Test setup for a new module

[Dominic Espinosa <dcespin fastmail fm>]

Hello,

I'm preparing to write a new rendering module for an experimental script. 
There are a lot of steps involved, and I'm interested to know if anyone 
has ideas about how to efficiently test the module. 

As far as I can tell, I will need to recompile the module with every 
change, and then run some kind of rendering test (how?) to see if the 
characters get drawn correctly (and they won't). I'm also not certain how 
to output diagnostic messages at various stages of the rendering process, 
or set useful breakpoints.

Suggestions? One other question: the font I drew stores the glyphs in the 
Unicode Private Use area. Will this pose any problem for the Pango 
mapping?

Thanks.