [MemberNotNull(nameof(_server))]
-    private void EnsureServer()
+    public void Initialize()
     {
         if (_server != null)
         {
@@ -211,7 +232,11 @@ private void ConfigureHostBuilder(IHostBuilder hostBuilder)
             webHostBuilder.UseTestServer();
         });
         _host = CreateHost(hostBuilder);
-        _server = (TestServer)_host.Services.GetRequiredService<IServer>();
+        _server = _host.Services.GetRequiredService<IServer>() as ITestServer;
+        if (_server is null)
+        {
+            throw new InvalidOperationException(Resources.InvalidTestServerConfiguration);
+        }
     }
 
     private void SetContentRoot(IWebHostBuilder builder)
@@ -426,7 +451,7 @@ private static void EnsureDepsFile()
     /// <param name="builder">The <see cref="IWebHostBuilder"/> used to
     /// create the server.</param>
     /// <returns>The <see cref="TestServer"/> with the bootstrapped application.</returns>
-    protected virtual TestServer CreateServer(IWebHostBuilder builder) => new(builder);
+    protected virtual ITestServer CreateServer(IWebHostBuilder builder) => new TestServer(builder);
 
     /// <summary>
     /// Creates the <see cref="IHost"/> with the bootstrapped application in <paramref name="builder"/>.
@@ -476,7 +501,7 @@ public HttpClient CreateClient(WebApplicationFactoryClientOptions options) =>
     /// <returns>The <see cref="HttpClient"/>.</returns>
     public HttpClient CreateDefaultClient(params DelegatingHandler[] handlers)
     {
-        EnsureServer();
+        Initialize();
 
         HttpClient client;
         if (handlers == null || handlers.Length == 0)
@@ -606,7 +631,7 @@ public virtual async ValueTask DisposeAsync()
 
     private sealed class DelegatedWebApplicationFactory : WebApplicationFactory<TEntryPoint>
     {
-        private readonly Func<IWebHostBuilder, TestServer> _createServer;
+        private readonly Func<IWebHostBuilder, ITestServer> _createServer;
         private readonly Func<IHostBuilder, IHost> _createHost;
         private readonly Func<IWebHostBuilder?> _createWebHostBuilder;
         private readonly Func<IHostBuilder?> _createHostBuilder;
@@ -615,7 +640,7 @@ private sealed class DelegatedWebApplicationFactory : WebApplicationFactory<TEnt
 
         public DelegatedWebApplicationFactory(
             WebApplicationFactoryClientOptions options,
-            Func<IWebHostBuilder, TestServer> createServer,
+            Func<IWebHostBuilder, ITestServer> createServer,
             Func<IHostBuilder, IHost> createHost,
             Func<IWebHostBuilder?> createWebHostBuilder,
             Func<IHostBuilder?> createHostBuilder,
@@ -633,7 +658,7 @@ public DelegatedWebApplicationFactory(
             _configuration = configureWebHost;
         }
 
-        protected override TestServer CreateServer(IWebHostBuilder builder) => _createServer(builder);
+        protected override ITestServer CreateServer(IWebHostBuilder builder) => _createServer(builder);
 
         protected override IHost CreateHost(IHostBuilder builder) => _createHost(builder);
 
diff --git a/src/Mvc/test/Mvc.FunctionalTests/ApiExplorerTest.cs b/src/Mvc/test/Mvc.FunctionalTests/ApiExplorerTest.cs
index 3386a5aabb6d..513b9946dce7 100644
--- a/src/Mvc/test/Mvc.FunctionalTests/ApiExplorerTest.cs
+++ b/src/Mvc/test/Mvc.FunctionalTests/ApiExplorerTest.cs
@@ -1573,7 +1573,7 @@ public async Task ApiExplorer_LogsInvokedDescriptionProvidersOnStartup()
     [Fact]
     public void ApiExplorer_BuildsMetadataForActionWithTypedResult()
     {
-        var apiDescCollectionProvider = Factory.Server.Services.GetService<IApiDescriptionGroupCollectionProvider>();
+        var apiDescCollectionProvider = Factory.Services.GetService<IApiDescriptionGroupCollectionProvider>();
         var testGroupName = nameof(ApiExplorerWithTypedResultController).Replace("Controller", string.Empty);
         var group = apiDescCollectionProvider.ApiDescriptionGroups.Items.Where(i => i.GroupName == testGroupName).SingleOrDefault();
         Assert.NotNull(group);
diff --git a/src/Mvc/test/Mvc.FunctionalTests/ComponentRenderingFunctionalTests.cs b/src/Mvc/test/Mvc.FunctionalTests/ComponentRenderingFunctionalTests.cs
index d319827f9a33..f194faa228d1 100644
--- a/src/Mvc/test/Mvc.FunctionalTests/ComponentRenderingFunctionalTests.cs
+++ b/src/Mvc/test/Mvc.FunctionalTests/ComponentRenderingFunctionalTests.cs
@@ -198,7 +198,7 @@ private HttpClient CreateClient(
 
