Always return chassis UUID in node's API representation

It should be returned no matter if a node belongs to a chassis (in
which case it is that chassis' UUID) or not (in which case it should
be None).

Closes-Bug: #1620749
Change-Id: If088f604ad9bb766d591d29466fdd1456734c8df

ironic/api/controllers/v1/node.py

@@ -635,7 +635,9 @@ class Node(base.APIBase):
         return self._chassis_uuid
 
     def _set_chassis_uuid(self, value):
-        if value and self._chassis_uuid != value:
+        if value in (wtypes.Unset, None):
+            self._chassis_uuid = value
+        elif self._chassis_uuid != value:
             try:
                 chassis = objects.Chassis.get(pecan.request.context, value)
                 self._chassis_uuid = chassis.uuid
@@ -648,8 +650,6 @@ class Node(base.APIBase):
                 # response for a POST request to create a Port
                 e.code = http_client.BAD_REQUEST
                 raise
-        elif value == wtypes.Unset:
-            self._chassis_uuid = wtypes.Unset
 
     uuid = types.uuid
     """Unique UUID for this node"""

ironic/tests/unit/api/v1/test_nodes.py

@@ -1662,9 +1662,12 @@ class TestPost(test_api_base.BaseApiTest):
         self.addCleanup(p.stop)
 
     @mock.patch.object(timeutils, 'utcnow')
-    def _test_create_node(self, mock_utcnow, headers=None, **kwargs):
+    def _test_create_node(self, mock_utcnow, headers=None,
+                          remove_chassis_uuid=False, **kwargs):
         headers = headers or {}
         ndict = test_api_utils.post_get_test_node(**kwargs)
+        if remove_chassis_uuid:
+            del ndict['chassis_uuid']
         test_time = datetime.datetime(2000, 1, 1, 0, 0)
         mock_utcnow.return_value = test_time
         response = self.post_json('/nodes', ndict,
@@ -1687,6 +1690,20 @@ class TestPost(test_api_base.BaseApiTest):
     def test_create_node(self):
         self._test_create_node()
 
+    def test_create_node_chassis_uuid_always_in_response(self):
+        result = self._test_create_node(chassis_uuid=None)
+        self.assertEqual(None, result['chassis_uuid'])
+        result = self._test_create_node(uuid=uuidutils.generate_uuid(),
+                                        remove_chassis_uuid=True)
+        self.assertEqual(None, result['chassis_uuid'])
+
+    def test_create_node_invalid_chassis(self):
+        ndict = test_api_utils.post_get_test_node(chassis_uuid=0)
+        response = self.post_json('/nodes', ndict, expect_errors=True)
+        self.assertEqual(http_client.BAD_REQUEST, response.status_int)
+        self.assertEqual('application/json', response.content_type)
+        self.assertTrue(response.json['error_message'])
+
     def test_create_node_explicit_network_interface(self):
         headers = {api_base.Version.string: '1.20'}
         result = self._test_create_node(headers=headers,

releasenotes/notes/always-return-chassis-uuid-4eecbc8da2170cb1.yaml

@@ -0,0 +1,5 @@
+---
+fixes:
+  - Fixed an issue of not returning ``chassis_uuid`` field of a node in API
+    responses if it does not belong to a chassis. It should be always returned,
+    either set to None, or to a corresponding chassis UUID.