Cleanup _interface class variables in compute

We've already removed these variables in Nova v3 tests.
  Change-Id: Ie9ad2242d20ce90fca74ca7a5390e0971f830caa
But we can remove these not only v3 tests but also v2 tests. This commit
sets _interface = 'json' to BaseV2ComputeTest and removes redundancy.

Change-Id: I10110b92ed9a34eedef210ad8408f78d64ba4ee6
diff --git a/tempest/api/compute/admin/test_aggregates.py b/tempest/api/compute/admin/test_aggregates.py
index 4818aa6..6797005 100644
--- a/tempest/api/compute/admin/test_aggregates.py
+++ b/tempest/api/compute/admin/test_aggregates.py
@@ -26,7 +26,6 @@
     """
 
     _host_key = 'OS-EXT-SRV-ATTR:host'
-    _interface = 'json'
 
     @classmethod
     def setUpClass(cls):
diff --git a/tempest/api/compute/admin/test_aggregates_negative.py b/tempest/api/compute/admin/test_aggregates_negative.py
index 7d92532..3d34d47 100644
--- a/tempest/api/compute/admin/test_aggregates_negative.py
+++ b/tempest/api/compute/admin/test_aggregates_negative.py
@@ -26,8 +26,6 @@
     Tests Aggregates API that require admin privileges
     """
 
-    _interface = 'json'
-
     @classmethod
     def setUpClass(cls):
         super(AggregatesAdminNegativeTestJSON, cls).setUpClass()
diff --git a/tempest/api/compute/admin/test_availability_zone.py b/tempest/api/compute/admin/test_availability_zone.py
index 283a45a..1387261 100644
--- a/tempest/api/compute/admin/test_availability_zone.py
+++ b/tempest/api/compute/admin/test_availability_zone.py
@@ -23,8 +23,6 @@
     Tests Availability Zone API List
     """
 
-    _interface = 'json'
-
     @classmethod
     def setUpClass(cls):
         super(AZAdminTestJSON, cls).setUpClass()
diff --git a/tempest/api/compute/admin/test_availability_zone_negative.py b/tempest/api/compute/admin/test_availability_zone_negative.py
index d13618c..8cc8bce 100644
--- a/tempest/api/compute/admin/test_availability_zone_negative.py
+++ b/tempest/api/compute/admin/test_availability_zone_negative.py
@@ -23,8 +23,6 @@
     Tests Availability Zone API List
     """
 
-    _interface = 'json'
-
     @classmethod
     def setUpClass(cls):
         super(AZAdminNegativeTestJSON, cls).setUpClass()
diff --git a/tempest/api/compute/admin/test_fixed_ips.py b/tempest/api/compute/admin/test_fixed_ips.py
index cfb2f0e..00bb9c3 100644
--- a/tempest/api/compute/admin/test_fixed_ips.py
+++ b/tempest/api/compute/admin/test_fixed_ips.py
@@ -21,7 +21,6 @@
 
 
 class FixedIPsTestJson(base.BaseV2ComputeAdminTest):
-    _interface = 'json'
 
     @classmethod
     def setUpClass(cls):
diff --git a/tempest/api/compute/admin/test_fixed_ips_negative.py b/tempest/api/compute/admin/test_fixed_ips_negative.py
index def9810..0faedb2 100644
--- a/tempest/api/compute/admin/test_fixed_ips_negative.py
+++ b/tempest/api/compute/admin/test_fixed_ips_negative.py
@@ -21,7 +21,6 @@
 
 
 class FixedIPsNegativeTestJson(base.BaseV2ComputeAdminTest):
-    _interface = 'json'
 
     @classmethod
     def setUpClass(cls):
diff --git a/tempest/api/compute/admin/test_flavors.py b/tempest/api/compute/admin/test_flavors.py
index 3e13bf8..05b763a 100644
--- a/tempest/api/compute/admin/test_flavors.py
+++ b/tempest/api/compute/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(FlavorsAdminTestJSON, cls).setUpClass()
diff --git a/tempest/api/compute/admin/test_flavors_access.py b/tempest/api/compute/admin/test_flavors_access.py
index da11ab5..4804ce4 100644
--- a/tempest/api/compute/admin/test_flavors_access.py
+++ b/tempest/api/compute/admin/test_flavors_access.py
@@ -25,8 +25,6 @@
     Add and remove Flavor Access require admin privileges.
     """
 
-    _interface = 'json'
-
     @classmethod
     def setUpClass(cls):
         super(FlavorsAccessTestJSON, cls).setUpClass()
diff --git a/tempest/api/compute/admin/test_flavors_access_negative.py b/tempest/api/compute/admin/test_flavors_access_negative.py
index c4d54b6..8fe3331 100644
--- a/tempest/api/compute/admin/test_flavors_access_negative.py
+++ b/tempest/api/compute/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(FlavorsAccessNegativeTestJSON, cls).setUpClass()
diff --git a/tempest/api/compute/admin/test_flavors_extra_specs.py b/tempest/api/compute/admin/test_flavors_extra_specs.py
index 1afa693..91145ec 100644
--- a/tempest/api/compute/admin/test_flavors_extra_specs.py
+++ b/tempest/api/compute/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(FlavorsExtraSpecsTestJSON, cls).setUpClass()
diff --git a/tempest/api/compute/admin/test_flavors_extra_specs_negative.py b/tempest/api/compute/admin/test_flavors_extra_specs_negative.py
index cdf97cc..a139c2f 100644
--- a/tempest/api/compute/admin/test_flavors_extra_specs_negative.py
+++ b/tempest/api/compute/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(FlavorsExtraSpecsNegativeTestJSON, cls).setUpClass()
diff --git a/tempest/api/compute/admin/test_flavors_negative.py b/tempest/api/compute/admin/test_flavors_negative.py
index ad4ceeb..49d49ef 100644
--- a/tempest/api/compute/admin/test_flavors_negative.py
+++ b/tempest/api/compute/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(FlavorsAdminNegativeTestJSON, cls).setUpClass()
diff --git a/tempest/api/compute/admin/test_hosts.py b/tempest/api/compute/admin/test_hosts.py
index a3b4b47..b4b3139 100644
--- a/tempest/api/compute/admin/test_hosts.py
+++ b/tempest/api/compute/admin/test_hosts.py
@@ -23,8 +23,6 @@
     Tests hosts API using admin privileges.
     """
 
