Can I use bootcamp to install another instance of OSX? Can I use bootcamp to partition my HDD and install another instance of OSX?

I want to run a test instance to try out untrusted software.

The boot camp assistant seems to insist on installing an instance of windows.
You dont need Bootcamp for that. Just open Disk utility and partition your disk. Then install OSX on the second partition. Then in your Start disk preference choose which OS to start as default or just hold option key on boot to select which os to run.