Idiotic restraint of trade. Six year apprenticeship? For interior design? A test developed by existing interior designers?
None of these ideas make any sense, unless you are already an interior designer trying to eliminate competition.
I don't favor any licensure for any job at all, but at least have a public safety rationale behind it. If you want to license a doctor because he may kill you, maybe, but how many fatalities have occurred due to bad interior design?