-    _interface = 'json'
-
     @classmethod
     def setUpClass(cls):
         super(HostsAdminTestJSON, cls).setUpClass()
diff --git a/tempest/api/compute/admin/test_hosts_negative.py b/tempest/api/compute/admin/test_hosts_negative.py
index cb034c9..0f26e84 100644
--- a/tempest/api/compute/admin/test_hosts_negative.py
+++ b/tempest/api/compute/admin/test_hosts_negative.py
@@ -24,8 +24,6 @@
     Tests hosts API using admin privileges.
     """
 
-    _interface = 'json'
-
     @classmethod
     def setUpClass(cls):
         super(HostsAdminNegativeTestJSON, cls).setUpClass()
diff --git a/tempest/api/compute/admin/test_hypervisor.py b/tempest/api/compute/admin/test_hypervisor.py
index 989c0d8..4e1b289 100644
--- a/tempest/api/compute/admin/test_hypervisor.py
+++ b/tempest/api/compute/admin/test_hypervisor.py
@@ -23,8 +23,6 @@
     Tests Hypervisors API that require admin privileges
     """
 
-    _interface = 'json'
-
     @classmethod
     def setUpClass(cls):
         super(HypervisorAdminTestJSON, cls).setUpClass()
diff --git a/tempest/api/compute/admin/test_hypervisor_negative.py b/tempest/api/compute/admin/test_hypervisor_negative.py
index e41bd18..be0153b 100644
--- a/tempest/api/compute/admin/test_hypervisor_negative.py
+++ b/tempest/api/compute/admin/test_hypervisor_negative.py
@@ -27,8 +27,6 @@
     Tests Hypervisors API that require admin privileges
     """
 
-    _interface = 'json'
-
     @classmethod
     def setUpClass(cls):
         super(HypervisorAdminNegativeTestJSON, cls).setUpClass()
diff --git a/tempest/api/compute/admin/test_instance_usage_audit_log.py b/tempest/api/compute/admin/test_instance_usage_audit_log.py
index c617178..13f504f 100644
--- a/tempest/api/compute/admin/test_instance_usage_audit_log.py
+++ b/tempest/api/compute/admin/test_instance_usage_audit_log.py
@@ -22,8 +22,6 @@
 
 class InstanceUsageAuditLogTestJSON(base.BaseV2ComputeAdminTest):
 
-    _interface = 'json'
-
     @classmethod
     def setUpClass(cls):
         super(InstanceUsageAuditLogTestJSON, cls).setUpClass()
diff --git a/tempest/api/compute/admin/test_instance_usage_audit_log_negative.py b/tempest/api/compute/admin/test_instance_usage_audit_log_negative.py
index 10bb1aa..e128d0c 100644
--- a/tempest/api/compute/admin/test_instance_usage_audit_log_negative.py
+++ b/tempest/api/compute/admin/test_instance_usage_audit_log_negative.py
@@ -23,8 +23,6 @@
 
 class InstanceUsageAuditLogNegativeTestJSON(base.BaseV2ComputeAdminTest):
 
-    _interface = 'json'
-
     @classmethod
     def setUpClass(cls):
         super(InstanceUsageAuditLogNegativeTestJSON, cls).setUpClass()
diff --git a/tempest/api/compute/admin/test_quotas.py b/tempest/api/compute/admin/test_quotas.py
index 81b0328..5af091e 100644
--- a/tempest/api/compute/admin/test_quotas.py
+++ b/tempest/api/compute/admin/test_quotas.py
@@ -19,7 +19,6 @@
 
 
 class QuotasAdminTestJSON(base.BaseV2ComputeAdminTest):
-    _interface = 'json'
     force_tenant_isolation = True
 
     @classmethod
diff --git a/tempest/api/compute/admin/test_quotas_negative.py b/tempest/api/compute/admin/test_quotas_negative.py
index 4c4acd4..5b2b5fd 100644
--- a/tempest/api/compute/admin/test_quotas_negative.py
+++ b/tempest/api/compute/admin/test_quotas_negative.py
@@ -22,7 +22,6 @@
 
 
 class QuotasAdminNegativeTestJSON(base.BaseV2ComputeAdminTest):
-    _interface = 'json'
     force_tenant_isolation = True
 
     @classmethod
diff --git a/tempest/api/compute/admin/test_security_groups.py b/tempest/api/compute/admin/test_security_groups.py
index 0cfa344..69ba2c2 100644
--- a/tempest/api/compute/admin/test_security_groups.py
+++ b/tempest/api/compute/admin/test_security_groups.py
@@ -24,7 +24,6 @@
 
 
 class SecurityGroupsTestAdminJSON(base.BaseV2ComputeAdminTest):
-    _interface = 'json'
 
     @classmethod
     def setUpClass(cls):
diff --git a/tempest/api/compute/admin/test_servers.py b/tempest/api/compute/admin/test_servers.py
index 3b7f221..40a4df7 100644
--- a/tempest/api/compute/admin/test_servers.py
+++ b/tempest/api/compute/admin/test_servers.py
@@ -25,7 +25,6 @@
     """
 
     _host_key = 'OS-EXT-SRV-ATTR:host'
-    _interface = 'json'
 
     @classmethod
     def setUpClass(cls):
diff --git a/tempest/api/compute/admin/test_servers_negative.py b/tempest/api/compute/admin/test_servers_negative.py
index 9580a06..dff4aaa 100644
--- a/tempest/api/compute/admin/test_servers_negative.py
+++ b/tempest/api/compute/admin/test_servers_negative.py
@@ -26,8 +26,6 @@
     Tests Servers API using admin privileges
     """
 
