Cleanup _interface class variables in compute/v3

We've already removed xml interface from Nova V3 APIs. So we can assume
the default is json. This commit sets _interface = 'json' to
BaseV3ComputeTest class and removes redundancy.

Change-Id: Ie9ad2242d20ce90fca74ca7a5390e0971f830caa
diff --git a/tempest/api/compute/base.py b/tempest/api/compute/base.py
index 72bb723..9162926 100644
--- a/tempest/api/compute/base.py
+++ b/tempest/api/compute/base.py
@@ -303,6 +303,8 @@
 
 class BaseV3ComputeTest(BaseComputeTest):
 
+    _interface = "json"
+
     @classmethod
     def setUpClass(cls):
         # By default compute tests do not create network resources
diff --git a/tempest/api/compute/v3/admin/test_aggregates.py b/tempest/api/compute/v3/admin/test_aggregates.py
index 20093e4..a00a5b5 100644
--- a/tempest/api/compute/v3/admin/test_aggregates.py
+++ b/tempest/api/compute/v3/admin/test_aggregates.py
@@ -26,7 +26,6 @@
     """
 
     _host_key = 'os-extended-server-attributes:host'
-    _interface = 'json'
 
     @classmethod
     def setUpClass(cls):
diff --git a/tempest/api/compute/v3/admin/test_aggregates_negative.py b/tempest/api/compute/v3/admin/test_aggregates_negative.py
index 5700460..1505f74 100644
--- a/tempest/api/compute/v3/admin/test_aggregates_negative.py
+++ b/tempest/api/compute/v3/admin/test_aggregates_negative.py
@@ -26,8 +26,6 @@
     Tests Aggregates API that require admin privileges
     """
 
-    _interface = 'json'
-
     @classmethod
     def setUpClass(cls):
         super(AggregatesAdminNegativeV3Test, cls).setUpClass()
diff --git a/tempest/api/compute/v3/admin/test_availability_zone.py b/tempest/api/compute/v3/admin/test_availability_zone.py
index 176751f..9ca8953 100644
--- a/tempest/api/compute/v3/admin/test_availability_zone.py
+++ b/tempest/api/compute/v3/admin/test_availability_zone.py
@@ -23,8 +23,6 @@
     Tests Availability Zone API List
     """
 
-    _interface = 'json'
-
     @classmethod
     def setUpClass(cls):
         super(AZAdminV3Test, cls).setUpClass()
diff --git a/tempest/api/compute/v3/admin/test_availability_zone_negative.py b/tempest/api/compute/v3/admin/test_availability_zone_negative.py
index 180f298..f3af6df 100644
--- a/tempest/api/compute/v3/admin/test_availability_zone_negative.py
+++ b/tempest/api/compute/v3/admin/test_availability_zone_negative.py
@@ -24,8 +24,6 @@
     Tests Availability Zone API List
     """
 
-    _interface = 'json'
-
     @classmethod
     def setUpClass(cls):
         super(AZAdminNegativeV3Test, cls).setUpClass()
diff --git a/tempest/api/compute/v3/admin/test_flavors.py b/tempest/api/compute/v3/admin/test_flavors.py
index 597c99b..401eb85 100644
--- a/tempest/api/compute/v3/admin/test_flavors.py
+++ b/tempest/api/compute/v3/admin/test_flavors.py
@@ -27,8 +27,6 @@
     Tests Flavors API Create and Delete that require admin privileges
     """
 
-    _interface = 'json'
-
     @classmethod
     def setUpClass(cls):
         super(FlavorsAdminV3Test, cls).setUpClass()
diff --git a/tempest/api/compute/v3/admin/test_flavors_access.py b/tempest/api/compute/v3/admin/test_flavors_access.py
index 43dc726..03305ff 100644
--- a/tempest/api/compute/v3/admin/test_flavors_access.py
+++ b/tempest/api/compute/v3/admin/test_flavors_access.py
@@ -25,8 +25,6 @@
     Add and remove Flavor Access require admin privileges.
     """
 
