430 lines
16 KiB
C#
430 lines
16 KiB
C#
// Copyright (c) .NET Foundation. All rights reserved.
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// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
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using System;
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using System.Collections.Generic;
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using System.Linq;
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using Microsoft.AspNetCore.Blazor.Components;
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using Microsoft.AspNetCore.Blazor.Rendering;
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using Microsoft.AspNetCore.Blazor.RenderTree;
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using Microsoft.AspNetCore.Blazor.Test.Shared;
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using Xunit;
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namespace Microsoft.AspNetCore.Blazor.Test
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{
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public class RendererTest
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{
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[Fact]
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public void CanRenderTopLevelComponents()
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{
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// Arrange
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var renderer = new TestRenderer();
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var component = new TestComponent(builder =>
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{
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builder.OpenElement(0, "my element");
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builder.AddText(1, "some text");
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builder.CloseElement();
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});
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// Act
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var componentId = renderer.AssignComponentId(component);
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renderer.RenderComponent(componentId);
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// Assert
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Assert.Collection(renderer.RenderTreesByComponentId[componentId],
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node => AssertNode.Element(node, "my element", 1),
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node => AssertNode.Text(node, "some text"));
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}
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[Fact]
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public void CanRenderNestedComponents()
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{
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// Arrange
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var renderer = new TestRenderer();
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var component = new TestComponent(builder =>
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{
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builder.AddText(0, "Hello");
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builder.OpenComponentElement<MessageComponent>(1);
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builder.CloseElement();
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});
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// Act/Assert
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var componentId = renderer.AssignComponentId(component);
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renderer.RenderComponent(componentId);
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var componentNode = renderer.RenderTreesByComponentId[componentId]
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.Single(node => node.NodeType == RenderTreeNodeType.Component);
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var nestedComponentId = componentNode.ComponentId;
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// The nested component exists
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Assert.IsType<MessageComponent>(componentNode.Component);
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((MessageComponent)(componentNode.Component)).Message = "Nested component output";
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// It isn't rendered until the consumer asks for it to be
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Assert.False(renderer.RenderTreesByComponentId.ContainsKey(nestedComponentId));
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// It can be rendered
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renderer.RenderComponent(nestedComponentId);
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Assert.Collection(renderer.RenderTreesByComponentId[nestedComponentId],
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node => AssertNode.Text(node, "Nested component output"));
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}
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[Fact]
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public void CanReRenderTopLevelComponents()
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{
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// Arrange
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var renderer = new TestRenderer();
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var component = new MessageComponent { Message = "Initial message" };
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var componentId = renderer.AssignComponentId(component);
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// Act/Assert: first render
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renderer.RenderComponent(componentId);
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Assert.Collection(renderer.RenderTreesByComponentId[componentId],
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node => AssertNode.Text(node, "Initial message"));
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// Act/Assert: second render
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component.Message = "Modified message";
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renderer.RenderComponent(componentId);
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Assert.Collection(renderer.RenderTreesByComponentId[componentId],
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node => AssertNode.Text(node, "Modified message"));
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}
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[Fact]
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public void CanReRenderNestedComponents()
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{
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// Arrange: parent component already rendered
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var renderer = new TestRenderer();
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var parentComponent = new TestComponent(builder =>
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{
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builder.OpenComponentElement<MessageComponent>(0);
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builder.CloseElement();
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});
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var parentComponentId = renderer.AssignComponentId(parentComponent);
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renderer.RenderComponent(parentComponentId);
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var nestedComponentNode = renderer.RenderTreesByComponentId[parentComponentId]
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.Single(node => node.NodeType == RenderTreeNodeType.Component);
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var nestedComponent = (MessageComponent)nestedComponentNode.Component;
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var nestedComponentId = nestedComponentNode.ComponentId;
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// Act/Assert: inital render
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nestedComponent.Message = "Render 1";
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renderer.RenderComponent(nestedComponentId);
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Assert.Collection(renderer.RenderTreesByComponentId[nestedComponentId],
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node => AssertNode.Text(node, "Render 1"));
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// Act/Assert: re-render
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nestedComponent.Message = "Render 2";
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renderer.RenderComponent(nestedComponentId);
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Assert.Collection(renderer.RenderTreesByComponentId[nestedComponentId],
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node => AssertNode.Text(node, "Render 2"));