-    _interface = 'json'
-
     @classmethod
     def setUpClass(cls):
         super(ServersAdminNegativeTestJSON, cls).setUpClass()
diff --git a/tempest/api/compute/admin/test_services.py b/tempest/api/compute/admin/test_services.py
index ac800fb..3e45d65 100644
--- a/tempest/api/compute/admin/test_services.py
+++ b/tempest/api/compute/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(ServicesAdminTestJSON, cls).setUpClass()
diff --git a/tempest/api/compute/admin/test_services_negative.py b/tempest/api/compute/admin/test_services_negative.py
index a1809c4..a4bf754 100644
--- a/tempest/api/compute/admin/test_services_negative.py
+++ b/tempest/api/compute/admin/test_services_negative.py
@@ -23,8 +23,6 @@
     Tests Services API. List and Enable/Disable require admin privileges.
     """
 
-    _interface = 'json'
-
     @classmethod
     def setUpClass(cls):
         super(ServicesAdminNegativeTestJSON, cls).setUpClass()
diff --git a/tempest/api/compute/admin/test_simple_tenant_usage.py b/tempest/api/compute/admin/test_simple_tenant_usage.py
index dcb9aed..2f1391b 100644
--- a/tempest/api/compute/admin/test_simple_tenant_usage.py
+++ b/tempest/api/compute/admin/test_simple_tenant_usage.py
@@ -22,8 +22,6 @@
 
 class TenantUsagesTestJSON(base.BaseV2ComputeAdminTest):
 
-    _interface = 'json'
-
     @classmethod
     def setUpClass(cls):
         super(TenantUsagesTestJSON, cls).setUpClass()
diff --git a/tempest/api/compute/admin/test_simple_tenant_usage_negative.py b/tempest/api/compute/admin/test_simple_tenant_usage_negative.py
index 2a30348..4ad3e1a 100644
--- a/tempest/api/compute/admin/test_simple_tenant_usage_negative.py
+++ b/tempest/api/compute/admin/test_simple_tenant_usage_negative.py
@@ -22,8 +22,6 @@
 
 class TenantUsagesNegativeTestJSON(base.BaseV2ComputeAdminTest):
 
-    _interface = 'json'
-
     @classmethod
     def setUpClass(cls):
         super(TenantUsagesNegativeTestJSON, cls).setUpClass()
diff --git a/tempest/api/compute/base.py b/tempest/api/compute/base.py
index 9162926..28d50c9 100644
--- a/tempest/api/compute/base.py
+++ b/tempest/api/compute/base.py
@@ -206,6 +206,8 @@
 
 class BaseV2ComputeTest(BaseComputeTest):
 
+    _interface = "json"
+
     @classmethod
     def setUpClass(cls):
         # By default compute tests do not create network resources
diff --git a/tempest/api/compute/certificates/test_certificates.py b/tempest/api/compute/certificates/test_certificates.py
index 79619bc..01fdc7c 100644
--- a/tempest/api/compute/certificates/test_certificates.py
+++ b/tempest/api/compute/certificates/test_certificates.py
@@ -18,7 +18,6 @@
 
 
 class CertificatesTestJSON(base.BaseV2ComputeTest):
-    _interface = 'json'
 
     @attr(type='gate')
     def test_create_and_get_root_certificate(self):
diff --git a/tempest/api/compute/flavors/test_flavors.py b/tempest/api/compute/flavors/test_flavors.py
index b0a7fed..98a8e29 100644
--- a/tempest/api/compute/flavors/test_flavors.py
+++ b/tempest/api/compute/flavors/test_flavors.py
@@ -18,7 +18,6 @@
 
 
 class FlavorsTestJSON(base.BaseV2ComputeTest):
-    _interface = 'json'
 
     @classmethod
     def setUpClass(cls):
diff --git a/tempest/api/compute/flavors/test_flavors_negative.py b/tempest/api/compute/flavors/test_flavors_negative.py
index 8ac6182..4ba5023 100644
--- a/tempest/api/compute/flavors/test_flavors_negative.py
+++ b/tempest/api/compute/flavors/test_flavors_negative.py
@@ -24,7 +24,6 @@
 
 class FlavorsListNegativeTestJSON(base.BaseV2ComputeTest,
                                   test.NegativeAutoTest):
-    _interface = 'json'
     _service = 'compute'
     _schema_file = 'compute/flavors/flavors_list.json'
 
@@ -37,7 +36,6 @@
 
 class FlavorDetailsNegativeTestJSON(base.BaseV2ComputeTest,
                                     test.NegativeAutoTest):
-    _interface = 'json'
     _service = 'compute'
     _schema_file = 'compute/flavors/flavor_details.json'
 
diff --git a/tempest/api/compute/floating_ips/test_floating_ips_actions.py b/tempest/api/compute/floating_ips/test_floating_ips_actions.py
index ea785b3..c0f7af0 100644
--- a/tempest/api/compute/floating_ips/test_floating_ips_actions.py
+++ b/tempest/api/compute/floating_ips/test_floating_ips_actions.py
@@ -20,7 +20,6 @@
 
 
 class FloatingIPsTestJSON(base.BaseFloatingIPsTest):
-    _interface = 'json'
     server_id = None
     floating_ip = None
 
diff --git a/tempest/api/compute/floating_ips/test_floating_ips_actions_negative.py b/tempest/api/compute/floating_ips/test_floating_ips_actions_negative.py
index f24343b..0c3663e 100644
--- a/tempest/api/compute/floating_ips/test_floating_ips_actions_negative.py
+++ b/tempest/api/compute/floating_ips/test_floating_ips_actions_negative.py
@@ -25,7 +25,6 @@
 
 
 class FloatingIPsNegativeTestJSON(base.BaseFloatingIPsTest):
-    _interface = 'json'
     server_id = None
 
     @classmethod
diff --git a/tempest/api/compute/floating_ips/test_list_floating_ips.py b/tempest/api/compute/floating_ips/test_list_floating_ips.py
index fa2d558..d69e33c 100644
--- a/tempest/api/compute/floating_ips/test_list_floating_ips.py
+++ b/tempest/api/compute/floating_ips/test_list_floating_ips.py
@@ -18,7 +18,6 @@
 
 
 class FloatingIPDetailsTestJSON(base.BaseV2ComputeTest):
-    _interface = 'json'
 
