unit tests fail under code coverage

12 unit tests fail when run with code coverage enabled. All of them located in 'test_debug_commands.py'. The stack trace is common:
ERROR: test_ping_all_with_ensure_port (test_debug_commands.TestDebugCommands)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/ishakhat/Work/quantum/.venv/local/lib/python2.7/site-packages/nose/case.py", line 133, in run
    self.runTest(result)
  File "/home/ishakhat/Work/quantum/.venv/local/lib/python2.7/site-packages/nose/case.py", line 151, in runTest
    test(result)
  File "/home/ishakhat/Work/quantum/.venv/local/lib/python2.7/site-packages/unittest2/case.py", line 398, in __call__
    return self.run(*args, **kwds)
  File "/home/ishakhat/Work/quantum/.venv/local/lib/python2.7/site-packages/unittest2/case.py", line 333, in run
    self.setUp()
  File "/home/ishakhat/Work/quantum/quantum/tests/unit/test_debug_commands.py", line 44, in setUp
    cfg.CONF(args=sys.argv, project='quantum')
  File "/home/ishakhat/Work/quantum/quantum/openstack/common/cfg.py", line 1024, in __call__
    self._cli_values, leftovers = self._parse_cli_opts(args)
  File "/home/ishakhat/Work/quantum/quantum/openstack/common/cfg.py", line 1529, in _parse_cli_opts
    values, leftovers = self._oparser.parse_args(args)
  File "/usr/lib/python2.7/optparse.py", line 1401, in parse_args
    self.error(str(err))
  File "/usr/lib/python2.7/optparse.py", line 1583, in error
    self.exit(2, "%s: error: %s\n" % (self.get_prog_name(), msg))
  File "/usr/lib/python2.7/optparse.py", line 1573, in exit
    sys.exit(status)
SystemExit: 2

The issue is in the line 44 of test_debug_commands:
  cfg.CONF(args=sys.argv, project='quantum')
When run with coverage there's an additional cli parameter '--with-coverage' that causes optparse to fall with error.

The possible fix is to add parameter specification:
@@ -40,6 +41,7 @@ class TestDebugCommands(unittest.TestCase):
     def setUp(self):
         cfg.CONF.register_opts(interface.OPTS)
         cfg.CONF.register_opts(QuantumDebugAgent.OPTS)
+ cfg.CONF.register_opt(cfg.StrOpt("with-coverage"))
         cfg.CONF(args=sys.argv, project='quantum')
         cfg.CONF.set_override('use_namespaces', True)
         cfg.CONF.root_helper = 'sudo'