I had some issues with libraries installed via npm (such as d3 and jsdom) causing segmentation faults in Mocha tests. Ultimately I realized that it wasn’t a problem with these node modules so much as it was with my node install itself. I had installed from source following this guide, but it wasn’t quit enough to get my node install right on Debian Squeeze. Install Node.js Dependencies Pretty standard stuff – make sure you’re up to date on these.