     @classmethod
     def setUpClass(cls):
diff --git a/tempest/api/compute/floating_ips/test_list_floating_ips_negative.py b/tempest/api/compute/floating_ips/test_list_floating_ips_negative.py
index 8d60e7d..5701be8 100644
--- a/tempest/api/compute/floating_ips/test_list_floating_ips_negative.py
+++ b/tempest/api/compute/floating_ips/test_list_floating_ips_negative.py
@@ -25,7 +25,6 @@
 
 
 class FloatingIPDetailsNegativeTestJSON(base.BaseV2ComputeTest):
-    _interface = 'json'
 
     @classmethod
     def setUpClass(cls):
diff --git a/tempest/api/compute/images/test_image_metadata.py b/tempest/api/compute/images/test_image_metadata.py
index 4115d65..ad211ce 100644
--- a/tempest/api/compute/images/test_image_metadata.py
+++ b/tempest/api/compute/images/test_image_metadata.py
@@ -22,7 +22,6 @@
 
 
 class ImagesMetadataTestJSON(base.BaseV2ComputeTest):
-    _interface = 'json'
 
     @classmethod
     def setUpClass(cls):
diff --git a/tempest/api/compute/images/test_image_metadata_negative.py b/tempest/api/compute/images/test_image_metadata_negative.py
index 4878936..7776c57 100644
--- a/tempest/api/compute/images/test_image_metadata_negative.py
+++ b/tempest/api/compute/images/test_image_metadata_negative.py
@@ -20,7 +20,6 @@
 
 
 class ImagesMetadataTestJSON(base.BaseV2ComputeTest):
-    _interface = 'json'
 
     @classmethod
     def setUpClass(cls):
diff --git a/tempest/api/compute/images/test_images.py b/tempest/api/compute/images/test_images.py
index 8964dcf..ed316ef 100644
--- a/tempest/api/compute/images/test_images.py
+++ b/tempest/api/compute/images/test_images.py
@@ -22,7 +22,6 @@
 
 
 class ImagesTestJSON(base.BaseV2ComputeTest):
-    _interface = 'json'
 
     @classmethod
     def setUpClass(cls):
diff --git a/tempest/api/compute/images/test_images_oneserver.py b/tempest/api/compute/images/test_images_oneserver.py
index 7d5593d..b152c3c 100644
--- a/tempest/api/compute/images/test_images_oneserver.py
+++ b/tempest/api/compute/images/test_images_oneserver.py
@@ -26,7 +26,6 @@
 
 
 class ImagesOneServerTestJSON(base.BaseV2ComputeTest):
-    _interface = 'json'
 
     def setUp(self):
         # NOTE(afazekas): Normally we use the same server with all test cases,
diff --git a/tempest/api/compute/images/test_images_oneserver_negative.py b/tempest/api/compute/images/test_images_oneserver_negative.py
index 82955d8..41a0590 100644
--- a/tempest/api/compute/images/test_images_oneserver_negative.py
+++ b/tempest/api/compute/images/test_images_oneserver_negative.py
@@ -27,7 +27,6 @@
 
 
 class ImagesOneServerNegativeTestJSON(base.BaseV2ComputeTest):
-    _interface = 'json'
 
     def tearDown(self):
         """Terminate test instances created after a test is executed."""
diff --git a/tempest/api/compute/images/test_list_image_filters.py b/tempest/api/compute/images/test_list_image_filters.py
index 9cff3a8..86ee4a4 100644
--- a/tempest/api/compute/images/test_list_image_filters.py
+++ b/tempest/api/compute/images/test_list_image_filters.py
@@ -24,7 +24,6 @@
 
 
 class ListImageFiltersTestJSON(base.BaseV2ComputeTest):
-    _interface = 'json'
 
     @classmethod
     def setUpClass(cls):
diff --git a/tempest/api/compute/images/test_list_image_filters_negative.py b/tempest/api/compute/images/test_list_image_filters_negative.py
index 3b19d3c..80d59a7 100644
--- a/tempest/api/compute/images/test_list_image_filters_negative.py
+++ b/tempest/api/compute/images/test_list_image_filters_negative.py
@@ -22,7 +22,6 @@
 
 
 class ListImageFiltersNegativeTestJSON(base.BaseV2ComputeTest):
-    _interface = 'json'
 
     @classmethod
     def setUpClass(cls):
diff --git a/tempest/api/compute/images/test_list_images.py b/tempest/api/compute/images/test_list_images.py
index ed38442..4074a7a 100644
--- a/tempest/api/compute/images/test_list_images.py
+++ b/tempest/api/compute/images/test_list_images.py
@@ -21,7 +21,6 @@
 
 
 class ListImagesTestJSON(base.BaseV2ComputeTest):
-    _interface = 'json'
 
     @classmethod
     def setUpClass(cls):
diff --git a/tempest/api/compute/keypairs/test_keypairs.py b/tempest/api/compute/keypairs/test_keypairs.py
index d4554bc..67fafed 100644
--- a/tempest/api/compute/keypairs/test_keypairs.py
+++ b/tempest/api/compute/keypairs/test_keypairs.py
@@ -19,7 +19,6 @@
 
 
 class KeyPairsTestJSON(base.BaseV2ComputeTest):
-    _interface = 'json'
 
     @classmethod
     def setUpClass(cls):
diff --git a/tempest/api/compute/keypairs/test_keypairs_negative.py b/tempest/api/compute/keypairs/test_keypairs_negative.py
index 93b0692..a91a9c2 100644
--- a/tempest/api/compute/keypairs/test_keypairs_negative.py
+++ b/tempest/api/compute/keypairs/test_keypairs_negative.py
@@ -21,7 +21,6 @@
 
 
 class KeyPairsNegativeTestJSON(base.BaseV2ComputeTest):
-    _interface = 'json'
 
     @classmethod
     def setUpClass(cls):
diff --git a/tempest/api/compute/limits/test_absolute_limits.py b/tempest/api/compute/limits/test_absolute_limits.py
index 0e234fb..d64fd57 100644
--- a/tempest/api/compute/limits/test_absolute_limits.py
+++ b/tempest/api/compute/limits/test_absolute_limits.py
@@ -18,7 +18,6 @@
 
 
 class AbsoluteLimitsTestJSON(base.BaseV2ComputeTest):
-    _interface = 'json'
 
