Auto Mocking NSubstitute with Castle Windsor

I was debating whether to make this blog post because it’s so damn simple to implement, but hey, if it saves someone else time, I did some good.

First of all, register an ILazyComponentLoader into Windsor:

var c = new WindsorContainer();

Then, the implementation of LazyComponentAutoMocker is simply this:

public class LazyComponentAutoMocker : ILazyComponentLoader
  public IRegistration Load(string key, Type service, IDictionary arguments)
    return Component.For(service).Instance(Substitute.For(new[] { service }, null));

And you’re done! Here’s a simple unit test example using only the code from above:

public void IDictionary_Add_Invoked()
  var dict = c.Resolve<IDictionary>();
  dict.Add(1, 1);
  dict.Received().Add(1, 1);

That was almost too easy.


For what it's worth, I found this helpful. I'm new to Castle Windsor as well as NSubstitute. This post was able to get me going a lot quicker than sifting through documentation. Thanks.