This Time it Will Hurt the North

In my amateur analysis I would say North Korea's actions will only harm itself.

• The Obama administration opened the door and eased negotiations for aid and power supplies to North Korea. These will become more hardline, if they resume at all.
• China has distanced itself from DPRK recently and this will continue this trend.
• China is worried about mass immigration if the DPRK falls or becomes fragile. This has encouraged them to prop up Pyongyang in the past. But if the US can broker a deal. Such as financing (from DPRK assets frozen in Switzerland?) or guaranteeing taking on refugees from the north then this could be solved.
• If this test is related to internal affairs in a bid to scare away outsiders interfering in the passover of power then it has only shown the weakness of the regime. Furthermore it may have just tipped the scales in in the minds of international negotiators that the only way to solve North Korea is regime change.
• The likely hood of war is minuscule but the Chines can literally not afford a long scale/damaging war between the US and North Korrea, never mind coming in on the DPRK's side. If the US bails on the Chinese deficit then China will sink. If the dollar falls so do China's cash reserves. Blessed be trade.
  
• South Korea has no choice now but to fall in even deeper with Japan and the US. North Korea's threats of war due to Seoul's relationships with the West will now be totally ignored.