in reply to Automated regression testing

If it is a command line application, you can use Test::Cmd or Test::Excpect. If it is a GUI, you can use Win32::GuiTest on Windows and X11::GUITest on Linux.

If you want to test the code, you could write XS-code that interacts with your C-Code. In the Perl script you can use the above mentioned modules for the TAP output.