Skip tests if glance is not available

There are some tests requiring glance service. If glance service
is not available, we want to skip those tests instead of failing
them. The following are the affected tests:
* test_commit_container
* test_run_container_with_image_driver_glance

Change-Id: Iee1f53c905863eb842535090a2bb67c3babf9b05

zun_tempest_plugin/tests/tempest/api/test_containers.py

@@ -19,6 +19,7 @@ import types
 from oslo_serialization import jsonutils as json
 from oslo_utils import encodeutils
 import six
+from tempest import config
 from tempest.lib.common.utils import data_utils
 from tempest.lib import decorators
 from tempest.lib import exceptions as lib_exc
@@ -29,6 +30,9 @@ from zun_tempest_plugin.tests.tempest import base
 from zun_tempest_plugin.tests.tempest import utils
 
 
+CONF = config.CONF
+
+
 class TestContainer(base.BaseZunTest):
 
     credentials = ['primary', 'admin']
@@ -122,6 +126,9 @@ class TestContainer(base.BaseZunTest):
 
     @decorators.idempotent_id('c32f93e3-da88-4c13-be38-25d2e662a28e')
     def test_run_container_with_image_driver_glance(self):
+        if not CONF.service_available.glance:
+            raise self.skipException("This test requires glance service")
+
         docker_base_url = self._get_docker_url()
         self.docker_client.pull_image(
             'cirros', docker_auth_url=docker_base_url)
@@ -522,6 +529,9 @@ class TestContainer(base.BaseZunTest):
         4. Create another container from the snapshot image
         5. Verify the pre-created file is there
         """
+        if not CONF.service_available.glance:
+            raise self.skipException("This test requires glance service")
+
         # This command creates a file inside the container
         command = ["/bin/sh", "-c", "echo hello > testfile;sleep 1000000"]
         _, model = self._run_container(command=command)