(PUP-500) Add additional tests cases

Test cases added that test that the current implementation does
not regress from its current behavior.

Regular resources are collected. Collection with override can be
done multiple times. Changing and amedning values work for 
regular resources as well as virtual.
Merge pull request #2841 from hlindberg/PUP-500_additional-collection-tests

(PUP-500) Add additional tests cases