Live tests always are more indicitave of progress than staged tests. Failure will even be a triumph because of what we learn....and the message sent to NK..ie: next time we won't fail....and your technology is puny.
How do we know their "test" is a test...really? [hee hee..] I say use a launch from N Korea as a "test" of our sub launched ballistic nuclear missiles and turn NK into glass in retaliation for their obvious preemptive nuclear strike on the US or Japan.
Of course, that's probably why I am not in charge.