-    _interface = 'json'
-
     @classmethod
     def setUpClass(cls):
         super(FlavorsAccessV3Test, cls).setUpClass()
diff --git a/tempest/api/compute/v3/admin/test_flavors_access_negative.py b/tempest/api/compute/v3/admin/test_flavors_access_negative.py
index 6a2e826..334d124 100644
--- a/tempest/api/compute/v3/admin/test_flavors_access_negative.py
+++ b/tempest/api/compute/v3/admin/test_flavors_access_negative.py
@@ -28,8 +28,6 @@
     Add and remove Flavor Access require admin privileges.
     """
 
-    _interface = 'json'
-
     @classmethod
     def setUpClass(cls):
         super(FlavorsAccessNegativeV3Test, cls).setUpClass()
diff --git a/tempest/api/compute/v3/admin/test_flavors_extra_specs.py b/tempest/api/compute/v3/admin/test_flavors_extra_specs.py
index 4d22027..29cd8db 100644
--- a/tempest/api/compute/v3/admin/test_flavors_extra_specs.py
+++ b/tempest/api/compute/v3/admin/test_flavors_extra_specs.py
@@ -26,8 +26,6 @@
     GET Flavor Extra specs can be performed even by without admin privileges.
     """
 
-    _interface = 'json'
-
     @classmethod
     def setUpClass(cls):
         super(FlavorsExtraSpecsV3Test, cls).setUpClass()
diff --git a/tempest/api/compute/v3/admin/test_flavors_extra_specs_negative.py b/tempest/api/compute/v3/admin/test_flavors_extra_specs_negative.py
index 98e6e3d..e9c04a3 100644
--- a/tempest/api/compute/v3/admin/test_flavors_extra_specs_negative.py
+++ b/tempest/api/compute/v3/admin/test_flavors_extra_specs_negative.py
@@ -27,8 +27,6 @@
     SET, UNSET, UPDATE Flavor Extra specs require admin privileges.
     """
 
-    _interface = 'json'
-
     @classmethod
     def setUpClass(cls):
         super(FlavorsExtraSpecsNegativeV3Test, cls).setUpClass()
diff --git a/tempest/api/compute/v3/admin/test_flavors_negative.py b/tempest/api/compute/v3/admin/test_flavors_negative.py
index f54de79..3f8a2da 100644
--- a/tempest/api/compute/v3/admin/test_flavors_negative.py
+++ b/tempest/api/compute/v3/admin/test_flavors_negative.py
@@ -27,8 +27,6 @@
     Tests Flavors API Create and Delete that require admin privileges
     """
 
-    _interface = 'json'
-
     @classmethod
     def setUpClass(cls):
         super(FlavorsAdminNegativeV3Test, cls).setUpClass()
diff --git a/tempest/api/compute/v3/admin/test_hosts.py b/tempest/api/compute/v3/admin/test_hosts.py
index 2c9369f..8cb1f23 100644
--- a/tempest/api/compute/v3/admin/test_hosts.py
+++ b/tempest/api/compute/v3/admin/test_hosts.py
@@ -23,8 +23,6 @@
     Tests hosts API using admin privileges.
     """
 
-    _interface = 'json'
-
     @classmethod
     def setUpClass(cls):
         super(HostsAdminV3Test, cls).setUpClass()
diff --git a/tempest/api/compute/v3/admin/test_hosts_negative.py b/tempest/api/compute/v3/admin/test_hosts_negative.py
index ac5d7de..79cd97f 100644
--- a/tempest/api/compute/v3/admin/test_hosts_negative.py
+++ b/tempest/api/compute/v3/admin/test_hosts_negative.py
@@ -24,8 +24,6 @@
     Tests hosts API using admin privileges.
     """
 
