Added wrapper of TestContext to make it easier to inherit from the test context in other test frameworks than xUnit

Author: egil

src/bunit.web/TestContextWrapper.cs

@@ -0,0 +1,90 @@
+using System;
+using Bunit.Rendering;
+using Microsoft.AspNetCore.Components;
+using Microsoft.JSInterop;
+
+namespace Bunit
+{
+	/// <summary>
+	/// Represents a class that wraps a <see cref="Bunit.TestContext"/>. Useful for
+	/// simplifying writing tests in NUnit and MSTest, which cannot
+	/// inherit directly from <see cref="Bunit.TestContext"/>.
+	/// </summary>
+	public abstract class TestContextWrapper
+	{
+		/// <summary>
+		/// Gets an instance of the wrapped <see cref="Bunit.TestContext"/>, if any.
+		/// </summary>
+		protected virtual TestContext? TestContext { get; set; }
+
+		/// <summary>
+		/// Gets the renderer used by the test context.
+		/// </summary>
+		public ITestRenderer Renderer => TestContext?.Renderer ?? throw new InvalidOperationException("The TestContext has not been initialized.");
+
+		/// <summary>
+		/// Gets the service collection and service provider that is used when a
+		/// component is rendered by the test context.
+		/// </summary>
+		public TestServiceProvider Services => TestContext?.Services ?? throw new InvalidOperationException("The TestContext has not been initialized.");
+
+		/// <summary>
+		/// Gets the service collection and service provider that is used when a
+		/// component is rendered by the test context.
+		/// </summary>
+		public RootRenderTree RenderTree => TestContext?.RenderTree ?? throw new InvalidOperationException("The TestContext has not been initialized.");
+
+		/// <summary>
+		/// Gets bUnits JSInterop, that allows setting up handlers for <see cref="IJSRuntime.InvokeAsync{TValue}(string, object[])"/> invocations
+		/// that components under tests will issue during testing. It also makes it possible to verify that the invocations has happened as expected.
+		/// </summary>
+		public BunitJSInterop JSInterop => TestContext?.JSInterop ?? throw new InvalidOperationException("The TestContext has not been initialized.");
+
+		/// <summary>
+		/// Instantiates and performs a first render of a component of type <typeparamref name="TComponent"/>.
+		/// </summary>
+		/// <typeparam name="TComponent">Type of the component to render.</typeparam>
+		/// <param name="parameters">Parameters to pass to the component when it is rendered.</param>
+		/// <returns>The rendered <typeparamref name="TComponent"/>.</returns>
+		public virtual IRenderedComponent<TComponent> RenderComponent<TComponent>(params ComponentParameter[] parameters)
+			where TComponent : IComponent
+			=> TestContext?.RenderComponent<TComponent>(parameters) ?? throw new InvalidOperationException("The TestContext has not been initialized.");
+
+		/// <summary>
+		/// Instantiates and performs a first render of a component of type <typeparamref name="TComponent"/>.
+		/// </summary>
+		/// <typeparam name="TComponent">Type of the component to render.</typeparam>
+		/// <param name="parameterBuilder">The ComponentParameterBuilder action to add type safe parameters to pass to the component when it is rendered.</param>
+		/// <returns>The rendered <typeparamref name="TComponent"/>.</returns>
+		public virtual IRenderedComponent<TComponent> RenderComponent<TComponent>(Action<ComponentParameterCollectionBuilder<TComponent>> parameterBuilder)
+			where TComponent : IComponent
+			=> TestContext?.RenderComponent<TComponent>(parameterBuilder) ?? throw new InvalidOperationException("The TestContext has not been initialized.");
+
+		/// <summary>
+		/// Renders the <paramref name="renderFragment"/> and returns the first <typeparamref name="TComponent"/> in the resulting render tree.
+		/// </summary>
+		/// <remarks>
+		/// Calling this method is equivalent to calling <c>Render(renderFragment).FindComponent&lt;TComponent&gt;()</c>.
+		/// </remarks>
+		/// <typeparam name="TComponent">The type of component to find in the render tree.</typeparam>
+		/// <param name="renderFragment">The render fragment to render.</param>
+		/// <returns>The <see cref="IRenderedComponent{TComponent}"/>.</returns>
+		public virtual IRenderedComponent<TComponent> Render<TComponent>(RenderFragment renderFragment)
+			where TComponent : IComponent
+			=> TestContext?.Render<TComponent>(renderFragment) ?? throw new InvalidOperationException("The TestContext has not been initialized.");
+
+		/// <summary>
+		/// Renders the <paramref name="renderFragment"/> and returns it as a <see cref="IRenderedFragment"/>.
+		/// </summary>
+		/// <param name="renderFragment">The render fragment to render.</param>
+		/// <returns>The <see cref="IRenderedFragment"/>.</returns>
+		public virtual IRenderedFragment Render(RenderFragment renderFragment)
+			=> TestContext?.Render(renderFragment) ?? throw new InvalidOperationException("The TestContext has not been initialized.");
+
+		/// <summary>
+		/// Dummy method required to allow Blazor's compiler to generate
+		/// C# from .razor files.
+		/// </summary>
+		protected virtual void BuildRenderTree(Microsoft.AspNetCore.Components.Rendering.RenderTreeBuilder builder) { }
+	}
+}