update the file package.json and put 'mocha' into /home/glz/.rvm/gems/ruby-2.0.0-p247/bin:/home/glz/.rvm/gems/ruby-2.0.0-p247@global/bin:/home/glz/.rvm/rubies/ruby-2.0.0-p247/bin:/home/glz/.rvm/bin:/usr/lib/lightdm/lightdm:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/home/glz/.nvm/v0.10.26/bin:/home/glz/greet/node_modules/mocha/bin