- create generic rule mixing tests

 - use it for testing BPM Order Rule and BPM Delivery Rule
 - test for building packing list from order using interaction workflow from BPM
 - updated docstrings and comments
 - refactor names for more generic test behaviour
 - use double editing instead of next transition to check stability of expand in case of duplicated lines


git-svn-id: https://svn.erp5.org/repos/public/erp5/trunk@28425 20353a03-c40f-0410-a6d1-a30d3c3de9de