[poppler] General interest: regression testing techniques for pdfs?

[Christian Feuersaenger]

Dear Developers,

I am author of a program which generates pdf output and as such I am 
thinking about improvements to my regression tests... perhaps I can 
learn from your very successful testing framework.

Is there some sort of automatic system which compares screenshots 
somehow? Or any other type of automatic comparison function? In that 
case, I would be interested in using a similar approach for my own 
work... and I would appreciate any hints.

Thanks!

Best regards

Christian