[Issue #527] Revive common ActionResults - Part 1.

1. Added HttpNotFound() to Controller.
2. Updated HttpStatusCodeResult to expose the StatusCode as a property.
3. Added unit tests for HttpNotFound() and for HttpStatusCodeResult.
4. Updated the MvcSample to add an action that uses HttpNotFound().
5. Brought back HttpNotFoundResult and added unit tests for it.

samples/MvcSample.Web/HomeController.cs

@@ -29,6 +29,11 @@ namespace MvcSample.Web
             return View();
         }
 
+        public ActionResult NotFound()
+        {
+            return HttpNotFound();
+        }
+
         /// <summary>
         /// Action that shows metadata when model is <c>null</c>.
         /// </summary>

src/Microsoft.AspNet.Mvc.Core/ActionResults/HttpNotFoundResult.cs

@@ -0,0 +1,19 @@
+// Copyright (c) Microsoft Open Technologies, Inc. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+namespace Microsoft.AspNet.Mvc
+{
+    /// <summary>
+    /// Represents an <see cref="HttpStatusCodeResult"/> that when
+    /// executed will produce a Not Found (404) response.
+    /// </summary>
+    public class HttpNotFoundResult : HttpStatusCodeResult
+    {
+        /// <summary>
+        /// Creates a new <see cref="HttpNotFoundResult"/> instance.
+        /// </summary>
+        public HttpNotFoundResult() : base(404)
+        {
+        }
+    }
+}

src/Microsoft.AspNet.Mvc.Core/ActionResults/HttpStatusCodeResult.cs

@@ -2,21 +2,35 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using System.Threading.Tasks;
+using Microsoft.AspNet.Http;
 
 namespace Microsoft.AspNet.Mvc
 {
+    /// <summary>
+    /// Represents an <see cref="ActionResult"/> that when executed will
+    /// produce an HTTP response with the given response status code.
+    /// </summary>
     public class HttpStatusCodeResult : ActionResult
     {
-        private int _statusCode;
-
+        /// <summary>
+        /// Initializes a new instance of the <see cref="HttpStatusCodeResult"/> class
+        /// with the given <paramref name="statusCode"/>.
+        /// </summary>
+        /// <param name="statusCode">The HTTP status code of the response.</param>
         public HttpStatusCodeResult(int statusCode)
         {
-            _statusCode = statusCode;
+            StatusCode = statusCode;
         }
 
+        /// <summary>
+        /// Gets the HTTP status code.
+        /// </summary>
+        public int StatusCode { get; private set; }
+
+        /// <inheritdoc />
         public override void ExecuteResult([NotNull] ActionContext context)
         {
-            context.HttpContext.Response.StatusCode = _statusCode;
+            context.HttpContext.Response.StatusCode = StatusCode;
         }
     }
 }

src/Microsoft.AspNet.Mvc.Core/Controller.cs

@@ -415,6 +415,16 @@ namespace Microsoft.AspNet.Mvc
             return new RedirectToRouteResult(Url, routeName, routeValues, permanent: true);
         }
 
+        /// <summary>
+        /// Creates an <see cref="HttpNotFoundResult"/> that produces a Not Found (404) response.
+        /// </summary>
+        /// <returns>The created <see cref="HttpNotFoundResult"/> for the response.</returns>
+        [NonAction]
+        public virtual HttpNotFoundResult HttpNotFound()
+        {
+            return new HttpNotFoundResult();
+        }
+
         /// <summary>
         /// Called before the action method is invoked.
         /// </summary>

src/Microsoft.AspNet.Mvc.Core/Microsoft.AspNet.Mvc.Core.kproj

@@ -29,6 +29,7 @@
     <Compile Include="ActionDescriptor.cs" />
     <Compile Include="ActionDescriptorProviderContext.cs" />
     <Compile Include="ActionDescriptorsCollection.cs" />
+    <Compile Include="ActionResults\HttpNotFoundResult.cs" />
     <Compile Include="OptionDescriptors\DefaultModelBinderProvider.cs" />
     <Compile Include="OptionDescriptors\DefaultValueProviderFactoryProvider.cs" />
     <Compile Include="OptionDescriptors\DefaultViewEngineProvider.cs" />

test/Microsoft.AspNet.Mvc.Core.Test/ActionResults/HttpNotFoundResultTests.cs

@@ -0,0 +1,17 @@
+using Xunit;
+
+namespace Microsoft.AspNet.Mvc
+{
+    public class HttpNotFoundResultTests
+    {
+        [Fact]
+        public void HttpNotFoundResult_InitializesStatusCode()
+        {
+            // Arrange & act
+            var notFound = new HttpNotFoundResult();
+
+            // Assert
+            Assert.Equal(404, notFound.StatusCode);
+        }
+    }
+}

test/Microsoft.AspNet.Mvc.Core.Test/ActionResults/HttpStatusCodeResultTests.cs

@@ -0,0 +1,30 @@
+using System.IO;
+using System.Threading.Tasks;
+using Microsoft.AspNet.PipelineCore;
+using Microsoft.AspNet.Routing;
+using Xunit;
+
+namespace Microsoft.AspNet.Mvc
+{
+    public class HttpStatusCodeResultTests
+    {
+        [Fact]
+        public void HttpStatusCodeResult_ExecuteResultSetsResponseStatusCode()
+        {
+            // Arrange
+            var result = new HttpStatusCodeResult(404);
+
+            var httpContext = new DefaultHttpContext();
+            var routeData = new RouteData();
+            var actionDescriptor = new ActionDescriptor();
+
+            var context = new ActionContext(httpContext, routeData, actionDescriptor);
+
+            // Act
+            result.ExecuteResult(context);
+
+            // Assert
+            Assert.Equal(404, httpContext.Response.StatusCode);
+        }
+    }
+}

test/Microsoft.AspNet.Mvc.Core.Test/ControllerTests.cs

@@ -357,6 +357,20 @@ namespace Microsoft.AspNet.Mvc.Test
             Assert.Equal(TypeHelper.ObjectToDictionary(routeValues), resultPermanent.RouteValues);
         }
 
+        [Fact]
+        public void HttpNotFound_SetsStatusCode()
+        {
+            // Arrange
+            var controller = new Controller();
+
+            // Act
+            var result = controller.HttpNotFound();
+
+            // Assert
+            Assert.IsType<HttpNotFoundResult>(result);
+            Assert.Equal(404, result.StatusCode);
+        }
+
         [Theory]
         [MemberData("PublicNormalMethodsFromController")]
         public void NonActionAttribute_IsOnEveryPublicNormalMethodFromController(MethodInfo method)

test/Microsoft.AspNet.Mvc.Core.Test/Microsoft.AspNet.Mvc.Core.Test.kproj

@@ -23,6 +23,8 @@
   <ItemGroup>
     <Compile Include="ActionAttributeTests.cs" />
     <Compile Include="ActionExecutorTests.cs" />
+    <Compile Include="ActionResults\HttpNotFoundResultTests.cs" />
+    <Compile Include="ActionResults\HttpStatusCodeResultTests.cs" />
     <Compile Include="ActionResults\ObjectContentResultTests.cs" />
     <Compile Include="ActionResults\ChallengeResultTest.cs" />
     <Compile Include="ActionResults\RedirectToActionResultTest.cs" />