diff --git a/src/Microsoft.AspNet.Mvc.Razor.Host/MvcRazorHost.cs b/src/Microsoft.AspNet.Mvc.Razor.Host/MvcRazorHost.cs
index 3477137d76..a4ad2047bc 100644
--- a/src/Microsoft.AspNet.Mvc.Razor.Host/MvcRazorHost.cs
+++ b/src/Microsoft.AspNet.Mvc.Razor.Host/MvcRazorHost.cs
@@ -103,9 +103,6 @@ namespace Microsoft.AspNet.Mvc.Razor
                     StartTagHelperWritingScopeMethodName = "StartTagHelperWritingScope",
                     EndTagHelperWritingScopeMethodName = "EndTagHelperWritingScope",
 
-                    WriteTagHelperAsyncMethodName = "WriteTagHelperAsync",
-                    WriteTagHelperToAsyncMethodName = "WriteTagHelperToAsync",
-
                     // Can't use nameof because IHtmlHelper is (also) not accessible here.
                     MarkAsHtmlEncodedMethodName = HtmlHelperPropertyName + ".Raw",
                     BeginAddHtmlAttributeValuesMethodName = "BeginAddHtmlAttributeValues",
@@ -113,6 +110,9 @@ namespace Microsoft.AspNet.Mvc.Razor
                     AddHtmlAttributeValueMethodName = "AddHtmlAttributeValue",
                     HtmlEncoderPropertyName = "HtmlEncoder",
                     TagHelperContentGetContentMethodName = nameof(TagHelperContent.GetContent),
+                    TagHelperOutputIsContentModifiedPropertyName = nameof(TagHelperOutput.IsContentModified),
+                    TagHelperOutputContentPropertyName = nameof(TagHelperOutput.Content),
+                    TagHelperOutputGetChildContentAsyncMethodName = nameof(TagHelperExecutionContext.GetChildContentAsync)
                 })
             {
                 BeginContextMethodName = "BeginContext",
diff --git a/src/Microsoft.AspNet.Mvc.Razor/RazorPage.cs b/src/Microsoft.AspNet.Mvc.Razor/RazorPage.cs
index 5e224193df..af6f9c3677 100644
--- a/src/Microsoft.AspNet.Mvc.Razor/RazorPage.cs
+++ b/src/Microsoft.AspNet.Mvc.Razor/RazorPage.cs
@@ -310,106 +310,6 @@ namespace Microsoft.AspNet.Mvc.Razor
             return tagHelperContentWrapperTextWriter.Content;
         }
 
-        /// <summary>
-        /// Writes the content of a specified <paramref name="tagHelperExecutionContext"/>.
-        /// </summary>
-        /// <param name="tagHelperExecutionContext">The execution context containing the content.</param>
-        /// <returns>
-        /// A <see cref="Task"/> that on completion writes the <paramref name="tagHelperExecutionContext"/> content.
-        /// </returns>
-        public Task WriteTagHelperAsync(TagHelperExecutionContext tagHelperExecutionContext)
-        {
-            if (tagHelperExecutionContext == null)
-            {
-                throw new ArgumentNullException(nameof(tagHelperExecutionContext));
-            }
-
-            return WriteTagHelperToAsync(Output, tagHelperExecutionContext);
-        }
-
-        /// <summary>
-        /// Writes the content of a specified <paramref name="tagHelperExecutionContext"/> to the specified
-        /// <paramref name="writer"/>.
-        /// </summary>
-        /// <param name="writer">The <see cref="TextWriter"/> instance to write to.</param>
-        /// <param name="tagHelperExecutionContext">The execution context containing the content.</param>
-        /// <returns>
-        /// A <see cref="Task"/> that on completion writes the <paramref name="tagHelperExecutionContext"/> content
-        /// to the <paramref name="writer"/>.
-        /// </returns>
-        public async Task WriteTagHelperToAsync(
-            TextWriter writer,
-            TagHelperExecutionContext tagHelperExecutionContext)
-        {
-            if (writer == null)
-            {
-                throw new ArgumentNullException(nameof(writer));
-            }
-
-            if (tagHelperExecutionContext == null)
-            {
-                throw new ArgumentNullException(nameof(tagHelperExecutionContext));
-            }
-
-            var tagHelperOutput = tagHelperExecutionContext.Output;
-            var isTagNameNullOrWhitespace = string.IsNullOrWhiteSpace(tagHelperOutput.TagName);
-
-            WriteTo(writer, tagHelperOutput.PreElement);
-
-            if (!isTagNameNullOrWhitespace)
-            {
-                writer.Write('<');
-                writer.Write(tagHelperOutput.TagName);
-
-                foreach (var attribute in tagHelperOutput.Attributes)
-                {
-                    writer.Write(' ');
-                    writer.Write(attribute.Name);
-
-                    if (!attribute.Minimized)
-                    {
-                        writer.Write("=\"");
-                        WriteTo(writer, HtmlEncoder, attribute.Value, escapeQuotes: true);
-                        writer.Write('"');
-                    }
-                }
-
-                if (tagHelperOutput.TagMode == TagMode.SelfClosing)
-                {
-                    writer.Write(" /");
-                }
-
-                writer.Write('>');
-            }
-
-            if (isTagNameNullOrWhitespace || tagHelperOutput.TagMode == TagMode.StartTagAndEndTag)
-            {
-                WriteTo(writer, tagHelperOutput.PreContent);
-                if (tagHelperOutput.IsContentModified)
-                {
-                    WriteTo(writer, tagHelperOutput.Content);
-                }
-                else if (tagHelperExecutionContext.ChildContentRetrieved)
-                {
-                    var childContent = await tagHelperExecutionContext.GetChildContentAsync(useCachedResult: true);
-                    WriteTo(writer, childContent);
-                }
-                else
-                {
-                    await tagHelperExecutionContext.ExecuteChildContentAsync();
-                }
-
-                WriteTo(writer, tagHelperOutput.PostContent);
-            }
-
-            if (!isTagNameNullOrWhitespace && tagHelperOutput.TagMode == TagMode.StartTagAndEndTag)
-            {
-                writer.Write(string.Format(CultureInfo.InvariantCulture, "</{0}>", tagHelperOutput.TagName));
-            }
-
-            WriteTo(writer, tagHelperOutput.PostElement);
-        }
-
         /// <summary>
         /// Writes the specified <paramref name="value"/> with HTML encoding to <see cref="Output"/>.
