From bb6114ce5094eca25c52a7a1a56156d512cba065 Mon Sep 17 00:00:00 2001 From: Tim Graham Date: Wed, 18 Dec 2024 06:50:48 -0500 Subject: [PATCH] Added DatabaseFeatures.rounds_to_even. This feature flag useful with MongoDB: "Rounding to the nearest even value supports more even distribution of rounded data than always rounding up or down." --- django/db/backends/base/features.py | 3 +++ tests/db_functions/comparison/test_cast.py | 3 ++- tests/db_functions/math/test_round.py | 3 ++- 3 files changed, 7 insertions(+), 2 deletions(-) diff --git a/django/db/backends/base/features.py b/django/db/backends/base/features.py index ef874d74db..53b48673de 100644 --- a/django/db/backends/base/features.py +++ b/django/db/backends/base/features.py @@ -382,6 +382,9 @@ class BaseDatabaseFeatures: # SQL to create a model instance using the database defaults. insert_test_table_with_defaults = None + # Does the Round() database function round to even? + rounds_to_even = False + # A set of dotted paths to tests in Django's test suite that are expected # to fail on this database. django_test_expected_failures = set() diff --git a/tests/db_functions/comparison/test_cast.py b/tests/db_functions/comparison/test_cast.py index 80375cc389..49cabdbd21 100644 --- a/tests/db_functions/comparison/test_cast.py +++ b/tests/db_functions/comparison/test_cast.py @@ -52,7 +52,8 @@ class CastTests(TestCase): ), ).get() self.assertEqual(float_obj.cast_f1_decimal, decimal.Decimal("-1.93")) - self.assertEqual(float_obj.cast_f2_decimal, decimal.Decimal("3.5")) + expected = "3.4" if connection.features.rounds_to_even else "3.5" + self.assertEqual(float_obj.cast_f2_decimal, decimal.Decimal(expected)) author_obj = Author.objects.annotate( cast_alias_decimal=Cast( "alias", models.DecimalField(max_digits=8, decimal_places=2) diff --git a/tests/db_functions/math/test_round.py b/tests/db_functions/math/test_round.py index 04ece4246d..c110dc71ca 100644 --- a/tests/db_functions/math/test_round.py +++ b/tests/db_functions/math/test_round.py @@ -112,7 +112,8 @@ class RoundTests(TestCase): IntegerModel.objects.create(normal=365) obj = IntegerModel.objects.annotate(normal_round=Round("normal", -1)).first() self.assertIsInstance(obj.normal_round, int) - self.assertEqual(obj.normal_round, 370) + expected = 360 if connection.features.rounds_to_even else 370 + self.assertEqual(obj.normal_round, expected) def test_transform(self): with register_lookup(DecimalField, Round):