Source: http://www.torontosun.com/2012/04/13/embarrassed-by-rocket-crash-north-korea-may-try-nuclear-test
Maybe it's just a ploy so everyone thinks they have nothing, while they sit back laughing with their secret weapon. ;p Or maybe they're just all about hype, rather than bite.
I think they should test one... preferably in the residence of that fat little toad that just became their leader.