The node-async-testing project is no longer maintained. Perhaps you should take a look at asynct or node-unit.
The author of this project feels that testing frameworks like this are inherently flawed in an async environment. They depend on your tests working how you expect them to, but the whole point of a testing framework is that you catch things you don't expect.
I do have some ideas for addressing this, but until that time, node-async-testing will have to wait...