-    _interface = 'json'
-
     @classmethod
     def setUpClass(cls):
         super(HostsAdminNegativeV3Test, cls).setUpClass()
diff --git a/tempest/api/compute/v3/admin/test_hypervisor.py b/tempest/api/compute/v3/admin/test_hypervisor.py
index 0f96bba..93d4441 100644
--- a/tempest/api/compute/v3/admin/test_hypervisor.py
+++ b/tempest/api/compute/v3/admin/test_hypervisor.py
@@ -23,8 +23,6 @@
     Tests Hypervisors API that require admin privileges
     """
 
-    _interface = 'json'
-
     @classmethod
     def setUpClass(cls):
         super(HypervisorAdminV3Test, cls).setUpClass()
diff --git a/tempest/api/compute/v3/admin/test_hypervisor_negative.py b/tempest/api/compute/v3/admin/test_hypervisor_negative.py
index aee354a..45642b7 100644
--- a/tempest/api/compute/v3/admin/test_hypervisor_negative.py
+++ b/tempest/api/compute/v3/admin/test_hypervisor_negative.py
@@ -27,8 +27,6 @@
     Tests Hypervisors API that require admin privileges
     """
 
-    _interface = 'json'
-
     @classmethod
     def setUpClass(cls):
         super(HypervisorAdminNegativeV3Test, cls).setUpClass()
diff --git a/tempest/api/compute/v3/admin/test_quotas.py b/tempest/api/compute/v3/admin/test_quotas.py
index b388b70..0c138bb 100644
--- a/tempest/api/compute/v3/admin/test_quotas.py
+++ b/tempest/api/compute/v3/admin/test_quotas.py
@@ -22,7 +22,6 @@
 
 
 class QuotasAdminV3Test(base.BaseV3ComputeAdminTest):
-    _interface = 'json'
     force_tenant_isolation = True
 
     @classmethod
diff --git a/tempest/api/compute/v3/admin/test_servers.py b/tempest/api/compute/v3/admin/test_servers.py
index 0dc3dbc..7787770 100644
--- a/tempest/api/compute/v3/admin/test_servers.py
+++ b/tempest/api/compute/v3/admin/test_servers.py
@@ -25,7 +25,6 @@
     """
 
     _host_key = 'os-extended-server-attributes:host'
-    _interface = 'json'
 
     @classmethod
     def setUpClass(cls):
diff --git a/tempest/api/compute/v3/admin/test_servers_negative.py b/tempest/api/compute/v3/admin/test_servers_negative.py
index a6a5736..cc1be4e 100644
--- a/tempest/api/compute/v3/admin/test_servers_negative.py
+++ b/tempest/api/compute/v3/admin/test_servers_negative.py
@@ -26,8 +26,6 @@
     Tests Servers API using admin privileges
     """
 
-    _interface = 'json'
-
     @classmethod
     def setUpClass(cls):
         super(ServersAdminNegativeV3Test, cls).setUpClass()
diff --git a/tempest/api/compute/v3/admin/test_services.py b/tempest/api/compute/v3/admin/test_services.py
index 8d6e549..914a2a4 100644
--- a/tempest/api/compute/v3/admin/test_services.py
+++ b/tempest/api/compute/v3/admin/test_services.py
@@ -24,8 +24,6 @@
     Tests Services API. List and Enable/Disable require admin privileges.
     """
 
-    _interface = 'json'
-
     @classmethod
     def setUpClass(cls):
         super(ServicesAdminV3Test, cls).setUpClass()
diff --git a/tempest/api/compute/v3/admin/test_services_negative.py b/tempest/api/compute/v3/admin/test_services_negative.py
index c270842..3168af2 100644
--- a/tempest/api/compute/v3/admin/test_services_negative.py
+++ b/tempest/api/compute/v3/admin/test_services_negative.py
@@ -25,8 +25,6 @@
     Tests Services API. List and Enable/Disable require admin privileges.
     """
 
