Unit tests for VCTH and model directive

src/Microsoft.AspNetCore.Mvc.Razor.Host/ModelDirective.cs

@@ -49,7 +49,7 @@ namespace Microsoft.AspNetCore.Mvc.Razor.Host
             return "dynamic";
         }
 
-        private class Pass : IRazorIRPass
+        internal class Pass : IRazorIRPass
         {
             public RazorEngine Engine { get; set; }
 

src/Microsoft.AspNetCore.Mvc.Razor.Host/ViewComponentTagHelperPass.cs

@@ -147,7 +147,7 @@ namespace Microsoft.AspNetCore.Mvc.Razor.Host
             writer.WriteAutoPropertyDeclaration(
                 "public",
                 $"global::Microsoft.AspNetCore.Mvc.Rendering.ViewContext",
-                "_context");
+                "ViewContext");
 
             var indexerAttributes = descriptor.Attributes.Where(a => a.IsIndexer);
 
@@ -187,19 +187,19 @@ namespace Microsoft.AspNetCore.Mvc.Razor.Host
                 writer.WriteInstanceMethodInvocation(
                     $"(_helper as global::Microsoft.AspNetCore.Mvc.ViewFeatures.IViewContextAware)?",
                     "Contextualize",
-                    new[] { "_context" });
+                    new[] { "ViewContext" });
 
                 var methodParameters = GetMethodParameters(descriptor);
-                var viewContentVariable = "viewContent";
+                var contentVariable = "content";
                 writer.Write("var ")
-                    .WriteStartAssignment(viewContentVariable)
+                    .WriteStartAssignment(contentVariable)
                     .WriteInstanceMethodInvocation($"await _helper", "InvokeAsync", methodParameters);
                 writer.WriteStartAssignment($"{outputVariable}.TagName")
                     .WriteLine("null;");
                 writer.WriteInstanceMethodInvocation(
                     $"{outputVariable}.Content",
                     "SetHtmlContent",
-                    new[] { viewContentVariable });
+                    new[] { contentVariable });
             }
         }
 
@@ -207,7 +207,7 @@ namespace Microsoft.AspNetCore.Mvc.Razor.Host
         {
             var propertyNames = descriptor.Attributes.Where(a => !a.IsIndexer).Select(attribute => attribute.PropertyName);
             var joinedPropertyNames = string.Join(", ", propertyNames);
-            var parametersString = $" new {{ { joinedPropertyNames } }}";
+            var parametersString = $"new {{ { joinedPropertyNames } }}";
 
             var viewComponentName = descriptor.PropertyBag[
                 ViewComponentTagHelperDescriptorConventions.ViewComponentNameKey];

test/Microsoft.AspNetCore.Mvc.Razor.Host.Test/Directives/SetBaseTypeChunkMergerTest.cs