         /// </summary>
@@ -437,7 +337,7 @@ namespace Microsoft.AspNet.Mvc.Razor
                 throw new ArgumentNullException(nameof(writer));
             }
 
-            WriteTo(writer, HtmlEncoder, value, escapeQuotes: false);
+            WriteTo(writer, HtmlEncoder, value);
         }
 
         /// <summary>
@@ -446,21 +346,13 @@ namespace Microsoft.AspNet.Mvc.Razor
         /// <param name="writer">The <see cref="TextWriter"/> instance to write to.</param>
         /// <param name="encoder">The <see cref="HtmlEncoder"/> to use when encoding <paramref name="value"/>.</param>
         /// <param name="value">The <see cref="object"/> to write.</param>
-        /// <param name="escapeQuotes">
-        /// If <c>true</c> escapes double quotes in a <paramref name="value"/> of type <see cref="HtmlString"/>.
-        /// Otherwise writes <see cref="HtmlString"/> values as-is.
-        /// </param>
         /// <remarks>
         /// <paramref name="value"/>s of type <see cref="IHtmlContent"/> are written using
         /// <see cref="IHtmlContent.WriteTo(TextWriter, HtmlEncoder)"/>.
         /// For all other types, the encoded result of <see cref="object.ToString"/> is written to the
         /// <paramref name="writer"/>.
         /// </remarks>
-        public static void WriteTo(
-            TextWriter writer,
-            HtmlEncoder encoder,
-            object value,
-            bool escapeQuotes)
+        public static void WriteTo(TextWriter writer, HtmlEncoder encoder, object value)
         {
             if (writer == null)
             {
@@ -480,28 +372,6 @@ namespace Microsoft.AspNet.Mvc.Razor
             var htmlContent = value as IHtmlContent;
             if (htmlContent != null)
             {
-                if (escapeQuotes)
-                {
-                    // In this case the text likely came directly from the Razor source. Since the original string is
-                    // an attribute value that may have been quoted with single quotes, must handle any double quotes
-                    // in the value. Writing the value out surrounded by double quotes.
-                    //
-                    // This is really not optimal from a perf point of view, but it's the best we can do for right now.
-                    using (var stringWriter = new StringWriter())
-                    {
-                        htmlContent.WriteTo(stringWriter, encoder);
-
-                        var stringValue = stringWriter.ToString();
-                        if (stringValue.Contains("\""))
-                        {
-                            stringValue = stringValue.Replace("\"", "&quot;");
-                        }
-
-                        writer.Write(stringValue);
-                        return;
-                    }
-                }
-
                 var htmlTextWriter = writer as HtmlTextWriter;
                 if (htmlTextWriter == null)
                 {
diff --git a/src/Microsoft.AspNet.Mvc.TagHelpers/TagHelperContentExtensions.cs b/src/Microsoft.AspNet.Mvc.TagHelpers/TagHelperContentExtensions.cs
index 8604fb30e8..8264cd9067 100644
--- a/src/Microsoft.AspNet.Mvc.TagHelpers/TagHelperContentExtensions.cs
+++ b/src/Microsoft.AspNet.Mvc.TagHelpers/TagHelperContentExtensions.cs
@@ -2,6 +2,7 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using System;
+using System.IO;
 using System.Text;
 using System.Text.Encodings.Web;
 using Microsoft.AspNet.Mvc.Razor;
@@ -23,7 +24,7 @@ namespace Microsoft.AspNet.Mvc.TagHelpers
         /// <param name="value">The <see cref="object"/> to write.</param>
         /// <returns><paramref name="content"/> after the write operation has completed.</returns>
         /// <remarks>
-        /// <paramref name="value"/>s of type <see cref="Html.Abstractions.IHtmlContent"/> are written using 
+        /// <paramref name="value"/>s of type <see cref="Html.Abstractions.IHtmlContent"/> are written using
         /// <see cref="Html.Abstractions.IHtmlContent.WriteTo(System.IO.TextWriter, HtmlEncoder)"/>.