     @classmethod
     def setUpClass(cls):
diff --git a/tempest/api/compute/limits/test_absolute_limits_negative.py b/tempest/api/compute/limits/test_absolute_limits_negative.py
index ac8af3b..f88699b 100644
--- a/tempest/api/compute/limits/test_absolute_limits_negative.py
+++ b/tempest/api/compute/limits/test_absolute_limits_negative.py
@@ -19,7 +19,6 @@
 
 
 class AbsoluteLimitsNegativeTestJSON(base.BaseV2ComputeTest):
-    _interface = 'json'
 
     @classmethod
     def setUpClass(cls):
diff --git a/tempest/api/compute/security_groups/test_security_group_rules.py b/tempest/api/compute/security_groups/test_security_group_rules.py
index 17bb489..b04ab8a 100644
--- a/tempest/api/compute/security_groups/test_security_group_rules.py
+++ b/tempest/api/compute/security_groups/test_security_group_rules.py
@@ -21,7 +21,6 @@
 
 
 class SecurityGroupRulesTestJSON(base.BaseSecurityGroupsTest):
-    _interface = 'json'
 
     @classmethod
     def setUpClass(cls):
diff --git a/tempest/api/compute/security_groups/test_security_group_rules_negative.py b/tempest/api/compute/security_groups/test_security_group_rules_negative.py
index 9c9e72c..0b53037 100644
--- a/tempest/api/compute/security_groups/test_security_group_rules_negative.py
+++ b/tempest/api/compute/security_groups/test_security_group_rules_negative.py
@@ -30,7 +30,6 @@
 
 
 class SecurityGroupRulesNegativeTestJSON(base.BaseSecurityGroupsTest):
-    _interface = 'json'
 
     @classmethod
     def setUpClass(cls):
diff --git a/tempest/api/compute/security_groups/test_security_groups.py b/tempest/api/compute/security_groups/test_security_groups.py
index b376edc..c063a4e 100644
--- a/tempest/api/compute/security_groups/test_security_groups.py
+++ b/tempest/api/compute/security_groups/test_security_groups.py
@@ -20,7 +20,6 @@
 
 
 class SecurityGroupsTestJSON(base.BaseSecurityGroupsTest):
-    _interface = 'json'
 
     @classmethod
     def setUpClass(cls):
diff --git a/tempest/api/compute/security_groups/test_security_groups_negative.py b/tempest/api/compute/security_groups/test_security_groups_negative.py
index edf38e9..735c7ce 100644
--- a/tempest/api/compute/security_groups/test_security_groups_negative.py
+++ b/tempest/api/compute/security_groups/test_security_groups_negative.py
@@ -25,7 +25,6 @@
 
 
 class SecurityGroupsNegativeTestJSON(base.BaseSecurityGroupsTest):
-    _interface = 'json'
 
     @classmethod
     def setUpClass(cls):
diff --git a/tempest/api/compute/servers/test_attach_interfaces.py b/tempest/api/compute/servers/test_attach_interfaces.py
index c8ab5ae..a21c411 100644
--- a/tempest/api/compute/servers/test_attach_interfaces.py
+++ b/tempest/api/compute/servers/test_attach_interfaces.py
@@ -24,7 +24,6 @@
 
 
 class AttachInterfacesTestJSON(base.BaseV2ComputeTest):
-    _interface = 'json'
 
     @classmethod
     def setUpClass(cls):
diff --git a/tempest/api/compute/servers/test_availability_zone.py b/tempest/api/compute/servers/test_availability_zone.py
index 748ba41..7b12555 100644
--- a/tempest/api/compute/servers/test_availability_zone.py
+++ b/tempest/api/compute/servers/test_availability_zone.py
@@ -23,8 +23,6 @@
     Tests Availability Zone API List
     """
 
-    _interface = 'json'
-
     @classmethod
     def setUpClass(cls):
         super(AZTestJSON, cls).setUpClass()
diff --git a/tempest/api/compute/servers/test_create_server.py b/tempest/api/compute/servers/test_create_server.py
index f705308..ddf37ce 100644
--- a/tempest/api/compute/servers/test_create_server.py
+++ b/tempest/api/compute/servers/test_create_server.py
@@ -28,7 +28,6 @@
 
 
 class ServersTestJSON(base.BaseV2ComputeTest):
-    _interface = 'json'
     run_ssh = CONF.compute.run_ssh
     disk_config = 'AUTO'
 
@@ -110,7 +109,6 @@
 
 
 class ServersWithSpecificFlavorTestJSON(base.BaseV2ComputeAdminTest):
-    _interface = 'json'
     run_ssh = CONF.compute.run_ssh
     disk_config = 'AUTO'
 
diff --git a/tempest/api/compute/servers/test_delete_server.py b/tempest/api/compute/servers/test_delete_server.py
index 6c0e37c..9772059 100644
--- a/tempest/api/compute/servers/test_delete_server.py
+++ b/tempest/api/compute/servers/test_delete_server.py
@@ -23,7 +23,6 @@
 class DeleteServersTestJSON(base.BaseV2ComputeTest):
     # NOTE: Server creations of each test class should be under 10
     # for preventing "Quota exceeded for instances"
-    _interface = 'json'
 
     @classmethod
     def setUpClass(cls):
@@ -89,7 +88,6 @@
 class DeleteServersAdminTestJSON(base.BaseV2ComputeAdminTest):
     # NOTE: Server creations of each test class should be under 10
     # for preventing "Quota exceeded for instances".
-    _interface = 'json'
 
     @classmethod
     def setUpClass(cls):
diff --git a/tempest/api/compute/servers/test_disk_config.py b/tempest/api/compute/servers/test_disk_config.py
index 0d79161..75a1234 100644
--- a/tempest/api/compute/servers/test_disk_config.py
+++ b/tempest/api/compute/servers/test_disk_config.py
@@ -23,7 +23,6 @@
 
 
 class ServerDiskConfigTestJSON(base.BaseV2ComputeTest):
-    _interface = 'json'
 
