1172 refactor authorization tests

Clean up and refactor authorization tests. More at http://dev.mconf.org/redmine/issues/1172
The newer rails version is giving out a deprecation warning about this, but we can discuss if we want to leave it at true or false. See explanation here http://makandracards.com/makandra/20303-how-to-silence-i18n-enforce_available_locales-deprecation-warnings