Those fucking North Koreans piss me off!
This is an act of WAR!
Granted, geographically, the safest area for North Korea to test fire a missile is over the sea of Japan (look at any map). Japan essentially blocks Korea from the Pacific ocean. I don't think a missile testing could be conducted from their location without flying it into Japan. Fly it into China? South Korea? There is no trajectory at which North Korea could fire a missile from the north-eastern missile bases without either violating another nation's airspace or physically attacking another country. Keep in mind that the ROK is between the DPRK and the Pacific to the south. I've traced sample trajectories from North-eastern DPRK and expanded them into the surrounding region. There is literally nowhere they could perform a missile test without infringing upon someone. The only possible solution would be to launch from the southern section of the country, which would open a small strip of ocean less than 100 miles wide to the south. If something were to go wrong, and the missile missed its target (remember, this is a test), it would likely hit the east coast of China.
However, whilst launching the test missile into the sea of Japan is obviously the safest and least provocative option, nevertheless, it is still an act of aggression, and essentially a declaration of war. Why? Because they shouldn't be test-firing missiles anyway, because North Korea is an unstable, evil regime with connections to Al Qaeda and other tyrants and terrorists. So yes, I believe this test-firing must be presented to the world as an act of aggression; nothing more nor less. Doing this will also help to maintain a threat of the evil rogue state, which is good for America, because it gives us a pretext to invade and occupy North Korea, or at least to keep our troops on South Korea--thereby maintaining US hegenomy in East Asia.
It is absolutely essential to maintain a threat of North Korea! This is absolutely necessary for the realization of the Project for a New American Century! Patriots, never forget this!