delete race in unit tests

[Steve Baker]

This exception is raised, but it does not cause a unit test failure:

Traceback (most recent call last):
  File "/usr/lib/python2.7/site-packages/eventlet/hubs/hub.py", line 346, in fire_timers
    timer()
  File "/usr/lib/python2.7/site-packages/eventlet/hubs/timer.py", line 56, in __call__
    cb(*args, **kw)
  File "/usr/lib/python2.7/site-packages/eventlet/greenthread.py", line 194, in main
    result = function(*args, **kwargs)
  File "heat/engine/parser.py", line 665, in delete
    action)
  File "heat/engine/parser.py", line 420, in state_set
    'status_reason': reason})
  File "heat/db/sqlalchemy/models.py", line 74, in update_and_save
    session.commit()
  File "/usr/lib64/python2.7/site-packages/sqlalchemy/orm/session.py", line 765, in commit
    self.transaction.commit()
  File "/usr/lib64/python2.7/site-packages/sqlalchemy/orm/session.py", line 370, in commit
    self._prepare_impl()
  File "/usr/lib64/python2.7/site-packages/sqlalchemy/orm/session.py", line 350, in _prepare_impl
    self.session.flush()
  File "heat/openstack/common/db/sqlalchemy/session.py", line 461, in _wrap
    raise exception.DBError(e)
DBError: UPDATE statement on table 'stack' expected to update 1 row(s); 0 were matched.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/100254

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/100254
Committed: https://git.openstack.org/cgit/openstack/heat/commit/?id=f1b55d0a95b67f3b1083084e8fe7f728109da960
Submitter: Jenkins
Branch: master

commit f1b55d0a95b67f3b1083084e8fe7f728109da960
Author: Thomas Herve <email address hidden>
Date: Mon Jun 16 15:53:50 2014 +0200

    Remove usages of threads in DummyThreadGroup

    The patch removes creation of threads in the DummyThreadGroup class
    during tests, returning a fake thread object instead. It removes some
    race condition triggering tracebacks during tests.

    Closes-Bug: #1330292
    Change-Id: I3214816a4173670d22385dbe67cc016d74c2ce18