Unit 3 Flashcards
What are use cases?
Use cases describe the limits of a functional system and eliminate sources of error early in the development process by documenting alternative courses of action during interaction for all action steps.
Use cases are a method of formulating user requirements for a system in natural language and thus in a way that can be understood by different project participants while following a stringent content structure.
What are user stories?
User stories are a way of documenting user requirements inspired by use cases but tailored to agile development processes. User stories are, therefore, much smaller in scope and are also used to estimate the work required for each iteration.
What is a use case specification?
A use case specification represents a detailed description of the interaction of a specific actor with the system, achieving a goal.
Name two popular formats of use cases?
The original form is that of a verbal description, but a diagrammatic representation is also possible.
Show me an example of a formulated use case?
EXAMPLE OF A FORMULATED USE CASE
- Primary actor: Applicant
- Goal in context: The applicant buys an item through the system and gets it delivered. Payment is not included.
- Scope: Business, i.e., the entire purchasing process, electronic and non-electronic, as it appears to employees
- Level: Summary
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Stakeholders and interests:
Applicant: Wants to get what they ordered easily Business: Controls spending but allow necessary purchases Seller: Wants to be paid for the goods delivered
- Preconditions: None
- Minimum guarantees: Each order that is shipped must be approved by an authorized representative. Orders are tracked so that the company receives an invoice only for the goods received.
- Guarantees of success: The applicant has received the goods and the correct amount will be charged for them.
- Trigger: Applicant decides to buy an item.
Show me an example of a main success scenario?
MAIN SUCCESS SCENARIO
- Applicant: Submits an application
- Approver: Checks remaining budget, price of goods, and complete application for submission
- Buyer: Checks contents of warehouse and finds best supplier for goods
- Authorizer: Signature of approver validates
- Buyer: Completes inquiry for order and arranges purchase order with seller
- Seller: Delivers goods to the receiving department and receives confirmation of delivery (beyond the scope)
- Recipient: Registers delivery and send goods to applicant
- Applicant: Marks application as delivered
What are the components of a use case specification?
- Actors: anything and everything with a behavior, including technical devices, institutions, or groups
- Stakeholder: anyone with a vested interest in the behavior of the system
- Primary actor: the entity that initiates an interaction with the system to achieve a specific goal
- Use case: a contract between all stakeholders regarding the behavior of the system
- Objective (scope): identifies the boundaries of the system to be designed
- Preconditions and guarantees: what must be true before and after the use case
- Main success scenario: a case in which the interaction between the primary actor and the system is smooth
- Extensions: alternatives to the main success scenario that describe where the interaction can go differently and fail
- A numbering scheme: this allows one to assign the extensions to the steps of the main success scenario
List the use case formats
- A full use case lists key features in a single-column layout, then presents the main success scenario using numbered steps, followed by the extensions that relate to those steps in their numbering.
- In the informal form of use cases, all central information is integrated into a short narrative text. The main success scenario in the first paragraph is followed by the extensions in another paragraph.
- The conversation format records the actions of the actor and the system in two distinct columns as a dialogue in which each action can be clearly assigned to one side or the other.
What are the steps in use case creation?
- Create an in-out list, staking out the scope of the system to be developed or deciding which functions will not be covered.
- Brainstorm all actors involved in the system under development (SuD) and create an actor-goal list, indicating the goals each actor is pursuing.
- Create a list of short descriptions of use cases (“briefs”) based on the actor-goal list
- Formulate the use case specification with all necessary components.
- If required, create a use case diagram in which the relationships between the use cases are visualized.
What are in-out lists?
With the help of in-out lists, specific functions of a system can be classified in the development team as to whether they are – and can be – part of the system (“in”) or not (“out”; Cockburn, 2001, p. 35)
What are user stories?
User stories are a method for documenting and managing requirements, especially in software programming. (Used in Agile Methods)
What is the structure of a user story?
The three components of a user story are the story card on which the user story is described, a set of acceptance criteria that determine when the story can be considered ready for implementation, and the conversations around the user story that are used to negotiate and flesh out the content for implementation
What does a story card do?
Each story card contains a concisely formulated user story that describes an actor, the goal they want to achieve, and the added value this goal has for them.
Provide an example of a user story structure:
As a [role/user], I want [goal/desire/function] so that [outcome/justification/benefit].
What is acceptance criteria?
The acceptance criteria are listed on the back of the story cards, describing when the user story on the front of the card is fulfilled.
