A grunt (v 0.4.5) dependency is throwing unexpected token on 'grunt test'

The purpose of my build is to run my unit tests through ‘grunt test’.

This is all my cicle.yml:

- gem install compass
- npm install -g bower
- npm install -g grunt-cli
- npm install
- bower install

- grunt test

All commands go through successfully but fails on ‘grunt test’ throwing the image error.

I tried leaving static versions in package.json, so that in circleCI machine, the packages installed are the same I have in my computer since tests run and pass locally. No luck with that.

I tried removing local grunt package to use globally installed grunt-cli and grunt on circleCI machine, both installed through the circle.yml file. No luck either. Still having the same error.

My config:
OS: Windows 8.1
Browser: Chrome 47.0.2526.106
Mobile: false
Cookies: true

The project is not public so I can’t share.