     @classmethod
     def setUpClass(cls):
diff --git a/tempest/api/compute/servers/test_instance_actions.py b/tempest/api/compute/servers/test_instance_actions.py
index 667b84f..dd31165 100644
--- a/tempest/api/compute/servers/test_instance_actions.py
+++ b/tempest/api/compute/servers/test_instance_actions.py
@@ -18,7 +18,6 @@
 
 
 class InstanceActionsTestJSON(base.BaseV2ComputeTest):
-    _interface = 'json'
 
     @classmethod
     def setUpClass(cls):
diff --git a/tempest/api/compute/servers/test_instance_actions_negative.py b/tempest/api/compute/servers/test_instance_actions_negative.py
index 2503eb2..e67b69d 100644
--- a/tempest/api/compute/servers/test_instance_actions_negative.py
+++ b/tempest/api/compute/servers/test_instance_actions_negative.py
@@ -20,7 +20,6 @@
 
 
 class InstanceActionsNegativeTestJSON(base.BaseV2ComputeTest):
-    _interface = 'json'
 
     @classmethod
     def setUpClass(cls):
diff --git a/tempest/api/compute/servers/test_list_server_filters.py b/tempest/api/compute/servers/test_list_server_filters.py
index fc0bb9f..837114c 100644
--- a/tempest/api/compute/servers/test_list_server_filters.py
+++ b/tempest/api/compute/servers/test_list_server_filters.py
@@ -24,7 +24,6 @@
 
 
 class ListServerFiltersTestJSON(base.BaseV2ComputeTest):
-    _interface = 'json'
 
     @classmethod
     def setUpClass(cls):
diff --git a/tempest/api/compute/servers/test_list_servers_negative.py b/tempest/api/compute/servers/test_list_servers_negative.py
index a0aefd8..97f16cc 100644
--- a/tempest/api/compute/servers/test_list_servers_negative.py
+++ b/tempest/api/compute/servers/test_list_servers_negative.py
@@ -21,7 +21,6 @@
 
 
 class ListServersNegativeTestJSON(base.BaseV2ComputeTest):
-    _interface = 'json'
     force_tenant_isolation = True
 
     @classmethod
diff --git a/tempest/api/compute/servers/test_multiple_create.py b/tempest/api/compute/servers/test_multiple_create.py
index cf4d646..40b9c16 100644
--- a/tempest/api/compute/servers/test_multiple_create.py
+++ b/tempest/api/compute/servers/test_multiple_create.py
@@ -19,7 +19,6 @@
 
 
 class MultipleCreateTestJSON(base.BaseV2ComputeTest):
-    _interface = 'json'
     _name = 'multiple-create-test'
 
     def _generate_name(self):
diff --git a/tempest/api/compute/servers/test_multiple_create_negative.py b/tempest/api/compute/servers/test_multiple_create_negative.py
index e289717..3dea521 100644
--- a/tempest/api/compute/servers/test_multiple_create_negative.py
+++ b/tempest/api/compute/servers/test_multiple_create_negative.py
@@ -20,7 +20,6 @@
 
 
 class MultipleCreateNegativeTestJSON(base.BaseV2ComputeTest):
-    _interface = 'json'
     _name = 'multiple-create-test'
 
     def _generate_name(self):
diff --git a/tempest/api/compute/servers/test_server_actions.py b/tempest/api/compute/servers/test_server_actions.py
index adf522b..bde0f57 100644
--- a/tempest/api/compute/servers/test_server_actions.py
+++ b/tempest/api/compute/servers/test_server_actions.py
@@ -29,7 +29,6 @@
 
 
 class ServerActionsTestJSON(base.BaseV2ComputeTest):
-    _interface = 'json'
     resize_available = CONF.compute_feature_enabled.resize
     run_ssh = CONF.compute.run_ssh
 
diff --git a/tempest/api/compute/servers/test_server_addresses.py b/tempest/api/compute/servers/test_server_addresses.py
index d5528c4..0c14dc2 100644
--- a/tempest/api/compute/servers/test_server_addresses.py
+++ b/tempest/api/compute/servers/test_server_addresses.py
@@ -21,7 +21,6 @@
 
 
 class ServerAddressesTestJSON(base.BaseV2ComputeTest):
-    _interface = 'json'
 
     @classmethod
     def setUpClass(cls):
diff --git a/tempest/api/compute/servers/test_server_addresses_negative.py b/tempest/api/compute/servers/test_server_addresses_negative.py
index c69c5eb..d37f7fa 100644
--- a/tempest/api/compute/servers/test_server_addresses_negative.py
+++ b/tempest/api/compute/servers/test_server_addresses_negative.py
@@ -19,7 +19,6 @@
 
 
 class ServerAddressesNegativeTestJSON(base.BaseV2ComputeTest):
-    _interface = 'json'
 
     @classmethod
     def setUpClass(cls):
diff --git a/tempest/api/compute/servers/test_server_metadata.py b/tempest/api/compute/servers/test_server_metadata.py
index ad4931c..448b8ff 100644
--- a/tempest/api/compute/servers/test_server_metadata.py
+++ b/tempest/api/compute/servers/test_server_metadata.py
@@ -18,7 +18,6 @@
 
 
 class ServerMetadataTestJSON(base.BaseV2ComputeTest):
-    _interface = 'json'
 
     @classmethod
     def setUpClass(cls):
diff --git a/tempest/api/compute/servers/test_server_metadata_negative.py b/tempest/api/compute/servers/test_server_metadata_negative.py
index e52ea4a..8b69c78 100644
--- a/tempest/api/compute/servers/test_server_metadata_negative.py
+++ b/tempest/api/compute/servers/test_server_metadata_negative.py
@@ -20,7 +20,6 @@
 
 
 class ServerMetadataNegativeTestJSON(base.BaseV2ComputeTest):
-    _interface = 'json'
 
     @classmethod
     def setUpClass(cls):
diff --git a/tempest/api/compute/servers/test_server_password.py b/tempest/api/compute/servers/test_server_password.py
index 06697a5..ad78f65 100644
--- a/tempest/api/compute/servers/test_server_password.py
+++ b/tempest/api/compute/servers/test_server_password.py
@@ -19,7 +19,6 @@
 
 
 class ServerPasswordTestJSON(base.BaseV2ComputeTest):
-    _interface = 'json'
 