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}
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[Fact]
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public void CanDispatchEventsToTopLevelComponents()
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{
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// Arrange: Render a component with an event handler
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var renderer = new TestRenderer();
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UIEventArgs receivedArgs = null;
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var component = new EventComponent
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{
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Handler = args => { receivedArgs = args; }
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};
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var componentId = renderer.AssignComponentId(component);
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renderer.RenderComponent(componentId);
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var (eventHandlerNodeIndex, _) = FirstWithIndex(
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renderer.RenderTreesByComponentId[componentId],
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node => node.AttributeEventHandlerValue != null);
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// Assert: Event not yet fired
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Assert.Null(receivedArgs);
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// Act/Assert: Event can be fired
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var eventArgs = new UIEventArgs();
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renderer.DispatchEvent(componentId, eventHandlerNodeIndex, eventArgs);
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Assert.Same(eventArgs, receivedArgs);
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}
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[Fact]
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public void CanDispatchEventsToNestedComponents()
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{
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UIEventArgs receivedArgs = null;
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// Arrange: Render parent component
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var renderer = new TestRenderer();
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var parentComponent = new TestComponent(builder =>
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{
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builder.OpenComponentElement<EventComponent>(0);
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builder.CloseElement();
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});
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var parentComponentId = renderer.AssignComponentId(parentComponent);
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renderer.RenderComponent(parentComponentId);
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// Arrange: Render nested component
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var nestedComponentNode = renderer.RenderTreesByComponentId[parentComponentId]
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.Single(node => node.NodeType == RenderTreeNodeType.Component);
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var nestedComponent = (EventComponent)nestedComponentNode.Component;
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nestedComponent.Handler = args => { receivedArgs = args; };
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var nestedComponentId = nestedComponentNode.ComponentId;
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renderer.RenderComponent(nestedComponentId);
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// Find nested component's event handler ndoe
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var (eventHandlerNodeIndex, _) = FirstWithIndex(
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renderer.RenderTreesByComponentId[nestedComponentId],
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node => node.AttributeEventHandlerValue != null);
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// Assert: Event not yet fired
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Assert.Null(receivedArgs);
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// Act/Assert: Event can be fired
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var eventArgs = new UIEventArgs();
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renderer.DispatchEvent(nestedComponentId, eventHandlerNodeIndex, eventArgs);
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Assert.Same(eventArgs, receivedArgs);
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}
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[Fact]
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public void CannotRenderUnknownComponents()
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{
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// Arrange
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var renderer = new TestRenderer();
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// Act/Assert
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Assert.Throws<ArgumentException>(() =>
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{
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renderer.RenderComponent(123);
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});
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}
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[Fact]
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public void CannotDispatchEventsToUnknownComponents()
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{
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// Arrange
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var renderer = new TestRenderer();
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// Act/Assert
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Assert.Throws<ArgumentException>(() =>
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{
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renderer.DispatchEvent(123, 0, new UIEventArgs());
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});
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}
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[Fact]
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public void ComponentsCanBeAssociatedWithMultipleRenderers()
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{
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// Arrange
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var renderer1 = new TestRenderer();
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var renderer2 = new TestRenderer();
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var component = new MessageComponent { Message = "Hello, world!" };
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var renderer1ComponentId = renderer1.AssignComponentId(component);
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renderer2.AssignComponentId(new TestComponent(null)); // Just so they don't get the same IDs
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var renderer2ComponentId = renderer2.AssignComponentId(component);
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// Act/Assert: Render component in renderer1
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renderer1.RenderComponent(renderer1ComponentId);
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Assert.True(renderer1.RenderTreesByComponentId.ContainsKey(renderer1ComponentId));
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Assert.False(renderer2.RenderTreesByComponentId.ContainsKey(renderer2ComponentId));
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// Act/Assert: Render same component in renderer2
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renderer2.RenderComponent(renderer2ComponentId);
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Assert.True(renderer2.RenderTreesByComponentId.ContainsKey(renderer2ComponentId));
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}
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[Fact]
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public void ComponentsAreNotPinnedInMemory()
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{
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// It's important that the Renderer base class does not itself pin in memory
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// any of the component instances that were attached to it (or by extension,
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// their descendants). This is because as the set of active components changes
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// over time, we need the GC to be able to release unused ones, and there isn't
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// any other mechanism for explicitly destroying components when they stop
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// being referenced.