         /// For all other types, the encoded result of <see cref="object.ToString"/>
         /// is written to the <paramref name="content"/>.
@@ -51,7 +52,16 @@ namespace Microsoft.AspNet.Mvc.TagHelpers
 
             using (var writer = new TagHelperContentWrapperTextWriter(encoding, content))
             {
-                RazorPage.WriteTo(writer, encoder, value, escapeQuotes: true);
+                using (var stringWriter = new StringWriter())
+                {
+                    RazorPage.WriteTo(stringWriter, encoder, value);
+
+                    // In this case the text likely came directly from the Razor source. Since the original string is
+                    // an attribute value that may have been quoted with single quotes, must handle any double quotes
+                    // in the value. Writing the value out surrounded by double quotes.
+                    var stringValue = stringWriter.ToString().Replace("\"", "&quot;");
+                    writer.Write(stringValue);
+                }
             }
 
             return content;
diff --git a/test/Microsoft.AspNet.Mvc.Razor.Host.Test/TestFiles/Output/Runtime/ModelExpressionTagHelper.cs b/test/Microsoft.AspNet.Mvc.Razor.Host.Test/TestFiles/Output/Runtime/ModelExpressionTagHelper.cs
index 294c59fc49..b267f58e5b 100644
--- a/test/Microsoft.AspNet.Mvc.Razor.Host.Test/TestFiles/Output/Runtime/ModelExpressionTagHelper.cs
+++ b/test/Microsoft.AspNet.Mvc.Razor.Host.Test/TestFiles/Output/Runtime/ModelExpressionTagHelper.cs
@@ -54,7 +54,7 @@ __Microsoft_AspNet_Mvc_Razor_InputTestTagHelper.For = CreateModelExpression(__mo
             __tagHelperExecutionContext.AddTagHelperAttribute("for", __Microsoft_AspNet_Mvc_Razor_InputTestTagHelper.For);
             __tagHelperExecutionContext.Output = await __tagHelperRunner.RunAsync(__tagHelperExecutionContext);
             BeginContext(120, 24, false);
-            await WriteTagHelperAsync(__tagHelperExecutionContext);
+            Write(__tagHelperExecutionContext.Output);
             EndContext();
             __tagHelperExecutionContext = __tagHelperScopeManager.End();
             BeginContext(144, 2, true);
@@ -73,7 +73,7 @@ __Microsoft_AspNet_Mvc_Razor_InputTestTagHelper.For = CreateModelExpression(__mo
             __tagHelperExecutionContext.AddTagHelperAttribute("for", __Microsoft_AspNet_Mvc_Razor_InputTestTagHelper.For);
             __tagHelperExecutionContext.Output = await __tagHelperRunner.RunAsync(__tagHelperExecutionContext);
             BeginContext(146, 27, false);
-            await WriteTagHelperAsync(__tagHelperExecutionContext);
+            Write(__tagHelperExecutionContext.Output);
             EndContext();
             __tagHelperExecutionContext = __tagHelperScopeManager.End();
         }
diff --git a/test/Microsoft.AspNet.Mvc.Razor.Test/RazorPageTest.cs b/test/Microsoft.AspNet.Mvc.Razor.Test/RazorPageTest.cs
index 2197bffd21..20417bb812 100644
--- a/test/Microsoft.AspNet.Mvc.Razor.Test/RazorPageTest.cs
+++ b/test/Microsoft.AspNet.Mvc.Razor.Test/RazorPageTest.cs
@@ -1222,767 +1222,6 @@ namespace Microsoft.AspNet.Mvc.Razor
             Assert.Equal("Hello world", HtmlContentUtilities.HtmlContentToString(((IHtmlContent)buffer[0])));
         }
 
-        public static TheoryData<TagHelperOutput, string> WriteTagHelper_InputData
-        {
-            get
-            {
-                // parameters: TagHelperOutput, expectedOutput
-                return new TheoryData<TagHelperOutput, string>
-                {
-                    {
-                        // parameters: TagName, Attributes, SelfClosing, PreContent, Content, PostContent
-                        GetTagHelperOutput(
-                            tagName:     "div",
-                            attributes:  new TagHelperAttributeList(),
-                            tagMode: TagMode.StartTagAndEndTag,
-                            preElement:  null,
-                            preContent:  null,
-                            content:     "Hello World!",
-                            postContent: null,
-                            postElement: null),
-                        "<div>Hello World!</div>"
-                    },
-                    {
-                        GetTagHelperOutput(
-                            tagName:     string.Empty,
-                            attributes:  new TagHelperAttributeList(),
-                            tagMode: TagMode.StartTagAndEndTag,
-                            preElement:  null,
-                            preContent:  null,
-                            content:     "Hello World!",
-                            postContent: null,
-                            postElement: null),
-                        "Hello World!"
-                    },
-                    {
-                        GetTagHelperOutput(
-                            tagName:     "  ",
-                            attributes:  new TagHelperAttributeList(),
-                            tagMode: TagMode.StartTagAndEndTag,
-                            preElement:  null,
-                            preContent:  null,
-                            content:     "Hello World!",
-                            postContent: null,
-                            postElement: null),
-                        "Hello World!"
