Define Missing Scenarios¶
When writing use cases, it’s important to consider not just the main success scenario, but also the various alternate and error scenarios that can occur. This helps ensure that all possible outcomes are accounted for and that the system can handle them gracefully.
Students should find missing scenarios in the example use case below and discuss them in with the tutor.
UC-01: Customer logs in to Online Banking¶
Primary actor: Customer (retail banking user) Supporting systems: Authentication Service, 2-Factor Service (SMS/Authenticator), Core Banking API, Email/Audit Log Stakeholders & interests:
- Customer — fast, secure access; clear feedback on success/failure
- Bank — protect accounts; meet compliance and audit requirements
- Security/Compliance — enforce lockouts, 2FA, logging
Preconditions¶
- Customer has an active account and online-banking access.
- Customer has valid credentials and (if required) a registered second factor.
- Bank web app is reachable.
Trigger¶
Customer navigates to the bank’s Login page.
Main Success Scenario (Basic Flow)¶
- System displays Login page with inputs for User ID and Password and a Log in button.
- Customer enters User ID and Password.
- Customer clicks Log in.
- System validates credentials with the Authentication Service.
- If the profile requires 2FA, the system prompts for a one-time code and delivers/requests it via the configured method.
- Customer enters the one-time code and submits.
- System validates the code, creates an authenticated session, records an audit entry, and fetches the customer’s summary from Core Banking.
- System redirects to Account Overview and displays a welcome banner with last successful login time.
- Use case ends successfully.
Postconditions (on success)¶
- Authenticated session is active; session metadata and audit trail recorded.
- Customer can navigate to account features.