Switch to using temporary "areas_2" API field

Depends on: https://github.com/alphagov/notifications-api/pull/3312

This is part of a multi-stage migration where we want to repurpose
the "areas" field in the existing API to something like "areas_2".

app/models/broadcast_message.py

@@ -88,19 +88,21 @@ class BroadcastMessage(JSONModel):
 
     @property
     def areas(self):
-        library_areas = self.get_areas(self._dict['areas'])
+        area_ids = self._dict['areas_2']['ids']
+        polygons = self._dict['areas_2']['simple_polygons']
+        library_areas = self.get_areas(area_ids)
 
         if library_areas:
-            if len(library_areas) != len(self._dict['areas']):
+            if len(library_areas) != len(area_ids):
                 raise RuntimeError(
-                    f'BroadcastMessage has {len(self._dict["areas"])} areas '
+                    f'BroadcastMessage has {len(area_ids)} areas '
                     f'but {len(library_areas)} found in the library'
                 )
             return library_areas
 
         return CustomBroadcastAreas(
-            area_ids=self._dict['areas'],
-            polygons=self._dict['simple_polygons'],
+            area_ids=area_ids,
+            polygons=polygons,
         )
 
     @property
@@ -218,15 +220,23 @@ class BroadcastMessage(JSONModel):
 
     def add_areas(self, *new_area_ids):
         area_ids = list(OrderedSet(
-            self._dict['areas'] + list(new_area_ids)
+            self._dict['areas_2']['ids'] + list(new_area_ids)
         ))
         simple_polygons = self.get_simple_polygons(areas=self.get_areas(area_ids))
-        self._update(areas=area_ids, simple_polygons=simple_polygons.as_coordinate_pairs_lat_long)
+
+        self._update(areas_2={
+            'ids': area_ids,
+            'simple_polygons': simple_polygons.as_coordinate_pairs_lat_long
+        })
 
     def remove_area(self, area_id):
-        area_ids = list(set(self._dict['areas']) - {area_id})
+        area_ids = list(set(self._dict['areas_2']['ids']) - {area_id})
         simple_polygons = self.get_simple_polygons(areas=self.get_areas(area_ids))
-        self._update(areas=area_ids, simple_polygons=simple_polygons.as_coordinate_pairs_lat_long)
+
+        self._update(areas_2={
+            'ids': area_ids,
+            'simple_polygons': simple_polygons.as_coordinate_pairs_lat_long
+        })
 
     def _set_status_to(self, status):
         broadcast_message_api_client.update_broadcast_message_status(

tests/__init__.py

@@ -696,10 +696,10 @@ def broadcast_message_json(
         'reference': reference,
 
         'personalisation': {},
-        'areas': area_ids or [
-            'ctry19-E92000001', 'ctry19-S92000003',
-        ],
-        'simple_polygons': simple_polygons or [],
+        'areas_2': {
+            'ids': area_ids or ['ctry19-E92000001', 'ctry19-S92000003'],
+            'simple_polygons': simple_polygons or [],
+        },
 
         'status': status,
 

tests/app/main/views/test_broadcast.py

@@ -1395,7 +1395,10 @@ def test_add_broadcast_area(
         service_id=SERVICE_ONE_ID,
         broadcast_message_id=fake_uuid,
         data={
-            'areas': ['ctry19-E92000001', 'ctry19-S92000003', 'ctry19-W92000004'], 'simple_polygons': coordinates
+            'areas_2': {
+                'ids': ['ctry19-E92000001', 'ctry19-S92000003', 'ctry19-W92000004'],
+                'simple_polygons': coordinates
+            }
         },
     )
 
@@ -1450,12 +1453,14 @@ def test_add_broadcast_sub_area_district_view(
         service_id=SERVICE_ONE_ID,
         broadcast_message_id=fake_uuid,
         data={
-            'simple_polygons': coordinates,
-            'areas': [
-                # These two areas are on the broadcast already
-                'ctry19-E92000001',
-                'ctry19-S92000003',
-            ] + expected_selected
+            'areas_2': {
+                'simple_polygons': coordinates,
+                'ids': [
+                    # These two areas are on the broadcast already
+                    'ctry19-E92000001',
+                    'ctry19-S92000003',
+                ] + expected_selected
+            }
         },
     )
 
@@ -1488,14 +1493,16 @@ def test_add_broadcast_sub_area_county_view(
         service_id=SERVICE_ONE_ID,
         broadcast_message_id=fake_uuid,
         data={
-            'simple_polygons': coordinates,
-            'areas': [
-                # These two areas are on the broadcast already
-                'ctry19-E92000001',
-                'ctry19-S92000003',
-            ] + [
-                'ctyua19-E10000016'
-            ]
+            'areas_2': {
+                'simple_polygons': coordinates,
+                'ids': [
+                    # These two areas are on the broadcast already
+                    'ctry19-E92000001',
+                    'ctry19-S92000003',
+                ] + [
+                    'ctyua19-E10000016'
+                ]
+            }
         },
     )
 
@@ -1532,8 +1539,10 @@ def test_remove_broadcast_area_page(
         service_id=SERVICE_ONE_ID,
         broadcast_message_id=fake_uuid,
         data={
-            'simple_polygons': coordinates,
-            'areas': ['ctry19-S92000003']
+            'areas_2': {
+                'simple_polygons': coordinates,
+                'ids': ['ctry19-S92000003']
+            },
         },
     )