nova.tests.unit.api.openstack.compute.contrib.test_block_device_mapping_v1 hits OverQuota with --concurrency=1

[Matt Riedemann]

If you run 'tox -e py27 -- --concurrency=1' you get a bunch of OverQuota errors in nova.tests.unit.api.openstack.compute.contrib.test_block_device_mapping_v1:

http://paste.openstack.org/show/191932/

e.g.:

nova.tests.unit.api.openstack.compute.contrib.test_block_device_mapping_v1.BlockDeviceMappingTestV2.test_create_instance_decide_format_legacy
---------------------------------------------------------------------------------------------------------------------------------------------

Captured traceback:
~~~~~~~~~~~~~~~~~~~
    Traceback (most recent call last):
      File "nova/tests/unit/api/openstack/compute/contrib/test_block_device_mapping_v1.py", line 399, in test_create_instance_decide_format_legacy
        self._test_create(params, override_controller=controller)
      File "nova/tests/unit/api/openstack/compute/contrib/test_block_device_mapping_v1.py", line 94, in _test_create
        override_controller.create(req, body=body).obj['server']
      File "nova/api/openstack/compute/servers.py", line 614, in create
        headers={'Retry-After': 0})
    webob.exc.HTTPForbidden: Quota exceeded for cores,instances: Requested 2, but already used 20 of 20 cores

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/163970

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/163970
Committed: https://git.openstack.org/cgit/openstack/nova/commit/?id=c943cbbc40654827f537773a90d77577a54dbe0b
Submitter: Jenkins
Branch: master

commit c943cbbc40654827f537773a90d77577a54dbe0b
Author: Sean Dague <email address hidden>
Date: Thu Mar 12 16:55:55 2015 -0400

    ensure DatabaseFixture removes db on cleanup

    The DatabaseFixture was previously just ensuring that tests which used
    it had a clean database when they started. It did not ensure there was
    no working database around when it wasn't being used, so tests which
    leaked into the database might pass even if they were listed as a
    NoDBTest, because there was an in memory test db from a prior run.

    This adds a cleanup path to the fixture which blows away the db at the
    end of the test (which itself is tested). There were 46 tests which
    failed when we got this isolation correct, and this changes all those
    test classes containing those tests to require a db. Many of these
    could have narrower fixes, but this returns us to an isolated state.

    Change-Id: Id0480035d8e615ae602da9737cd2c94bc7967067
    Closes-Bug: #1431519
    Closes-Bug: #1431551