Integrating Requirements Engineering into Software Development Processes

1. SEG3101 (Fall 2018) Integrating Requirements Engineering into Software Development Processes Daniel Amyot, University of Ottawa Based on Powerpoint slides by Gunter Mussbacher (2009) and material from S. Somé 2008, D. Amyot 2008-2017, XP, EPF, SPEM, RUP, SEMAT, ISO

2. Table of Contents • Software Process Engineering and Frameworks • SPEM, EPF, RUP • Agile Methods • Overview • Extreme Programming (XP), Practices, and Process • Lean Software Development • Scrum • DevOps • Conclusions • Role of RE and Comparison • Standards • Perfection is attained not when there is no longer anything to add, but when there is no longer anything to take away.1 [1] Antoine de Saint-Exupéry (1900 - 1944), “Wind, Sand and Stars”

3. Software Process Engineering & Frameworks

4. SW Process Engineering Agile Methods Overview Extreme Programming Practices XP Process Conclusion Software Process Engineering • Software process engineering consists in developing software development processes suitable for a given environment (organization, nature of projects/software, social and financial constraints, etc.) • Such processes include (requirements engineering) activities, roles, and artefacts (or work products, i.e.: documents, models, code…) • Metamodel: Activity Role Artefact

5. SW Process Engineering Agile Methods Overview Extreme Programming Practices XP Process Conclusion Basic concepts • Artefact • Data element produced during the development • e.g.: document, diagram, report, source code, model, etc. • Role • Set of skills and responsibilities • e.g.: project manager, analyst, developer, etc. • Activity • Small, definable, reusable task that can be allocated to a single role • e.g.: developing detailed use cases

6. SW Process Engineering Agile Methods Overview Extreme Programming Practices XP Process Conclusion Tools/Standards for Process Engineering • Customizable software process engineering frameworks • Predefined and extensible development roles, activities, and artifacts • OMG standard: Software & Systems Process Engineering Metamodel specification (SPEM), Version 2.0, April 2008 • http://www.omg.org/spec/SPEM/2.0/ • Successor of IBM’s Rational Unified Process (RUP), a commercial framework • Eclipse Process Framework (EPF) – an Eclipse Project • Predefined and extensible roles, tasks, and development styles • http://www.eclipse.org/epf/ • Sample process specified with SPEM/EPF: OpenUP (interactive Wiki) • Free EPF Composer tool • Sample commercial tool: Rational Method Composer (RMC) • A tool for defining and monitoring your own development process • http://www-03.ibm.com/software/products/en/rmc

7. SW Process Engineering Agile Methods Overview Extreme Programming Practices XP Process Conclusion RMC Sample Snapshots

8. SW Process Engineering Agile Methods Overview Extreme Programming Practices XP Process Conclusion Rational Unified Process (RUP) • One commercial implementation of the Unified Process • Developed by Jacobson, Booch, Rumbaugh (1996-2003) • An IBM product. Old but still influential… • OpenUP is a more recent and simpler version, less versatile though • Vocabulary and concepts • Artefacts, roles, disciplines, activities • Use case-driven, architecture-centered, iterative, incremental, risk management-oriented • RUP is a process framework • not a process on its own • Intended to be customized to project needs Use Case-Driven Process

9. SW Process Engineering Agile Methods Overview Extreme Programming Practices XP Process Conclusion Business Modeling Discipline – Artefacts

10. SW Process Engineering Agile Methods Overview Extreme Programming Practices XP Process Conclusion Business Modeling Discipline – Roles & Activities

11. SW Process Engineering Agile Methods Overview Extreme Programming Practices XP Process Conclusion Requirements Discipline – Artefacts

12. SW Process Engineering Agile Methods Overview Extreme Programming Practices XP Process Conclusion Requirements Discipline – Roles & Activities

13. SW Process Engineering Agile Methods Overview Extreme Programming Practices XP Process Conclusion Careful! • SPM, EPF and RUP are not processes! • They are framework that allow creating your own process • SPEM offers best practices • Guidelines for creating good documents, models, designs... • Characteristics of RUP • Use case-driven • Iterative, incremental, and oriented towards risk management • Architecture-centered (NFRs and models, with UML) • Focus on having the right process (neither too heavy nor insufficient) • Unfortunately, it is difficult to know where to be minimal and easy to make a process too heavy by being too cautious ...