@@ -1,94 +0,0 @@
-// Copyright (c) .NET Foundation. All rights reserved.
-// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
-
-using Microsoft.AspNetCore.Razor.Chunks;
-using Xunit;
-
-namespace Microsoft.AspNetCore.Mvc.Razor.Directives
-{
-    public class SetBaseTypeChunkMergerTest
-    {
-        #if OLD_RAZOR
-        [Theory]
-        [InlineData("MyApp.BaseType<TModel>", "MyApp.BaseType<Person>")]
-        [InlineData("TestBaseType", "TestBaseType")]
-        public void Visit_UpdatesTModelTokenToMatchModelType(string typeName, string expectedValue)
-        {
-            // Arrange
-            var chunk = new SetBaseTypeChunk
-            {
-                TypeName = typeName,
-            };
-            var merger = new SetBaseTypeChunkMerger("Person");
-
-            // Act
-            merger.VisitChunk(chunk);
-
-            // Assert
-            Assert.Equal(expectedValue, chunk.TypeName);
-        }
-
-        [Fact]
-        public void Merge_SetsBaseTypeIfItHasNotBeenSetInChunkTree()
-        {
-            // Arrange
-            var expected = "MyApp.Razor.MyBaseType";
-            var merger = new SetBaseTypeChunkMerger("dynamic");
-            var chunkTree = new ChunkTree();
-            var inheritedChunks = new[]
-            {
-                new SetBaseTypeChunk { TypeName = expected }
-            };
-
-            // Act
-            merger.MergeInheritedChunks(chunkTree, inheritedChunks);
-
-            // Assert
-            var chunk = Assert.Single(chunkTree.Children);
-            var setBaseTypeChunk = Assert.IsType<SetBaseTypeChunk>(chunk);
-            Assert.Equal(expected, setBaseTypeChunk.TypeName);
-        }
-
-        [Fact]
-        public void Merge_IgnoresSetBaseTypeChunksIfChunkTreeContainsOne()
-        {
-            // Arrange
-            var merger = new SetBaseTypeChunkMerger("dynamic");
-            var chunkTree = new ChunkTree();
-            var inheritedChunks = new[]
-            {
-                 new SetBaseTypeChunk { TypeName = "MyBaseType2" }
-            };
-
-            // Act
-            merger.VisitChunk(new SetBaseTypeChunk { TypeName = "MyBaseType1" });
-            merger.MergeInheritedChunks(chunkTree, inheritedChunks);
-
-            // Assert
-            Assert.Empty(chunkTree.Children);
-        }
-
-        [Fact]
-        public void Merge_PicksLastBaseTypeChunkFromChunkTree()
-        {
-            // Arrange
-            var merger = new SetBaseTypeChunkMerger("dynamic");
-            var chunkTree = new ChunkTree();
-            var inheritedChunks = new Chunk[]
-            {
-                 new SetBaseTypeChunk { TypeName = "MyBase2" },
-                 new LiteralChunk(),
-                 new SetBaseTypeChunk { TypeName = "MyBase1" },
-            };
-
-            // Act
-            merger.MergeInheritedChunks(chunkTree, inheritedChunks);
-
-            // Assert
-            var chunk = Assert.Single(chunkTree.Children);
-            var setBaseTypeChunk = Assert.IsType<SetBaseTypeChunk>(chunk);
-            Assert.Equal("MyBase1", setBaseTypeChunk.TypeName);
-        }
-#endif
-    }
-}

test/Microsoft.AspNetCore.Mvc.Razor.Host.Test/Internal/ViewComponentTagHelperChunkVisitorTest.cs

@@ -1,61 +0,0 @@
-// Copyright (c) .NET Foundation. All rights reserved.
-// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
-
-using System.Collections.Generic;
-using System.Reflection;
-using Microsoft.AspNetCore.Razor.Chunks;
-using Microsoft.AspNetCore.Razor.CodeGenerators;
-using Xunit;
-
-namespace Microsoft.AspNetCore.Mvc.Razor.Host.Test.Internal
-{
-    public class ViewComponentTagHelperChunkVisitorTest
-    {
-        #if OLD_RAZOR
-        public static TheoryData CodeGenerationData
-        {
-            get
-            {
-                var oneInstanceChunks = ChunkVisitorTestFactory.GetTestChunks(visitedTagHelperChunks: true);
-                var twoInstanceChunks = ChunkVisitorTestFactory.GetTestChunks(visitedTagHelperChunks: true);
-                twoInstanceChunks.Add(twoInstanceChunks[twoInstanceChunks.Count - 1]);
-
-                return new TheoryData<IList<Chunk>>
-                {
-                    oneInstanceChunks,
-                    twoInstanceChunks
-                };
-            }
-        }
-
-        [Theory]
-        [MemberData(nameof(CodeGenerationData))]
-        public void Accept_CorrectlyGeneratesCode(IList<Chunk> chunks)
-        {
-            // Arrange
-            var writer = new CSharpCodeWriter();
-            var context = ChunkVisitorTestFactory.CreateCodeGeneratorContext();
-            var chunkVisitor = new ViewComponentTagHelperChunkVisitor(writer, context);
-
-            var assembly = typeof(ViewComponentTagHelperChunkVisitorTest).GetTypeInfo().Assembly;
-            var path = "TestFiles/Output/Runtime/GeneratedViewComponentTagHelperClasses.cs";
-            var expectedOutput = ResourceFile.ReadResource(assembly, path, sourceFile: true);
-
-            // Act
-            chunkVisitor.Accept(chunks);
-            var resultOutput = writer.GenerateCode();
-
-#if GENERATE_BASELINES
-            if (!string.Equals(expectedOutput, resultOutput, System.StringComparison.Ordinal))
-            {
-                ResourceFile.UpdateFile(assembly, path, expectedOutput, resultOutput);
-            }
-#else
-            // Assert
-            Assert.Equal(expectedOutput, resultOutput, ignoreLineEndingDifferences: true);
-#endif
-
-        }
-#endif
-    }
-}