         // We configure the inner handler with a handler to this TestServer instance so that calls to the
         // server can get routed properly.
-        loopHandler.InnerHandler = fixture.Server.CreateHandler();
+        loopHandler.InnerHandler = fixture.TestServer.CreateHandler();
 
         void ConfigureTestWeatherForecastService(IServiceCollection services) =>
             // We configure the test service here with an HttpClient that uses this loopback handler to talk
diff --git a/src/Mvc/test/Mvc.FunctionalTests/Infrastructure/MvcTestFixture.cs b/src/Mvc/test/Mvc.FunctionalTests/Infrastructure/MvcTestFixture.cs
index 45c33dad7268..488fb0a6f602 100644
--- a/src/Mvc/test/Mvc.FunctionalTests/Infrastructure/MvcTestFixture.cs
+++ b/src/Mvc/test/Mvc.FunctionalTests/Infrastructure/MvcTestFixture.cs
@@ -42,7 +42,7 @@ protected override void ConfigureWebHost(IWebHostBuilder builder)
                 });
     }
 
-    protected override TestServer CreateServer(IWebHostBuilder builder)
+    protected override ITestServer CreateServer(IWebHostBuilder builder)
     {
         var originalCulture = CultureInfo.CurrentCulture;
         var originalUICulture = CultureInfo.CurrentUICulture;
diff --git a/src/Mvc/test/Mvc.FunctionalTests/TestingInfrastructureInheritanceTests.cs b/src/Mvc/test/Mvc.FunctionalTests/TestingInfrastructureInheritanceTests.cs
index 9f4162734292..5a97d3c8daee 100644
--- a/src/Mvc/test/Mvc.FunctionalTests/TestingInfrastructureInheritanceTests.cs
+++ b/src/Mvc/test/Mvc.FunctionalTests/TestingInfrastructureInheritanceTests.cs
@@ -141,7 +141,7 @@ protected override void ConfigureWebHost(IWebHostBuilder builder)
             base.ConfigureWebHost(builder);
         }
 
-        protected override TestServer CreateServer(IWebHostBuilder builder)
+        protected override ITestServer CreateServer(IWebHostBuilder builder)
         {
             CreateServerCalled = true;
             return base.CreateServer(builder);

From 1f621554cee8f8c3021103062eab212520a2234b Mon Sep 17 00:00:00 2001
From: Artak Mkrtchyan <artakm@microsoft.com>
Date: Tue, 11 Feb 2025 17:12:00 -0800
Subject: [PATCH 2/3] - Generate relative contentRoot paths in test manifests -
 Fixed the public API declarations - React to changes in the
 WebApplicationFactory - Use solution-relative contentRoot path, when the path
 from metadata either is not available or doesn't exist. - If none of the
 paths exist, use the AppContext.BaseDirectory instead. - Fix tests with
 outdated expectations

---
 .../Infrastructure/ServerFactory.cs           |  2 +-
 .../src/GenerateMvcTestManifestTask.cs        | 47 ++++++++++++++++++-
 src/Mvc/Mvc.Testing/src/PublicAPI.Shipped.txt |  2 +
 .../Mvc.Testing/src/PublicAPI.Unshipped.txt   |  3 ++
 .../Mvc.Testing/src/WebApplicationFactory.cs  | 20 +++++---
 .../TestingInfrastructureInheritanceTests.cs  | 22 +++++++--
 6 files changed, 84 insertions(+), 12 deletions(-)

diff --git a/src/Identity/test/Identity.FunctionalTests/Infrastructure/ServerFactory.cs b/src/Identity/test/Identity.FunctionalTests/Infrastructure/ServerFactory.cs
index 91aef38de10b..2b9957dec452 100644
--- a/src/Identity/test/Identity.FunctionalTests/Infrastructure/ServerFactory.cs
+++ b/src/Identity/test/Identity.FunctionalTests/Infrastructure/ServerFactory.cs
@@ -63,7 +63,7 @@ protected override IHost CreateHost(IHostBuilder builder)
         return result;
     }
 
