public void CorrectRequestForMaintenance() { var factory = Substitute.For <IConnection>(); var client = new DatabasesClient(factory); var maintenance = new Models.Requests.MaintenanceWindow(); client.Maintenance("1", maintenance); var parameters = Arg.Is <List <Parameter> >(list => (string)list[0].Value == "1"); factory.Received().ExecuteRaw("databases/{id}/maintenance", parameters, maintenance, Method.POST); }