Add test for null values.
Add test for null values.
guilhermeblanco/cache,mpdude/cache,doctrine/cache,Rican7/cache,robocoder/cache,piwik/cache,doktorsitesi/cache,jenniferyien/cache,Tobion/cache,robocoder/cache,anonpain/cache,Ocramius/cache,jeskew/cache,doktorsitesi/cache