Difference between revisions of "Use Cases"

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(Created page with "= Intro = * Use cases can be used to '''capture''' the systems ''functional'' requirements. * Defined the systems functional acceptance tests. * A use case does two things: # De...")
 
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* A scenario is a description of a '''sequence of actions''' that is a way of achieving a goal.
 
* A scenario is a description of a '''sequence of actions''' that is a way of achieving a goal.
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* The main success scenario is the usual/main/straightforward way of achieving the goal.
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* All scenarios have
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** A precondition : required condition before starting.
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** Interaction steps
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** Postcondition :
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*** Guaranteed state of world once use case exits. ''successful precondition holds for successful exit.''
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*** Exception scenarios : error/alternative cases. May result in different postcondition.
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** A minimal postcondition: Something that guarantees to protect stakeholder interests.
  
  
 
[[Category:REQE]]
 
[[Category:REQE]]

Revision as of 11:24, 31 October 2011

Intro

  • Use cases can be used to capture the systems functional requirements.
  • Defined the systems functional acceptance tests.
  • A use case does two things:
  1. Describe how an actor achieves a goal using the system. This is described in terms of scenarios.
  2. Interests of stakeholder are protected by the system.

Actor

  • An actor is someone or something external to the system and who interacts with the system.

Scenario

  • A scenario is a description of a sequence of actions that is a way of achieving a goal.
  • The main success scenario is the usual/main/straightforward way of achieving the goal.
  • All scenarios have
    • A precondition : required condition before starting.
    • Interaction steps
    • Postcondition :
      • Guaranteed state of world once use case exits. successful precondition holds for successful exit.
      • Exception scenarios : error/alternative cases. May result in different postcondition.
    • A minimal postcondition: Something that guarantees to protect stakeholder interests.