Fix test

Author: HaoK

test/Microsoft.AspNetCore.Mvc.Test/MvcServiceCollectionExtensionsTest.cs

@@ -31,6 +31,7 @@
 using Microsoft.AspNetCore.Mvc.ViewFeatures;
 using Microsoft.AspNetCore.Mvc.ViewFeatures.Internal;
 using Microsoft.AspNetCore.Routing;
+using Microsoft.Extensions.Configuration;
 using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Extensions.DependencyInjection.Extensions;
 using Microsoft.Extensions.ObjectPool;
@@ -261,6 +262,7 @@ public void AddMvc_NoScopedServiceIsReferredToByASingleton()
             services.AddSingleton<IHostingEnvironment>(GetHostingEnvironment());
             services.AddSingleton<ObjectPoolProvider, DefaultObjectPoolProvider>();
             services.AddSingleton<DiagnosticSource>(new DiagnosticListener("Microsoft.AspNet"));
+            services.AddSingleton<IConfiguration>(new ConfigurationBuilder().Build());
             services.AddLogging();
             services.AddOptions();
             services.AddMvc();