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var renderer = new NoOpRenderer();
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AssertCanBeCollected(() =>
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{
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var component = new TestComponent(null);
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renderer.AssignComponentId(component);
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return component;
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});
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}
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[Fact]
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public void CannotRenderComponentsIfGCed()
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{
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// Arrange
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var renderer = new NoOpRenderer();
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// Act
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var componentId = new Func<int>(() =>
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{
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var component = new TestComponent(builder =>
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throw new NotImplementedException("Should not be invoked"));
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return renderer.AssignComponentId(component);
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})();
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// Since there are no unit test references to 'component' here, the GC
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// should be able to collect it
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GC.Collect();
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GC.WaitForPendingFinalizers();
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// Assert
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Assert.ThrowsAny<Exception>(() =>
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{
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renderer.RenderComponent(componentId);
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});
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}
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[Fact]
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public void CanRenderComponentsIfNotGCed()
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{
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// Arrange
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var renderer = new NoOpRenderer();
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var didRender = false;
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// Act
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var component = new TestComponent(builder =>
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{
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didRender = true;
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});
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var componentId = renderer.AssignComponentId(component);
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// Unlike the preceding test, we still have a reference to the component
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// instance on the stack here, so the following should not cause it to
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// be collected. Then when we call RenderComponent, there should be no error.
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GC.Collect();
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GC.WaitForPendingFinalizers();
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renderer.RenderComponent(componentId);
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// Assert
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Assert.True(didRender);
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}
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[Fact]
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public void PreservesChildComponentInstancesWithNoAttributes()
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{
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// Arrange: First render, capturing child component instance
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var renderer = new TestRenderer();
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var message = "Hello";
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var component = new TestComponent(builder =>
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{
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builder.AddText(0, message);
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builder.OpenComponentElement<MessageComponent>(1);
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builder.CloseElement();
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});
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var rootComponentId = renderer.AssignComponentId(component);
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renderer.RenderComponent(rootComponentId);
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var nestedComponentInstance = (MessageComponent)renderer.RenderTreesByComponentId[rootComponentId]
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.Single(node => node.NodeType == RenderTreeNodeType.Component)
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.Component;
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// Act: Second render
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message = "Modified message";
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renderer.RenderComponent(rootComponentId);
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// Assert
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Assert.Collection(renderer.RenderTreesByComponentId[rootComponentId],
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node => AssertNode.Text(node, "Modified message"),
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node => Assert.Same(nestedComponentInstance, node.Component));
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}
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private class NoOpRenderer : Renderer
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{
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public new int AssignComponentId(IComponent component)
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=> base.AssignComponentId(component);
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public new void RenderComponent(int componentId)
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=> base.RenderComponent(componentId);
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protected internal override void UpdateDisplay(int componentId, RenderTreeDiff renderTreeDiff)
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{
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}
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}
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private class TestRenderer : Renderer
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{
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public IDictionary<int, ArrayRange<RenderTreeNode>> RenderTreesByComponentId { get; }
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= new Dictionary<int, ArrayRange<RenderTreeNode>>();
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public new int AssignComponentId(IComponent component)
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=> base.AssignComponentId(component);
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public new void RenderComponent(int componentId)
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=> base.RenderComponent(componentId);
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public new void DispatchEvent(int componentId, int renderTreeIndex, UIEventArgs args)
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=> base.DispatchEvent(componentId, renderTreeIndex, args);
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protected internal override void UpdateDisplay(int componentId, RenderTreeDiff renderTreeDiff)
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{
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RenderTreesByComponentId[componentId] = renderTreeDiff.CurrentState;
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}
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}
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private class TestComponent : IComponent
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{
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private Action<RenderTreeBuilder> _renderAction;
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public TestComponent(Action<RenderTreeBuilder> renderAction)
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{
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_renderAction = renderAction;
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}
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public void BuildRenderTree(RenderTreeBuilder builder)
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=> _renderAction(builder);
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}
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private class MessageComponent : IComponent
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{
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public string Message { get; set; }
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public void BuildRenderTree(RenderTreeBuilder builder)
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{
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builder.AddText(0, Message);
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}
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}
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private class EventComponent : IComponent
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{
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public UIEventHandler Handler { get; set; }
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public void BuildRenderTree(RenderTreeBuilder builder)
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{
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builder.OpenElement(0, "some element");
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builder.AddAttribute(1, "some event", Handler);
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builder.CloseElement();
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}
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}
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void AssertCanBeCollected(Func<object> targetFactory)
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{
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// We have to construct the WeakReference in a separate scope
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// otherwise its target won't be collected on this GC cycle
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var weakRef = new Func<WeakReference>(
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() => new WeakReference(targetFactory()))();
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GC.Collect();
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GC.WaitForPendingFinalizers();
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Assert.Null(weakRef.Target);
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}
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(int, T) FirstWithIndex<T>(IEnumerable<T> items, Predicate<T> predicate)
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{
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var index = 0;
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foreach (var item in items)
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{
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if (predicate(item))
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{
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return (index, item);
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}
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index++;
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}
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throw new InvalidOperationException("No matching element was found.");
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}
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}
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}
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