[Exim] possible: testing before installation of upgrade?

I can't seem to figure out a way to do this:

I've compiled exim 4.30 w/sa-exim and exiscan patches -- with no error
currently, i have exim 4.23 w/sa-exim and exiscan running

i'd like to find some way to test the 4.30 build before installing --
to make sure that i didn't mess up and configuration variable

is there any way to do this? perhaps specify an alt destination dir in
Local/Makefile or "make install" and run 4.3 in testing mode
concurrently?