Add sys_uuid property to Adapter

This adds a sys_uuid to the Adapter class. The ManagedSystem uuid
should never change, so the Adapter class is given a sys_uuid property
and caches the value. This will allow us to use the adapter property
as the parent uuid when addressing CHILD objects.

Change-Id: Iee9933c8f6afe0c9ab13d72f7327676d6f8dd47a

pypowervm/adapter.py

@@ -596,6 +596,7 @@ def __init__(self, session=None, use_cache=False, helpers=None):
 
         self.session = session if session else Session()
         self._helpers = self._standardize_helper_list(helpers)
+        self._sys_uuid = None
 
     @staticmethod
     def _standardize_helper_list(helpers):
@@ -609,6 +610,14 @@ def helpers(self):
         """Returns a copy of the list of helpers for the adapter."""
         return list(self._helpers) if self._helpers else []
 
+    @property
+    def sys_uuid(self):
+        if self._sys_uuid is None:
+            # Can't use the wrapper here without a local import
+            resp = self.read('ManagedSystem')
+            self._sys_uuid = resp.feed.entries[0].uuid
+        return self._sys_uuid
+
     @property
     def traits(self):
         return self.session.traits

pypowervm/tests/test_adapter.py

@@ -842,6 +842,24 @@ def test_extract_atom(self, mock_fromstring, mock_unm_ent, mock_unm_feed):
         mock_unm_feed.assert_not_called()
         mock_unm_ent.assert_not_called()
 
+    @mock.patch('pypowervm.adapter.Adapter.read')
+    def test_sys_uuid(self, mock_read):
+
+        # Set and return the sys_uuid if not yet defined
+        adapter = adp.Adapter(self.sess)
+        mock_resp = mock.MagicMock()
+        mock_resp.feed.entries[0].uuid = 'uuid'
+        mock_read.return_value = mock_resp
+        sys_uuid = adapter.sys_uuid
+        mock_read.assert_called_once_with('ManagedSystem')
+        self.assertEqual('uuid', sys_uuid)
+        self.assertEqual('uuid', adapter._sys_uuid)
+
+        # Return sys_uuid if defined already
+        mock_read.reset_mock()
+        sys_uuid = adapter.sys_uuid
+        mock_read.assert_not_called()
+
 
 class TestElement(testtools.TestCase):
     def setUp(self):