[Exim] testing Perl functions outside of Exim

Hello,

I'm hoping to use the Embedded Perl facility for some extended testing
within my system filter. I am also using the Exim::expand_string() function
within my code.

Q: Can I test/debug my Perl functions OUTSIDE of Exim if I somehow mockup
the Exim:: package? (obviously, I'll have to 'fake' the values of the Exim
vars I wish to use, i.e. $local_part). Are there any examples of this
scenario?

-with thanks,
Mike Scott