Where to start in writing test programs for electronics

[Manatee]

I would like to write test programs that will collect data over the
serial port, control instruments, plot data as its collected, and save
that data to a file. I have partially figured out instrument control
and have downloaded numpy and matplot. I am having trouble pulling it
together as regards feeding realtime data into matplot. I am reading
as much as I can in all areas and I'm hoping someone can give me some
guidance or tips as to how best to proceed with this. Thanks in
advance.