-    _interface = 'json'
-
     @classmethod
     def setUpClass(cls):
         super(ServicesAdminNegativeV3Test, cls).setUpClass()
diff --git a/tempest/api/compute/v3/certificates/test_certificates.py b/tempest/api/compute/v3/certificates/test_certificates.py
index 5c980c0..ce025fc 100644
--- a/tempest/api/compute/v3/certificates/test_certificates.py
+++ b/tempest/api/compute/v3/certificates/test_certificates.py
@@ -18,7 +18,6 @@
 
 
 class CertificatesV3Test(base.BaseV3ComputeTest):
-    _interface = 'json'
 
     @attr(type='gate')
     def test_create_and_get_root_certificate(self):
diff --git a/tempest/api/compute/v3/flavors/test_flavors.py b/tempest/api/compute/v3/flavors/test_flavors.py
index 812358f..a0bbba6 100644
--- a/tempest/api/compute/v3/flavors/test_flavors.py
+++ b/tempest/api/compute/v3/flavors/test_flavors.py
@@ -18,7 +18,6 @@
 
 
 class FlavorsV3Test(base.BaseV3ComputeTest):
-    _interface = 'json'
 
     @classmethod
     def setUpClass(cls):
diff --git a/tempest/api/compute/v3/flavors/test_flavors_negative.py b/tempest/api/compute/v3/flavors/test_flavors_negative.py
index 3d4100a..346f6d6 100644
--- a/tempest/api/compute/v3/flavors/test_flavors_negative.py
+++ b/tempest/api/compute/v3/flavors/test_flavors_negative.py
@@ -24,7 +24,6 @@
 
 class FlavorsListNegativeV3Test(base.BaseV3ComputeTest,
                                 test.NegativeAutoTest):
-    _interface = 'json'
     _service = 'computev3'
     _schema_file = 'compute/flavors/flavors_list_v3.json'
 
@@ -37,7 +36,6 @@
 
 class FlavorDetailsNegativeV3Test(base.BaseV3ComputeTest,
                                   test.NegativeAutoTest):
-    _interface = 'json'
     _service = 'computev3'
     _schema_file = 'compute/flavors/flavor_details_v3.json'
 
diff --git a/tempest/api/compute/v3/images/test_images.py b/tempest/api/compute/v3/images/test_images.py
index b045630..656f7ba 100644
--- a/tempest/api/compute/v3/images/test_images.py
+++ b/tempest/api/compute/v3/images/test_images.py
@@ -22,7 +22,6 @@
 
 
 class ImagesV3Test(base.BaseV3ComputeTest):
-    _interface = 'json'
 
     @classmethod
     def setUpClass(cls):
diff --git a/tempest/api/compute/v3/images/test_images_oneserver.py b/tempest/api/compute/v3/images/test_images_oneserver.py
index 1ded4e4..48a885e 100644
--- a/tempest/api/compute/v3/images/test_images_oneserver.py
+++ b/tempest/api/compute/v3/images/test_images_oneserver.py
@@ -26,7 +26,6 @@
 
 
 class ImagesOneServerV3Test(base.BaseV3ComputeTest):
-    _interface = 'json'
 
     def setUp(self):
         # NOTE(afazekas): Normally we use the same server with all test cases,
diff --git a/tempest/api/compute/v3/images/test_images_oneserver_negative.py b/tempest/api/compute/v3/images/test_images_oneserver_negative.py
index 8d2517e..7679eee 100644
--- a/tempest/api/compute/v3/images/test_images_oneserver_negative.py
+++ b/tempest/api/compute/v3/images/test_images_oneserver_negative.py
@@ -27,7 +27,6 @@
 
 
 class ImagesOneServerNegativeV3Test(base.BaseV3ComputeTest):
-    _interface = 'json'
 
     def tearDown(self):
         """Terminate test instances created after a test is executed."""
diff --git a/tempest/api/compute/v3/keypairs/test_keypairs.py b/tempest/api/compute/v3/keypairs/test_keypairs.py
index 8eef811..668a295 100644
--- a/tempest/api/compute/v3/keypairs/test_keypairs.py
+++ b/tempest/api/compute/v3/keypairs/test_keypairs.py
@@ -19,7 +19,6 @@
 
 
 class KeyPairsV3Test(base.BaseV3ComputeTest):
-    _interface = 'json'
 
