I've never heard of testing a kernel in any way other than the most 
straightforward:  boot with it.  Just give it a name like new.netbsd 
(there are actually conventions for the name, but I can't remember at the 
moment), and put that name in the Booter utility and try it.

Later.

-- 
Colin Wood                                      ender@is.rice.edu
Consultant                                        Rice University
Information Technology Services                       Houston, TX