test/Microsoft.AspNetCore.Mvc.Razor.Host.Test/ModelDirectiveTest.cs

@@ -0,0 +1,223 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System.IO;
+using System.Text;
+using Microsoft.AspNetCore.Razor.Evolution;
+using Microsoft.AspNetCore.Razor.Evolution.Intermediate;
+using Xunit;
+
+namespace Microsoft.AspNetCore.Mvc.Razor.Host
+{
+    public class ModelDirectiveTest
+    {
+        [Fact]
+        public void ModelDirective_GetModelType_GetsTypeFromLastWellFormedDirective()
+        {
+            // Arrange
+            var codeDocument = CreateDocument(@"
+@model Type1
+@model Type2
+@model
+");
+
+            var engine = CreateEngine();
+
+            var irDocument = CreateIRDocument(engine, codeDocument);
+
+            // Act
+            var result = ModelDirective.GetModelType(irDocument);
+
+            // Assert
+            Assert.Equal("Type2", result);
+        }
+
+        [Fact]
+        public void ModelDirective_GetModelType_DefaultsToDynamic()
+        {
+            // Arrange
+            var codeDocument = CreateDocument(@" ");
+
+            var engine = CreateEngine();
+
+            var irDocument = CreateIRDocument(engine, codeDocument);
+
+            // Act
+            var result = ModelDirective.GetModelType(irDocument);
+
+            // Assert
+            Assert.Equal("dynamic", result);
+        }
+
+        [Fact]
+        public void ModelDirectivePass_Execute_ReplacesTModelInBaseType()
+        {
+            // Arrange
+            var codeDocument = CreateDocument(@"
+@inherits BaseType<TModel>
+@model Type1
+");
+
+            var engine = CreateEngine();
+            var pass = new ModelDirective.Pass()
+            {
+                Engine = engine,
+            };
+
+            var irDocument = CreateIRDocument(engine, codeDocument);
+
+            // Act
+            pass.Execute(codeDocument, irDocument);
+
+            // Assert
+            var @class = FindClassNode(irDocument);
+            Assert.NotNull(@class);
+            Assert.Equal("BaseType<Type1>", @class.BaseType);
+        }
+
+        [Fact]
+        public void ModelDirectivePass_Execute_ReplacesTModelInBaseType_DifferentOrdering()
+        {
+            // Arrange
+            var codeDocument = CreateDocument(@"
+@model Type1
+@inherits BaseType<TModel>
+@model Type2
+");
+
+            var engine = CreateEngine();
+            var pass = new ModelDirective.Pass()
+            {
+                Engine = engine,
+            };
+
+            var irDocument = CreateIRDocument(engine, codeDocument);
+
+            // Act
+            pass.Execute(codeDocument, irDocument);
+
+            // Assert
+            var @class = FindClassNode(irDocument);
+            Assert.NotNull(@class);
+            Assert.Equal("BaseType<Type2>", @class.BaseType);
+        }
+
+        [Fact]
+        public void ModelDirectivePass_Execute_NoOpWithoutTModel()
+        {
+            // Arrange
+            var codeDocument = CreateDocument(@"
+@inherits BaseType
+@model Type1
+");
+
+            var engine = CreateEngine();
+            var pass = new ModelDirective.Pass()
+            {
+                Engine = engine,
+            };
+
+            var irDocument = CreateIRDocument(engine, codeDocument);
+
+            // Act
+            pass.Execute(codeDocument, irDocument);
+
+            // Assert
+            var @class = FindClassNode(irDocument);
+            Assert.NotNull(@class);
+            Assert.Equal("BaseType", @class.BaseType);
+        }
+
+        [Fact]
+        public void ModelDirectivePass_Execute_ReplacesTModelInBaseType_DefaultDynamic()
+        {
+            // Arrange
+            var codeDocument = CreateDocument(@"
+@inherits BaseType<TModel>
+");
+
+            var engine = CreateEngine();
+            var pass = new ModelDirective.Pass()
+            {
+                Engine = engine,
+            };
+
+            var irDocument = CreateIRDocument(engine, codeDocument);
+
+            // Act
+            pass.Execute(codeDocument, irDocument);
+
+            // Assert
+            var @class = FindClassNode(irDocument);
+            Assert.NotNull(@class);
+            Assert.Equal("BaseType<dynamic>", @class.BaseType);
+        }
+
+        private RazorCodeDocument CreateDocument(string content)
+        {
+            using (var stream = new MemoryStream())
+            {
+                var bytes = Encoding.UTF8.GetBytes(content);
+                stream.Write(bytes, 0, bytes.Length);
+                stream.Seek(0L, SeekOrigin.Begin);
+
+                var source = RazorSourceDocument.ReadFrom(stream, "test.cshtml");
+                return RazorCodeDocument.Create(source);
+            }
+        }
+
+        private ClassDeclarationIRNode FindClassNode(RazorIRNode node)
+        {
+            var visitor = new ClassNodeVisitor();
+            visitor.Visit(node);
+            return visitor.Node;
+        }
+
+        private RazorEngine CreateEngine()
+        {
+            return RazorEngine.Create(b =>
+            {
+                // Notice we're not registering the ModelDirective.Pass here so we can run it on demand.
+                b.AddDirective(ModelDirective.Directive);
+            });
+        }
+
+        private DocumentIRNode CreateIRDocument(RazorEngine engine, RazorCodeDocument codeDocument)
+        {
+            for (var i = 0; i < engine.Phases.Count; i++)
+            {
+                var phase = engine.Phases[i];
+                phase.Execute(codeDocument);
+
+                if (phase is IRazorIRPhase)
+                {
+                    break;
+                }
+            }
+
+            return codeDocument.GetIRDocument();
+        }
+
+        private string GetCSharpContent(RazorIRNode node)
+        {
+            var builder = new StringBuilder();
+            for (var i = 0; i < node.Children.Count; i++)
+            {
+                var child = node.Children[i] as CSharpTokenIRNode;
+                builder.Append(child.Content);
+            }
+
+            return builder.ToString();
+        }
+
+        private class ClassNodeVisitor : RazorIRNodeWalker
+        {
+            public ClassDeclarationIRNode Node { get; set; }
+
+            public override void VisitClass(ClassDeclarationIRNode node)
+            {
+                Node = node;
+            }
+        }
+    }
+}