-                    },
-                    {
-                        GetTagHelperOutput(
-                            tagName:     "p",
-                            attributes:  new TagHelperAttributeList() { { "test", "testVal" } },
-                            tagMode: TagMode.StartTagAndEndTag,
-                            preElement:  null,
-                            preContent:  null,
-                            content:     "Hello World!",
-                            postContent: null,
-                            postElement: null),
-                        "<p test=\"HtmlEncode[[testVal]]\">Hello World!</p>"
-                    },
-                    {
-                        GetTagHelperOutput(
-                            tagName:     "p",
-                            attributes:  new TagHelperAttributeList() { { "test", "testVal" }, { "something", "  spaced  " } },
-                            tagMode: TagMode.StartTagAndEndTag,
-                            preElement:  null,
-                            preContent:  null,
-                            content:     "Hello World!",
-                            postContent: null,
-                            postElement: null),
-                        "<p test=\"HtmlEncode[[testVal]]\" something=\"HtmlEncode[[  spaced  ]]\">Hello World!</p>"
-                    },
-                    {
-                        GetTagHelperOutput(
-                            tagName:     "p",
-                            attributes:  new TagHelperAttributeList()
-                            {
-                                ["test"] = new TagHelperAttribute
-                                {
-                                    Name = "test",
-                                    Minimized = true
-                                },
-                            },
-                            tagMode: TagMode.StartTagAndEndTag,
-                            preElement:  null,
-                            preContent:  null,
-                            content:     "Hello World!",
-                            postContent: null,
-                            postElement: null),
-                        "<p test>Hello World!</p>"
-                    },
-                    {
-                        GetTagHelperOutput(
-                            tagName:     "p",
-                            attributes:  new TagHelperAttributeList()
-                            {
-                                ["test"] = new TagHelperAttribute
-                                {
-                                    Name = "test",
-                                    Minimized = true
-                                },
-                                ["test2"] = new TagHelperAttribute
-                                {
-                                    Name = "test2",
-                                    Minimized = true
-                                },
-                            },
-                            tagMode: TagMode.StartTagAndEndTag,
-                            preElement:  null,
-                            preContent:  null,
-                            content:     "Hello World!",
-                            postContent: null,
-                            postElement: null),
-                        "<p test test2>Hello World!</p>"
-                    },
-                    {
-                        GetTagHelperOutput(
-                            tagName:     "p",
-                            attributes:  new TagHelperAttributeList()
-                            {
-                                ["first"] = "unminimized",
-                                ["test"] = new TagHelperAttribute
-                                {
-                                    Name = "test",
-                                    Minimized = true
-                                },
-                            },
-                            tagMode: TagMode.StartTagAndEndTag,
-                            preElement:  null,
-                            preContent:  null,
-                            content:     "Hello World!",
-                            postContent: null,
-                            postElement: null),
-                        "<p first=\"HtmlEncode[[unminimized]]\" test>Hello World!</p>"
-                    },
-                    {
-                        GetTagHelperOutput(
-                            tagName:     "p",
-                            attributes:  new TagHelperAttributeList()
-                            {
-                                ["test"] = new TagHelperAttribute
-                                {
-                                    Name = "test",
-                                    Minimized = true
-                                },
-                                ["last"] = "unminimized",
-                            },
-                            tagMode: TagMode.StartTagAndEndTag,
-                            preElement:  null,
-                            preContent:  null,
-                            content:     "Hello World!",
-                            postContent: null,
-                            postElement: null),
-                        "<p test last=\"HtmlEncode[[unminimized]]\">Hello World!</p>"
-                    },
-                    {
-                        GetTagHelperOutput(
-                            tagName:     "p",
-                            attributes:  new TagHelperAttributeList() { { "test", "testVal" } },
-                            tagMode: TagMode.SelfClosing,
-                            preElement:  null,
-                            preContent:  null,
-                            content:     "Hello World!",
-                            postContent: null,
-                            postElement: null),
-                        "<p test=\"HtmlEncode[[testVal]]\" />"
-                    },
-                    {
-                        GetTagHelperOutput(
-                            tagName:     "p",
-                            attributes:  new TagHelperAttributeList() { { "test", "testVal" }, { "something", "  spaced  " } },
-                            tagMode: TagMode.SelfClosing,
-                            preElement:  null,
-                            preContent:  null,
-                            content:     "Hello World!",
-                            postContent: null,
-                            postElement: null),
-                        "<p test=\"HtmlEncode[[testVal]]\" something=\"HtmlEncode[[  spaced  ]]\" />"
-                    },
-                    {
-                        GetTagHelperOutput(
-                            tagName:     "p",
-                            attributes:  new TagHelperAttributeList() { { "test", "testVal" } },
-                            tagMode: TagMode.StartTagOnly,
-                            preElement:  null,
-                            preContent:  null,
-                            content:     "Hello World!",
-                            postContent: null,
-                            postElement: null),
-                        "<p test=\"HtmlEncode[[testVal]]\">"