-    protected override TestServer CreateServer(IWebHostBuilder builder)
+    protected override ITestServer CreateServer(IWebHostBuilder builder)
     {
         var result = base.CreateServer(builder);
         EnsureDatabaseCreated(result.Host.Services);
diff --git a/src/Mvc/Mvc.Testing.Tasks/src/GenerateMvcTestManifestTask.cs b/src/Mvc/Mvc.Testing.Tasks/src/GenerateMvcTestManifestTask.cs
index d5adc6fae699..8b8df20de470 100644
--- a/src/Mvc/Mvc.Testing.Tasks/src/GenerateMvcTestManifestTask.cs
+++ b/src/Mvc/Mvc.Testing.Tasks/src/GenerateMvcTestManifestTask.cs
@@ -1,8 +1,10 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
+using System;
 using System.Collections.Generic;
 using System.IO;
+using System.Linq;
 using System.Runtime.Serialization.Json;
 using System.Text;
 using Microsoft.Build.Framework;
@@ -33,11 +35,14 @@ public override bool Execute()
     {
         using var fileStream = File.Create(ManifestPath);
         var output = new Dictionary<string, string>();
+        var manifestDirectory = Path.GetDirectoryName(ManifestPath);
+
         foreach (var project in Projects)
         {
             var contentRoot = project.GetMetadata("ContentRoot");
             var assemblyName = project.GetMetadata("Identity");
-            output[assemblyName] = contentRoot;
+            var relativeContentRoot = GetRelativePath(manifestDirectory, contentRoot);
+            output[assemblyName] = relativeContentRoot;
         }
 
         var serializer = new DataContractJsonSerializer(typeof(Dictionary<string, string>), new DataContractJsonSerializerSettings
@@ -49,4 +54,44 @@ public override bool Execute()
 