test/Microsoft.AspNetCore.Mvc.Razor.Host.Test/StringTextBuffer.cs

@@ -1,49 +0,0 @@
-// Copyright (c) .NET Foundation. All rights reserved.
-// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
-
-using System;
-using Microsoft.AspNetCore.Razor.Text;
-
-namespace Microsoft.AspNetCore.Mvc.Razor
-{
-    public class StringTextBuffer : ITextBuffer, IDisposable
-    {
-        private string _buffer;
-        public bool Disposed { get; set; }
-
-        public StringTextBuffer(string buffer)
-        {
-            _buffer = buffer;
-        }
-
-        public int Length
-        {
-            get { return _buffer.Length; }
-        }
-
-        public int Position { get; set; }
-
-        public int Read()
-        {
-            if (Position >= _buffer.Length)
-            {
-                return -1;
-            }
-            return _buffer[Position++];
-        }
-
-        public int Peek()
-        {
-            if (Position >= _buffer.Length)
-            {
-                return -1;
-            }
-            return _buffer[Position];
-        }
-
-        public void Dispose()
-        {
-            Disposed = true;
-        }
-    }
-}

test/Microsoft.AspNetCore.Mvc.Razor.Host.Test/TestFiles/Output/Runtime/GeneratedViewComponentTagHelperClasses.cs

