Fix the removal of skip_unless_config decorator in Tempest

That decorator was not really useful as there's already a similar
decorator in testtools.

Note, I am still going to propose something (worst case a revert) to
fix the already released version of this Tempest plugin.

Change-Id: I578c5b5e1c83aa7a41a334a49eceff2b90a60767

designate_tempest_plugin/tests/scenario/v2/test_zones.py

@@ -16,6 +16,7 @@ from tempest import test
 from tempest import config
 from tempest.lib import decorators
 from tempest.lib import exceptions as lib_exc
+import testtools
 
 from designate_tempest_plugin.tests import base
 from designate_tempest_plugin.common import waiters
@@ -89,7 +90,9 @@ class ZonesTest(base.BaseDnsV2Test):
     @test.attr(type='slow')
     @decorators.skip_because(bug='1623576')
     @decorators.idempotent_id('ad8d1f5b-da66-46a0-bbee-14dc84a5d791')
-    @config.skip_unless_config('dns', 'nameservers')
+    @testtools.skipUnless(
+        config.CONF.dns.nameservers,
+        "Config option dns.nameservers is missing or empty")
     def test_zone_create_propagates_to_nameservers(self):
         LOG.info('Create a zone')
         _, zone = self.client.create_zone()
@@ -101,7 +104,9 @@ class ZonesTest(base.BaseDnsV2Test):
     @test.attr(type='slow')
     @decorators.skip_because(bug='1623576')
     @decorators.idempotent_id('d13d3095-c78f-4aae-8fe3-a74ccc335c84')
-    @config.skip_unless_config('dns', 'nameservers')
+    @testtools.skipUnless(
+        config.CONF.dns.nameservers,
+        "Config option dns.nameservers is missing or empty")
     def test_zone_delete_propagates_to_nameservers(self):
         LOG.info('Create a zone')
         _, zone = self.client.create_zone()

requirements.txt

@@ -5,4 +5,5 @@
 dnspython>=1.14.0;python_version=='2.7' # http://www.dnspython.org/LICENSE
 dnspython3!=1.13.0,!=1.14.0,>=1.12.0;python_version>='3.0' # http://www.dnspython.org/LICENSE
 ddt>=1.0.1 # MIT
+testtools>=1.4.0 # MIT
 tempest>=14.0.0 # Apache-2.0