Map<String, Object> nested = new HashMap<>();
        nested.put("NestedKey", "nestedValue");
        source.put("NestedMap", nested);

        Map<String, Object> result = searchLogHelper.toLowerHyphen(source);

        assertEquals("value1", result.get("test_key"));
        assertEquals("value2", result.get("another_test_key"));

        @SuppressWarnings("unchecked")