Edge case

As explained in Architecture Modernization: Socio-technical alignment of software, strategy, and structure

An edge case is an uncommon or exceptional scenario that occurs outside the primary expected path of a process.

An edge case is an uncommon or exceptional scenario outside the primary expected path. In domain modeling, exploring edge cases exposes hidden complexity without losing sight of the business narrative. section 7.1.1

Use edge cases to improve collaborative domain exploration:

• Model them as branches below the main timeline so the primary flow remains visible while alternative outcomes become explicit. section 7.1.1
• Balance detail carefully: overly abstract events hide complexity, while overly technical events obscure the domain narrative. section 7.1.1
• Zoom into important timeline events with Example Mapping, inviting participants to discover varied scenarios and hidden complexity. section 7.4.1

Cancellation after warehouse dispatch

Start with the Cancel Order action and its expected Order Canceled event. If a customer requests a refund after the order has left the warehouse, branch to Cancellation Denied instead. This alternative may reveal a need to model voucher-related scenarios separately. section 7.4.1

Figure 7.4 Modeling edge cases as branches below the main timeline

Use the branching visualization to keep edge cases connected to the main timeline without presenting them as part of the primary flow. section 7.1.1

How Architecture Modernization: Socio-technical alignment of software, strategy, and structure covers it

How deep it goes

Models alternative scenarios as timeline branches and zooms into selected events with Example Mapping.

Examples

Uses cancellation after warehouse dispatch, Cancellation Denied, voucher scenarios, and branches beneath an EventStorming timeline.

What you can do after

Practice/perform scenario mapping that uncovers alternative outcomes and hidden domain complexity around selected events.

How it connects

Connects edge cases to EventStorming, domain events, event granularity, and Example Mapping.

liveBookmanning.com

Read Architecture Modernization: Socio-technical alignment of software, strategy, and structure on liveBook Get the book at manning.com

Also explained in

• 

  liveBookmanning.com
  Learn AI-Assisted Python Programming, Second EditionAn edge case is a software-testing scenario involving an uncommon, boundary, or otherwise exceptional input that may expose defects.
• 

  liveBookmanning.com
  The AI Pocket BookA rare or unusual situation that falls outside common patterns seen during training or testing.
• 

  liveBookmanning.com
  Unit Testing Principles, Practices, and PatternsA boundary or unusual condition in a business scenario that may require distinct behavioral verification.
• 

  liveBookmanning.com
  Shipping Go: Develop, deliver, discuss, design, and go againAn edge case is a rare or extreme input or operating condition that can expose unexpected software behavior.
• 

  liveBookmanning.com
  Functional Programming in JavaScript
• 

  liveBookmanning.com
  The Art of CodeAn edge case is an input or operating condition at an unusual or boundary value where software behavior may differ from the typical case.

Compare how 7 books explain edge case →

Related concepts

• testused by · A test is a procedure or check that evaluates behavior using specified inputs or evidence against expected results or criteria.
• happy pathcontrasts with · A happy path is the expected execution flow in which valid inputs and normal conditions lead to a successful outcome without errors or exceptional handling.
• synthetic dataused by · Synthetic data is data generated artificially rather than collected directly from the target process, often to approximate its properties or meet specified requirements.
• error handlingaddressed by · Error handling is the practice of detecting, representing, propagating, reporting, and responding to errors or failures during software operation.
• asynchronous programmingproduced by · Asynchronous programming is an execution approach in which operations can progress independently without requiring the initiating flow to wait for their completion or an immediate response.

This explainer was generated by Manning's knowledge graph from the text of Architecture Modernization: Socio-technical alignment of software, strategy, and structure. The section links point to the parts of the book it draws on.