Functional specification
A functional specification is a document describing a system’s externally observable purpose, capabilities, required behavior, requirements, and use cases without prescribing implementation details.
Software Design for Python Programmers
A functional specification is an external document that states an application's intended capabilities, requirements, objectives, and use cases without internal implementation details.
- How it is used
- Defines the application clients approve before developers design and build it.
- How deep it goes
- Lists requirements and use cases, optionally adding black-box tests, but defers internal implementation details to design.
- Examples
- Uses a Book Catalogue scenario and external black-box tests with specified inputs, actions, and expected results.
- What you can do after
- Evaluate whether clients and developers agree on the application’s intended behavior before implementation proceeds.
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Object-Oriented Software Design in C++
A document that describes an application's externally observable purpose, behavior, and requirements without internal implementation details.
- How it is used
- Defines the application clients approve and developers verify through testing before implementation details determine the design.
- How deep it goes
- Specifies contents, language, use cases, and optional black-box tests while deferring internal implementation details to the design specification.
- Examples
- Uses a Book Catalogue example involving book storage and search, plus external black-box test inputs and expected results.
- What you can do after
- Evaluate whether an application addresses client needs and verify its observable functional and nonfunctional behavior.
Read how Object-Oriented Software Design in C++ explains functional specification →
Related concepts
- specificationcontrasts with · A specification is a formal or informal description of the required or intended behavior, properties, interfaces, or constraints of a system or component.
- requirementsproduced by · A requirement is a stated need, capability, quality, condition, or constraint that a system, product, solution, or project is expected to satisfy.
- help fileequivalent to · A PowerShell help file is documentation describing a command, feature, or concept, including its syntax, parameters, behavior, or usage.
- use casehas part · A use case is a description of a situation or interaction in which a system, method, or capability is applied to achieve or support a goal or outcome.
- functional requirementhas part · A functional requirement specifies a behavior or capability that a system must provide or enable.
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