I used this page a lot and tried all of the answers, but from my beginner's starting point, I found them quite confusing. Once I had any trouble, I was flummoxed as to how to fix them.
This solution is really simple to get started with, if not fully documented yet, so I recommend it for people like myself who want to do TDD but aren't sure how testing in JavaScript works and which libraries plug into what:
https://github.com/mad-eye/meteor-mocha-web
FYI, I found that I also need to use the router Atmosphere package to make a '/tests' route to run and display the results from the tests, as I didn't want it to clutter my app every time it loads.