Fixed Internal Attributes #111 (#112)

* Fixed Internal Attributes #111

Signed-off-by: samtrion <me@samtrion.net>

* Fixed spacing

* Fixed spacing, second try

* I'm so sorry, please squash

* Update src/bunit.web/Rendering/Internal/Htmlizer.cs

Co-Authored-By: Egil Hansen <egil@assimilated.dk>

* Added theory for handling internal attributes

Signed-off-by: samtrion <me@samtrion.net>

* Added explanation

Signed-off-by: samtrion <me@samtrion.net>

* Added test, which confirms correctly prefixed attributes

Signed-off-by: samtrion <me@samtrion.net>

Author: samtrion

src/bunit.web.tests/Rendering/Internal/HtmlizerTests.cs

@@ -0,0 +1,99 @@
+namespace Bunit.Rendering.Internal
+{
+	using Microsoft.AspNetCore.Components;
+	using Microsoft.AspNetCore.Components.Rendering;
+	using Microsoft.AspNetCore.Components.Web;
+	using Xunit;
+
+	public class HtmlizerTests : ComponentTestFixture
+	{
+		public static TheoryData GetOnClickData()
+		{
+			return new TheoryData<bool, bool>
+			{
+				{ false, true },
+				{ true, false },
+				{ true, true }
+			};
+		}
+
+		[Theory(DisplayName =
+			"The component is rendered without internal Blazor attributes, " +
+			"regardless of the PreventDefault and StopPropagation settings.")]
+		[MemberData(nameof(GetOnClickData))]
+		public void Test001(bool stopPropagation, bool preventDefault)
+		{
+			//Arrange
+			var component = RenderComponent<Htmlizer01Component>(
+				EventCallback<MouseEventArgs>(nameof(Htmlizer01Component.OnClick), OnClickCallback),
+				Parameter(nameof(Htmlizer01Component.OnClickStopPropagation), stopPropagation),
+				Parameter(nameof(Htmlizer01Component.OnClickPreventDefault), preventDefault));
+
+			//Act
+
+			//Assert
+			component.MarkupMatches("<button type=\"button\">Click me!</button>");
+			void OnClickCallback(MouseEventArgs e)
+			{
+				// NOTE: This line is only for the completeness of the EventCallback
+				Assert.NotNull(e);
+			}
+		}
+
+		[Theory(DisplayName = "The component contains correctly prefixed internal attributes.")]
+		[MemberData(nameof(GetOnClickData))]
+		public void Test002(bool stopPropagation, bool preventDefault)
+		{
+			//Arrange
+			var component = RenderComponent<Htmlizer01Component>(
+				EventCallback<MouseEventArgs>(nameof(Htmlizer01Component.OnClick), OnClickCallback),
+				Parameter(nameof(Htmlizer01Component.OnClickStopPropagation), stopPropagation),
+				Parameter(nameof(Htmlizer01Component.OnClickPreventDefault), preventDefault));
+
+			//Act
+			var button = component.Find("button");
+
+			//Assert
+			Assert.Equal(stopPropagation, button.HasAttribute("blazor:__internal_stopPropagation_onclick"));
+			Assert.Equal(preventDefault, button.HasAttribute("blazor:__internal_preventDefault_onclick"));
+
+			void OnClickCallback(MouseEventArgs e)
+			{
+				// NOTE: This line is only for the completeness of the EventCallback
+				Assert.NotNull(e);
+			}
+		}
+
+		private class Htmlizer01Component : ComponentBase
+		{
+			[Parameter]
+			public EventCallback<MouseEventArgs> OnClick { get; set; }
+
+			[Parameter]
+			public bool OnClickPreventDefault { get; set; }
+
+			[Parameter]
+			public bool OnClickStopPropagation { get; set; }
+
+			/// <inheritdoc />
+			protected override void BuildRenderTree(RenderTreeBuilder builder)
+			{
+				base.BuildRenderTree(builder);
+
+				builder.OpenElement(0, "button");
+				builder.AddAttribute(1, "type", "button");
+
+				if (OnClick.HasDelegate)
+				{
+					builder.AddAttribute(2, "onclick", Microsoft.AspNetCore.Components.EventCallback.Factory.Create(this, OnClick));
+					builder.AddEventStopPropagationAttribute(3, "onclick", OnClickStopPropagation);
+					builder.AddEventPreventDefaultAttribute(4, "onclick", OnClickPreventDefault);
+				}
+
+				builder.AddContent(5, "Click me!");
+
+				builder.CloseElement();
+			}
+		}
+	}
+}

src/bunit.web/Rendering/Internal/Htmlizer.cs

@@ -20,6 +20,8 @@ internal class Htmlizer
             "area", "base", "br", "col", "embed", "hr", "img", "input", "link", "meta", "param", "source", "track", "wbr"
         };
 
+        private const string BLAZOR_INTERNAL_ATTR_PREFIX = "__internal_";
+
         public const string BLAZOR_ATTR_PREFIX = "blazor:";
         public const string ELEMENT_REFERENCE_ATTR_NAME = BLAZOR_ATTR_PREFIX + "elementreference";
 
@@ -220,6 +222,14 @@ private static int RenderAttributes(
 
                 switch (frame.AttributeValue)
                 {
+                    case bool flag when flag && frame.AttributeName.StartsWith(BLAZOR_INTERNAL_ATTR_PREFIX, StringComparison.Ordinal):
+                        // NOTE: This was added to make it more obvious
+                        // that this is a generated/special blazor attribute
+                        //	for internal usage                    
+                        result.Add(" ");
+                        result.Add(BLAZOR_ATTR_PREFIX);
+                        result.Add(frame.AttributeName);
+                        break;                    
                     case bool flag when flag:
                         result.Add(" ");
                         result.Add(frame.AttributeName);