     @classmethod
     def setUpClass(cls):
diff --git a/tempest/api/compute/servers/test_server_personality.py b/tempest/api/compute/servers/test_server_personality.py
index bb14a4c..b581faf 100644
--- a/tempest/api/compute/servers/test_server_personality.py
+++ b/tempest/api/compute/servers/test_server_personality.py
@@ -21,7 +21,6 @@
 
 
 class ServerPersonalityTestJSON(base.BaseV2ComputeTest):
-    _interface = 'json'
 
     @classmethod
     def setUpClass(cls):
diff --git a/tempest/api/compute/servers/test_server_rescue.py b/tempest/api/compute/servers/test_server_rescue.py
index 826317d..48f2e14 100644
--- a/tempest/api/compute/servers/test_server_rescue.py
+++ b/tempest/api/compute/servers/test_server_rescue.py
@@ -19,7 +19,6 @@
 
 
 class ServerRescueTestJSON(base.BaseV2ComputeTest):
-    _interface = 'json'
 
     @classmethod
     def setUpClass(cls):
diff --git a/tempest/api/compute/servers/test_server_rescue_negative.py b/tempest/api/compute/servers/test_server_rescue_negative.py
index ffd79fa..277f28f 100644
--- a/tempest/api/compute/servers/test_server_rescue_negative.py
+++ b/tempest/api/compute/servers/test_server_rescue_negative.py
@@ -20,7 +20,6 @@
 
 
 class ServerRescueNegativeTestJSON(base.BaseV2ComputeTest):
-    _interface = 'json'
 
     @classmethod
     def setUpClass(cls):
diff --git a/tempest/api/compute/servers/test_servers.py b/tempest/api/compute/servers/test_servers.py
index 7167a8b..9674463 100644
--- a/tempest/api/compute/servers/test_servers.py
+++ b/tempest/api/compute/servers/test_servers.py
@@ -19,7 +19,6 @@
 
 
 class ServersTestJSON(base.BaseV2ComputeTest):
-    _interface = 'json'
 
     @classmethod
     def setUpClass(cls):
diff --git a/tempest/api/compute/servers/test_servers_negative.py b/tempest/api/compute/servers/test_servers_negative.py
index e0181b9..4cccbd6 100644
--- a/tempest/api/compute/servers/test_servers_negative.py
+++ b/tempest/api/compute/servers/test_servers_negative.py
@@ -27,7 +27,6 @@
 
 
 class ServersNegativeTestJSON(base.BaseV2ComputeTest):
-    _interface = 'json'
 
     def setUp(self):
         super(ServersNegativeTestJSON, self).setUp()
diff --git a/tempest/api/compute/servers/test_servers_negative_new.py b/tempest/api/compute/servers/test_servers_negative_new.py
index 2b2fcf1..42ace76 100644
--- a/tempest/api/compute/servers/test_servers_negative_new.py
+++ b/tempest/api/compute/servers/test_servers_negative_new.py
@@ -24,7 +24,6 @@
 
 class GetConsoleOutputNegativeTestJSON(base.BaseV2ComputeTest,
                                        test.NegativeAutoTest):
-    _interface = 'json'
     _service = 'compute'
     _schema_file = 'compute/servers/get_console_output.json'
 
diff --git a/tempest/api/compute/servers/test_virtual_interfaces.py b/tempest/api/compute/servers/test_virtual_interfaces.py
index 95703d4..6354996 100644
--- a/tempest/api/compute/servers/test_virtual_interfaces.py
+++ b/tempest/api/compute/servers/test_virtual_interfaces.py
@@ -23,7 +23,6 @@
 
 
 class VirtualInterfacesTestJSON(base.BaseV2ComputeTest):
-    _interface = 'json'
 
     @classmethod
     def setUpClass(cls):
diff --git a/tempest/api/compute/servers/test_virtual_interfaces_negative.py b/tempest/api/compute/servers/test_virtual_interfaces_negative.py
index f73218c..87289d8 100644
--- a/tempest/api/compute/servers/test_virtual_interfaces_negative.py
+++ b/tempest/api/compute/servers/test_virtual_interfaces_negative.py
@@ -21,7 +21,6 @@
 
 
 class VirtualInterfacesNegativeTestJSON(base.BaseV2ComputeTest):
-    _interface = 'json'
 
     @classmethod
     def setUpClass(cls):
diff --git a/tempest/api/compute/test_authorization.py b/tempest/api/compute/test_authorization.py
index ed72061..fd73cc5 100644
--- a/tempest/api/compute/test_authorization.py
+++ b/tempest/api/compute/test_authorization.py
@@ -27,7 +27,6 @@
 
 
 class AuthorizationTestJSON(base.BaseV2ComputeTest):
-    _interface = 'json'
 
     @classmethod
     def setUpClass(cls):
diff --git a/tempest/api/compute/test_extensions.py b/tempest/api/compute/test_extensions.py
index 55146e5..674ca9a 100644
--- a/tempest/api/compute/test_extensions.py
+++ b/tempest/api/compute/test_extensions.py
@@ -26,7 +26,6 @@
 
 
 class ExtensionsTestJSON(base.BaseV2ComputeTest):
-    _interface = 'json'
 
     @test.attr(type='gate')
     def test_list_extensions(self):
diff --git a/tempest/api/compute/test_live_block_migration.py b/tempest/api/compute/test_live_block_migration.py
index 1df4159..1319f68 100644
--- a/tempest/api/compute/test_live_block_migration.py
+++ b/tempest/api/compute/test_live_block_migration.py
@@ -25,7 +25,6 @@
 
 class LiveBlockMigrationTestJSON(base.BaseV2ComputeAdminTest):
     _host_key = 'OS-EXT-SRV-ATTR:host'
-    _interface = 'json'
 
     @classmethod
     def setUpClass(cls):
diff --git a/tempest/api/compute/test_live_block_migration_negative.py b/tempest/api/compute/test_live_block_migration_negative.py
index e1a264e..c10818e 100644
--- a/tempest/api/compute/test_live_block_migration_negative.py
+++ b/tempest/api/compute/test_live_block_migration_negative.py
@@ -25,7 +25,6 @@
 
 class LiveBlockMigrationNegativeTestJSON(base.BaseV2ComputeAdminTest):
     _host_key = 'OS-EXT-SRV-ATTR:host'
-    _interface = 'json'
 
