Best way to have a FreeBSD VM for automated testing?

Hi all,

I'm in repeatable build land, working in Linux and developing a FreeBSD 
appliance.

For tests, I need to run a FreeBSD VM, put some Python code and test 
data into it, run the script, and get the test results back.

Repeatability means: Everything done with the VM needs to be scriptable 
(using a GUI for exploring is okay but things have to translate).
Which in turn means that every setup step for a FreeBSD image comes with 
a pretty high coding and maintenance cost.

So my question is:
What's the FreeBSD image that has the least number of steps to get the 
base system up and running? I suppose it's the VM-IMAGES section, but is 
this correct?

Follow-up question:
The startup time needs to be as fast as possible. Sub-second would be 
great ("don't disrupt the developer's thought stream").
I see the boot process from a vanilla VM-IMAGES image takes multiple 
seconds; can this be sped up to just a few seconds, or do I need to run 
the setup and create a VM snapshot at which the VM starts for each test run?

Regards,
Jo