@@ -1,58 +0,0 @@
-[Microsoft.AspNetCore.Razor.TagHelpers.HtmlTargetElementAttribute("foo")]
-public class __Generated__FooViewComponentTagHelper : Microsoft.AspNetCore.Razor.TagHelpers.TagHelper
-{
-    private readonly global::Microsoft.AspNetCore.Mvc.IViewComponentHelper _viewComponentHelper = null;
-    public __Generated__FooViewComponentTagHelper(global::Microsoft.AspNetCore.Mvc.IViewComponentHelper viewComponentHelper)
-    {
-        _viewComponentHelper = viewComponentHelper;
-    }
-    [Microsoft.AspNetCore.Razor.TagHelpers.HtmlAttributeNotBoundAttribute, global::Microsoft.AspNetCore.Mvc.ViewFeatures.ViewContextAttribute]
-    public global::Microsoft.AspNetCore.Mvc.Rendering.ViewContext ViewContext { get; set; }
-    public System.String Attribute { get; set; }
-    public override async global::System.Threading.Tasks.Task ProcessAsync(Microsoft.AspNetCore.Razor.TagHelpers.TagHelperContext context, Microsoft.AspNetCore.Razor.TagHelpers.TagHelperOutput output)
-    {
-        (_viewComponentHelper as global::Microsoft.AspNetCore.Mvc.ViewFeatures.IViewContextAware)?.Contextualize(ViewContext);
-        var viewContent = await _viewComponentHelper.InvokeAsync("Foo",  new { Attribute });
-        output.TagName = null;
-        output.Content.SetHtmlContent(viewContent);
-    }
-}
-[Microsoft.AspNetCore.Razor.TagHelpers.HtmlTargetElementAttribute("bar")]
-public class __Generated__BarViewComponentTagHelper : Microsoft.AspNetCore.Razor.TagHelpers.TagHelper
-{
-    private readonly global::Microsoft.AspNetCore.Mvc.IViewComponentHelper _viewComponentHelper = null;
-    public __Generated__BarViewComponentTagHelper(global::Microsoft.AspNetCore.Mvc.IViewComponentHelper viewComponentHelper)
-    {
-        _viewComponentHelper = viewComponentHelper;
-    }
-    [Microsoft.AspNetCore.Razor.TagHelpers.HtmlAttributeNotBoundAttribute, global::Microsoft.AspNetCore.Mvc.ViewFeatures.ViewContextAttribute]
-    public global::Microsoft.AspNetCore.Mvc.Rendering.ViewContext ViewContext { get; set; }
-    public System.String Attribute { get; set; }
-    public override async global::System.Threading.Tasks.Task ProcessAsync(Microsoft.AspNetCore.Razor.TagHelpers.TagHelperContext context, Microsoft.AspNetCore.Razor.TagHelpers.TagHelperOutput output)
-    {
-        (_viewComponentHelper as global::Microsoft.AspNetCore.Mvc.ViewFeatures.IViewContextAware)?.Contextualize(ViewContext);
-        var viewContent = await _viewComponentHelper.InvokeAsync("Bar",  new { Attribute });
-        output.TagName = null;
-        output.Content.SetHtmlContent(viewContent);
-    }
-}
-[Microsoft.AspNetCore.Razor.TagHelpers.HtmlTargetElementAttribute("bee")]
-public class __Generated__BeeViewComponentTagHelper : Microsoft.AspNetCore.Razor.TagHelpers.TagHelper
-{
-    private readonly global::Microsoft.AspNetCore.Mvc.IViewComponentHelper _viewComponentHelper = null;
-    public __Generated__BeeViewComponentTagHelper(global::Microsoft.AspNetCore.Mvc.IViewComponentHelper viewComponentHelper)
-    {
-        _viewComponentHelper = viewComponentHelper;
-    }
-    [Microsoft.AspNetCore.Razor.TagHelpers.HtmlAttributeNotBoundAttribute, global::Microsoft.AspNetCore.Mvc.ViewFeatures.ViewContextAttribute]
-    public global::Microsoft.AspNetCore.Mvc.Rendering.ViewContext ViewContext { get; set; }
-    public System.Collections.Generic.Dictionary<global::System.String, global::System.Collections.Generic.List<global::System.Int32>> Attribute { get; set; }
-     = new System.Collections.Generic.Dictionary<global::System.String, global::System.Collections.Generic.List<global::System.Int32>>();
-    public override async global::System.Threading.Tasks.Task ProcessAsync(Microsoft.AspNetCore.Razor.TagHelpers.TagHelperContext context, Microsoft.AspNetCore.Razor.TagHelpers.TagHelperOutput output)
-    {
-        (_viewComponentHelper as global::Microsoft.AspNetCore.Mvc.ViewFeatures.IViewContextAware)?.Contextualize(ViewContext);
-        var viewContent = await _viewComponentHelper.InvokeAsync("Bee",  new { Attribute });
-        output.TagName = null;
-        output.Content.SetHtmlContent(viewContent);
-    }
-}

