What Is a Use Case, Purpose of Use Case and How to Write Use Case?

 

Use Case

Use cases serve as a powerful way to outline and understand how users interact with a system or product. They're like detailed stories that capture various scenarios, including:

1. Success scenarios: These describe the expected and desired interactions between the user and the system. They outline how the system should ideally behave when everything goes right.

2. Failure scenarios: These highlight potential issues or errors that might occur during interaction. They cover what happens when things don’t go as planned and help prepare for handling such situations.

3. Critical variations or exceptions: These are deviations from the standard paths outlined in the success scenarios. They often involve edge cases or unique scenarios that need special attention.

Use cases are valuable not just for developers but also for quality assurance teams. They help ensure that the software is tested comprehensively, covering both regular and edge-case scenarios.

Purpose of  Use Case

The purpose of a use case is to:

• Manage scope
• Establish Requirements
• Outline the ways a user will interact with the system 
• Visualize system architecture
• Communicate technical requirements to business stakeholders
• Risk management

How to Write Use case

Writing a use case involves creating a detailed narrative that outlines how a user interacts with a system or product to achieve a specific goal. Here's a step-by-step guide to writing a use case:

Identify the Actors: Start by identifying the different actors or users who will interact with the system. Actors can be primary users, administrators, external systems, etc.
Define the Goal or Objective: Clearly state the goal the user intends to achieve by interacting with the system. This goal forms the basis of your use case.
Outline Preconditions: Describe any conditions that must be true before the use case can begin. For instance, the user might need to be logged in or have specific permissions.
Describe the Main Flow: Write down the sequence of steps the user takes to accomplish their goal. Use clear and concise language to describe each step in the user's actions.
Document Alternate Flows: Identify any alternative paths or deviations from the main flow. These can include exceptional scenarios, error handling, or alternate approaches to achieving the goal.
Include Postconditions: Outline what the system will look like or what state it will be in after the use case is completed successfully.