The Meteor documentation is woefully and/or intentionally silent on the subject of testing, other than this one quote:
Great care has been taken to give the core Meteor packages the minimal set of dependencies, so you can use your favorite templating, testing, or DOM manipulation frameworks.
So I guess you're free to test however you like, which is supposed to be a feature.
There are a number of fine testing tools that would be applicable to a Meteor webapp, Mocha being one example.