test/Microsoft.AspNetCore.Mvc.Razor.Host.Test/ViewComponentTagHelperPassTest.cs

@@ -0,0 +1,336 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+using System.Text;
+using Microsoft.AspNetCore.Mvc.ViewFeatures;
+using Microsoft.AspNetCore.Razor.Evolution;
+using Microsoft.AspNetCore.Razor.Evolution.Intermediate;
+using Microsoft.AspNetCore.Razor.Evolution.Legacy;
+using Xunit;
+using ErrorSink = Microsoft.AspNetCore.Razor.Evolution.Legacy.ErrorSink;
+
+namespace Microsoft.AspNetCore.Mvc.Razor.Host
+{
+    public class ViewComponentTagHelperPassTest
+    {
+        [Fact]
+        public void ViewComponentTagHelperPass_Execute_IgnoresRegularTagHelper()
+        {
+            // Arrange
+            var codeDocument = CreateDocument(@"
+@addTagHelper TestTagHelper, TestAssembly
+<p foo=""17"">");
+
+            var tagHelpers = new[]
+            {
+                new TagHelperDescriptor()
+                {
+                    AssemblyName = "TestAssembly",
+                    TypeName = "TestTagHelper",
+                    TagName = "p",
+                    Attributes = new TagHelperAttributeDescriptor[]
+                    {
+                        new TagHelperAttributeDescriptor()
+                        {
+                            TypeName = "System.Int32",
+                            Name = "Foo",
+                        }
+
+                    }
+                }
+            };
+
+            var engine = CreateEngine(tagHelpers);
+            var pass = new ViewComponentTagHelperPass()
+            {
+                Engine = engine,
+            };
+
+            var irDocument = CreateIRDocument(engine, codeDocument);
+
+            // Act
+            pass.Execute(codeDocument, irDocument);
+
+            // Assert
+            var @class = FindClassNode(irDocument);
+            Assert.Equal(2, @class.Children.Count); // No class node created for a VCTH
+            for (var i = 0; i < @class.Children.Count; i++)
+            {
+                Assert.IsNotType<CSharpStatementIRNode>(@class.Children[i]);
+            }
+        }
+
+        [Fact]
+        public void ViewComponentTagHelperPass_Execute_CreatesViewComponentTagHelper()
+        {
+            // Arrange
+            var codeDocument = CreateDocument(@"
+@addTagHelper TestTagHelper, TestAssembly
+<tagcloud foo=""17"">");
+
+            var tagHelpers = new[]
+            {
+                new TagHelperDescriptor()
+                {
+                    AssemblyName = "TestAssembly",
+                    TypeName = "TestTagHelper",
+                    TagName = "tagcloud",
+                    Attributes = new TagHelperAttributeDescriptor[]
+                    {
+                        new TagHelperAttributeDescriptor()
+                        {
+                            TypeName = "System.Int32",
+                            Name = "Foo",
+                            PropertyName = "Foo",
+                        }
+
+                    }
+                }
+            };
+
+            tagHelpers[0].PropertyBag.Add(ViewComponentTagHelperDescriptorConventions.ViewComponentNameKey, "TagCloud");
+
+            var engine = CreateEngine(tagHelpers);
+            var pass = new ViewComponentTagHelperPass()
+            {
+                Engine = engine,
+            };
+
+            var irDocument = CreateIRDocument(engine, codeDocument);
+
+            var expectedVCTHName = "AspNetCore.Generated_test.__Generated__TagCloudViewComponentTagHelper";
+
+            // Act
+            pass.Execute(codeDocument, irDocument);
+
+            // Assert
+            var tagHelper = FindTagHelperNode(irDocument);
+            Assert.Equal(expectedVCTHName, Assert.IsType<CreateTagHelperIRNode>(tagHelper.Children[1]).TagHelperTypeName);
+            Assert.Equal(expectedVCTHName, Assert.IsType<SetTagHelperPropertyIRNode>(tagHelper.Children[2]).TagHelperTypeName);
+
+
+            var @class = FindClassNode(irDocument);
+            Assert.Equal(3, @class.Children.Count);
+
+            var vcthClass = Assert.IsType<CSharpStatementIRNode>(@class.Children[2]);
+            Assert.Equal(@"[Microsoft.AspNetCore.Razor.TagHelpers.HtmlTargetElementAttribute(""tagcloud"")]