     @classmethod
     def setUpClass(cls):
diff --git a/tempest/api/compute/v3/keypairs/test_keypairs_negative.py b/tempest/api/compute/v3/keypairs/test_keypairs_negative.py
index ae22ccc..e426b85 100644
--- a/tempest/api/compute/v3/keypairs/test_keypairs_negative.py
+++ b/tempest/api/compute/v3/keypairs/test_keypairs_negative.py
@@ -21,7 +21,6 @@
 
 
 class KeyPairsNegativeV3Test(base.BaseV3ComputeTest):
-    _interface = 'json'
 
     @classmethod
     def setUpClass(cls):
diff --git a/tempest/api/compute/v3/servers/test_attach_interfaces.py b/tempest/api/compute/v3/servers/test_attach_interfaces.py
index 272cb53..a3046c7 100644
--- a/tempest/api/compute/v3/servers/test_attach_interfaces.py
+++ b/tempest/api/compute/v3/servers/test_attach_interfaces.py
@@ -24,7 +24,6 @@
 
 
 class AttachInterfacesV3Test(base.BaseV3ComputeTest):
-    _interface = 'json'
 
     @classmethod
     def setUpClass(cls):
diff --git a/tempest/api/compute/v3/servers/test_attach_volume.py b/tempest/api/compute/v3/servers/test_attach_volume.py
index 2edf934..8577aab 100644
--- a/tempest/api/compute/v3/servers/test_attach_volume.py
+++ b/tempest/api/compute/v3/servers/test_attach_volume.py
@@ -24,7 +24,6 @@
 
 
 class AttachVolumeV3Test(base.BaseV3ComputeTest):
-    _interface = 'json'
     run_ssh = CONF.compute.run_ssh
 
     def __init__(self, *args, **kwargs):
diff --git a/tempest/api/compute/v3/servers/test_create_server.py b/tempest/api/compute/v3/servers/test_create_server.py
index 0825381..a212ca5 100644
--- a/tempest/api/compute/v3/servers/test_create_server.py
+++ b/tempest/api/compute/v3/servers/test_create_server.py
@@ -28,7 +28,6 @@
 
 
 class ServersV3Test(base.BaseV3ComputeTest):
-    _interface = 'json'
     run_ssh = CONF.compute.run_ssh
     disk_config = 'AUTO'
 
@@ -119,7 +118,6 @@
 
 
 class ServersWithSpecificFlavorV3Test(base.BaseV3ComputeAdminTest):
-    _interface = 'json'
     run_ssh = CONF.compute.run_ssh
     disk_config = 'AUTO'
 
diff --git a/tempest/api/compute/v3/servers/test_instance_actions.py b/tempest/api/compute/v3/servers/test_instance_actions.py
index 5a8465c..7d25100 100644
--- a/tempest/api/compute/v3/servers/test_instance_actions.py
+++ b/tempest/api/compute/v3/servers/test_instance_actions.py
@@ -18,7 +18,6 @@
 
 
 class InstanceActionsV3Test(base.BaseV3ComputeTest):
-    _interface = 'json'
 
     @classmethod
     def setUpClass(cls):
diff --git a/tempest/api/compute/v3/servers/test_list_server_filters.py b/tempest/api/compute/v3/servers/test_list_server_filters.py
index e08125b..ec31e8e 100644
--- a/tempest/api/compute/v3/servers/test_list_server_filters.py
+++ b/tempest/api/compute/v3/servers/test_list_server_filters.py
@@ -24,7 +24,6 @@
 
 
 class ListServerFiltersV3Test(base.BaseV3ComputeTest):
-    _interface = 'json'
 
