This even surprised Russia, a country that usually is not too adamant a supporter of stopping North Korea (compared with the US, or Japan). A Russian foreign ministry source was quoted of saying "The launch of short-range missiles by the Korean People's Democratic Republic causes bewilderment." I'm guessing that this "testing of limits" by North Korea even surprised China, because just last week, the premier, Wen Jiabao visited North Korea, and N.K said that it was willing to go back to the negotiating table.
Clearly, North Korea is just trying to test the other countries and see what they will do. I think if the US and its allies really want to get the message through that N.K's actions are not okay, they should be more assertive. The US already sent an aircraft carrier to the South Korean port of Busan. Still, I do not think that is enough.
North Korea right now is acting like a toddler (toddler with nukes that is). It keeps wanting to see what it can do before getting a scolding. Maybe the US and its allies should start giving out more than just "scoldings" and convince other countries to start sanctioning. About 75% of people already think that North Korea is at least somewhat of a threat to the US in terms of nuclear engagements, so I think the US should take initiative (since it is the big dog in the world right now) and kill the beast in its infancy.
Picture this:
PLUS 
-Henry Zhang