decouple test events from its base class

test event needs only vitrage client and not
all the clients that are created in the base class
this creates problems when running tempest not in
a devstack enviroment for example when trying
to run puppet-openstack-integration

Change-Id: If0e0e1d132463a29d62e1979591484e616ca06d6

vitrage_tempest_tests/tests/api/event/test_events.py

@@ -15,22 +15,26 @@
 
 from datetime import datetime
 from oslo_log import log as logging
+from oslotest import base
 
 from vitrage.common.constants import DatasourceProperties as DSProps
 from vitrage.common.constants import EntityCategory
 from vitrage.common.constants import EventProperties as EventProps
 from vitrage.common.constants import VertexProperties as VProps
-from vitrage_tempest_tests.tests.api.base import BaseApiTest
+from vitrage import keystone_client
+from vitrageclient import client as v_client
 
 LOG = logging.getLogger(__name__)
 
 
-class TestEvents(BaseApiTest):
+class TestEvents(base.BaseTestCase):
     """Test class for Vitrage event API"""
 
+    # noinspection PyPep8Naming
     @classmethod
     def setUpClass(cls):
-        super(TestEvents, cls).setUpClass()
+        cls.vitrage_client = \
+            v_client.Client('1', session=keystone_client.get_session(cls.conf))
 
     def test_send_doctor_event(self):
         """Sending an event in Doctor format should result in an alarm"""