         return !Log.HasLoggedErrors;
     }
+
+    private static string GetRelativePath(string? relativeTo, string path)
+    {
+        if (string.IsNullOrEmpty(relativeTo))
+        {
+            return path;
+        }
+
+        // Ensure the paths are absolute
+        string absoluteRelativeTo = Path.GetFullPath(relativeTo);
+        string absolutePath = Path.GetFullPath(path);
+
+        // Split the paths into their components
+        string[] relativeToParts = absoluteRelativeTo.TrimEnd(Path.DirectorySeparatorChar).Split(Path.DirectorySeparatorChar);
+        string[] pathParts = absolutePath.TrimEnd(Path.DirectorySeparatorChar).Split(Path.DirectorySeparatorChar);
+
+        // Find the common base path length
+        int commonLength = 0;
+        while (commonLength < relativeToParts.Length && commonLength < pathParts.Length &&
+               string.Equals(relativeToParts[commonLength], pathParts[commonLength], StringComparison.OrdinalIgnoreCase))
+        {
+            commonLength++;
+        }
+
+        // Calculate the number of directories to go up from the relativeTo path
+        int upDirectories = relativeToParts.Length - commonLength;
+
+        // Build the relative path
+        string relativePath = string.Join(Path.DirectorySeparatorChar.ToString(), new string[upDirectories].Select(_ => "..").ToArray());
+        if (commonLength < pathParts.Length)
+        {
+            if (relativePath.Length > 0)
+            {
+                relativePath += Path.DirectorySeparatorChar;
+            }
+            relativePath += string.Join(Path.DirectorySeparatorChar.ToString(), pathParts.Skip(commonLength));
+        }
+
+        return relativePath;
+    }
 }
diff --git a/src/Mvc/Mvc.Testing/src/PublicAPI.Shipped.txt b/src/Mvc/Mvc.Testing/src/PublicAPI.Shipped.txt
index 46f1e43e4eac..cd734b7284fb 100644
--- a/src/Mvc/Mvc.Testing/src/PublicAPI.Shipped.txt
+++ b/src/Mvc/Mvc.Testing/src/PublicAPI.Shipped.txt
@@ -16,6 +16,7 @@ Microsoft.AspNetCore.Mvc.Testing.WebApplicationFactory<TEntryPoint>.CreateDefaul
 Microsoft.AspNetCore.Mvc.Testing.WebApplicationFactory<TEntryPoint>.CreateDefaultClient(System.Uri! baseAddress, params System.Net.Http.DelegatingHandler![]! handlers) -> System.Net.Http.HttpClient!
 Microsoft.AspNetCore.Mvc.Testing.WebApplicationFactory<TEntryPoint>.Dispose() -> void
 Microsoft.AspNetCore.Mvc.Testing.WebApplicationFactory<TEntryPoint>.Factories.get -> System.Collections.Generic.IReadOnlyList<Microsoft.AspNetCore.Mvc.Testing.WebApplicationFactory<TEntryPoint!>!>!
+Microsoft.AspNetCore.Mvc.Testing.WebApplicationFactory<TEntryPoint>.Server.get -> Microsoft.AspNetCore.TestHost.TestServer!
 Microsoft.AspNetCore.Mvc.Testing.WebApplicationFactory<TEntryPoint>.WebApplicationFactory() -> void
 Microsoft.AspNetCore.Mvc.Testing.WebApplicationFactory<TEntryPoint>.WithWebHostBuilder(System.Action<Microsoft.AspNetCore.Hosting.IWebHostBuilder!>! configuration) -> Microsoft.AspNetCore.Mvc.Testing.WebApplicationFactory<TEntryPoint!>!
 Microsoft.AspNetCore.Mvc.Testing.WebApplicationFactoryClientOptions
@@ -40,6 +41,7 @@ virtual Microsoft.AspNetCore.Mvc.Testing.WebApplicationFactory<TEntryPoint>.Conf
 virtual Microsoft.AspNetCore.Mvc.Testing.WebApplicationFactory<TEntryPoint>.ConfigureWebHost(Microsoft.AspNetCore.Hosting.IWebHostBuilder! builder) -> void
 virtual Microsoft.AspNetCore.Mvc.Testing.WebApplicationFactory<TEntryPoint>.CreateHost(Microsoft.Extensions.Hosting.IHostBuilder! builder) -> Microsoft.Extensions.Hosting.IHost!
 virtual Microsoft.AspNetCore.Mvc.Testing.WebApplicationFactory<TEntryPoint>.CreateHostBuilder() -> Microsoft.Extensions.Hosting.IHostBuilder?
+virtual Microsoft.AspNetCore.Mvc.Testing.WebApplicationFactory<TEntryPoint>.CreateServer(Microsoft.AspNetCore.Hosting.IWebHostBuilder! builder) -> Microsoft.AspNetCore.TestHost.TestServer!
 virtual Microsoft.AspNetCore.Mvc.Testing.WebApplicationFactory<TEntryPoint>.CreateWebHostBuilder() -> Microsoft.AspNetCore.Hosting.IWebHostBuilder?
 virtual Microsoft.AspNetCore.Mvc.Testing.WebApplicationFactory<TEntryPoint>.Dispose(bool disposing) -> void
 virtual Microsoft.AspNetCore.Mvc.Testing.WebApplicationFactory<TEntryPoint>.DisposeAsync() -> System.Threading.Tasks.ValueTask
diff --git a/src/Mvc/Mvc.Testing/src/PublicAPI.Unshipped.txt b/src/Mvc/Mvc.Testing/src/PublicAPI.Unshipped.txt
index 68910e215fc2..e5eca1955b3d 100644
--- a/src/Mvc/Mvc.Testing/src/PublicAPI.Unshipped.txt
+++ b/src/Mvc/Mvc.Testing/src/PublicAPI.Unshipped.txt
@@ -1,5 +1,8 @@
 #nullable enable
 Microsoft.AspNetCore.Mvc.Testing.WebApplicationFactory<TEntryPoint>.Initialize() -> void
+*REMOVED*Microsoft.AspNetCore.Mvc.Testing.WebApplicationFactory<TEntryPoint>.Server.get -> Microsoft.AspNetCore.TestHost.TestServer!
 Microsoft.AspNetCore.Mvc.Testing.WebApplicationFactory<TEntryPoint>.Server.get -> Microsoft.AspNetCore.TestHost.TestServer?
 Microsoft.AspNetCore.Mvc.Testing.WebApplicationFactory<TEntryPoint>.TestServer.get -> Microsoft.AspNetCore.TestHost.ITestServer?
+*REMOVED*virtual Microsoft.AspNetCore.Mvc.Testing.WebApplicationFactory<TEntryPoint>.CreateServer(Microsoft.AspNetCore.Hosting.IWebHostBuilder! builder) -> Microsoft.AspNetCore.TestHost.TestServer!
 virtual Microsoft.AspNetCore.Mvc.Testing.WebApplicationFactory<TEntryPoint>.CreateServer(Microsoft.AspNetCore.Hosting.IWebHostBuilder! builder) -> Microsoft.AspNetCore.TestHost.ITestServer!
+
diff --git a/src/Mvc/Mvc.Testing/src/WebApplicationFactory.cs b/src/Mvc/Mvc.Testing/src/WebApplicationFactory.cs
index b2aae99e95eb..fbe66ee9cff9 100644
--- a/src/Mvc/Mvc.Testing/src/WebApplicationFactory.cs
+++ b/src/Mvc/Mvc.Testing/src/WebApplicationFactory.cs
@@ -246,17 +246,23 @@ private void SetContentRoot(IWebHostBuilder builder)
             return;
         }
 
