Extend OSC "node list" cmd to fetch nodes without instance UUID

The openstackclient command to get a list of nodes is 'openstack baremetal
node list'. It has the optional argument '--associated'. If this is
specified, it will return nodes that are associated with instances
(ie, node.instance_uuid is set to some UUID). However, there is no way to
filter the nodes to get ones that are NOT associated with instances.

Added "--unassociated" option and unit testcase for this.

Change-Id: Iad60e92335bab4eb4a71aedb4e90d34d0186c5cc
Closes-bug: #1619091

ironicclient/osc/v1/baremetal_node.py

@@ -453,12 +453,16 @@ class ListBaremetalNode(command.Lister):
             default=False,
             help="List nodes in maintenance mode.",
         )
-        parser.add_argument(
+        associated_group = parser.add_mutually_exclusive_group()
+        associated_group.add_argument(
             '--associated',
-            dest='associated',
             action='store_true',
-            default=False,
-            help="List only nodes associated with an instance."
+            help=_('List only nodes associated with an instance.'),
+        )
+        associated_group.add_argument(
+            '--unassociated',
+            action='store_true',
+            help=_('List only nodes not associated with an instance.'),
         )
         parser.add_argument(
             '--provision-state',
@@ -511,7 +515,9 @@ class ListBaremetalNode(command.Lister):
         params['limit'] = parsed_args.limit
         params['marker'] = parsed_args.marker
         if parsed_args.associated:
-            params['associated'] = parsed_args.associated
+            params['associated'] = True
+        if parsed_args.unassociated:
+            params['associated'] = False
         if parsed_args.maintenance:
             params['maintenance'] = parsed_args.maintenance
         if parsed_args.provision_state:

ironicclient/tests/unit/osc/v1/test_baremetal_node.py

@@ -580,6 +580,39 @@ class TestBaremetalList(TestBaremetal):
             **kwargs
         )
 
+    def test_baremetal_list_unassociated(self):
+        arglist = [
+            '--unassociated',
+        ]
+        verifylist = [
+            ('associated', False),
+        ]
+
+        parsed_args = self.check_parser(self.cmd, arglist, verifylist)
+
+        self.cmd.take_action(parsed_args)
+
+        # Set expected values
+        kwargs = {
+            'marker': None,
+            'limit': None,
+            'associated': False,
+        }
+
+        self.baremetal_mock.node.list.assert_called_with(
+            **kwargs
+        )
+
+    def test_baremetal_list_both_associated_unassociated_not_allowed(self):
+        arglist = [
+            '--associated', '--unassociated',
+        ]
+        verifylist = []
+
+        self.assertRaises(oscutils.ParserException,
+                          self.check_parser,
+                          self.cmd, arglist, verifylist)
+
     def test_baremetal_list_provision_state(self):
         arglist = [
             '--provision-state', 'active',

releasenotes/notes/osc-node-list-unassociated-60e46958a0abc3e5.yaml

@@ -0,0 +1,7 @@
+---
+features:
+  - |
+    Adds an option ``--unassociated`` to the
+    ``openstack baremetal node list`` command. It provides the
+    ability to get a list of the nodes that are not associated
+    with instances.