Address review comments

- XML comments for changed `TemplateInfo` properties
- correct `DefaultDisplayTemplateTests` and `DefaultEditorTemplateTests` namespaces
- add a couple of low-level `TemplateInfo` tests

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

@@ -29,12 +29,27 @@ namespace Microsoft.AspNet.Mvc
             _visitedObjects = new HashSet<object>(original._visitedObjects);
         }
 
+        /// <summary>
+        /// Gets or sets the formatted model value.
+        /// </summary>
+        /// <remarks>
+        /// Will never return <c>null</c> to avoid problems when using HTML helpers within a template.  Otherwise the
+        /// helpers could find elements in the `ViewDataDictionary`, not the intended Model properties.
+        /// </remarks>
+        /// <value>The formatted model value.</value>
         public object FormattedModelValue
         {
             get { return _formattedModelValue; }
             set { _formattedModelValue = value ?? string.Empty; }
         }
 
+        /// <summary>
+        /// Gets or sets the HTML field prefix.
+        /// </summary>
+        /// <remarks>
+        /// Will never return <c>null</c> for consistency with <see cref="FormattedModelValue"/>.
+        /// </remarks>
+        /// <value>The HTML field prefix.</value>
         public string HtmlFieldPrefix
         {
             get { return _htmlFieldPrefix; }

test/Microsoft.AspNet.Mvc.Core.Test/Rendering/DefaultDisplayTemplatesTests.cs

@@ -9,7 +9,7 @@ using Microsoft.AspNet.Mvc.Rendering;
 using Moq;
 using Xunit;
 
-namespace Microsoft.AspNet.Mvc.Core.Test
+namespace Microsoft.AspNet.Mvc.Core
 {
     public class DefaultDisplayTemplateTests
     {

test/Microsoft.AspNet.Mvc.Core.Test/Rendering/DefaultEditorTemplatesTests.cs

@@ -9,7 +9,7 @@ using Microsoft.AspNet.Mvc.Rendering;
 using Moq;
 using Xunit;
 
-namespace Microsoft.AspNet.Mvc.Core.Test
+namespace Microsoft.AspNet.Mvc.Core
 {
     public class DefaultEditorTemplatesTests
     {

test/Microsoft.AspNet.Mvc.Core.Test/Rendering/ViewDataOfTTest.cs

@@ -5,7 +5,7 @@ using System;
 using Microsoft.AspNet.Mvc.ModelBinding;
 using Xunit;
 
-namespace Microsoft.AspNet.Mvc.Rendering
+namespace Microsoft.AspNet.Mvc
 {
     public class ViewDataOfTTest
     {
@@ -37,7 +37,7 @@ namespace Microsoft.AspNet.Mvc.Rendering
         public void SettingModelWorksForCompatibleTypes()
         {
             // Arrange
-            string value = "some value";
+            var value = "some value";
             var viewDataOfT = new ViewDataDictionary<object>(new DataAnnotationsModelMetadataProvider());
             ViewDataDictionary viewData = viewDataOfT;
 
@@ -47,5 +47,47 @@ namespace Microsoft.AspNet.Mvc.Rendering
             // Assert
             Assert.Same(value, viewDataOfT.Model);
         }
+
+        [Fact]
+        public void PropertiesInitializedCorrectly()
+        {
+            // Arrange
+            var viewData = new ViewDataDictionary<string>(new DataAnnotationsModelMetadataProvider());
+
+            // Act & Assert
+            Assert.Empty(viewData);
+            Assert.Equal(0, viewData.Count);
+            Assert.False(viewData.IsReadOnly);
+
+            Assert.NotNull(viewData.Keys);
+            Assert.Empty(viewData.Keys);
+
+            Assert.Null(viewData.Model);
+            Assert.NotNull(viewData.ModelMetadata);
+            Assert.NotNull(viewData.ModelState);
+
+            Assert.NotNull(viewData.TemplateInfo);
+            Assert.Equal(0, viewData.TemplateInfo.TemplateDepth);
+            Assert.Equal(string.Empty, viewData.TemplateInfo.FormattedModelValue);
+            Assert.Equal(string.Empty, viewData.TemplateInfo.HtmlFieldPrefix);
+
+            Assert.NotNull(viewData.Values);
+            Assert.Empty(viewData.Values);
+        }
+
+        [Fact]
+        public void TemplateInfoPropertiesAreNeverNull()
+        {
+            // Arrange
+            var viewData = new ViewDataDictionary<string>(new DataAnnotationsModelMetadataProvider());
+
+            // Act
+            viewData.TemplateInfo.FormattedModelValue = null;
+            viewData.TemplateInfo.HtmlFieldPrefix = null;
+
+            // Assert
+            Assert.Equal(string.Empty, viewData.TemplateInfo.FormattedModelValue);
+            Assert.Equal(string.Empty, viewData.TemplateInfo.HtmlFieldPrefix);
+        }
     }
 }