public void CorrectRequestForAddUser() { var factory = Substitute.For <IConnection>(); var client = new DatabasesClient(factory); var user = new Models.Requests.DatabaseUser(); client.AddUser("1", user); var parameters = Arg.Is <List <Parameter> >(list => (string)list[0].Value == "1"); factory.Received().ExecuteRequest <DatabaseUser>("databases/{id}/users", parameters, user, "user", Method.POST); }