Refs #31197 -- Added tests for combined expressions in CheckConstraint.check.

Thanks Adam Johnson for the report.

Fixed in 306b687520.

tests/migrations/test_operations.py

@@ -1816,6 +1816,34 @@ class OperationTests(OperationTestBase):
             Pony(pink=3, weight=3.0),
         ])
 
+    @skipUnlessDBFeature('supports_table_check_constraints')
+    def test_add_constraint_combinable(self):
+        app_label = 'test_addconstraint_combinable'
+        operations = [
+            CreateModel(
+                'Book',
+                fields=[
+                    ('id', models.AutoField(primary_key=True)),
+                    ('read', models.PositiveIntegerField()),
+                    ('unread', models.PositiveIntegerField()),
+                ],
+            ),
+        ]
+        from_state = self.apply_operations(app_label, ProjectState(), operations)
+        constraint = models.CheckConstraint(
+            check=models.Q(read=(100 - models.F('unread'))),
+            name='test_addconstraint_combinable_sum_100',
+        )
+        operation = migrations.AddConstraint('Book', constraint)
+        to_state = from_state.clone()
+        operation.state_forwards(app_label, to_state)
+        with connection.schema_editor() as editor:
+            operation.database_forwards(app_label, editor, from_state, to_state)
+        Book = to_state.apps.get_model(app_label, 'Book')
+        with self.assertRaises(IntegrityError), transaction.atomic():
+            Book.objects.create(read=70, unread=10)
+        Book.objects.create(read=70, unread=30)
+
     @skipUnlessDBFeature('supports_table_check_constraints')
     def test_remove_constraint(self):
         project_state = self.set_up_test_model("test_removeconstraint", constraints=[