The version of color.js used in node-qunit is 0.6.0. This version however has an issue where if a different version of colors is used by another module in the project, throws an error.
More details - https://gist.github.com/1451296
This issue is fixed in version 0.6.0-1 Marak/colors.js@3c2eb9d
Solution - upgrade package.json to include the newer version of color dependency.