AutoMock - How to unit test with Keyed Registrations?

Question

I'm having trouble writing tests around a factory that uses Autofac keyed registrations.

In an Autofac module, I register things like this:

builder.RegisterType<TypeAMessageHandler>().As<IMessageHandler>()
    .Keyed<IMessageHandler>(MessageTypeEnum.A);

builder.RegisterType<TypeBMessageHandler>().As<IMessageHandler>()
    .Keyed<IMessageHandler>(MessageTypeEnum.B);

builder.RegisterType<MessageHandlerFactory().As<IMessageHandlerFactory>();

Then the constructor for the factory gets a nice Index injected into its constructor by Autofac:

public MessageHandlerFactory(
    IIndex<MessageTypeEnum, IMessageHandler> messageTypeToHandlerMap)

However, I can't figure out how to inject an IIndex<,> for unit testing with Automock, when I use automock.Create<MessageHandlerFactory>(). Telling the AutoMock to Provide message handler implementations doesn't get them into the keyed index. Creating an explicit implementation of IIndex and asking Automock to Provide that also doesn't work - in both cases, my factory gets an empty IIndex<,> injected.

What is the right way to test keyed registrations?

Answer 1

I found the AutoMock doesn't really have built in support for keyed components, but does has overloads of the factory methods that let you configure the container.

So this works:

var messageAMock = new Mock<IMessageHandler>();
var autoMock = AutoMock.GetStrict(builder => builder.RegisterInstance(messageAMock.Object).Keyed<IMessageHandler>(MessageTypeEnum.A));