ToString before regexMatch.

Author: WaVEV

django_mongodb/features.py

@@ -254,7 +254,6 @@ def django_test_expected_failures(self):
             "db_functions.datetime.test_extract_trunc.DateFunctionTests.test_extract_year_exact_lookup",
             # FieldDoesNotExist with ordering.
             "model_fields.test_jsonfield.TestQuerying.test_ordering_grouping_by_count",
-            "model_fields.test_jsonfield.TestQuerying.test_obj_subquery_lookup",
         },
         "Count doesn't work in QuerySet.annotate()": {
             "annotations.tests.AliasTests.test_alias_annotate_with_aggregation",