Substituting registered container components for testing

Jun 18, 2015

I want to test my services end-to-end. I want to guarantee I’m testing behaviour and not implementation. I do not want my tests to be brittle and I want to refactor. I want to test that my container registration conventions work. I want my tests to run in milliseconds not seconds, be repeatable and not dependent upon physical infrastructure such as persisted state, or items on a queue. I need my tests to run in-memory only. My code is persistence ignorant. So I need to substitute my persistent data-store with in-memory testing implementations.

How do I substitute container components already registered by convention with my in-memory implementations? Without making changes to the production code?

I have created a simple Windsor facility that is only averrable to the test assembly. When resolving pre-configured container components it substitues them.

Here is an example, whereby a bootstrapped container has components substituted in a test:

Now the components that use a service bus,, hbase or persistent store are substituted with appropriate test doubles like a mock, stub, or in-memory store. I can now test the behaviour of the service without bastardising my container conventions to substitute components that are expensive and superfluous to the SUT.

And here is the first stab at my implementation: