one unittest fails with test run in one thread

[Valeriy Ponomaryov]

If run unittests with "./run_tests.sh" (1 thread by default), we get next error:

======================================================================
FAIL: manila.tests.test_test.IsolationTestCase.test_service_isolation
----------------------------------------------------------------------
Traceback (most recent call last):
_StringException: pythonlogging:'': {{{Starting manila-share node (version 2013.2)}}}

Traceback (most recent call last):
  File "/home/vponomaryov/Documents/python/projects/manila/manila/tests/test_test.py", line 34, in test_service_isolation
    self.start_service('share')
  File "/home/vponomaryov/Documents/python/projects/manila/manila/test.py", line 194, in start_service
    svc.start()
  File "/home/vponomaryov/Documents/python/projects/manila/manila/service.py", line 374, in start
    self.manager.init_host()
  File "/home/vponomaryov/Documents/python/projects/manila/manila/share/manager.py", line 84, in init_host
    share_server=share_server)
  File "/home/vponomaryov/Documents/python/projects/manila/manila/share/drivers/generic.py", line 86, in wrap
    raise exception.ManilaException(_('Share server backend '
ManilaException: Share server backend details missing.

But if run with "./run_tests.sh --concurrency 4" no error appears. Thats why bug did not appear in master via tox, tox uses bunch of threads by default.
Also, adding some new tests makes it appear.
So, we have some combination of tests with some influence, if they are in one thread.

It is caused by merge of https://github.com/stackforge/manila/commit/dd4bd5c48722f478fc62b959a2367e91002d4e0d

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/115354
Committed: https://git.openstack.org/cgit/stackforge/manila/commit/?id=ecea45689fdebf409b06311cc8e84b2e609967e1
Submitter: Jenkins
Branch: master

commit ecea45689fdebf409b06311cc8e84b2e609967e1
Author: vponomaryov <email address hidden>
Date: Tue Aug 19 20:29:59 2014 +0300

    Fix failing of unittests in one thread

    With change of default driver, that is used for unittests one additional
    method 'ensure_share' was not mocked, that caused problems running
    unittests in one thread.

    Change-Id: Iea08207bb6200c37f5608d222dccdfbdc509b234
    Closes-Bug: #1358854