-        var fromFile = File.Exists("MvcTestingAppManifest.json");
-        var contentRoot = fromFile ? GetContentRootFromFile("MvcTestingAppManifest.json") : GetContentRootFromAssembly();
-
-        if (contentRoot != null)
+        string? contentRoot = null;
+        if (File.Exists("MvcTestingAppManifest.json"))
         {
-            builder.UseContentRoot(contentRoot);
+            var manifestContentRoot = GetContentRootFromFile("MvcTestingAppManifest.json");
+            if (manifestContentRoot is not null && Directory.Exists(manifestContentRoot))
+            {
+                contentRoot = manifestContentRoot;
+            }
         }
-        else
+
+        contentRoot ??= GetContentRootFromAssembly();
+        if (contentRoot is null || !Directory.Exists(contentRoot))
         {
-            builder.UseSolutionRelativeContentRoot(typeof(TEntryPoint).Assembly.GetName().Name!);
+            contentRoot = AppContext.BaseDirectory;
         }
+
+        builder.UseContentRoot(contentRoot);
     }
 
     private static string? GetContentRootFromFile(string file)
diff --git a/src/Mvc/test/Mvc.FunctionalTests/TestingInfrastructureInheritanceTests.cs b/src/Mvc/test/Mvc.FunctionalTests/TestingInfrastructureInheritanceTests.cs
index 5a97d3c8daee..74fc71cf56f8 100644
--- a/src/Mvc/test/Mvc.FunctionalTests/TestingInfrastructureInheritanceTests.cs
+++ b/src/Mvc/test/Mvc.FunctionalTests/TestingInfrastructureInheritanceTests.cs
@@ -27,8 +27,13 @@ public void TestingInfrastructure_WebHost_WithWebHostBuilderRespectsCustomizatio
         Assert.Equal(new[] { "ConfigureWebHost", "Customization", "FurtherCustomization" }, factory.ConfigureWebHostCalled.ToArray());
         Assert.True(factory.CreateServerCalled);
         Assert.True(factory.CreateWebHostBuilderCalled);
-        // GetTestAssemblies is not called when reading content roots from MvcAppManifest
-        Assert.False(factory.GetTestAssembliesCalled);
+
+        // When run locally on the developer machine, the test manifest will be generated,
+        // and the content root will be read from the manifest file.
+        // However, when run in CI, the relative path in the metadata will not exist,
+        // and the content root lookup logic will probe the test assemblies too.
+        //Assert.False(factory.GetTestAssembliesCalled);
+
         Assert.True(factory.CreateHostBuilderCalled);
         Assert.False(factory.CreateHostCalled);
     }
@@ -45,7 +50,13 @@ public void TestingInfrastructure_GenericHost_WithWithHostBuilderRespectsCustomi
 
