As far as I know, DDK is used to DEVELOP (and not to test) a driver. Testing drivers might be done in the more conventional ways other software components are tested in.
Maybe, you'd like to elaborate more on your query.
Anyway, do provide me with related information, if you find any, regarding testing with DDK. I would be interested.
Just to add a thought, you will find that Microsoft's articles on this are very thorough and are used by many other groups who utilize the DDK approach. As such, you might consider what you can abstract out of the Microsoft articles to benefit whatever you are working on. (Keep in mind this is even more so the case if you are dealing with software that is working on Microsoft Windows since, in that case, Microsoft's articles are probably right up your alley because their DDK information is relevant to any device drivers on Windows.)
Is there something specific you are trying to do that you find you need more information on? It might be more helpful if we approach things from that direction.