PCB Panelization tool/SW and adding test connections
As gbulmer says, panelize.ulp is an Eagle tool that does this.  There are some clear drawbacks to using this tool, IMO-  mostly with respect to how all the components end up numbered.

There are some usable tools, like gerbmerge (see http://www.instructables.com/id/Panelizing-PCBs-for-Seeed-Using-Eagle-Free-Light/) that do a very reasonable job, for free. Also, most fab houses will panelize for you (make them earn those NRE's!!)

However, your requirement that you have test connections on the runners, and you're using Eagle, severely limits your options.  I think panelize.ulp is about the best you can do.