Fix the 2 previously added tests, they were all wrong: test what happen when...

Fix the 2 previously added tests, they were all wrong: test what happen when activity generates the error.
Add one more test for a bug found while coding above fix: object path is not a tuple when the path (string) is given to Message instance.
Add 2 more tests which test what was intended for the 2 first tests: test what happen when CMFActivity generates the error.


git-svn-id: https://svn.erp5.org/repos/public/erp5/trunk@18501 20353a03-c40f-0410-a6d1-a30d3c3de9de