refs #26 add test for CommonHelper
refs #26 add test for CommonHelper

wangjun/open-slideshare,wangjun/open-slideshare,ryuzee/open-slideshare,jaambee/open-slideshare,ryuzee/open-slideshare,jaambee/open-slideshare,wangjun/open-slideshare,ryuzee/open-slideshare,jaambee/open-slideshare