Add some additional logging to ErrorPageMiddlewareWebSite (dotnet#8049)

* Add some additional logging to ErrorPageMiddlewareWebSite

DeveloperExceptionMiddleware will log an error if rendering the exception page
throws. The test failure in https://github.com/aspnet/AspNetCore-Internal/issues/1730
suggests that we encountered an error like so but do not have anything further to go by.

This change adds logging to the test so we could identify possible issues

Author: pranavkm

src/Mvc/test/Mvc.FunctionalTests/ErrorPageTests.cs

@@ -1,27 +1,44 @@
 // Copyright (c) .NET Foundation. All rights reserved.
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
+using System;
+using System.Linq;
 using System.Net;
 using System.Net.Http;
 using System.Net.Http.Headers;
 using System.Text.Encodings.Web;
 using System.Threading.Tasks;
-using Microsoft.AspNetCore.Mvc.Razor.Internal;
+using Microsoft.AspNetCore.Hosting;
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.Logging;
+using Microsoft.Extensions.Logging.Testing;
 using Xunit;
+using Xunit.Abstractions;
 
 namespace Microsoft.AspNetCore.Mvc.FunctionalTests
 {
     /// <summary>
     /// Functional test to verify the error reporting of Razor compilation by diagnostic middleware.
     /// </summary>
-    public class ErrorPageTests : IClassFixture<MvcTestFixture<ErrorPageMiddlewareWebSite.Startup>>
+    public class ErrorPageTests : IClassFixture<MvcTestFixture<ErrorPageMiddlewareWebSite.Startup>>, IDisposable
     {
         private static readonly string PreserveCompilationContextMessage = HtmlEncoder.Default.Encode(
             "One or more compilation references are missing. Ensure that your project is referencing " +
             "'Microsoft.NET.Sdk.Web' and the 'PreserveCompilationContext' property is not set to false.");
-        public ErrorPageTests(MvcTestFixture<ErrorPageMiddlewareWebSite.Startup> fixture)
+        private readonly AssemblyTestLog _assemblyTestLog;
+
+        public ErrorPageTests(
+            MvcTestFixture<ErrorPageMiddlewareWebSite.Startup> fixture,
+            ITestOutputHelper testOutputHelper)
         {
-            Client = fixture.CreateDefaultClient();
+            _assemblyTestLog = AssemblyTestLog.ForAssembly(GetType().Assembly);
+
+            var loggerProvider = _assemblyTestLog.CreateLoggerFactory(testOutputHelper, GetType().Name);
+
+            var factory = fixture.Factories.FirstOrDefault() ?? fixture.WithWebHostBuilder(b => b.UseStartup<ErrorPageMiddlewareWebSite.Startup>());
+            Client = factory
+                .WithWebHostBuilder(builder => builder.ConfigureLogging(l => l.Services.AddSingleton<ILoggerFactory>(loggerProvider)))
+                .CreateDefaultClient();
         }
 
         public HttpClient Client { get; }
@@ -144,5 +161,10 @@ public async void AggregateException_FlattensInnerExceptions()
             Assert.Contains(nullReferenceException, content);
             Assert.Contains(indexOutOfRangeException, content);
         }
+
+        public void Dispose()
+        {
+            _assemblyTestLog.Dispose();
+        }
     }
 }