Software Development Life Cycle (SDLC)

• Testing happens throughout the software development life cycle (SDLC)
• Testing is part of a software development lifecycle model
• Different forms of testing exist in levels and types
• The life cycle model impacts testing significantly

Software Development Cycle

• Period from deciding to develop software to when it is delivered
• Includes requirements, design, implementation, test, and sometimes installation/checkout phases -Phases may overlap or iterate depending on the approach used
• Sometimes used to describe a longer period that includes when the software is no longer enhanced or its entire life

Software Life Cycle

• The period from when a software product is conceptualized until it is no longer usable
• Includes concept, requirements, design, implementation, test, installation/checkout, operation/maintenance, and sometimes retirement phases -Phases may also overlap or iterate

Software Development Models

• A software process model presents a description of a process from a specific perspective
• Important testing characteristics
  • Every development activity has a corresponding test activity
  • Each test level has specific test objectives
  • Test analysis and design should start during the corresponding development activity
  • Testers should help define/refine requirements and design

Sequential Development Models

• A software development lifecycle model where a system develops linearly through discrete, successive phases without overlap
  • Examples: Waterfall, V-model

Waterfall Model

• One of the first process development models
• Best for well-understood problems with minimal or no requirements changes
• Simple to explain to customers
• Presents a high-level view of the development process as a sequence of activities
• Phases are marked by milestones and deliverables (artifacts)

Strengths and Drawbacks of the Waterfall Model

• Strengths
  • Simplifies process
  • Provides well documented phases to clarify decisions, create audit trails, and concrete milestones
• Drawbacks:
  • Lacks guidance on handling changes during development, assuming frozen requirements
  • It has no iterative activities for creating a final product

V-Model

• Includes four test levels
  • Component, integration, system, and acceptance testing
• Test level: Specific instantiation of a test process
• Iterative models start with a product and refine it
• Incremental models complete one piece at a time

Iterative and Incremental Development

• Incremental development model: Component/system developed through increments
• Iterative development model: Component/system developed through repeated cycles
• Iterative and incremental models issues:
  • Need for more regression testing
  • Defects outside the scope of an iteration/increment
  • Less thorough testing

RUP (Rational Unified Process)

• Example of incremental and iterative development
• Involves four steps
  • Inception
  • Elaboration
  • Construction
  • Transition

Scrum

• An iterative and incremental framework for effective team collaboration used in Agile development
• Uses small Teams
• Consists of key roles:
  • The Product Owner
  • The Development Team
  • The Scrum Master

Kanban Board

• The Kanban system originated in manufacturing at Toyota
• Principles
  • Limits for activities
  • Strong focus on customer needs

Spiral Model

• Risk-based model
• Involves four steps:
  • Determine objectives
  • Identify risks and alternatives
  • Develop and test
  • Plan the next iteration

Agile Development

• It is a group of software development methodologies
• Uses teams of around 5 to 9 people
• Agile Manifesto (2001) values:
  • Individuals and interactions over processes and tools
  • Working software over comprehensive documentation
  • Customer collaboration over contract negotiation
  • Responding to change over following a plan

Agile; Benefits for Testing

• Focuses on good quality code
• Includes testing with self-organizing teams
• Has accessibility of business stakeholders and a simplicity of design

Agile; Challenges for Testing

• New test basis needing different kinds of testers
• There is a perception that testers are not needed because of constant time constrains and complicated testing

SDLC Models

There is not a "best" model, most suitable model depends on

• The project goal, type of product being developed, business priorities or and risk

Commercial off-the-shelf (COTS)

• A type of product developed in an identical format for a large number of customers in the general market.

Explore the software development life cycle (SDLC), from initial concept to retirement. Understand the phases, including requirements, design, implementation, testing, and maintenance. Discover various software development models and their impact on the testing process.