random sqlite related failure during unit testing

Example:

vmware_nsx.tests.unit.services.qos.test_nsxv3_notification.TestQosNsxV3Notification.test_policy_delete_profile
--------------------------------------------------------------------------------------------------------------

Captured traceback-1:
~~~~~~~~~~~~~~~~~~~~~
    Traceback (most recent call last):
      File "/usr/lib/python2.7/dist-packages/fixtures/fixture.py", line 125, in cleanUp
        return self._cleanups(raise_errors=raise_first)
      File "/usr/lib/python2.7/dist-packages/fixtures/callmany.py", line 89, in __call__
        reraise(error[0], error[1], error[2])
      File "/usr/lib/python2.7/dist-packages/fixtures/callmany.py", line 83, in __call__
        cleanup(*args, **kwargs)
      File "/usr/lib/python2.7/dist-packages/neutron/tests/unit/testlib_api.py", line 98, in <lambda>
        self.addCleanup(lambda: self._delete_from_schema(engine))
      File "/usr/lib/python2.7/dist-packages/neutron/tests/unit/testlib_api.py", line 83, in _delete_from_schema
        conn.execute(table.delete())
      File "/usr/lib/python2.7/dist-packages/sqlalchemy/engine/base.py", line 914, in execute
        return meth(self, multiparams, params)
      File "/usr/lib/python2.7/dist-packages/sqlalchemy/sql/elements.py", line 323, in _execute_on_connection
        return connection._execute_clauseelement(self, multiparams, params)
      File "/usr/lib/python2.7/dist-packages/sqlalchemy/engine/base.py", line 1010, in _execute_clauseelement
        compiled_sql, distilled_params
      File "/usr/lib/python2.7/dist-packages/sqlalchemy/engine/base.py", line 1146, in _execute_context
        context)
      File "/usr/lib/python2.7/dist-packages/sqlalchemy/engine/base.py", line 1337, in _handle_dbapi_exception
        util.raise_from_cause(newraise, exc_info)
      File "/usr/lib/python2.7/dist-packages/sqlalchemy/util/compat.py", line 203, in raise_from_cause
        reraise(type(exception), exception, tb=exc_tb, cause=cause)
      File "/usr/lib/python2.7/dist-packages/sqlalchemy/engine/base.py", line 1139, in _execute_context
        context)
      File "/usr/lib/python2.7/dist-packages/sqlalchemy/engine/default.py", line 450, in do_execute
        cursor.execute(statement, parameters)
    oslo_db.exception.DBNonExistentTable: (sqlite3.OperationalError) no such table: nsxv_lbaas_l7policy_bindings [SQL: u'DELETE FROM nsxv_lbaas_l7policy_bindings']

Captured traceback:
~~~~~~~~~~~~~~~~~~~
    Traceback (most recent call last):
      File "vmware_nsx/tests/unit/services/qos/test_nsxv3_notification.py", line 44, in setUp
        super(TestQosNsxV3Notification, self).setUp()
      File "/usr/lib/python2.7/dist-packages/neutron/tests/unit/services/qos/base.py", line 23, in setUp
        super(BaseQosTestCase, self).setUp()
      File "vmware_nsx/tests/unit/nsx_v3/test_plugin.py", line 170, in setUp
        ext_mgr=ext_mgr)
      File "/usr/lib/python2.7/dist-packages/neutron/tests/unit/db/test_db_base_plugin_v2.py", line 132, in setUp
        self.api = router.APIRouter()
      File "/usr/lib/python2.7/dist-packages/neutron/api/v2/router.py", line 77, in __init__
        manager.init()
      File "/usr/lib/python2.7/dist-packages/neutron/manager.py", line 291, in init
        NeutronManager.get_instance()
      File "/usr/lib/python2.7/dist-packages/neutron/manager.py", line 241, in get_instance
        cls._create_instance()
      File "/usr/lib/python2.7/dist-packages/oslo_concurrency/lockutils.py", line 274, in inner
        return f(*args, **kwargs)
      File "/usr/lib/python2.7/dist-packages/neutron/manager.py", line 227, in _create_instance
        cls._instance = cls()
      File "/usr/lib/python2.7/dist-packages/neutron/manager.py", line 131, in __init__
        plugin_provider)
      File "/usr/lib/python2.7/dist-packages/neutron/manager.py", line 164, in _get_plugin_instance
        return plugin_class()
      File "/usr/lib/python2.7/dist-packages/neutron/quota/resource_registry.py", line 127, in wrapper
        return f(*args, **kwargs)
      File "vmware_nsx/plugins/nsx_v3/plugin.py", line 205, in __init__
        self._process_security_group_logging()
      File "vmware_nsx/plugins/nsx_v3/plugin.py", line 479, in _process_security_group_logging
        utils.spawn_n(process_security_group_logging)
      File "/usr/lib/python2.7/dist-packages/mock/mock.py", line 1062, in __call__
        return _mock_self._mock_call(*args, **kwargs)
      File "/usr/lib/python2.7/dist-packages/mock/mock.py", line 1128, in _mock_call
        ret_val = effect(*args, **kwargs)
      File "vmware_nsx/tests/unit/nsx_v/test_plugin.py", line 3298, in <lambda>
        c_utils.spawn_n = mock.Mock(side_effect=lambda f: f())
      File "vmware_nsx/plugins/nsx_v3/plugin.py", line 466, in process_security_group_logging
        sg_logging.LOGGING])
      File "vmware_nsx/plugins/nsx_v3/plugin.py", line 3171, in get_security_groups
