It seems at the moment there's no way to have a DB server available when running tests. Is that correct? Until that happens, I don't imagine WP tests will be able to run.
I haven't looked into integrating with the test harness, but the test suite was pretty easy to get running locally. Unfortunately it crashes halfway through, but up until that point, the majority of the tests passed.
They mention the compatibility of the projects unit tests with their own testing so perhaps WordPress has some things in their test setup that didn't fit. They mentioned CakePHP as another example that wasn't included.