14. SW Process Engineering Agile Methods Overview Extreme Programming Practices XP Process Conclusion SPEM and Agility? • A definition of agile processes can lead to a cumbersome process… • A definition of rich processes can lead to an agile process… • There is no contradiction between SPEM/RUP and agility! • Actually… • In 2006, IBM created OpenUP, a subset of RUP tailored for the delivery of Agile projects released as an open source method specified with SPEM • http://www1.osu.cz/~zacek/OpenUP/ • http://en.wikipedia.org/wiki/OpenUP • Artifacts for RE: glossary, vision, requirements, use case models, and use cases

15. SW Process Engineering Agile Methods Overview Extreme Programming Practices XP Process Conclusion In Addition… “The idea of specifying requirements independently of designing and building a system is solidified by management pressure to outsource, conceptualize development as independent phases and make enforceable contracts.” The Dangerous Dogmas of Software Engineering P. Ralph, B. Oates (2018)https://arxiv.org/ftp/arxiv/papers/1802/1802.06321.pdf

16. Agile Methods

17. SW Process Engineering Agile Methods Overview Extreme Programming Practices XP Process Conclusion Agile Manifesto (http://agilemanifesto.org)

18. SW Process Engineering Agile Methods Overview Extreme Programming Practices XP Process Conclusion Values of Agile Methods (1) • Individuals and Interactions vs. Process and Tools • Individuals create value, therefore focus on them • Without a skilled craftsman, the best tools are useless • Working Software vs. Comprehensive Documentation • A heavy process generates exhaustive documentation with all its drawbacks: ambiguity of language, cost of preparation, cost of maintenance to keep it up-to-date… • These documents are an illusion of progress • In agile methods, a single criterion measures the progress of a project: working software! • Documentation is a concrete support that helps produce software

19. SW Process Engineering Agile Methods Overview Extreme Programming Practices XP Process Conclusion Values of Agile Methods (2) • Customer Collaboration vs. Contract Negotiation • If negotiation protects you more or less from financial risk, it can cause project failure and result in endless trials where everybody loses eventually • We must abandon the war with the customer / supplier and think as one team with a common goal: a successful project • Responding to Change vs. Following a Plan • A predefined plan tends to make us unresponsive to events that occur during the project • Agile methods are designed to accommodate change, ensuring an accurate and adaptive strategic plan

20. SW Process Engineering Agile Methods Overview Extreme Programming Practices XP Process Conclusion Principles of the Agile Manifesto (1) • Our highest priority is to satisfy the customer through early and continuous delivery of valuable software • Welcome changing requirements, even late in development – agile processes harness change for the customer's competitive advantage • Deliver working software frequently, from a couple of weeks to a couple of months, with a preference for the shorter period • Business people and developers must work together daily throughout the project • Build projects around motivated individuals – give them the environment and support they need, and trust them to get the job done • The most efficient and effective method of conveying information to and within a development team is face-to-face conversation

21. SW Process Engineering Agile Methods Overview Extreme Programming Practices XP Process Conclusion Principles of the Agile Manifesto (2) • Working software is the primary measure of project progress • Agile processes promote a sustainable pace of development – the sponsors, developers, and users should be able to maintain a constant pace indefinitely • Continuous attention to technical excellence and good design enhances agility • Simplicity – the art of maximizing the amount of work not done – is essential • The best architectures, requirements, and designs emerge from self-organizing teams • At regular intervals, the team reflects on how to become more effective, then tunes and adjusts its behavior accordingly

23. Extreme Programming (XP) Lean software development Scrum Open Unified Process (OpenUP) Kanban (development) Adaptive Software Development (ASD) Crystal Clear DSDM Feature Driven Development Agile documentation Agile ICONIX Microsoft Solutions Framework (MSF) Agile Data Agile Modeling Essential Unified Process (EssUP) Getting Real Scrum of scrums Scaled Agile Framework DevOps … SW Process Engineering Agile Methods Overview Extreme Programming Practices XP Process Conclusion Examples of Agile Approaches