         // Assert
         Assert.Equal(new[] { "ConfigureWebHost", "Customization", "FurtherCustomization" }, factory.ConfigureWebHostCalled.ToArray());
-        Assert.False(factory.GetTestAssembliesCalled);
+
+        // When run locally on the developer machine, the test manifest will be generated,
+        // and the content root will be read from the manifest file.
+        // However, when run in CI, the relative path in the metadata will not exist,
+        // and the content root lookup logic will probe the test assemblies too.
+        //Assert.False(factory.GetTestAssembliesCalled);
+
         Assert.True(factory.CreateHostBuilderCalled);
         Assert.True(factory.CreateHostCalled);
         Assert.False(factory.CreateServerCalled);
@@ -128,7 +139,12 @@ public void Dispose()
 
     private class CustomizedFactory<TEntryPoint> : WebApplicationFactory<TEntryPoint> where TEntryPoint : class
     {
+        // GetTestAssemblies is not called when reading content roots from MvcAppManifest,
+        // and the content root specified in the manifest is a path that exists.
+        // Otherwise, the WebApplicationFactory will try to look for the referenced assemblies which have
+        // `WebApplicationFactoryContentRootAttribute` applied to them, to extract the content root path from that metadata.
         public bool GetTestAssembliesCalled { get; private set; }
+
         public bool CreateWebHostBuilderCalled { get; private set; }
         public bool CreateHostBuilderCalled { get; private set; }
         public bool CreateServerCalled { get; private set; }

From d2b036f07812720bfdce9853d2673b61f3f7c088 Mon Sep 17 00:00:00 2001
From: Artak Mkrtchyan <artakm@microsoft.com>
Date: Tue, 18 Feb 2025 14:55:19 -0800
Subject: [PATCH 3/3] Avoid a breaking change with the CreateServer method.
 Mark CreateServer as obsolete and introduce a new CreateTestServer method.

---
 .../Infrastructure/ServerFactory.cs           |  4 +--
 .../Mvc.Testing/src/PublicAPI.Unshipped.txt   |  3 +-
 .../Mvc.Testing/src/WebApplicationFactory.cs  | 29 ++++++++++++++-----
 .../Infrastructure/MvcTestFixture.cs          |  4 +--
 .../TestingInfrastructureInheritanceTests.cs  |  4 +--
 5 files changed, 28 insertions(+), 16 deletions(-)

diff --git a/src/Identity/test/Identity.FunctionalTests/Infrastructure/ServerFactory.cs b/src/Identity/test/Identity.FunctionalTests/Infrastructure/ServerFactory.cs
index 2b9957dec452..4d04c04dbcbc 100644
--- a/src/Identity/test/Identity.FunctionalTests/Infrastructure/ServerFactory.cs
+++ b/src/Identity/test/Identity.FunctionalTests/Infrastructure/ServerFactory.cs
@@ -63,9 +63,9 @@ protected override IHost CreateHost(IHostBuilder builder)
         return result;
     }
 
-    protected override ITestServer CreateServer(IWebHostBuilder builder)
+    protected override ITestServer CreateTestServer(IWebHostBuilder builder)
     {
-        var result = base.CreateServer(builder);
+        var result = base.CreateTestServer(builder);
         EnsureDatabaseCreated(result.Host.Services);
         return result;
     }
diff --git a/src/Mvc/Mvc.Testing/src/PublicAPI.Unshipped.txt b/src/Mvc/Mvc.Testing/src/PublicAPI.Unshipped.txt
index e5eca1955b3d..5137f91f4690 100644
--- a/src/Mvc/Mvc.Testing/src/PublicAPI.Unshipped.txt
+++ b/src/Mvc/Mvc.Testing/src/PublicAPI.Unshipped.txt
@@ -3,6 +3,5 @@ Microsoft.AspNetCore.Mvc.Testing.WebApplicationFactory<TEntryPoint>.Initialize()
 *REMOVED*Microsoft.AspNetCore.Mvc.Testing.WebApplicationFactory<TEntryPoint>.Server.get -> Microsoft.AspNetCore.TestHost.TestServer!
 Microsoft.AspNetCore.Mvc.Testing.WebApplicationFactory<TEntryPoint>.Server.get -> Microsoft.AspNetCore.TestHost.TestServer?
 Microsoft.AspNetCore.Mvc.Testing.WebApplicationFactory<TEntryPoint>.TestServer.get -> Microsoft.AspNetCore.TestHost.ITestServer?
-*REMOVED*virtual Microsoft.AspNetCore.Mvc.Testing.WebApplicationFactory<TEntryPoint>.CreateServer(Microsoft.AspNetCore.Hosting.IWebHostBuilder! builder) -> Microsoft.AspNetCore.TestHost.TestServer!
-virtual Microsoft.AspNetCore.Mvc.Testing.WebApplicationFactory<TEntryPoint>.CreateServer(Microsoft.AspNetCore.Hosting.IWebHostBuilder! builder) -> Microsoft.AspNetCore.TestHost.ITestServer!
+virtual Microsoft.AspNetCore.Mvc.Testing.WebApplicationFactory<TEntryPoint>.CreateTestServer(Microsoft.AspNetCore.Hosting.IWebHostBuilder! builder) -> Microsoft.AspNetCore.TestHost.ITestServer!
 
