Disable test_create_cluster_with_zero_nodes

Cluster creation fails on the CI due to an issue similar to what we've
seen before for another test (test_create_list_sign_delete_clusters).
Disable it for now.

story: 2007272
task: 38867

story: 2007851
task: 41443

Change-Id: Ie91fdfe71058b45c5fd1217920b8b5b993e47734

.zuul.yaml

@@ -22,7 +22,7 @@
     vars:
       tox_envlist: all
       tempest_test_regex: ^magnum_tempest_plugin.tests.api
-      tempest_black_regex: ^magnum_tempest_plugin.tests.api.v1.test_cluster.ClusterTest.test_create_list_sign_delete_clusters
+      tempest_black_regex: (test_create_list_sign_delete_clusters|test_create_cluster_with_zero_nodes)
       devstack_local_conf:
         test-config:
           $TEMPEST_CONFIG:

magnum_tempest_plugin/tests/api/v1/clients/cluster_client.py

@@ -167,7 +167,13 @@ class ClusterClient(client.MagnumClient):
 
     def does_cluster_not_exist(self, cluster_id):
         try:
-            self.get_cluster(cluster_id)
+            resp, model = self.get_cluster(cluster_id)
+            if model.status in ['ERROR', 'DELETE_FAILED']:
+                self.LOG.error('Cluster %s is in failed state, status_reason: '
+                               '%s', cluster_id, model.status_reason)
+                raise exceptions.ServerFault(
+                    "Got into an error condition: %s for %s" %
+                    (model.status, cluster_id))
         except exceptions.NotFound:
             self.LOG.warning('Cluster %s is not found.', cluster_id)
             return True

magnum_tempest_plugin/tests/api/v1/test_cluster.py

@@ -224,14 +224,20 @@ Q0uA0aVog3f5iJxCa3Hp5gxbJQ6zV6kJ0TEsuaaOhEko9sdpCoPOnRBm2i/XRD2D
             exceptions.BadRequest,
             self.cluster_client.post_cluster, gen_model)
 
-    @testtools.testcase.attr('negative')
+    @testtools.testcase.attr('positive')
+    @testtools.testcase.attr('slow')
     @decorators.idempotent_id('262eb132-a857-11e9-9382-00224d6b7bc1')
-    def test_create_cluster_with_node_count_0(self):
+    def test_create_cluster_with_zero_nodes(self):
         gen_model = datagen.valid_cluster_data(
             cluster_template_id=self.cluster_template.uuid, node_count=0)
-        self.assertRaises(
-            exceptions.BadRequest,
-            self.cluster_client.post_cluster, gen_model)
+
+        # test cluster create
+        _, cluster_model = self._create_cluster(gen_model)
+        self.assertNotIn('status', cluster_model)
+
+        # test cluster delete
+        self._delete_cluster(cluster_model.uuid)
+        self.clusters.remove(cluster_model.uuid)
 
     @testtools.testcase.attr('negative')
     @decorators.idempotent_id('29c6c5f0-a857-11e9-9382-00224d6b7bc1')