        default_sg=default_sg)
      File "/usr/lib/python2.7/dist-packages/neutron/db/api.py", line 166, in wrapped
        return method(*args, **kwargs)
      File "/usr/lib/python2.7/dist-packages/neutron/db/api.py", line 95, in wrapped
        setattr(e, '_RETRY_EXCEEDED', True)
      File "/usr/lib/python2.7/dist-packages/oslo_utils/excutils.py", line 220, in __exit__
        self.force_reraise()
      File "/usr/lib/python2.7/dist-packages/oslo_utils/excutils.py", line 196, in force_reraise
        six.reraise(self.type_, self.value, self.tb)
      File "/usr/lib/python2.7/dist-packages/neutron/db/api.py", line 91, in wrapped
        return f(*args, **kwargs)
      File "/usr/lib/python2.7/dist-packages/oslo_db/api.py", line 151, in wrapper
        ectxt.value = e.inner_exc
      File "/usr/lib/python2.7/dist-packages/oslo_utils/excutils.py", line 220, in __exit__
        self.force_reraise()
      File "/usr/lib/python2.7/dist-packages/oslo_utils/excutils.py", line 196, in force_reraise
        six.reraise(self.type_, self.value, self.tb)
      File "/usr/lib/python2.7/dist-packages/oslo_db/api.py", line 139, in wrapper
        return f(*args, **kwargs)
      File "/usr/lib/python2.7/dist-packages/neutron/db/api.py", line 131, in wrapped
        traceback.format_exc())
      File "/usr/lib/python2.7/dist-packages/oslo_utils/excutils.py", line 220, in __exit__
        self.force_reraise()
      File "/usr/lib/python2.7/dist-packages/oslo_utils/excutils.py", line 196, in force_reraise
        six.reraise(self.type_, self.value, self.tb)
      File "/usr/lib/python2.7/dist-packages/neutron/db/api.py", line 126, in wrapped
        return f(*dup_args, **dup_kwargs)
      File "/usr/lib/python2.7/dist-packages/neutron/db/securitygroups_db.py", line 157, in get_security_groups
        page_reverse=page_reverse)
      File "/usr/lib/python2.7/dist-packages/neutron/db/common_db_mixin.py", line 276, in _get_collection
        for c in query]
      File "/usr/lib/python2.7/dist-packages/sqlalchemy/orm/query.py", line 2761, in __iter__
        return self._execute_and_instances(context)
      File "/usr/lib/python2.7/dist-packages/sqlalchemy/orm/query.py", line 2776, in _execute_and_instances
        result = conn.execute(querycontext.statement, self._params)
      File "/usr/lib/python2.7/dist-packages/sqlalchemy/engine/base.py", line 914, in execute
        return meth(self, multiparams, params)
      File "/usr/lib/python2.7/dist-packages/sqlalchemy/sql/elements.py", line 323, in _execute_on_connection
        return connection._execute_clauseelement(self, multiparams, params)
      File "/usr/lib/python2.7/dist-packages/sqlalchemy/engine/base.py", line 1010, in _execute_clauseelement
        compiled_sql, distilled_params
      File "/usr/lib/python2.7/dist-packages/sqlalchemy/engine/base.py", line 1146, in _execute_context
        context)
      File "/usr/lib/python2.7/dist-packages/sqlalchemy/engine/base.py", line 1337, in _handle_dbapi_exception
        util.raise_from_cause(newraise, exc_info)
      File "/usr/lib/python2.7/dist-packages/sqlalchemy/util/compat.py", line 203, in raise_from_cause
        reraise(type(exception), exception, tb=exc_tb, cause=cause)
      File "/usr/lib/python2.7/dist-packages/sqlalchemy/engine/base.py", line 1139, in _execute_context
        context)
      File "/usr/lib/python2.7/dist-packages/sqlalchemy/engine/default.py", line 450, in do_execute
        cursor.execute(statement, parameters)
    oslo_db.exception.DBNonExistentTable: (sqlite3.OperationalError) no such table: securitygroups [SQL: u'SELECT securitygroups.project_id AS securitygroups_project_id, securitygroups.id AS securitygroups_id, securitygroups.name AS securitygroups_name, securitygroups.standard_attr_id AS securitygroups_standard_attr_id, standardattributes_1.id AS standardattributes_1_id, standardattributes_1.resource_type AS standardattributes_1_resource_type, standardattributes_1.description AS standardattributes_1_description, standardattributes_1.revision_number AS standardattributes_1_revision_number, standardattributes_1.created_at AS standardattributes_1_created_at, standardattributes_1.updated_at AS standardattributes_1_updated_at, nsx_extended_security_group_properties_1.security_group_id AS nsx_extended_security_group_properties_1_security_group_id, nsx_extended_security_group_properties_1.logging AS nsx_extended_security_group_properties_1_logging, nsx_extended_security_group_properties_1.provider AS nsx_extended_security_group_properties_1_provider, nsx_extended_security_group_properties_1.policy AS nsx_extended_security_group_properties_1_policy \nFROM securitygroups LEFT OUTER JOIN standardattributes AS standardattributes_1 ON standardattributes_1.id = securitygroups.standard_attr_id LEFT OUTER JOIN nsx_extended_security_group_properties AS nsx_extended_security_group_properties_1 ON securitygroups.id = nsx_extended_security_group_properties_1.security_group_id']