diff --git a/src/Mvc/Mvc.Testing/src/WebApplicationFactory.cs b/src/Mvc/Mvc.Testing/src/WebApplicationFactory.cs
index fbe66ee9cff9..efb6e33b6b6f 100644
--- a/src/Mvc/Mvc.Testing/src/WebApplicationFactory.cs
+++ b/src/Mvc/Mvc.Testing/src/WebApplicationFactory.cs
@@ -22,9 +22,9 @@ namespace Microsoft.AspNetCore.Mvc.Testing;
 /// </summary>
 /// <typeparam name="TEntryPoint">A type in the entry point assembly of the application.
 /// Typically the Startup or Program classes can be used.</typeparam>
-/// <remarks>The default behavior of the <see cref="CreateServer(IWebHostBuilder)"/> implementation
+/// <remarks>The default behavior of the <see cref="CreateTestServer(IWebHostBuilder)"/> implementation
 /// creates a new <see cref="TestHost.TestServer"/> instance as an in-memory server to utilize for testing.
-/// If the developers wants, they can override the <see cref="CreateServer(IWebHostBuilder)"/> method to return a customer <see cref="ITestServer"/> implementation,
+/// If the developers wants, they can override the <see cref="CreateTestServer(IWebHostBuilder)"/> method to return a customer <see cref="ITestServer"/> implementation,
 /// and provide an adapter over a real web server, if needed. If done so, the <see cref="CreateClient()"/> and similar methods will
 /// create <see cref="HttpClient"/> instances configured to interact with the provided test server instead.</remarks>
 public partial class WebApplicationFactory<TEntryPoint> : IDisposable, IAsyncDisposable where TEntryPoint : class
@@ -86,7 +86,7 @@ public TestServer? Server
     }
 
     /// <summary>
-    /// Gets the <see cref="ITestServer"/> instance created by the underyling <see cref="CreateServer(IWebHostBuilder)"/> call.
+    /// Gets the <see cref="ITestServer"/> instance created by the underyling <see cref="CreateTestServer(IWebHostBuilder)"/> call.
     /// </summary>
     public ITestServer? TestServer
     {
@@ -136,7 +136,7 @@ internal virtual WebApplicationFactory<TEntryPoint> WithWebHostBuilderCore(Actio
     {
         var factory = new DelegatedWebApplicationFactory(
             ClientOptions,
-            CreateServer,
+            CreateTestServer,
             CreateHost,
             CreateWebHostBuilder,
             CreateHostBuilder,
@@ -218,7 +218,7 @@ public void Initialize()
         {
             SetContentRoot(builder);
             _configuration(builder);
-            _server = CreateServer(builder);
+            _server = CreateTestServer(builder);
         }
     }
 
