I was seduced, eg [1], by the fact that the Tape (the "tap-producing test harness for node and browsers") unit testing tool does less. Not only does it not litter your Javascript universe with globals, it does a lot less magic stuff.
I am in the early stages of a new project and decided to do the right thing and test everything from the first moment. Having been irritated by the amount of arcane stuff in Mocha, I drank the koolaid and rewrote my starter testing for Tape.
Bad move.
Tape is simple to use but, when I started doing real development and a new test didn't run, I needed to debug and couldn't.
Turns out that Tape suppresses console.log(), process.exit(), etc. Of course, there are other ways to debug Javascript, but I am a fan of print-trace, ie, console.log() and you cannot use console.log() with Tape.
Searching the web, I found that this is not something that is not something that is noted very often. I don't know why. If I had known this, I would not use Tape. In fact, I am going to revert to using Mocha. The elimination of testing globals is not sufficiently compelling to make it worth changing my approach to debugging.
[1] Why I use Tape Instead of Mocha & So Should You - http://tqwhite.org?F7A285