Unit Tests Don't Work on Cubes

I've been building web sites for a while now. I've been writing code, object oriented style for the better part of a decade. Unit testing I've been doing for all of about 1-2 years to various degrees. Nothing super advanced yet, and slowly I'm getting some of the more advanced unit testing methods figured out. Not so much advanced, but just newer methods for testing in different situations. So now I've figured out web service unit tests, database unit tests, and all sorts of other ways to unit test things. So my question is, how does one unit test a cube?