As a scrum/agile system student, I find the situation where you have to write up a user story in the classical form and at the same time, describe the behaviour of parallel workflow, very hard. As a very simple and general example that can describe the situation, we can write this user story:
As a user that wants to purchase an article, I want to be able to pay with MasterCard, so that the purchased order can be set to status 'to deliver'.
On this user story, there are tons of different "user task alternate workflow" or situations that can define different processes (not necessary errors), like:
While a customer places an order, their credit card failed
While a customer places an order, their user session times out
While a customer uses an ATM machine, the machine runs out of receipts and needs to warn the customer
While a customer places an order, their credit card number doesn't exist
While a customer places an order, the PIN failed
(maybe are not the best examples, but just for describing side effects).
In Agile/Scrum system, you can only describe the desired behaviour, but not the side effects/parallel workflows.
How do you advice me to put in the backlog stories that covers these situations?
How do you advice me to create stories that follow a "Task Process Workflow Diagram"? (this second question is different but related)