Fixed #24959 -- Fixed queries using negative timedeltas on MySQL and Oracle.

1 files changed, 20 insertions, 0 deletions

diff --git a/tests/expressions/tests.py b/tests/expressions/tests.py
index f8301b7161..c6daa504b1 100644
--- a/tests/expressions/tests.py
+++ b/tests/expressions/tests.py
@@ -1043,6 +1043,26 @@ class FTimeDeltaTests(TestCase):
         ).order_by('name')
         self.assertQuerysetEqual(over_estimate, ['e3', 'e4'], lambda e: e.name)
 
+    def test_negative_timedelta_update(self):
+        # subtract 30 seconds, 30 minutes, 2 hours and 2 days
+        experiments = Experiment.objects.filter(name='e0').annotate(
+            start_sub_seconds=F('start') + datetime.timedelta(seconds=-30),
+        ).annotate(
+            start_sub_minutes=F('start_sub_seconds') + datetime.timedelta(minutes=-30),
+        ).annotate(
+            start_sub_hours=F('start_sub_minutes') + datetime.timedelta(hours=-2),
+        ).annotate(
+            new_start=F('start_sub_hours') + datetime.timedelta(days=-2),
+        )
+        expected_start = datetime.datetime(2010, 6, 23, 9, 45, 0)
+        if connection.features.supports_microsecond_precision:
+            # subtract 30 microseconds
+            experiments = experiments.annotate(new_start=F('new_start') + datetime.timedelta(microseconds=-30))
+            expected_start += datetime.timedelta(microseconds=+746970)
+        experiments.update(start=F('new_start'))
+        e0 = Experiment.objects.get(name='e0')
+        self.assertEqual(e0.start, expected_start)
+
 
 class ValueTests(TestCase):
     def test_update_TimeField_using_Value(self):