Testing the Gutenprint printer drivers for CUPS
by running the drivers via the cupsfilter program.

The cupsfilter program can be run by any normal user
so that the tests do not require 'root' privileges.

Basically what happens is (bash-like syntax):

input_file="/tmp/gutenprint.test.ps"
echo -e '%!\n100 200 300 400 rectstroke\nshowpage' >$input_file
output_file="/tmp/gutenprint.test.out"
for PPD in $( ls -1 /usr/share/cups/model/gutenprint/5.2/C/* )
do /usr/sbin/cupsfilter -p $PPD -m printer/foo -e $input_file 2>&1 1>$output_file | grep PID
   file $output_file
done

See "man cupsfilter".

See also the section "How to test a printer driver package" in
https://en.opensuse.org/openSUSE:How_to_contribute_to_the_Printing_project