     @classmethod
     def setUpClass(cls):
diff --git a/tempest/api/compute/v3/servers/test_list_servers_negative.py b/tempest/api/compute/v3/servers/test_list_servers_negative.py
index 09e1bb6..9a46193 100644
--- a/tempest/api/compute/v3/servers/test_list_servers_negative.py
+++ b/tempest/api/compute/v3/servers/test_list_servers_negative.py
@@ -21,7 +21,6 @@
 
 
 class ListServersNegativeV3Test(base.BaseV3ComputeTest):
-    _interface = 'json'
     force_tenant_isolation = True
 
     @classmethod
diff --git a/tempest/api/compute/v3/servers/test_multiple_create.py b/tempest/api/compute/v3/servers/test_multiple_create.py
index dee4407..23e0854 100644
--- a/tempest/api/compute/v3/servers/test_multiple_create.py
+++ b/tempest/api/compute/v3/servers/test_multiple_create.py
@@ -19,7 +19,6 @@
 
 
 class MultipleCreateV3Test(base.BaseV3ComputeTest):
-    _interface = 'json'
     _name = 'multiple-create-test'
 
     def _generate_name(self):
diff --git a/tempest/api/compute/v3/servers/test_server_actions.py b/tempest/api/compute/v3/servers/test_server_actions.py
index 6584b93..e642715 100644
--- a/tempest/api/compute/v3/servers/test_server_actions.py
+++ b/tempest/api/compute/v3/servers/test_server_actions.py
@@ -28,7 +28,6 @@
 
 
 class ServerActionsV3Test(base.BaseV3ComputeTest):
-    _interface = 'json'
     resize_available = CONF.compute_feature_enabled.resize
     run_ssh = CONF.compute.run_ssh
 
diff --git a/tempest/api/compute/v3/servers/test_server_addresses.py b/tempest/api/compute/v3/servers/test_server_addresses.py
index 038e254..335bd3d 100644
--- a/tempest/api/compute/v3/servers/test_server_addresses.py
+++ b/tempest/api/compute/v3/servers/test_server_addresses.py
@@ -22,7 +22,6 @@
 
 
 class ServerAddressesV3Test(base.BaseV3ComputeTest):
-    _interface = 'json'
 
     @classmethod
     def setUpClass(cls):
diff --git a/tempest/api/compute/v3/servers/test_server_metadata.py b/tempest/api/compute/v3/servers/test_server_metadata.py
index 13c82dd..0e4ef07 100644
--- a/tempest/api/compute/v3/servers/test_server_metadata.py
+++ b/tempest/api/compute/v3/servers/test_server_metadata.py
@@ -18,7 +18,6 @@
 
 
 class ServerMetadataV3Test(base.BaseV3ComputeTest):
-    _interface = 'json'
 
     @classmethod
     def setUpClass(cls):
diff --git a/tempest/api/compute/v3/servers/test_server_metadata_negative.py b/tempest/api/compute/v3/servers/test_server_metadata_negative.py
index ce6c340..ec2bc8c 100644
--- a/tempest/api/compute/v3/servers/test_server_metadata_negative.py
+++ b/tempest/api/compute/v3/servers/test_server_metadata_negative.py
@@ -19,7 +19,6 @@
 
 
 class ServerMetadataV3NegativeTest(base.BaseV3ComputeTest):
-    _interface = 'json'
 
     @classmethod
     def setUpClass(cls):
diff --git a/tempest/api/compute/v3/servers/test_server_password.py b/tempest/api/compute/v3/servers/test_server_password.py
index 579a8a5..fc0b145 100644
--- a/tempest/api/compute/v3/servers/test_server_password.py
+++ b/tempest/api/compute/v3/servers/test_server_password.py
@@ -19,7 +19,6 @@
 
 
 class ServerPasswordV3Test(base.BaseV3ComputeTest):
-    _interface = 'json'
 
     @classmethod
     def setUpClass(cls):
diff --git a/tempest/api/compute/v3/servers/test_server_rescue.py b/tempest/api/compute/v3/servers/test_server_rescue.py
index fa7def0..5d7f91d 100644
--- a/tempest/api/compute/v3/servers/test_server_rescue.py
+++ b/tempest/api/compute/v3/servers/test_server_rescue.py
@@ -20,7 +20,6 @@
 
 
 class ServerRescueV3Test(base.BaseV3ComputeTest):
-    _interface = 'json'
 