-                    },
-                    {
-                        GetTagHelperOutput(
-                            tagName:     "p",
-                            attributes:  new TagHelperAttributeList() { { "test", "testVal" }, { "something", "  spaced  " } },
-                            tagMode: TagMode.StartTagOnly,
-                            preElement:  null,
-                            preContent:  null,
-                            content:     "Hello World!",
-                            postContent: null,
-                            postElement: null),
-                        "<p test=\"HtmlEncode[[testVal]]\" something=\"HtmlEncode[[  spaced  ]]\">"
-                    },
-                    {
-                        GetTagHelperOutput(
-                            tagName:     "p",
-                            attributes:  new TagHelperAttributeList(),
-                            tagMode: TagMode.StartTagAndEndTag,
-                            preElement:  null,
-                            preContent:  "Hello World!",
-                            content:     null,
-                            postContent: null,
-                            postElement: null),
-                        "<p>Hello World!</p>"
-                    },
-                    {
-                        GetTagHelperOutput(
-                            tagName:     "p",
-                            attributes:  new TagHelperAttributeList(),
-                            tagMode: TagMode.StartTagAndEndTag,
-                            preElement:  null,
-                            preContent:  null,
-                            content:     "Hello World!",
-                            postContent: null,
-                            postElement: null),
-                        "<p>Hello World!</p>"
-                    },
-                    {
-                        GetTagHelperOutput(
-                            tagName:     "p",
-                            attributes:  new TagHelperAttributeList(),
-                            tagMode: TagMode.StartTagAndEndTag,
-                            preElement:  null,
-                            preContent:  null,
-                            content:     null,
-                            postContent: "Hello World!",
-                            postElement: null),
-                        "<p>Hello World!</p>"
-                    },
-                    {
-                        GetTagHelperOutput(
-                            tagName:     "p",
-                            attributes:  new TagHelperAttributeList(),
-                            tagMode: TagMode.StartTagAndEndTag,
-                            preElement:  null,
-                            preContent:  "Hello",
-                            content:     "Test",
-                            postContent: "World!",
-                            postElement: null),
-                        "<p>HelloTestWorld!</p>"
-                    },
-                    {
-                        GetTagHelperOutput(
-                            tagName:     "p",
-                            attributes:  new TagHelperAttributeList(),
-                            tagMode: TagMode.SelfClosing,
-                            preElement:  null,
-                            preContent:  "Hello",
-                            content:     "Test",
-                            postContent: "World!",
-                            postElement: null),
-                        "<p />"
-                    },
-                    {
-                        GetTagHelperOutput(
-                            tagName:     "p",
-                            attributes:  new TagHelperAttributeList(),
-                            tagMode: TagMode.StartTagOnly,
-                            preElement:  null,
-                            preContent:  "Hello",
-                            content:     "Test",
-                            postContent: "World!",
-                            postElement: null),
-                        "<p>"
-                    },
-                    {
-                        GetTagHelperOutput(
-                            tagName:     "custom",
-                            attributes:  new TagHelperAttributeList(),
-                            tagMode: TagMode.StartTagAndEndTag,
-                            preElement:  null,
-                            preContent:  "Hello",
-                            content:     "Test",
-                            postContent: "World!",
-                            postElement: null),
-                        "<custom>HelloTestWorld!</custom>"
-                    },
-                    {
-                        GetTagHelperOutput(
-                            tagName:     "random",
-                            attributes:  new TagHelperAttributeList(),
-                            tagMode: TagMode.SelfClosing,
-                            preElement:  null,
-                            preContent:  "Hello",
-                            content:     "Test",
-                            postContent: "World!",
-                            postElement: null),
-                        "<random />"
-                    },
-                    {
-                        GetTagHelperOutput(
-                            tagName:     "random",
-                            attributes:  new TagHelperAttributeList(),
-                            tagMode: TagMode.StartTagOnly,
-                            preElement:  null,
-                            preContent:  "Hello",
-                            content:     "Test",
-                            postContent: "World!",
-                            postElement: null),
-                        "<random>"
-                    },
-                    {
-                        GetTagHelperOutput(
-                            tagName:     "custom",
-                            attributes:  new TagHelperAttributeList(),
-                            tagMode: TagMode.StartTagAndEndTag,
-                            preElement:  "Before",
-                            preContent:  null,
-                            content:     null,
-                            postContent: null,
-                            postElement: null),
-                        "Before<custom></custom>"
-                    },
-                    {
-                        GetTagHelperOutput(
-                            tagName:     string.Empty,
-                            attributes:  new TagHelperAttributeList(),
-                            tagMode: TagMode.StartTagAndEndTag,
-                            preElement:  "Before",
-                            preContent:  null,
-                            content:     null,
-                            postContent: null,
-                            postElement: null),
-                        "Before"
-                    },
-                    {
-                        GetTagHelperOutput(
-                            tagName:     string.Empty,
-                            attributes:  new TagHelperAttributeList { { "test", "testVal" } },
