add order_by support for prefetch_related

tests/test_prefetch_related.py

@@ -228,6 +228,7 @@ async def test_prefetch_related_with_select_related():
 
             album = await Album.objects.select_related(['tracks', 'shops']).filter(name='Malibu').prefetch_related(
                 ['cover_pictures', 'shops__division']).get()
+
             assert len(album.tracks) == 0
             assert len(album.cover_pictures) == 2
             assert album.shops[0].division.name == 'Div 1'
@@ -240,14 +241,15 @@ async def test_prefetch_related_with_select_related():
 
             album = await Album.objects.select_related('tracks__tonation__rand_set').filter(
                 name='Malibu').prefetch_related(
-                ['cover_pictures', 'shops__division']).get()
+                ['cover_pictures', 'shops__division']).order_by(
+                ['-shops__name', '-cover_pictures__artist', 'shops__division__name']).get()
             assert len(album.tracks) == 3
             assert album.tracks[0].tonation == album.tracks[2].tonation == ton1
             assert len(album.cover_pictures) == 2
-            assert album.cover_pictures[0].artist == 'Artist 1'
+            assert album.cover_pictures[0].artist == 'Artist 2'
 
             assert len(album.shops) == 2
-            assert album.shops[0].name == 'Shop 1'
+            assert album.shops[0].name == 'Shop 2'
             assert album.shops[0].division.name == 'Div 1'
 
             track = await Track.objects.select_related('album').prefetch_related(

tests/test_queryset_utils.py

@@ -1,5 +1,11 @@
+import databases
+import sqlalchemy
+
+import ormar
 from ormar.models.excludable import Excludable
+from ormar.queryset.prefetch_query import sort_models
 from ormar.queryset.utils import translate_list_to_dict, update_dict_from_list, update
+from tests.settings import DATABASE_URL
 
 
 def test_empty_excludable():
@@ -96,3 +102,43 @@ def test_updating_dict_inc_set_with_dict_inc_set():
         "cc": {"aa": {"xx", "yy", "oo", "zz", "ii"}, "bb": Ellipsis},
         "uu": Ellipsis,
     }
+
+
+database = databases.Database(DATABASE_URL, force_rollback=True)
+metadata = sqlalchemy.MetaData()
+
+
+class SortModel(ormar.Model):
+    class Meta:
+        tablename = "sorts"
+        metadata = metadata
+        database = database
+
+    id: int = ormar.Integer(primary_key=True)
+    name: str = ormar.String(max_length=100)
+    sort_order: int = ormar.Integer()
+
+
+def test_sorting_models():
+    models = [
+        SortModel(id=1, name='Alice', sort_order=0),
+        SortModel(id=2, name='Al', sort_order=1),
+        SortModel(id=3, name='Zake', sort_order=1),
+        SortModel(id=4, name='Will', sort_order=0),
+        SortModel(id=5, name='Al', sort_order=2),
+        SortModel(id=6, name='Alice', sort_order=2)
+    ]
+    orders_by = {'name': 'asc', 'none': {}, 'sort_order': 'desc'}
+    models = sort_models(models, orders_by)
+    assert models[5].name == 'Zake'
+    assert models[0].name == 'Al'
+    assert models[1].name == 'Al'
+    assert [model.id for model in models] == [5, 2, 6, 1, 4, 3]
+
+    orders_by = {'name': 'asc', 'none': set('aa'), 'id': 'asc'}
+    models = sort_models(models, orders_by)
+    assert [model.id for model in models] == [2, 5, 1, 6, 4, 3]
+
+    orders_by = {'sort_order': 'asc', 'none': ..., 'id': 'asc', 'uu': 2, 'aa': None}
+    models = sort_models(models, orders_by)
+    assert [model.id for model in models] == [1, 4, 2, 3, 5, 6]