(Note: I'm looking to add someone as a collaborator/maintainer if you're interested let me know.)
https://github.com/visionmedia/mocha/wiki/Third-party-reporters describes using third party reporters in mocha.
Basically, have your project's package.json be like:
{
"devDependencies": {
"mocha-teamcity-reporter": ">=0.0.1"
}
}
Then call mocha with:
mocha --reporter mocha-teamcity-reporter test