Agile development, software engineering
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Agile development focuses on effective communication, customer collaboration, and incremental delivery of working software. The key principles of agile development according to the Agile Alliance include satisfying customers, welcoming changing requirements, frequent delivery, collaboration between business and development teams, and self-organizing teams. Extreme Programming (XP) is an agile process model that emphasizes planning with user stories, simple design, pair programming, unit testing, and frequent integration and testing.
![Extreme Programming (XP) - 1
• The most widely used agile process, originally proposed by
Kent Beck [BEC99]
• XP uses an object-oriented approach as its preferred
development paradigm
• Defines four (4) framework activities
– Planning
– Design
– Coding
– Testing](https://image.slidesharecdn.com/agiledevelopmentsoftwareengineering-170107070838/85/Agile-development-software-engineering-8-320.jpg)
Agile development, software engineering
- 2. What is Agility? • Effective response to change • Effective communication among all stakeholders • Drawing the customer onto the team; eliminate the “us and them” attitude • Organizing a team so that it is in control of the work performed • Rapid, incremental delivery of software
- 3. Principles to achieve agility – by the Agile Alliance (1) 1. Highest priority -> satisfy the customer 2. Welcome changing requirements 3. Deliver working software frequently 4. Business people and developers must work together 5. Build projects around motivated individuals 6. Emphasize face-to-face conversation
- 4. Principles to achieve agility – by the Agile Alliance (2) 7. Working software is the primary measure of progress 8. Agile processes promote sustainable development 9. Continuous attention to technical excellence and good design enhances agility 10. Simplicity – the art of maximizing the amount of work not done – is essential 11. The best designs emerge from self-organizing teams 12. The team tunes and adjusts its behavior to become more effective
- 5. Agile Software Process – Three Key Assumptions • Difficulty in predicting changes of requirements and customer priorities • For many types of s/w, design and construction are added • Analysis, design, construction, and testing are not as predictable as we might like
- 6. Agile Software Process • An agile process must be adaptable • It must adapt incrementally • Requires customer feedback • An effective catalyst for customer feedback is an operational prototype
- 7. 7 Agile Process Models • Extreme Programming (XP) • Adaptive Software Development (ASD) • Dynamic Systems Development Method (DSDM) • Scrum • Crystal • Feature Driven Development (FDD) • Agile Modeling (AM)
- 8. Extreme Programming (XP) - 1 • The most widely used agile process, originally proposed by Kent Beck [BEC99] • XP uses an object-oriented approach as its preferred development paradigm • Defines four (4) framework activities – Planning – Design – Coding – Testing
- 9. Extreme Programming (XP) - 2 planning planning designdesign coding coding testtest refactoring user stories values acceptance test criteria iteration plan simple design CRC cards spike solutions prototypes pair programming unit test continuous integration acceptance testing software increment project velocity computed software increment project velocity computed Release
- 10. XP - Planning • Begins with the creation of a set of stories (also called user stories) • Each story is written by the customer and is placed on an index card • The customer assigns a value (i.e. a priority) to the story • Agile team assesses each story and assigns a cost • Stories are grouped to for a deliverable increment • A commitment is made on delivery date • After the first increment “project velocity” is used to help define subsequent delivery dates for other increments
- 11. XP - Design • Follows the keep it simple principle • Encourage the use of CRC (class-responsibility-collaborator) cards • For difficult design problems, suggests the creation of “spike solutions”—a design prototype • Encourages “refactoring”—an iterative refinement of the internal program design • Design occurs both before and after coding commences
- 12. XP - Coding • Recommends the construction of a series of unit tests for each of the stories before coding commences • Encourages “pair programming” – Mechanism for real-time problem solving and real-time quality assurance – Keeps the developers focused on the problem at hand • Needs continuous integration with other portions (stories) of the s/w, which provides a “smoke testing” environment
- 13. XP - Testing • Unit tests should be implemented using a framework to make testing automated. This encourages a regression testing strategy. • Integration and validation testing can occur on a daily basis • Acceptance tests, also called customer tests, are specified by the customer and executed to assess customer visible functionality • Acceptance tests are derived from user stories
Editor's Notes
- #15: http://www.extremeprogramming.org/map/project.html