feat: Enable RenderMode cascading to the Component

Author: linkdotnet

CHANGELOG.md

@@ -7,7 +7,7 @@ All notable changes to **bUnit** will be documented in this file. The project ad
 ## [Unreleased]
 
 ### Added
-- Added support for `RendererInfo` (`.net9.0`).
+- Added support for `RendererInfo` and `AssignedRenderMode` (`.net9.0`).
 
 ## [1.36.0] - 2024-11-12
 

src/bunit.core/Rendering/TestRenderer.cs

@@ -241,6 +241,27 @@ protected override IComponent ResolveComponentForRenderMode(Type componentType,
 	}
 #endif
 
+#if NET9_0_OR_GREATER
+	/// <inheritdoc/>
+	protected override IComponentRenderMode? GetComponentRenderMode(IComponent component)
+	{
+		ArgumentNullException.ThrowIfNull(component);
+
+		var renderModeAttribute = component.GetType()
+			.GetCustomAttribute<RenderModeAttribute>();
+
+		if (renderModeAttribute is not null)
+		{
+			return renderModeAttribute.Mode;
+		}
+
+		var parentComponentState = GetComponentState(component).ParentComponentState;
+		return parentComponentState is not null
+			? GetComponentRenderMode(parentComponentState.Component)
+			: null;
+	}
+#endif
+
 	/// <inheritdoc/>
 	internal Task SetDirectParametersAsync(IRenderedFragmentBase renderedComponent, ParameterView parameters)
 	{

tests/bunit.core.tests/Rendering/RenderModeTests.cs

@@ -0,0 +1,73 @@
+#if NET9_0_OR_GREATER
+using Bunit.TestAssets.RenderModes;
+
+namespace Bunit.Rendering;
+
+public class RenderModeTests : TestContext
+{
+	[Fact(DisplayName = "TestRenderer provides RendererInfo")]
+	public void Test001()
+	{
+		Renderer.SetRendererInfo(new RendererInfo("Server", true));
+		var cut = RenderComponent<RendererInfoComponent>();
+
+		cut.MarkupMatches("""
+		                  <p>Is interactive: True</p>
+		                  <p>Rendermode: Server</p>
+		                  """);
+	}
+
+	[Fact(DisplayName = "Renderer throws exception if RendererInfo is not specified")]
+	public void Test002()
+	{
+		Action act = () => RenderComponent<RendererInfoComponent>();
+
+		act.ShouldThrow<MissingRendererInfoException>();
+	}
+
+	[Fact(DisplayName = "Renderer should set the RenderModeAttribute on the component")]
+	public void Test003()
+	{
+		var cut = RenderComponent<ComponentWithServerRenderMode>();
+		
+		cut.MarkupMatches("<div>Assigned render mode: InteractiveServerRenderMode</div>");
+	}
+	
+	[Fact(DisplayName = "The AssignedRenderMode is based on the RenderModeAttribute in the component hierarchy where parent component has no RenderMode")]
+	public void Test004()
+	{
+		var cut = RenderComponent<ComponentWithoutRenderMode>(
+			c => c.AddChildContent<ComponentWithWebAssemblyRenderMode>());
+
+		cut.MarkupMatches("""
+		                  <div>Parent assigned render mode: </div>
+		                  <div>Assigned render mode: InteractiveWebAssemblyRenderMode</div>
+		                  """);
+	}
+
+	[Fact(DisplayName = "Parent and child render mode is specified")]
+	public void Test005()
+	{
+		var cut = RenderComponent<ComponentWithWebAssemblyRenderMode>(
+			c => c.AddChildContent<ComponentWithServerRenderMode>());
+
+		cut.MarkupMatches("""
+		                  <div>Parent assigned render mode: InteractiveWebAssemblyRenderMode</div>
+		                  <div>Assigned render mode: InteractiveServerRenderMode</div>
+		                  """);
+	}
+
+	[Fact(DisplayName = "Parent and child render mode is not specified")]
+	public void Test006()
+	{		
+		var cut = RenderComponent<ComponentWithoutRenderMode>(
+			c => c.AddChildContent<ComponentWithoutRenderMode>());
+
+		cut.MarkupMatches("""
+		                  <div>Parent assigned render mode: </div>
+		                  <div>Assigned render mode: </div>
+		                  """);
+		
+	}
+}
+#endif

tests/bunit.core.tests/Rendering/RendererInfoTests.cs

@@ -0,0 +1,15 @@
+@{
+#if NET9_0_OR_GREATER
+}
+
+@rendermode Microsoft.AspNetCore.Components.Web.RenderMode.InteractiveServer
+<div>@(ChildContent is not null ? "Parent assigned" : "Assigned") render mode: @AssignedRenderMode?.GetType().Name</div>
+@ChildContent
+
+@code {
+	[Parameter] public RenderFragment? ChildContent { get; set; }
+}
+
+@{
+#endif
+}

tests/bunit.testassets/RenderModes/ComponentWithServerRenderMode.razor

@@ -0,0 +1,15 @@
+@{
+#if NET9_0_OR_GREATER
+}
+
+@rendermode Microsoft.AspNetCore.Components.Web.RenderMode.InteractiveWebAssembly
+<div>@(ChildContent is not null ? "Parent assigned" : "Assigned") render mode: @AssignedRenderMode?.GetType().Name</div>
+@ChildContent
+
+@code {
+	[Parameter] public RenderFragment? ChildContent { get; set; }
+}
+
+@{
+#endif
+}

tests/bunit.testassets/RenderModes/ComponentWithWebAssemblyRenderMode.razor

@@ -0,0 +1,14 @@
+@{
+#if NET9_0_OR_GREATER
+}
+
+<div>@(ChildContent is not null ? "Parent assigned" : "Assigned") render mode: @AssignedRenderMode?.GetType().Name</div>
+@ChildContent
+
+@code {
+	[Parameter] public RenderFragment? ChildContent { get; set; }
+}
+
+@{
+#endif
+}