+public class __Generated__TagCloudViewComponentTagHelper : Microsoft.AspNetCore.Razor.TagHelpers.TagHelper
+{
+    private readonly global::Microsoft.AspNetCore.Mvc.IViewComponentHelper _helper = null;
+    public __Generated__TagCloudViewComponentTagHelper(global::Microsoft.AspNetCore.Mvc.IViewComponentHelper helper)
+    {
+        _helper = helper;
+    }
+    [Microsoft.AspNetCore.Razor.TagHelpers.HtmlAttributeNotBoundAttribute, global::Microsoft.AspNetCore.Mvc.ViewFeatures.ViewContextAttribute]
+    public global::Microsoft.AspNetCore.Mvc.Rendering.ViewContext ViewContext { get; set; }
+    public System.Int32 Foo { get; set; }
+    public override async global::System.Threading.Tasks.Task ProcessAsync(Microsoft.AspNetCore.Razor.TagHelpers.TagHelperContext context, Microsoft.AspNetCore.Razor.TagHelpers.TagHelperOutput output)
+    {
+        (_helper as global::Microsoft.AspNetCore.Mvc.ViewFeatures.IViewContextAware)?.Contextualize(ViewContext);
+        var content = await _helper.InvokeAsync(""TagCloud"", new { Foo });
+        output.TagName = null;
+        output.Content.SetHtmlContent(content);
+    }
+}
+", vcthClass.Content);
+        }
+
+        [Fact]
+        public void ViewComponentTagHelperPass_Execute_CreatesViewComponentTagHelper_WithIndexer()
+        {
+            // Arrange
+            var codeDocument = CreateDocument(@"
+@addTagHelper TestTagHelper, TestAssembly
+<tagcloud tag-foo=""17"">");
+
+            var tagHelpers = new[]
+            {
+                new TagHelperDescriptor()
+                {
+                    AssemblyName = "TestAssembly",
+                    TypeName = "TestTagHelper",
+                    TagName = "tagcloud",
+                    Attributes = new TagHelperAttributeDescriptor[]
+                    {
+                        new TagHelperAttributeDescriptor()
+                        {
+                            TypeName = "System.Collections.Generic.Dictionary<System.String, System.Int32>",
+                            Name = "foo",
+                            PropertyName = "Tags",
+                            IsIndexer = false,
+                        },
+                        new TagHelperAttributeDescriptor()
+                        {
+                            TypeName = "System.Collections.Generic.Dictionary<System.String, System.Int32>",
+                            Name = "foo-",
+                            PropertyName = "Tags",
+                            IsIndexer = true,
+                        }
+
+                    }
+                }
+            };
+
+            tagHelpers[0].PropertyBag.Add(ViewComponentTagHelperDescriptorConventions.ViewComponentNameKey, "TagCloud");
+
+            var engine = CreateEngine(tagHelpers);
+            var pass = new ViewComponentTagHelperPass()
+            {
+                Engine = engine,
+            };
+
+            var irDocument = CreateIRDocument(engine, codeDocument);
+
+            var expectedVCTHName = "AspNetCore.Generated_test.__Generated__TagCloudViewComponentTagHelper";
+
+            // Act
+            pass.Execute(codeDocument, irDocument);
+
+            // Assert
+            var tagHelper = FindTagHelperNode(irDocument);
+            Assert.Equal(expectedVCTHName, Assert.IsType<CreateTagHelperIRNode>(tagHelper.Children[1]).TagHelperTypeName);
+            Assert.IsType<AddPreallocatedTagHelperHtmlAttributeIRNode>(tagHelper.Children[2]);
+
+            var @class = FindClassNode(irDocument);
+            Assert.Equal(4, @class.Children.Count);
+
+            var vcthClass = Assert.IsType<CSharpStatementIRNode>(@class.Children[3]);
+            Assert.Equal(@"[Microsoft.AspNetCore.Razor.TagHelpers.HtmlTargetElementAttribute(""tagcloud"")]
+public class __Generated__TagCloudViewComponentTagHelper : Microsoft.AspNetCore.Razor.TagHelpers.TagHelper
+{
+    private readonly global::Microsoft.AspNetCore.Mvc.IViewComponentHelper _helper = null;
+    public __Generated__TagCloudViewComponentTagHelper(global::Microsoft.AspNetCore.Mvc.IViewComponentHelper helper)
+    {
+        _helper = helper;
+    }
+    [Microsoft.AspNetCore.Razor.TagHelpers.HtmlAttributeNotBoundAttribute, global::Microsoft.AspNetCore.Mvc.ViewFeatures.ViewContextAttribute]
+    public global::Microsoft.AspNetCore.Mvc.Rendering.ViewContext ViewContext { get; set; }