-                            tagMode: TagMode.SelfClosing,
-                            preElement:  "Before",
-                            preContent:  null,
-                            content:     null,
-                            postContent: null,
-                            postElement: null),
-                        "Before"
-                    },
-                    {
-                        GetTagHelperOutput(
-                            tagName:     "custom",
-                            attributes:  new TagHelperAttributeList { { "test", "testVal" } },
-                            tagMode: TagMode.SelfClosing,
-                            preElement:  "Before",
-                            preContent:  null,
-                            content:     null,
-                            postContent: null,
-                            postElement: null),
-                        "Before<custom test=\"HtmlEncode[[testVal]]\" />"
-                    },
-                    {
-                        GetTagHelperOutput(
-                            tagName:     "custom",
-                            attributes:  new TagHelperAttributeList(),
-                            tagMode: TagMode.SelfClosing,
-                            preElement:  "Before",
-                            preContent:  null,
-                            content:     null,
-                            postContent: null,
-                            postElement: null),
-                        "Before<custom />"
-                    },
-                    {
-                        GetTagHelperOutput(
-                            tagName:     string.Empty,
-                            attributes:  new TagHelperAttributeList { { "test", "testVal" } },
-                            tagMode: TagMode.StartTagOnly,
-                            preElement:  "Before",
-                            preContent:  null,
-                            content:     null,
-                            postContent: null,
-                            postElement: null),
-                        "Before"
-                    },
-                    {
-                        GetTagHelperOutput(
-                            tagName:     "custom",
-                            attributes:  new TagHelperAttributeList { { "test", "testVal" } },
-                            tagMode: TagMode.StartTagOnly,
-                            preElement:  "Before",
-                            preContent:  null,
-                            content:     null,
-                            postContent: null,
-                            postElement: null),
-                        "Before<custom test=\"HtmlEncode[[testVal]]\">"
-                    },
-                    {
-                        GetTagHelperOutput(
-                            tagName:     "custom",
-                            attributes:  new TagHelperAttributeList(),
-                            tagMode: TagMode.StartTagOnly,
-                            preElement:  "Before",
-                            preContent:  null,
-                            content:     null,
-                            postContent: null,
-                            postElement: null),
-                        "Before<custom>"
-                    },
-                    {
-                        GetTagHelperOutput(
-                            tagName:     "custom",
-                            attributes:  new TagHelperAttributeList(),
-                            tagMode: TagMode.StartTagAndEndTag,
-                            preElement:  null,
-                            preContent:  null,
-                            content:     null,
-                            postContent: null,
-                            postElement: "After"),
-                        "<custom></custom>After"
-                    },
-                    {
-                        GetTagHelperOutput(
-                            tagName:     string.Empty,
-                            attributes:  new TagHelperAttributeList(),
-                            tagMode: TagMode.StartTagAndEndTag,
-                            preElement:  null,
-                            preContent:  null,
-                            content:     null,
-                            postContent: null,
-                            postElement: "After"),
-                        "After"
-                    },
-                    {
-                        GetTagHelperOutput(
-                            tagName:     string.Empty,
-                            attributes:  new TagHelperAttributeList { { "test", "testVal" } },
-                            tagMode: TagMode.SelfClosing,
-                            preElement:  null,
-                            preContent:  null,
-                            content:     null,
-                            postContent: null,
-                            postElement: "After"),
-                        "After"
-                    },
-                    {
-                        GetTagHelperOutput(
-                            tagName:     "custom",
-                            attributes:  new TagHelperAttributeList { { "test", "testVal" } },
-                            tagMode: TagMode.SelfClosing,
-                            preElement:  null,
-                            preContent:  null,
-                            content:     null,
-                            postContent: null,
-                            postElement: "After"),
-                        "<custom test=\"HtmlEncode[[testVal]]\" />After"
-                    },
-                    {
-                        GetTagHelperOutput(
-                            tagName:     "custom",
-                            attributes:  new TagHelperAttributeList(),
-                            tagMode: TagMode.SelfClosing,
-                            preElement:  null,
-                            preContent:  null,
-                            content:     null,
-                            postContent: null,
-                            postElement: "After"),
-                        "<custom />After"
-                    },
-                    {
-                        GetTagHelperOutput(
-                            tagName:     string.Empty,
-                            attributes:  new TagHelperAttributeList { { "test", "testVal" } },
-                            tagMode: TagMode.StartTagOnly,
-                            preElement:  null,
-                            preContent:  null,
-                            content:     null,
-                            postContent: null,
-                            postElement: "After"),
-                        "After"
-                    },
-                    {
-                        GetTagHelperOutput(
-                            tagName:     "custom",
-                            attributes:  new TagHelperAttributeList { { "test", "testVal" } },
-                            tagMode: TagMode.StartTagOnly,
-                            preElement:  null,
-                            preContent:  null,