@@ -457,12 +457,25 @@ private static void EnsureDepsFile()
     /// <param name="builder">The <see cref="IWebHostBuilder"/> used to
     /// create the server.</param>
     /// <returns>The <see cref="TestServer"/> with the bootstrapped application.</returns>
-    protected virtual ITestServer CreateServer(IWebHostBuilder builder) => new TestServer(builder);
+    [Obsolete("This method is obsolete. Consider utilizing the CreateTestServer method instead.")]
+    protected virtual TestServer CreateServer(IWebHostBuilder builder) => new TestServer(builder);
+
+    /// <summary>
+    /// Creates the <see cref="ITestServer"/> with the bootstrapped application in <paramref name="builder"/>.
+    /// This is only called for applications using <see cref="IWebHostBuilder"/>. Applications based on
+    /// <see cref="IHostBuilder"/> will use <see cref="CreateHost"/> instead.
+    /// </summary>
+    /// <param name="builder">The <see cref="IWebHostBuilder"/> used to
+    /// create the server.</param>
+    /// <returns>The <see cref="ITestServer"/> with the bootstrapped application.</returns>
+#pragma warning disable CS0618 // Type or member is obsolete
+    protected virtual ITestServer CreateTestServer(IWebHostBuilder builder) => CreateServer(builder);
+#pragma warning restore CS0618 // Type or member is obsolete
 
     /// <summary>
     /// Creates the <see cref="IHost"/> with the bootstrapped application in <paramref name="builder"/>.
     /// This is only called for applications using <see cref="IHostBuilder"/>. Applications based on
-    /// <see cref="IWebHostBuilder"/> will use <see cref="CreateServer"/> instead.
+    /// <see cref="IWebHostBuilder"/> will use <see cref="CreateTestServer"/> instead.
     /// </summary>
     /// <param name="builder">The <see cref="IHostBuilder"/> used to create the host.</param>
     /// <returns>The <see cref="IHost"/> with the bootstrapped application.</returns>
@@ -664,7 +677,7 @@ public DelegatedWebApplicationFactory(
             _configuration = configureWebHost;
         }
 
-        protected override ITestServer CreateServer(IWebHostBuilder builder) => _createServer(builder);
+        protected override ITestServer CreateTestServer(IWebHostBuilder builder) => _createServer(builder);
 
         protected override IHost CreateHost(IHostBuilder builder) => _createHost(builder);
 
diff --git a/src/Mvc/test/Mvc.FunctionalTests/Infrastructure/MvcTestFixture.cs b/src/Mvc/test/Mvc.FunctionalTests/Infrastructure/MvcTestFixture.cs
index 488fb0a6f602..af517efa27e4 100644
--- a/src/Mvc/test/Mvc.FunctionalTests/Infrastructure/MvcTestFixture.cs
+++ b/src/Mvc/test/Mvc.FunctionalTests/Infrastructure/MvcTestFixture.cs
@@ -42,7 +42,7 @@ protected override void ConfigureWebHost(IWebHostBuilder builder)
                 });
     }
 
-    protected override ITestServer CreateServer(IWebHostBuilder builder)
+    protected override ITestServer CreateTestServer(IWebHostBuilder builder)
     {
         var originalCulture = CultureInfo.CurrentCulture;
         var originalUICulture = CultureInfo.CurrentUICulture;
@@ -50,7 +50,7 @@ protected override ITestServer CreateServer(IWebHostBuilder builder)
         {
             CultureInfo.CurrentCulture = new CultureInfo("en-GB");
             CultureInfo.CurrentUICulture = new CultureInfo("en-US");
-            return base.CreateServer(builder);
+            return base.CreateTestServer(builder);
         }
         finally
         {
diff --git a/src/Mvc/test/Mvc.FunctionalTests/TestingInfrastructureInheritanceTests.cs b/src/Mvc/test/Mvc.FunctionalTests/TestingInfrastructureInheritanceTests.cs
index 74fc71cf56f8..b73ab67bbb8a 100644
--- a/src/Mvc/test/Mvc.FunctionalTests/TestingInfrastructureInheritanceTests.cs
+++ b/src/Mvc/test/Mvc.FunctionalTests/TestingInfrastructureInheritanceTests.cs
@@ -157,10 +157,10 @@ protected override void ConfigureWebHost(IWebHostBuilder builder)
             base.ConfigureWebHost(builder);
         }
 
-        protected override ITestServer CreateServer(IWebHostBuilder builder)
+        protected override ITestServer CreateTestServer(IWebHostBuilder builder)
         {
             CreateServerCalled = true;
-            return base.CreateServer(builder);
+            return base.CreateTestServer(builder);
         }
 
         protected override IHost CreateHost(IHostBuilder builder)