Added integration test validating the model building for endpoint with typed result return type

Author: mkArtakMSFT

src/Mvc/test/Mvc.FunctionalTests/ApiExplorerTest.cs

@@ -11,6 +11,11 @@
 using Microsoft.Extensions.Logging;
 using System.Reflection;
 using Xunit.Abstractions;
+using Microsoft.AspNetCore.Mvc.ApplicationModels;
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.AspNetCore.Mvc.ApiExplorer;
+using Microsoft.AspNetCore.Http.HttpResults;
+using Microsoft.AspNetCore.Http;
 
 namespace Microsoft.AspNetCore.Mvc.FunctionalTests;
 
@@ -1565,6 +1570,26 @@ public async Task ApiExplorer_LogsInvokedDescriptionProvidersOnStartup()
         Assert.Contains(TestSink.Writes, w => w.Message.Equals("Executing API description provider 'JsonPatchOperationsArrayProvider' from assembly Microsoft.AspNetCore.Mvc.NewtonsoftJson v42.42.42.42.", StringComparison.Ordinal));
     }
 
+    [Fact]
+    public void ApiExplorer_BuildsMetadataForActionWithTypedResult()
+    {
+        var apiDescCollectionProvider = Factory.Server.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);
+        var apiDescription = Assert.Single<ApiDescription>(group.Items);
+
+        var responseType = Assert.Single(apiDescription.SupportedResponseTypes);
+        Assert.Equal(StatusCodes.Status200OK, responseType.StatusCode);
+        Assert.Equal(typeof(Product), responseType.Type);
+
+        Assert.NotNull(apiDescription.ActionDescriptor.EndpointMetadata);
+        var producesResponseTypeMetadata = apiDescription.ActionDescriptor.EndpointMetadata.OfType<ProducesResponseTypeMetadata>().SingleOrDefault();
+        Assert.NotNull(producesResponseTypeMetadata);
+        Assert.Equal(StatusCodes.Status200OK, producesResponseTypeMetadata.StatusCode);
+        Assert.Equal(typeof(Product), producesResponseTypeMetadata.Type);
+    }
+
     private IEnumerable<string> GetSortedMediaTypes(ApiExplorerResponseType apiResponseType)
     {
         return apiResponseType.ResponseFormats

src/Mvc/test/WebSites/ApiExplorerWebSite/ApiExplorerWebSite.csproj

@@ -7,6 +7,7 @@
   <ItemGroup>
     <Reference Include="Microsoft.AspNetCore.Mvc" />
     <Reference Include="Microsoft.AspNetCore.Mvc.Formatters.Xml" />
+    <Reference Include="Microsoft.AspNetCore.Http.Results" />
     <Reference Include="Microsoft.AspNetCore.Mvc.NewtonsoftJson" />
 
     <Reference Include="Microsoft.AspNetCore.Server.IISIntegration" />

src/Mvc/test/WebSites/ApiExplorerWebSite/Controllers/ApiExplorerWithTypedResultController.cs

@@ -0,0 +1,14 @@
+// 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.Http.HttpResults;
+using Microsoft.AspNetCore.Mvc;
+
+namespace ApiExplorerWebSite;
+
+[Route("ApiExplorerWithTypedResult/[Action]")]
+public class ApiExplorerWithTypedResultController : Controller
+{
+    [HttpGet]
+    public Ok<Product> GetProduct() => TypedResults.Ok(new Product { Name = "Test product" });
+}