get_user has different behavior for db and ldap drivers

[Devin Carlen]

The db auth driver raises NotFound if a user lookup fails, while ldap auth driver returns None.

This inconsistency needs to be fixed, and causes problems further down the line and forces developers to awkwardly handle both scenarios.

[Mark McLoughlin (markmc)]

Looks like it's still a problem

e.g. LdapDriver.get_user() should raise UserNotFound if __get_ldap_user() returns None

[John Griffith (john-griffith)]

Fairly straightforward to change in ldapdriver.py, but look out when you try and run the test_auth.py tests!!! Trying to figure out the issue, adding "assertRaises()" doesn't seem to be working out.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/3741

[John Griffith (john-griffith)]

Submitted to gerrit for review Change-Id: Ia13af759931ca0c7327d54184730537bafbe52ae

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/3741
Committed: http://github.com/openstack/nova/commit/fa295d1278ef43fe2e90902006a5d073d78173ad
Submitter: Jenkins
Branch: master

commit fa295d1278ef43fe2e90902006a5d073d78173ad
Author: john-griffith <email address hidden>
Date: Thu Feb 2 22:15:58 2012 -0700

    get_user behavior in ldapdriver

    * Addresses bug 744462

    Rather than ldapdriver.get_user() returning None for non-existent
    user, this change implements exception.LDAPUserNotFound to more
    closely match the behavior of other drivers (db).

    Change was made in public method only, and _check_user_exists()
    which uses get_user() now catches and returns None if applicable.
    Implemented test of NotFound exception in base auth test class.

    Change-Id: Ia13af759931ca0c7327d54184730537bafbe52ae