diff --git a/src/Razor/Microsoft.AspNetCore.Razor.Language/src/DefaultRazorProjectEngine.cs b/src/Razor/Microsoft.AspNetCore.Razor.Language/src/DefaultRazorProjectEngine.cs
index 1099be4c72..c8fc4f6f9b 100644
--- a/src/Razor/Microsoft.AspNetCore.Razor.Language/src/DefaultRazorProjectEngine.cs
+++ b/src/Razor/Microsoft.AspNetCore.Razor.Language/src/DefaultRazorProjectEngine.cs
@@ -88,19 +88,21 @@ namespace Microsoft.AspNetCore.Razor.Language
             return CreateCodeDocumentCore(sourceDocument, projectItem.FileKind, importSourceDocuments, tagHelpers: null, configureParser, configureCodeGeneration);
         }
 
-        protected RazorCodeDocument CreateCodeDocumentCore(
+        protected internal RazorCodeDocument CreateCodeDocumentCore(
             RazorSourceDocument sourceDocument, 
-            string fileKind, 
-            IReadOnlyList<RazorSourceDocument> importSourceDocuments, 
-            IReadOnlyList<TagHelperDescriptor> tagHelpers,
-            Action<RazorParserOptionsBuilder> configureParser,
-            Action<RazorCodeGenerationOptionsBuilder> configureCodeGeneration)
+            string fileKind = null, 
+            IReadOnlyList<RazorSourceDocument> importSourceDocuments = null, 
+            IReadOnlyList<TagHelperDescriptor> tagHelpers = null,
+            Action<RazorParserOptionsBuilder> configureParser = null,
+            Action<RazorCodeGenerationOptionsBuilder> configureCodeGeneration = null)
         {
             if (sourceDocument == null)
             {
                 throw new ArgumentNullException(nameof(sourceDocument));
             }
 
+            importSourceDocuments = importSourceDocuments ?? Array.Empty<RazorSourceDocument>();
+
             var parserOptions = GetRequiredFeature<IRazorParserOptionsFactoryProjectFeature>().Create(fileKind, builder =>
             {
                 ConfigureParserOptions(builder);
diff --git a/src/Razor/test/Microsoft.AspNetCore.Razor.Test.Common/Language/IntegrationTests/RazorIntegrationTestBase.cs b/src/Razor/test/Microsoft.AspNetCore.Razor.Test.Common/Language/IntegrationTests/RazorIntegrationTestBase.cs
index 36166cfa79..aa716ece02 100644
--- a/src/Razor/test/Microsoft.AspNetCore.Razor.Test.Common/Language/IntegrationTests/RazorIntegrationTestBase.cs
+++ b/src/Razor/test/Microsoft.AspNetCore.Razor.Test.Common/Language/IntegrationTests/RazorIntegrationTestBase.cs
@@ -348,16 +348,6 @@ namespace Microsoft.AspNetCore.Razor.Language.IntegrationTests
 
         protected static string FullTypeName<T>() => typeof(T).FullName.Replace('+', '.');
 
-        protected RenderTreeFrame[] GetRenderTree(IComponent component)
-        {
-            throw null;
-        }
-
-        protected RenderTreeFrame[] GetFrames(RenderFragment fragment)
-        {
-            throw null;
-        }
-
         protected static void AssertSourceEquals(string expected, CompileToCSharpResult generated)
         {
             // Normalize the paths inside the expected result to match the OS paths