resource group diff method based on flat model keys

orchestrator/model/resources.py

@@ -134,6 +134,12 @@ class ResourceGroup(Resource):
     def resources(self):
         return list(self.__resources.values())
 
+    def diff(self, other):
+        flat_self = self.flatten()
+        flat_other = other.flatten()
+        diff_keys = set(flat_self.keys()).symmetric_difference(flat_other.keys())
+        return {key: flat_self.get(key, flat_other.get(key)) for key in diff_keys}
+
     def flatten(self, fqn=None):
         flat = dict()
         for resource in self.resources:

tests/test_resources.py

+import copy
 import json
 from unittest.case import TestCase
 
@@ -251,6 +252,7 @@ class ResourceGroupTest(TestCase):
                             ResourceGroup(id='some_group', resources=[resource2]))
 
     def test_resource_group_flatten(self):
+        # given
         tree_dict = {
             'id': 'root',
             'type': 'group',
@@ -284,7 +286,54 @@ class ResourceGroupTest(TestCase):
             'root.level-1.instance-3.type': 'instance'
         }
 
+        # when
         tree_resource = Resource(tree_dict)
         flat_dict = tree_resource.flatten()
 
+        # then
         self.assertEqual(expected_flat_dict, flat_dict)
+
+    def test_resource_group_diff(self):
+        # given
+        tree_dict1 = {
+            'id': 'root',
+            'type': 'group',
+            'resources': [
+                {
+                    'id': 'instance-1',
+                    'type': 'instance'
+                },
+                {
+                    'id': 'level-1',
+                    'type': 'group',
+                    'resources': [
+                        {
+                            'id': 'instance-2',
+                            'type': 'instance'
+                        },
+                        {
+                            'id': 'instance-3',
+                            'type': 'instance'
+                        }
+                    ]
+                }
+            ]
+        }
+        group1 = ResourceGroup(tree_dict1)
+
+        tree_dict2 = copy.deepcopy(tree_dict1)
+        del tree_dict2['resources'][0]
+        group2 = ResourceGroup(tree_dict2)
+
+        expected_diff = {
+            'root.instance-1.id': 'instance-1',
+            'root.instance-1.type': 'instance',
+        }
+
+        # when
+        diff1 = group1.diff(group2)
+        diff2 = group2.diff(group1)
+
+        # then
+        self.assertEqual(diff1, diff2)
+        self.assertEqual(expected_diff, diff1)