     @classmethod
     def setUpClass(cls):
diff --git a/tempest/api/compute/v3/servers/test_servers.py b/tempest/api/compute/v3/servers/test_servers.py
index 5480e31..426ee8d 100644
--- a/tempest/api/compute/v3/servers/test_servers.py
+++ b/tempest/api/compute/v3/servers/test_servers.py
@@ -19,7 +19,6 @@
 
 
 class ServersV3Test(base.BaseV3ComputeTest):
-    _interface = 'json'
 
     @classmethod
     def setUpClass(cls):
diff --git a/tempest/api/compute/v3/servers/test_servers_negative.py b/tempest/api/compute/v3/servers/test_servers_negative.py
index 12e0ad8..cb5e93d 100644
--- a/tempest/api/compute/v3/servers/test_servers_negative.py
+++ b/tempest/api/compute/v3/servers/test_servers_negative.py
@@ -27,7 +27,6 @@
 
 
 class ServersNegativeV3Test(base.BaseV3ComputeTest):
-    _interface = 'json'
 
     def setUp(self):
         super(ServersNegativeV3Test, self).setUp()
diff --git a/tempest/api/compute/v3/test_extensions.py b/tempest/api/compute/v3/test_extensions.py
index 09f5ab4..3c612df 100644
--- a/tempest/api/compute/v3/test_extensions.py
+++ b/tempest/api/compute/v3/test_extensions.py
@@ -25,7 +25,6 @@
 
 
 class ExtensionsV3Test(base.BaseV3ComputeTest):
-    _interface = 'json'
 
     @test.attr(type='gate')
     def test_list_extensions(self):
diff --git a/tempest/api/compute/v3/test_live_block_migration.py b/tempest/api/compute/v3/test_live_block_migration.py
index 43b4e2b..33d2bd9 100644
--- a/tempest/api/compute/v3/test_live_block_migration.py
+++ b/tempest/api/compute/v3/test_live_block_migration.py
@@ -24,7 +24,6 @@
 
 class LiveBlockMigrationV3Test(base.BaseV3ComputeAdminTest):
     _host_key = 'os-extended-server-attributes:host'
-    _interface = 'json'
 
     @classmethod
     def setUpClass(cls):
diff --git a/tempest/api/compute/v3/test_live_block_migration_negative.py b/tempest/api/compute/v3/test_live_block_migration_negative.py
index 4d820d8..0e0eff5 100644
--- a/tempest/api/compute/v3/test_live_block_migration_negative.py
+++ b/tempest/api/compute/v3/test_live_block_migration_negative.py
@@ -25,7 +25,6 @@
 
 class LiveBlockMigrationV3NegativeTest(base.BaseV3ComputeAdminTest):
     _host_key = 'os-extended-server-attributes:host'
-    _interface = 'json'
 
     @classmethod
     def setUpClass(cls):
diff --git a/tempest/api/compute/v3/test_quotas.py b/tempest/api/compute/v3/test_quotas.py
index 33b90ff..b53d9be 100644
--- a/tempest/api/compute/v3/test_quotas.py
+++ b/tempest/api/compute/v3/test_quotas.py
@@ -18,7 +18,6 @@
 
 
 class QuotasV3Test(base.BaseV3ComputeTest):
-    _interface = 'json'
 
     @classmethod
     def setUpClass(cls):
diff --git a/tempest/api/compute/v3/test_version.py b/tempest/api/compute/v3/test_version.py
index 9161d4d..1a74e35 100644
--- a/tempest/api/compute/v3/test_version.py
+++ b/tempest/api/compute/v3/test_version.py
@@ -19,7 +19,6 @@
 
 
 class VersionV3Test(base.BaseV3ComputeTest):
-    _interface = 'json'
 
     @test.attr(type='gate')
     def test_version(self):