Layout property needs to be propogated between nested view starts

Fixes #1364

src/Microsoft.AspNet.Mvc.Razor/RazorView.cs

@@ -150,13 +150,17 @@ namespace Microsoft.AspNet.Mvc.Razor
         {
             var viewStarts = _viewStartProvider.GetViewStartPages(_razorPage.Path);
 
+            string layout = null;
             foreach (var viewStart in viewStarts)
             {
+                // Copy the layout value from the previous view start (if any) to the current.
+                viewStart.Layout = layout;
                 await RenderPageCoreAsync(viewStart, context);
-
-                // Copy over interesting properties from the ViewStart page to the entry page.
-                _razorPage.Layout = viewStart.Layout;
+                layout = viewStart.Layout;
             }
+
+            // Copy over interesting properties from the ViewStart page to the entry page.
+            _razorPage.Layout = layout;
         }
 
         private async Task RenderLayoutAsync(ViewContext context,

test/Microsoft.AspNet.Mvc.FunctionalTests/ViewEngineTests.cs

@@ -196,5 +196,25 @@ component-content";
             // Assert
             Assert.Equal(expected, body.Trim());
         }
+
+        [Fact]
+        public async Task LayoutValueIsPassedBetweenNestedViewStarts()
+        {
+            // Arrange
+            var expected = string.Join(Environment.NewLine,
+                                       "<title>viewstart-value</title>",
+                                       "",
+                                       "~/Views/NestedViewStarts/NestedViewStarts/Layout.cshtml",
+                                       "index-content");
+            var server = TestServer.Create(_provider, _app);
+            var client = server.CreateClient();
+
+            // Act
+            var body = await client.GetStringAsync("http://localhost/NestedViewStarts");
+
+            // Assert
+            Assert.Equal(expected, body.Trim());
+        }
     }
-}
+}
+ 

test/Microsoft.AspNet.Mvc.Razor.Test/RazorViewTest.cs

@@ -714,6 +714,80 @@ section-content-2";
             Assert.True(executed);
         }
 
+        [Fact]
+        public async Task RenderAsync_CopiesLayoutPropertyFromViewStart()
+        {
+            // Arrange
+            var expectedViewStart = "Layout1";
+            var expectedPage = "Layout2";
+            string actualViewStart = null;
+            string actualPage = null;
+            var page = new TestableRazorPage(v =>
+            {
+                actualPage = v.Layout;
+                // Clear it out because we don't care about rendering the layout in this test.
+                v.Layout = null;
+            });
+            var viewStart1 = new TestableRazorPage(v =>
+            {
+                v.Layout = expectedViewStart;
+            });
+            var viewStart2 = new TestableRazorPage(v =>
+            {
+                actualViewStart = v.Layout;
+                v.Layout = expectedPage;
+            });
+            var pageFactory = Mock.Of<IRazorPageFactory>();
+
+            var view = new RazorView(pageFactory,
+                                     Mock.Of<IRazorPageActivator>(),
+                                     CreateViewStartProvider(viewStart1, viewStart2));
+            view.Contextualize(page, isPartial: false);
+            var viewContext = CreateViewContext(view);
+
+            // Act
+            await view.RenderAsync(viewContext);
+
+            // Assert
+            Assert.Equal(expectedViewStart, actualViewStart);
+            Assert.Equal(expectedPage, actualPage);
+        }
+
+        [Fact]
+        public async Task ResettingLayout_InViewStartCausesItToBeResetInPage()
+        {
+            // Arrange
+            var expected = "Layout";
+            string actual = null;
+
+            var page = new TestableRazorPage(v =>
+            {
+                Assert.Null(v.Layout);
+            });
+            var viewStart1 = new TestableRazorPage(v =>
+            {
+                v.Layout = expected;
+            });
+            var viewStart2 = new TestableRazorPage(v =>
+            {
+                actual = v.Layout;
+                v.Layout = null;
+            });
+            var pageFactory = Mock.Of<IRazorPageFactory>();
+
+            var view = new RazorView(pageFactory,
+                                     Mock.Of<IRazorPageActivator>(),
+                                     CreateViewStartProvider(viewStart1, viewStart2));
+            view.Contextualize(page, isPartial: false);
+            var viewContext = CreateViewContext(view);
+
+            // Act
+            await view.RenderAsync(viewContext);
+
+            // Assert
+            Assert.Equal(expected, actual);
+        }
+
         private static TextWriter CreateBufferedWriter()
         {
             var mockWriter = new Mock<TextWriter>();

test/WebSites/RazorWebSite/Controllers/NestedViewStartsController.cs

@@ -0,0 +1,15 @@
+// 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.
+
+using Microsoft.AspNet.Mvc;
+
+namespace RazorWebSite.Controllers
+{
+    public class NestedViewStartsController : Controller
+    {
+        public ViewResult Index()
+        {
+            return View("NestedViewStarts/Index");
+        }
+    }
+}

test/WebSites/RazorWebSite/Views/NestedViewStarts/NestedViewStarts/Index.cshtml

@@ -0,0 +1 @@
+index-content

test/WebSites/RazorWebSite/Views/NestedViewStarts/NestedViewStarts/Layout.cshtml

@@ -0,0 +1,2 @@
+<title>@ViewData["title"]</title>
+@RenderBody()

test/WebSites/RazorWebSite/Views/NestedViewStarts/NestedViewStarts/_ViewStart.cshtml

@@ -0,0 +1,4 @@
+@{
+    ViewData["Title"] = "viewstart-value";
+}
+@Layout

test/WebSites/RazorWebSite/Views/NestedViewStarts/_viewstart.cshtml

@@ -0,0 +1,3 @@
+@{
+    Layout = "~/Views/NestedViewStarts/NestedViewStarts/Layout.cshtml";
+}