Fixed #19259 -- Added group by selected primary keys support.

tests/aggregation_regress/tests.py

@@ -7,10 +7,11 @@ from operator import attrgetter
 
 from django.contrib.contenttypes.models import ContentType
 from django.core.exceptions import FieldError
+from django.db import connection
 from django.db.models import (
     F, Q, Avg, Count, Max, StdDev, Sum, Value, Variance,
 )
-from django.test import TestCase, skipUnlessDBFeature
+from django.test import TestCase, skipUnlessAnyDBFeature, skipUnlessDBFeature
 from django.test.utils import Approximate
 from django.utils import six
 
@@ -1011,7 +1012,7 @@ class AggregationTests(TestCase):
         # Check that the query executes without problems.
         self.assertEqual(len(qs.exclude(publisher=-1)), 6)
 
-    @skipUnlessDBFeature("allows_group_by_pk")
+    @skipUnlessAnyDBFeature('allows_group_by_pk', 'allows_group_by_selected_pks')
     def test_aggregate_duplicate_columns(self):
         # Regression test for #17144
 
@@ -1041,7 +1042,7 @@ class AggregationTests(TestCase):
             ]
         )
 
-    @skipUnlessDBFeature("allows_group_by_pk")
+    @skipUnlessAnyDBFeature('allows_group_by_pk', 'allows_group_by_selected_pks')
     def test_aggregate_duplicate_columns_only(self):
         # Works with only() too.
         results = Author.objects.only('id', 'name').annotate(num_contacts=Count('book_contact_set'))
@@ -1067,13 +1068,14 @@ class AggregationTests(TestCase):
             ]
         )
 
-    @skipUnlessDBFeature("allows_group_by_pk")
+    @skipUnlessAnyDBFeature('allows_group_by_pk', 'allows_group_by_selected_pks')
     def test_aggregate_duplicate_columns_select_related(self):
         # And select_related()
         results = Book.objects.select_related('contact').annotate(
             num_authors=Count('authors'))
         _, _, grouping = results.query.get_compiler(using='default').pre_sql_setup()
-        self.assertEqual(len(grouping), 1)
+        # In the case of `group_by_selected_pks` we also group by contact.id because of the select_related.
+        self.assertEqual(len(grouping), 1 if connection.features.allows_group_by_pk else 2)
         self.assertIn('id', grouping[0][0])
         self.assertNotIn('name', grouping[0][0])
         self.assertNotIn('contact', grouping[0][0])