CR comments

- change order a bit and add a unit test

src/Microsoft.AspNet.Hosting/HostingServices.cs

@@ -23,13 +23,13 @@ namespace Microsoft.AspNet.Hosting
                 services.AddTransient(service, sp => fallbackProvider.GetService(service));
             }
 
-            services.AddSingleton<IServiceManifest>(sp => new HostingManifest(services));
-
             if (configureHostServices != null)
             {
                 configureHostServices(services);
             }
 
+            services.AddSingleton<IServiceManifest>(sp => new HostingManifest(services));
+
             return services;
         }
 

test/Microsoft.AspNet.Hosting.Tests/HostingServicesFacts.cs

@@ -119,6 +119,33 @@ namespace Microsoft.AspNet.Hosting.Tests
             Assert.Same(singleton, provider.GetRequiredService<IFakeService>());
         }
 
+        [Fact]
+        public void CreateAdditionalServices_IncludesServicesInManifest()
+        {
+            // Arrange
+            var fallbackServices = new ServiceCollection();
+            fallbackServices.AddTransient<IFakeService, FakeService>();
+            fallbackServices.AddInstance<IServiceManifest>(new ServiceManifest(
+                new Type[] {
+                    typeof(IFakeService),
+                }));
+            var expectedInstance = new FakeService();
+            var services = HostingServices.Create(
+                fallbackServices.BuildServiceProvider(),
+                additionalHostServices => additionalHostServices.AddInstance<IFakeServiceInstance>(expectedInstance));
+
+            // Act
+            var provider = services.BuildServiceProvider();
+            var instance = provider.GetRequiredService<IFakeServiceInstance>();
+            var anotherInstance = provider.GetRequiredService<IFakeServiceInstance>();
+            var manifest = provider.GetRequiredService<IServiceManifest>();
+
+            // Assert
+            Assert.Same(expectedInstance, instance);
+            Assert.Same(expectedInstance, anotherInstance);
+            Assert.Contains(typeof(IFakeServiceInstance), manifest.Services);
+        }
+
         [Fact]
         public void CanHideImportedServices()
         {