Use Case Testing

Use case testing designs tests based on use cases — descriptions of how actors (users) interact with the system to achieve specific goals. Each use case includes a main success scenario and alternative/error scenarios.

Use case structure:

• Actor: Who performs the action (e.g., registered user)
• Precondition: What must be true before starting
• Main flow: The happy path (steps to achieve the goal)
• Alternative flows: Different paths to success
• Exception flows: Error/failure paths
• Postcondition: The state after completion

Example — 'Purchase Course':

• Actor: Registered student
• Precondition: Student is logged in, course is published
• Main flow: Browse → Select → Add to cart → Checkout → Payment → Confirmation
• Alt flow 1: Student already owns course → Show 'Already enrolled'
• Alt flow 2: Student has a coupon → Apply discount
• Exception 1: Payment fails → Show error, allow retry
• Exception 2: Course sold out → Show waitlist option

Each flow becomes one or more test cases. Use case testing ensures you test the system from the user's perspective, covering both happy and unhappy paths.