Add /lots/ find method returning nested lots

ereuse_devicehub/resources/lot/views.py

@@ -1,13 +1,14 @@
 import uuid
-from typing import Set
+from collections import deque
+from typing import List, Set
 
 import marshmallow as ma
-from flask import request
+from flask import jsonify, request
 from teal.resource import View
 
 from ereuse_devicehub.db import db
 from ereuse_devicehub.resources.device.models import Device
-from ereuse_devicehub.resources.lot.models import Lot
+from ereuse_devicehub.resources.lot.models import Lot, Path
 
 
 class LotView(View):
@@ -25,6 +26,49 @@ class LotView(View):
         lot = Lot.query.filter_by(id=id).one()  # type: Lot
         return self.schema.jsonify(lot)
 
+    def find(self, args: dict):
+        """Returns all lots as required for DevicehubClient::
+
+            [
+                {title: 'lot1',
+                nodes: [{title: 'child1', nodes:[]}]
+            ]
+        """
+        nodes = []
+        for model in Path.query:  # type: Path
+            path = deque(model.path.path.split('.'))
+            self._p(nodes, path)
+        return jsonify({
+            'items': nodes,
+            'url': request.path
+        })
+
+    def _p(self, nodes: List[dict], path: deque):
+        """Recursively creates the nested lot structure.
+
+        Every recursive step consumes path (a deque of lot_id),
+        trying to find it as the value of id in nodes, otherwise
+        it adds itself. Then moves to the node's children.
+        """
+        lot_id = uuid.UUID(path.popleft().replace('_', '-'))
+        try:
+            # does lot_id exist already in node?
+            node = next(part for part in nodes if lot_id == part['id'])
+        except StopIteration:
+            lot = Lot.query.filter_by(id=lot_id).one()
+            node = {
+                'id': lot_id,
+                'title': lot.name,
+                'url': lot.url.to_text(),
+                'closed': lot.closed,
+                'updated': lot.updated,
+                'created': lot.created,
+                'nodes': []
+            }
+            nodes.append(node)
+        if path:
+            self._p(node['nodes'], path)
+
 
 class LotBaseChildrenView(View):
     """Base class for adding / removing children devices and

tests/test_lot.py

@@ -122,7 +122,7 @@ def test_lot_multiple_parents():
 
 
 @pytest.mark.usefixtures(conftest.auth_app_context.__name__)
-def test_lot_unite_graphs():
+def test_lot_unite_graphs_and_find():
     """Adds and removes children uniting already existing graphs.
 
     1  3
@@ -220,7 +220,12 @@ def test_post_add_children_view(user: UserClient):
     assert parent['children'][0]['id'] == child['id']
     child, _ = user.get(res=Lot, item=child['id'])
     assert child['parents'][0]['id'] == parent['id']
-    return child['id']
+
+    lots = user.get(res=Lot)[0]['items']
+    assert len(lots) == 1
+    assert lots[0]['title'] == 'Parent'
+    assert len(lots[0]['nodes']) == 1
+    assert lots[0]['nodes'][0]['title'] == 'Child'
 
 
 def test_lot_post_add_remove_device_view(app: Devicehub, user: UserClient):