edit assertion for MongoDB's even rounding

Author: timgraham

tests/db_functions/comparison/test_cast.py

@@ -52,7 +52,8 @@ def test_cast_to_decimal_field(self):
             ),
         ).get()
         self.assertEqual(float_obj.cast_f1_decimal, decimal.Decimal("-1.93"))
-        self.assertEqual(float_obj.cast_f2_decimal, decimal.Decimal("3.5"))
+        # MongoDB rounds to 3.4 instead of 3.5 like other databases.
+        self.assertEqual(float_obj.cast_f2_decimal, decimal.Decimal("3.4"))
         author_obj = Author.objects.annotate(
             cast_alias_decimal=Cast(
                 "alias", models.DecimalField(max_digits=8, decimal_places=2)