在Castle Windsor 3中，在单元测试中覆盖现有的组件注册 [英] In Castle Windsor 3, override an existing component registration in a unit test

问题描述

我正尝试在自动化测试中使用Castle Windsor，例如：

I am attempting to use Castle Windsor in my automated tests like so:

在每次测试中：

• Setup（）函数创建一个Windsor容器，注册每个组件的默认实现


• Test 函数通过方法 IWindsorContainer.Resolve< T> 访问组件，并测试其行为


• TearDown（）函数处理温莎容器（以及任何已创建的组件）

• The Setup() function creates a Windsor container, registering default implementations of each component
• The Test function access the components via the method IWindsorContainer.Resolve<T>, and tests their behavior
• The TearDown() function disposes of the Windsor container (and any created components)

例如，我可能有15个测试可以访问组件，这些测试间接地导致创建 IMediaPlayerProxyFactory 组件。 SetUp 函数注册了一个足够好的实现 IMediaPlayerProxyFactory ，所以我没有在此注册的维护负担。 15个测试中的每一个。

For example, I might have 15 tests which accesses components which indirectly results in the creation of an IMediaPlayerProxyFactory component. The SetUp function registers a good-enough implementation IMediaPlayerProxyFactory, so I don't have the maintenance burden of registering this in each of the 15 tests.

但是，我现在正在编写一个测试 Test_MediaPlayerProxyFactoryThrowsException ，确认我的系统能够优雅地处理 IMediaPlayerProxyFactory 组件出现错误。在测试方法中，我创建了特殊的模拟实现，现在我想将其注入到框架中：

However, I'm now writing a test Test_MediaPlayerProxyFactoryThrowsException, confirming my system elegantly handles an error from the IMediaPlayerProxyFactory component. In the test method I've created my special mock implementation, and now I want to inject it into the framework:

this.WindsorContainer.Register(
                                 Component.For<IMediaPlayerProxyFactory>()
                                          .Instance(mockMediaPlayerProxyFactory)
                              );

但是温莎抛出了 Castle.MicroKernel.ComponentRegistrationException ，并显示消息已经有一个具有该名称的组件。

But Windsor throws a Castle.MicroKernel.ComponentRegistrationException, with the message "There is already a component with that name."

有什么方法可以使我的 mockMediaPlayerProxyFactory 是 IMediaPlayerProxyFactory 的默认实例，丢弃已注册的组件吗？

Is there any way that I can make my mockMediaPlayerProxyFactory be the default instance for the IMediaPlayerProxyFactory, discarding the component that's already registered?

---

根据文档，温莎城堡3允许注册覆盖，但我只能找到一个示例：

---

According to the documentation, Castle Windsor 3 allows for registration overrides, but I could only find one example:

Container.Register(
    Classes.FromThisAssembly()
        .BasedOn<IEmptyService>()
        .WithService.Base()
        .ConfigureFor<EmptyServiceA>(c => c.IsDefault()));

ConfigureFor 是 BasedOnDescriptor 类。就我而言，我没有使用 FromDescriptor 或 BasedOnDescriptor 。

ConfigureFor is a method of the BasedOnDescriptor class. In my case I'm not using the FromDescriptor or BasedOnDescriptor.

推荐答案

创建覆盖实例必须做两件事：

There are two things that you have to do to create an overriding instance:

1. 为其分配一个唯一名称


2. 调用 IsDefault 方法

1. Assign it a unique name
2. Call the IsDefault method

因此，使示例生效：

this.WindsorContainer.Register(
                             Component.For<IMediaPlayerProxyFactory>()
                                      .Instance(mockMediaPlayerProxyFactory)
                                      .IsDefault()
                                      .Named("OverridingFactory")
                          );

由于我计划在许多测试中使用此主要模板，因此我创建了自己的扩展方法：

Because I plan to use this overriding patten in many tests, I've created my own extension method:

public static class TestWindsorExtensions
{
    public static ComponentRegistration<T> OverridesExistingRegistration<T>(this ComponentRegistration<T> componentRegistration) where T : class
    {
        return componentRegistration
                            .Named(Guid.NewGuid().ToString())
                            .IsDefault();
    }
}

现在，示例可以简化为：

Now the example can be simplified to:

this.WindsorContainer.Register(
                             Component.For<IMediaPlayerProxyFactory>()
                                      .Instance(mockMediaPlayerProxyFactory)
                                      .OverridesExistingRegistration()
                          );

---

稍后编辑

版本3.1引入了 IsFallback 方法。如果我使用 IsFallback 注册所有初始组件，则任何新注册都会自动覆盖这些初始注册。如果当时该功能可用，我会走那条路。

Version 3.1 introduces the IsFallback method. If I register all my initial components with IsFallback, then any new registrations will automatically override these initial registrations. I would have gone down that path if the functionality was available at the time.

https://github.com/castleproject/Windsor/blob/master/docs/whats-new-3.1.md#fallback-components

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