This issue was assigned to me, however I will not be able to work on this issue in the immediate future. In order to create a truer sense of the state of this issue and to allow other developers to have chance to become involved, I am removing myself as the assignee of this issue. For more information, see http://docs.moodle.org/dev/Changes_to_issue_assignment
@Petr Škoda can this be closed? Three years seems a heck of a long time to be hanging around for something which was not triaged and yet is a Major issue? Very ODD!
I can see there are already some tests for themes and outputlib, closing.