-                            content:     null,
-                            postContent: null,
-                            postElement: "After"),
-                        "<custom test=\"HtmlEncode[[testVal]]\">After"
-                    },
-                    {
-                        GetTagHelperOutput(
-                            tagName:     "custom",
-                            attributes:  new TagHelperAttributeList(),
-                            tagMode: TagMode.StartTagOnly,
-                            preElement:  null,
-                            preContent:  null,
-                            content:     null,
-                            postContent: null,
-                            postElement: "After"),
-                        "<custom>After"
-                    },
-                    {
-                        GetTagHelperOutput(
-                            tagName:     "custom",
-                            attributes:  new TagHelperAttributeList(),
-                            tagMode: TagMode.StartTagAndEndTag,
-                            preElement:  "Before",
-                            preContent:  "Hello",
-                            content:     "Test",
-                            postContent: "World!",
-                            postElement: "After"),
-                        "Before<custom>HelloTestWorld!</custom>After"
-                    },
-                    {
-                        GetTagHelperOutput(
-                            tagName:     "custom",
-                            attributes:  new TagHelperAttributeList { { "test", "testVal" } },
-                            tagMode: TagMode.StartTagAndEndTag,
-                            preElement:  "Before",
-                            preContent:  "Hello",
-                            content:     "Test",
-                            postContent: "World!",
-                            postElement: "After"),
-                        "Before<custom test=\"HtmlEncode[[testVal]]\">HelloTestWorld!</custom>After"
-                    },
-                    {
-                        GetTagHelperOutput(
-                            tagName:     "custom",
-                            attributes:  new TagHelperAttributeList(),
-                            tagMode: TagMode.SelfClosing,
-                            preElement:  "Before",
-                            preContent:  "Hello",
-                            content:     "Test",
-                            postContent: "World!",
-                            postElement: "After"),
-                        "Before<custom />After"
-                    },
-                    {
-                        GetTagHelperOutput(
-                            tagName:     string.Empty,
-                            attributes:  new TagHelperAttributeList(),
-                            tagMode: TagMode.SelfClosing,
-                            preElement:  "Before",
-                            preContent:  "Hello",
-                            content:     "Test",
-                            postContent: "World!",
-                            postElement: "After"),
-                        "BeforeHelloTestWorld!After"
-                    },
-                    {
-                        GetTagHelperOutput(
-                            tagName:     "custom",
-                            attributes:  new TagHelperAttributeList(),
-                            tagMode: TagMode.StartTagOnly,
-                            preElement:  "Before",
-                            preContent:  "Hello",
-                            content:     "Test",
-                            postContent: "World!",
-                            postElement: "After"),
-                        "Before<custom>After"
-                    },
-                    {
-                        GetTagHelperOutput(
-                            tagName:     string.Empty,
-                            attributes:  new TagHelperAttributeList(),
-                            tagMode: TagMode.StartTagOnly,
-                            preElement:  "Before",
-                            preContent:  "Hello",
-                            content:     "Test",
-                            postContent: "World!",
-                            postElement: "After"),
-                        "BeforeHelloTestWorld!After"
-                    },
-                    {
-                        GetTagHelperOutput(
-                            tagName:     string.Empty,
-                            attributes:  new TagHelperAttributeList(),
-                            tagMode: TagMode.StartTagAndEndTag,
-                            preElement:  "Before",
-                            preContent:  "Hello",
-                            content:     "Test",
-                            postContent: "World!",
-                            postElement: "After"),
-                        "BeforeHelloTestWorld!After"
-                    },
-                    {
-                        GetTagHelperOutput(
-                            tagName:     string.Empty,
-                            attributes:  new TagHelperAttributeList { { "test", "testVal" } },
-                            tagMode: TagMode.StartTagAndEndTag,
-                            preElement:  "Before",
-                            preContent:  "Hello",
-                            content:     "Test",
-                            postContent: "World!",
-                            postElement: "After"),
-                        "BeforeHelloTestWorld!After"
-                    },
-                };
-            }
-        }
-
-        [Theory]
-        [MemberData(nameof(WriteTagHelper_InputData))]
-        public async Task WriteTagHelperAsync_WritesFormattedTagHelper(TagHelperOutput output, string expected)
-        {
-            // Arrange
-            var writer = new StringCollectionTextWriter(Encoding.UTF8);
-            var context = CreateViewContext(writer);
-            var tagHelperExecutionContext = new TagHelperExecutionContext(
-                tagName: output.TagName,
-                tagMode: output.TagMode,
-                items: new Dictionary<object, object>(),
-                uniqueId: string.Empty,
-                executeChildContentAsync: () => Task.FromResult(result: true),
-                startTagHelperWritingScope: () => { },
-                endTagHelperWritingScope: () => new DefaultTagHelperContent());
-            tagHelperExecutionContext.Output = output;
-
-            // Act
-            var page = CreatePage(p =>
-            {
-                p.HtmlEncoder = new HtmlTestEncoder();
-                p.WriteTagHelperAsync(tagHelperExecutionContext).Wait();
-            }, context);
-            await page.ExecuteAsync();
-
-            // Assert
-            Assert.Equal(expected, HtmlContentUtilities.HtmlContentToString(writer.Content));
-        }
-
-        [Theory]
-        // This is a scenario where GetChildContentAsync is called.
-        [InlineData(true, "HelloWorld!", "<p>HelloWorld!</p>")]
-        // This is a scenario where ExecuteChildContentAsync is called.
