Fix skipping of tests

The plugin defines a 'magnum' option in the '[service_available]' group
but does not respect it, so if the plugin is installed but
[service_available]/magnum=false, the tests will still run unless
blacklisted. This patch corrects the issue by defining the tempest
skip_checks class method. This also requires using the correct tempest
base class as recommended in the tempest guide[1].

[1] https://docs.openstack.org/tempest/latest/write_tests.html

Change-Id: I6b9a8f802129fa800d9f4a3eadd8943962c951c0

magnum_tempest_plugin/common/base.py

@@ -14,15 +14,17 @@ import logging
 import os
 import subprocess
 
-from tempest.lib import base
+from tempest import config
+from tempest import test
 
 import magnum_tempest_plugin
 
 
+CONF = config.CONF
 COPY_LOG_HELPER = "magnum_tempest_plugin/tests/contrib/copy_instance_logs.sh"
 
 
-class BaseMagnumTest(base.BaseTestCase):
+class BaseMagnumTest(test.BaseTestCase):
     """Sets up configuration required for functional tests"""
 
     LOG = logging.getLogger(__name__)
@@ -30,6 +32,15 @@ class BaseMagnumTest(base.BaseTestCase):
     def __init__(self, *args, **kwargs):
         super(BaseMagnumTest, self).__init__(*args, **kwargs)
 
+    @classmethod
+    def skip_checks(cls):
+        super(BaseMagnumTest, cls).skip_checks()
+
+        if not CONF.service_available.magnum:
+            skip_msg = ("%s skipped as magnum is not available"
+                        % cls.__name__)
+            raise cls.skipException(skip_msg)
+
     @classmethod
     def copy_logs_handler(cls, get_nodes_fn, coe, keypair):
         """Copy logs closure.