Adding functional test to verify error page middleware includes raw compilation content.

test/Microsoft.AspNetCore.Mvc.FunctionalTests/ErrorPageTests.cs

@@ -74,6 +74,8 @@ namespace Microsoft.AspNetCore.Mvc.FunctionalTests
             // Arrange
             var expectedMessage = "The type or namespace name 'NamespaceDoesNotExist' could not be found ("
                 + "are you missing a using directive or an assembly reference?)";
+            var expectedCompilationContent = "public class _Views_ErrorFromViewImports_Index_cshtml : "
+                + "Microsoft.AspNetCore.Mvc.Razor.RazorPage<dynamic>";
             var expectedMediaType = MediaTypeHeaderValue.Parse("text/html; charset=utf-8");
 
             // Act
@@ -86,6 +88,7 @@ namespace Microsoft.AspNetCore.Mvc.FunctionalTests
             Assert.Contains("/Views/ErrorFromViewImports/_ViewImports.cshtml", content);
             Assert.Contains(expectedMessage, content);
             Assert.Contains(PreserveCompilationContextMessage, content);
+            Assert.Contains(expectedCompilationContent, content);
         }
 
         [Fact]