-        [InlineData(false, "HelloWorld!", "<p></p>")]
-        public async Task WriteTagHelperAsync_WritesContentAppropriately(
-            bool childContentRetrieved, string input, string expected)
-        {
-            // Arrange
-            var defaultTagHelperContent = new DefaultTagHelperContent();
-            var writer = new StringCollectionTextWriter(Encoding.UTF8);
-            var context = CreateViewContext(writer);
-            var tagHelperExecutionContext = new TagHelperExecutionContext(
-                tagName: "p",
-                tagMode: TagMode.StartTagAndEndTag,
-                items: new Dictionary<object, object>(),
-                uniqueId: string.Empty,
-                executeChildContentAsync: () =>
-                {
-                    defaultTagHelperContent.AppendHtml(input);
-                    return Task.FromResult(result: true);
-                },
-                startTagHelperWritingScope: () => { },
-                endTagHelperWritingScope: () => defaultTagHelperContent);
-            tagHelperExecutionContext.Output = new TagHelperOutput(
-                tagName: "p",
-                attributes: new TagHelperAttributeList(),
-                getChildContentAsync: (_) => Task.FromResult<TagHelperContent>(new DefaultTagHelperContent()));
-            if (childContentRetrieved)
-            {
-                await tagHelperExecutionContext.GetChildContentAsync(useCachedResult: true);
-            }
-
-            // Act
-            var page = CreatePage(p =>
-            {
-                p.HtmlEncoder = new HtmlTestEncoder();
-                p.WriteTagHelperAsync(tagHelperExecutionContext).Wait();
-            }, context);
-            await page.ExecuteAsync();
-
-            // Assert
-            Assert.Equal(expected, HtmlContentUtilities.HtmlContentToString(writer.Content));
-        }
-
-        [Fact]
-        public async Task WriteTagHelperToAsync_WritesToSpecifiedWriter()
-        {
-            // Arrange
-            var writer = new StringCollectionTextWriter(Encoding.UTF8);
-            var context = CreateViewContext(new StringWriter());
-            var tagHelperExecutionContext = new TagHelperExecutionContext(
-                tagName: "p",
-                tagMode: TagMode.StartTagAndEndTag,
-                items: new Dictionary<object, object>(),
-                uniqueId: string.Empty,
-                executeChildContentAsync: () => { return Task.FromResult(result: true); },
-                startTagHelperWritingScope: () => { },
-                endTagHelperWritingScope: () => new DefaultTagHelperContent());
-            tagHelperExecutionContext.Output = new TagHelperOutput(
-                tagName: "p",
-                attributes: new TagHelperAttributeList(),
-                getChildContentAsync: (_) => Task.FromResult<TagHelperContent>(new DefaultTagHelperContent()));
-            tagHelperExecutionContext.Output.Content.AppendHtml("Hello World!");
-
-            // Act
-            var page = CreatePage(p =>
-            {
-                p.HtmlEncoder = new HtmlTestEncoder();
-                p.WriteTagHelperToAsync(writer, tagHelperExecutionContext).Wait();
-            }, context);
-            await page.ExecuteAsync();
-
-            // Assert
-            Assert.Equal("<p>Hello World!</p>", HtmlContentUtilities.HtmlContentToString(writer.Content));
-        }
-
-        [Theory]
-        [MemberData(nameof(WriteTagHelper_InputData))]
-        public async Task WriteTagHelperToAsync_WritesFormattedTagHelper(TagHelperOutput output, string expected)
-        {
-            // Arrange
-            var writer = new StringCollectionTextWriter(Encoding.UTF8);
-            var context = CreateViewContext(new StringWriter());
-            var tagHelperExecutionContext = new TagHelperExecutionContext(
-                tagName: output.TagName,
-                tagMode: output.TagMode,
-                items: new Dictionary<object, object>(),
-                uniqueId: string.Empty,
-                executeChildContentAsync: () => Task.FromResult(result: true),
-                startTagHelperWritingScope: () => { },
-                endTagHelperWritingScope: () => new DefaultTagHelperContent());
-            tagHelperExecutionContext.Output = output;
-
-            // Act
-            var page = CreatePage(p =>
-            {
-                p.HtmlEncoder = new HtmlTestEncoder();
-                p.WriteTagHelperToAsync(writer, tagHelperExecutionContext).Wait();
-            }, context);
-            await page.ExecuteAsync();
-
-            // Assert
-            Assert.Equal(expected, HtmlContentUtilities.HtmlContentToString(writer.Content));
-        }
-
-        private static TagHelperOutput GetTagHelperOutput(
-            string tagName,
-            TagHelperAttributeList attributes,
-            TagMode tagMode,
-            string preElement,
-            string preContent,
-            string content,
-            string postContent,
-            string postElement)
-        {
-            var output = new TagHelperOutput(
-                tagName,
-                attributes,
-                getChildContentAsync: (_) => Task.FromResult<TagHelperContent>(new DefaultTagHelperContent()))
-            {
-                TagMode = tagMode
-            };
-
-            output.PreElement.AppendHtml(preElement);
-            output.PreContent.AppendHtml(preContent);
-            output.Content.AppendHtml(content);
-            output.PostContent.AppendHtml(postContent);
-            output.PostElement.AppendHtml(postElement);
-
-            return output;
-        }
-
         private static TestableRazorPage CreatePage(
             Action<TestableRazorPage> executeAction,
             ViewContext context = null)