Skip tests when service barbican is enabled

We shouldn't run this tests when service Barbican enabled
because of they doesn't support Image Signature Verification.

This scenarios verifying in Barbican Tempest Plugin.

list of skipped tests:
tempest.scenario.test_snapshot_pattern.TestSnapshotPattern.test_snapshot_pattern
tempest.scenario.test_encrypted_cinder_volumes.TestEncryptedCinderVolumes.test_encrypted_cinder_volumes_luks
tempest.scenario.test_encrypted_cinder_volumes.TestEncryptedCinderVolumes.test_encrypted_cinder_volumes_cryptsetup
tempest.scenario.test_minimum_basic.TestMinimumBasicScenario.test_minimum_basic_scenario

Change-Id: I1450d3c0921840829f3a1abf6840a7aa6e5b429f
Related-prod: PROD-22487
diff --git a/tempest/scenario/test_encrypted_cinder_volumes.py b/tempest/scenario/test_encrypted_cinder_volumes.py
index b5220e9..c201c90 100644
--- a/tempest/scenario/test_encrypted_cinder_volumes.py
+++ b/tempest/scenario/test_encrypted_cinder_volumes.py
@@ -13,6 +13,8 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
+import testtools
+
 from tempest.common import utils
 from tempest import config
 from tempest.lib import decorators
@@ -54,6 +56,8 @@
 
     @decorators.idempotent_id('79165fb4-5534-4b9d-8429-97ccffb8f86e')
     @decorators.attr(type='slow')
+    @testtools.skipIf(getattr(CONF.service_available, 'barbican', True),
+                      '"Image Signature Verification enabled")')
     @utils.services('compute', 'volume', 'image')
     def test_encrypted_cinder_volumes_luks(self):
         server = self.launch_instance()
@@ -64,6 +68,8 @@
 
     @decorators.idempotent_id('cbc752ed-b716-4717-910f-956cce965722')
     @decorators.attr(type='slow')
+    @testtools.skipIf(getattr(CONF.service_available, 'barbican', True),
+                      '"Image Signature Verification enabled")')
     @utils.services('compute', 'volume', 'image')
     def test_encrypted_cinder_volumes_cryptsetup(self):
         server = self.launch_instance()
diff --git a/tempest/scenario/test_minimum_basic.py b/tempest/scenario/test_minimum_basic.py
index 29f1743..b69cc07 100644
--- a/tempest/scenario/test_minimum_basic.py
+++ b/tempest/scenario/test_minimum_basic.py
@@ -105,6 +105,8 @@
                           'The public_network_id option must be specified.')
     @testtools.skipUnless(CONF.network_feature_enabled.floating_ips,
                           'Floating ips are not available')
+    @testtools.skipIf(getattr(CONF.service_available, 'barbican', True),
+                      '"Image Signature Verification enabled")')
     @utils.services('compute', 'volume', 'image', 'network')
     def test_minimum_basic_scenario(self):
         image = self.glance_image_create()
diff --git a/tempest/scenario/test_snapshot_pattern.py b/tempest/scenario/test_snapshot_pattern.py
index b51a781..b29433c 100644
--- a/tempest/scenario/test_snapshot_pattern.py
+++ b/tempest/scenario/test_snapshot_pattern.py
@@ -44,6 +44,8 @@
     @decorators.attr(type='slow')
     @testtools.skipUnless(CONF.network.public_network_id,
                           'The public_network_id option must be specified.')
+    @testtools.skipIf(getattr(CONF.service_available, 'barbican', True),
+                      '"Image Signature Verification enabled")')
     @utils.services('compute', 'network', 'image')
     def test_snapshot_pattern(self):
         # prepare for booting an instance