One of the things that irritates me the most about unit testing some classes in a Spring context, is initialising them with all their dependencies. This is especially true of Spring framework extensions, like FactoryBean implementations or *Aware implementations. It is cumbersome to add all the dependencies, and easy to forget to call the bean lifecycle methods, like the afterPropertiesSet method from InitializingBean.

The Spring base classes for unit testing help quite a lot, but there are still some things that are fiddly. E.g. in many cases it is necessary to disambiguate autowiring, so…

I was on site with some clients the other day, and they asked me about unit testing and mock objects. I decided to write up some of the discussion we had as a tutorial on creating dependencies (collaborators) for unit testing. We discuss two options, stubbing and mock objects and give some simple examples that illustrate the usage, and the advantages and disadvantages of both approaches.

It is common in unit tests to mock or stub collaborators of the class under test so that the test is independent of the implementation of the collaborators. It is also a useful thing to be able to do to…