Best Unit Testing framework for Linux system administration scripting?

[Bryan Berry]

I manage a team of 5 linux sysadmins and I am trying to transition us
from lengthy, mostly unreadable shell scripts to python scripting. After
a few tutorials, I have been infected with the unit testing bug.

Our scripts create custom versions of Fedora Core, build and deploy web
software, and test servers post-installation for proper configuration.

Friends in the python community, which unit testing frameworks do you
recommend for these purposes? I have looked at unittest and py.test so
far and prefer py.test after a cursory examination.

Also, can anyone point to me tutorials, resources on using unit testing
in system administration?

thanks,