     @classmethod
     def setUpClass(cls):
diff --git a/tempest/api/compute/test_quotas.py b/tempest/api/compute/test_quotas.py
index 112e4fb..b97ab2c 100644
--- a/tempest/api/compute/test_quotas.py
+++ b/tempest/api/compute/test_quotas.py
@@ -18,7 +18,6 @@
 
 
 class QuotasTestJSON(base.BaseV2ComputeTest):
-    _interface = 'json'
 
     @classmethod
     def setUpClass(cls):
diff --git a/tempest/api/compute/v3/admin/test_quotas_negative.py b/tempest/api/compute/v3/admin/test_quotas_negative.py
index c9f14f8..d138e80 100644
--- a/tempest/api/compute/v3/admin/test_quotas_negative.py
+++ b/tempest/api/compute/v3/admin/test_quotas_negative.py
@@ -20,7 +20,6 @@
 
 
 class QuotasAdminNegativeV3Test(base.BaseV3ComputeAdminTest):
-    _interface = 'json'
     force_tenant_isolation = True
 
     @classmethod
diff --git a/tempest/api/compute/v3/servers/test_availability_zone.py b/tempest/api/compute/v3/servers/test_availability_zone.py
index feac9a1..5a1e07e 100644
--- a/tempest/api/compute/v3/servers/test_availability_zone.py
+++ b/tempest/api/compute/v3/servers/test_availability_zone.py
@@ -23,8 +23,6 @@
     Tests Availability Zone API List
     """
 
-    _interface = 'json'
-
     @classmethod
     def setUpClass(cls):
         super(AZV3Test, cls).setUpClass()
diff --git a/tempest/api/compute/v3/servers/test_delete_server.py b/tempest/api/compute/v3/servers/test_delete_server.py
index 0dfe60e..4b11335 100644
--- a/tempest/api/compute/v3/servers/test_delete_server.py
+++ b/tempest/api/compute/v3/servers/test_delete_server.py
@@ -22,7 +22,6 @@
 class DeleteServersV3Test(base.BaseV3ComputeTest):
     # NOTE: Server creations of each test class should be under 10
     # for preventing "Quota exceeded for instances".
-    _interface = 'json'
 
     @classmethod
     def setUpClass(cls):
@@ -89,7 +88,6 @@
 class DeleteServersAdminV3Test(base.BaseV3ComputeAdminTest):
     # NOTE: Server creations of each test class should be under 10
     # for preventing "Quota exceeded for instances".
-    _interface = 'json'
 
     @classmethod
     def setUpClass(cls):
diff --git a/tempest/api/compute/v3/servers/test_instance_actions_negative.py b/tempest/api/compute/v3/servers/test_instance_actions_negative.py
index bd741e0..b0a7050 100644
--- a/tempest/api/compute/v3/servers/test_instance_actions_negative.py
+++ b/tempest/api/compute/v3/servers/test_instance_actions_negative.py
@@ -20,7 +20,6 @@
 
 
 class InstanceActionsNegativeV3Test(base.BaseV3ComputeTest):
-    _interface = 'json'
 
     @classmethod
     def setUpClass(cls):
diff --git a/tempest/api/compute/v3/servers/test_multiple_create_negative.py b/tempest/api/compute/v3/servers/test_multiple_create_negative.py
index 57bb807..f208bc0 100644
--- a/tempest/api/compute/v3/servers/test_multiple_create_negative.py
+++ b/tempest/api/compute/v3/servers/test_multiple_create_negative.py
@@ -20,7 +20,6 @@
 
 
 class MultipleCreateV3NegativeTest(base.BaseV3ComputeTest):
-    _interface = 'json'
     _name = 'multiple-create-negative-test'
 
     def _generate_name(self):
diff --git a/tempest/api/compute/volumes/test_attach_volume.py b/tempest/api/compute/volumes/test_attach_volume.py
index 7a60196..3c5feed 100644
--- a/tempest/api/compute/volumes/test_attach_volume.py
+++ b/tempest/api/compute/volumes/test_attach_volume.py
@@ -24,7 +24,6 @@
 
 
 class AttachVolumeTestJSON(base.BaseV2ComputeTest):
-    _interface = 'json'
     run_ssh = CONF.compute.run_ssh
 
     def __init__(self, *args, **kwargs):
diff --git a/tempest/api/compute/volumes/test_volumes_get.py b/tempest/api/compute/volumes/test_volumes_get.py
index 73e3b3a..c3d6ba6 100644
--- a/tempest/api/compute/volumes/test_volumes_get.py
+++ b/tempest/api/compute/volumes/test_volumes_get.py
@@ -24,8 +24,6 @@
 
 class VolumesGetTestJSON(base.BaseV2ComputeTest):
 
-    _interface = 'json'
-
     @classmethod
     def setUpClass(cls):
         super(VolumesGetTestJSON, cls).setUpClass()
diff --git a/tempest/api/compute/volumes/test_volumes_list.py b/tempest/api/compute/volumes/test_volumes_list.py
index 48b1b7e..9867c64 100644
--- a/tempest/api/compute/volumes/test_volumes_list.py
+++ b/tempest/api/compute/volumes/test_volumes_list.py
@@ -31,8 +31,6 @@
     VOLUME_BACKING_FILE_SIZE is atleast 4G in your localrc
     """
 
-    _interface = 'json'
-
     @classmethod
     def setUpClass(cls):
         super(VolumesTestJSON, cls).setUpClass()
diff --git a/tempest/api/compute/volumes/test_volumes_negative.py b/tempest/api/compute/volumes/test_volumes_negative.py
index 85b30e2..cecaf62 100644
--- a/tempest/api/compute/volumes/test_volumes_negative.py
+++ b/tempest/api/compute/volumes/test_volumes_negative.py
@@ -25,7 +25,6 @@
 
 
 class VolumesNegativeTest(base.BaseV2ComputeTest):
-    _interface = 'json'
 
     @classmethod
     def setUpClass(cls):