Testing of backend list_role_assignments needs to be improved

[Henry Nash]

Although we have quite comprehensive testing of the various filter options on list_role_assignment at the controller level, we don;t have these at the backend manager level. This will become crucial since we are pushing the filtering down into the driver level AND will be rewriting many of the other assignment listing methods to simply call list_role_assignments.

https://github.com/openstack/keystone/blob/32d2267b2cfb004965505267b4e060a49e15c643/keystone/tests/test_backend.py
https://github.com/openstack/keystone/blob/1a9038925dec5acf803c338a5c494515d60e0323/keystone/tests/test_backend_ldap.py

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/151623

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/151962

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/153897

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/154302

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/154485

[Lance Bragstad (lbragstad)]

Since this is targeted to k-3, do the reviews listed in the comments need to be added to https://gist.github.com/dolph/651c6a1748f69637abd0

[Steve Martinelli (stevemar)]

Marking this as fix released - all patches that were partial fixes have been merged and no new patches in 6 months.