convert uids to list before passing to make_*_task

RoleResolver returns set of uids, but functions, which
make tasks want list.

Change-Id: I959a61a53ff55da400423ac871a2b61366c75f9a
Closes-Bug: #1606823
(cherry picked from commit 68c0d42ae0)

nailgun/nailgun/orchestrator/plugins_serializers.py

@@ -73,7 +73,7 @@ class BasePluginDeploymentHooksSerializer(object):
                             'not supported', task)
 
             if make_task:
-                yield self._serialize_task(make_task(uids, task), task)
+                yield self._serialize_task(make_task(list(uids), task), task)
 
     def _set_tasks_defaults(self, plugin, tasks):
         for task in tasks:

nailgun/nailgun/test/unit/test_plugins_serializers.py

@@ -15,6 +15,7 @@
 #    under the License.
 
 import copy
+import json
 import mock
 
 from nailgun import consts
@@ -41,9 +42,23 @@ class TestBasePluginDeploymentHooksSerializer(base.BaseTestCase):
         self.hook = BasePluginDeploymentHooksSerializer(
             self.nodes,
             self.cluster,
-            resolver=NullResolver([x['id'] for x in self.nodes])
+            resolver=NullResolver({x['id'] for x in self.nodes})
         )
 
+    def test_tasks_are_serializable(self):
+        stage = 'pre_deployment'
+        role = 'controller'
+
+        plugin = mock.Mock()
+        plugin.full_name = 'plugin_name'
+        plugin.tasks = [
+            {'type': 'shell', 'role': role, 'id': '1', 'stage': stage,
+             'parameters': {'cmd': 'test1', 'cwd': '/', 'timeout': 15}},
+        ]
+
+        raw_result = list(self.hook.deployment_tasks([plugin], stage))
+        json.dumps(raw_result)
+
     def test_original_order_of_deployment_tasks(self):
         stage = 'pre_deployment'
         role = 'controller'