I’ve been asked to work on changing a number of classes that are core to the system we work on. The classes in question each require 5 – 10 different related objects, which themselves need a similiar amount of objects.
Data is also pulled in from several data sources, and the project uses EJB2 so when testing, I’m running without a container to pull in the dependencies I need!
I’m beginning to get overwhelmed with this task. I have tried unit testing with JUnit and Easymock, but as soon as I mock or stub one thing, I find it needs lots more. Everything seems to be quite tightly coupled such that I’m reaching about 3 or 4 levels out with my stubs in order to prevent NullPointerExceptions.
Usually with this type of task, I would simply make changes and test as I went along. But the shortest build cycle is about 10 minutes, and I like to code with very short iterations between executions (probably because I’m not very confident with my ability to write flawless code).
Anyone know a good strategy / workflow to get out of this quagmire?
As you suggest, it sounds like your main problem is that the API you are working with is too tightly coupled. If you have the ability to modify the API, it can be very helpful to hide immediate dependencies behind interfaces so that you can cut off your dependency graph at the immediate dependency.
If this is not possible, an Auto-Mocking Container may be of help. This is basically a container that automatically figures out how to return a mock with good default behavior for nested abstractions. As I work on the .NET framework, I can’t recommend any for Java.
If you would like to read up on unit testing patterns and best practices, I can only recommend xUnit Test Patterns.
For strategies for decoupling tightly coupled code I recommend Working Effectively with Legacy Code.