How do I include custom CSS files in the styles dropdown? I am trying to include custom css file to ckeditor.

It doesn't show css file in styles drop-down list.

I have included this two lines of code into;

 /drupal/sites/all/modules/ckeditor/ckeditor.config.js

 config.extraPlugins = 'stylesheetparser';
 config.contentsCss = 'test.css';


Thanks a lot for the help.
Have tried going adding the css file via the configuration page?

yoursite.com/admin/config/content/ckeditor/edit/

navigate to the page, edit the target profile and click on the CSS link to expand the configuration pane... you should be able to tell CKeditor what to do from there. I'm not sure if its necessary but you may need to refresh the site's cache before the new files get picked up. 
hope this helps.