+    public System.Collections.Generic.Dictionary<System.String, System.Int32> Tags { get; set; }
+     = new System.Collections.Generic.Dictionary<System.String, System.Int32>();
+    public override async global::System.Threading.Tasks.Task ProcessAsync(Microsoft.AspNetCore.Razor.TagHelpers.TagHelperContext context, Microsoft.AspNetCore.Razor.TagHelpers.TagHelperOutput output)
+    {
+        (_helper as global::Microsoft.AspNetCore.Mvc.ViewFeatures.IViewContextAware)?.Contextualize(ViewContext);
+        var content = await _helper.InvokeAsync(""TagCloud"", new { Tags });
+        output.TagName = null;
+        output.Content.SetHtmlContent(content);
+    }
+}
+", vcthClass.Content);
+        }
+
+        private RazorCodeDocument CreateDocument(string content)
+        {
+            using (var stream = new MemoryStream())
+            {
+                var bytes = Encoding.UTF8.GetBytes(content);
+                stream.Write(bytes, 0, bytes.Length);
+                stream.Seek(0L, SeekOrigin.Begin);
+
+                var source = RazorSourceDocument.ReadFrom(stream, "test.cshtml");
+                return RazorCodeDocument.Create(source);
+            }
+        }
+
+        private RazorEngine CreateEngine(params TagHelperDescriptor[] tagHelpers)
+        {
+            return RazorEngine.Create(b =>
+            {
+                b.Features.Add(new MvcViewDocumentClassifierPass());
+
+                b.Features.Add(new TagHelperFeature(tagHelpers));
+            });
+        }
+
+        private DocumentIRNode CreateIRDocument(RazorEngine engine, RazorCodeDocument codeDocument)
+        {
+            for (var i = 0; i < engine.Phases.Count; i++)
+            {
+                var phase = engine.Phases[i];
+                phase.Execute(codeDocument);
+
+                if (phase is IRazorIRPhase)
+                {
+                    break;
+                }
+            }
+
+            return codeDocument.GetIRDocument();
+        }
+
+        private ClassDeclarationIRNode FindClassNode(RazorIRNode node)
+        {
+            var visitor = new ClassDeclarationNodeVisitor();
+            visitor.Visit(node);
+            return visitor.Node;
+        }
+
+        private TagHelperIRNode FindTagHelperNode(RazorIRNode node)
+        {
+            var visitor = new TagHelperNodeVisitor();
+            visitor.Visit(node);
+            return visitor.Node;
+        }
+
+        private string GetCSharpContent(RazorIRNode node)
+        {
+            var builder = new StringBuilder();
+            for (var i = 0; i < node.Children.Count; i++)
+            {
+                var child = node.Children[i] as CSharpTokenIRNode;
+                builder.Append(child.Content);
+            }
+
+            return builder.ToString();
+        }
+
+        private class ClassDeclarationNodeVisitor : RazorIRNodeWalker
+        {
+            public ClassDeclarationIRNode Node { get; set; }
+
+            public override void VisitClass(ClassDeclarationIRNode node)
+            {
+                Node = node;
+            }
+        }
+
+        private class TagHelperNodeVisitor : RazorIRNodeWalker
+        {
+            public TagHelperIRNode Node { get; set; }
+
+            public override void VisitTagHelper(TagHelperIRNode node)
+            {
+                Node = node;
+            }
+        }
+
+        private class TagHelperFeature : ITagHelperFeature
+        {
+            public TagHelperFeature(TagHelperDescriptor[] tagHelpers)
+            {
+                Resolver = new TagHelperDescriptorResolver(tagHelpers);
+            }
+
+            public RazorEngine Engine { get; set; }
+
+            public ITagHelperDescriptorResolver Resolver { get; }
+        }
+
+        private class TagHelperDescriptorResolver : ITagHelperDescriptorResolver
+        {
+            public TagHelperDescriptorResolver(TagHelperDescriptor[] tagHelpers)
+            {
+                TagHelpers = tagHelpers;
+            }
+
+            public TagHelperDescriptor[] TagHelpers { get; }
+
+            public IEnumerable<TagHelperDescriptor> Resolve(ErrorSink errorSink)
+            {
+                return TagHelpers;
+            }
+        }
+    }
+}