24. SW Process Engineering Agile Methods Overview Extreme Programming Practices XP Process Conclusion When to Use Agile Methods in General? • The culture of the organization is supportive of collaboration • Team members are trusted (competence & confidence) • The organization is willing to live with the decisions developers make • Fewer but competent team members • Ideally less than 10 co-located team members • Environment that facilitates rapid communication between team members • Agile approaches are appropriate when requirements are difficult to predict, or change often • Situation where prototyping is required

25. SW Process Engineering Agile Methods Overview Extreme Programming Practices XP Process Conclusion When Is Using Agile Difficult? • Agile approaches are not appropriate for every project • Hard to use for • Large projects (>20 developers) • Scalable Agile Framework, Scrum of Scrums and others aim to address this issue • Distributed teams • Working environments not adapted to communication/collaboration • Critical applications (business-critical, safety-critical…) • Projects where a substantial specification is required prior to coding • When structure is rigid, e.g., military “Command-and-control” type projects

26. SW Process Engineering Agile Methods Overview Extreme Programming Practices XP Process Conclusion Does AgilityWork? Float like a butterfly, Sting like a bee

27. SW Process Engineering Agile Methods Overview Extreme Programming Practices XP Process Conclusion Extreme Programming (XP) (1) • Software is Listening, Testing, Coding, Designing. That’s all there is to software. Anyone who tells you different is selling something.1 • Listen to customers while gathering requirements, develop test cases (functional tests and unit tests), code the objects, design (refactor) as more objects are added to the system • Listen – Test Design – Code – Test • XP is a software development approach introduced by Kent Beck, Ward Cunningham, Ron Jeffries (~2000) • Lightweight process model for OO software development • Quick product delivery while retaining flexibility and maintaining quality • Indented for small to medium size projects with a well integrated team • Small teams (up to 10-15 programmers) Design Test [1] Kent Beck, author of Extreme Programming Explained

28. SW Process Engineering Agile Methods Overview Extreme Programming Practices XP Process Conclusion Extreme Programming (XP) (2) • Why extreme? • XP is based on the extreme application of 13 practices (guidelines or rules) that support each other • There is no real new practice (most existed under RUP), but the combination of practices and their extreme application is new • Code is at the centre of the process • All non-production related tasks are superfluous • Technical documentation = commented source code • Other documentation is a waste of time (e.g., UML diagrams) • Elements of success • Common workplace and working hours • All tests must be automated and executed in short time • On-site customer • Developer and client must commit 100% to XP practices

29. SW Process Engineering Agile Methods Overview Extreme Programming Practices XP Process Conclusion 13 XP Practices Source: http://www.xprogramming.com/

30. Activities (cont’d) Frequent Releases Spike Solutions Pair Programming Simple Design Writing and Running Tests Refactoring Collective Code Ownership Continuous Integration 40 Hour Week Coding Standards Stand Up Meeting Roles Clients (and tester), developer, sponsors Artefacts Metaphors User stories (prioritized) Tasks, unit tests, functional tests, code Activities Writing User Stories On-site Customer Planning Game Backlog System Metaphor SW Process Engineering Agile Methods Overview Extreme Programming Practices XP Process Conclusion Elements of Extreme Programming

31. SW Process Engineering Agile Methods Overview Extreme Programming Practices XP Process Conclusion User Stories • A short description of the behavior of the system from the point of view of the customer/user • Use the customer/user’s terminology without technical jargon • Ideally written by the customers/users at first • Card, Conversation, Confirmation • Are used to create time estimates for release planning • Replace a large requirements document

32. SW Process Engineering Agile Methods Overview Extreme Programming Practices XP Process Conclusion On-site Customer • The customer must always be available to: • Resolve ambiguities • Set priorities • Provide test cases • User stories are not detailed, so there are always questions to ask the customer • Customer is considered part of the team

33. SW Process Engineering Agile Methods Overview Extreme Programming Practices XP Process Conclusion Planning Game (1) • Pieces • User Stories • Players • Customer & Developer • Moves • User story writing • Requirements are written by the customer on small index cards (simple, effective… and disposable) • User stories are written in business language and describe things that the system needs to do • Each user story is assigned a business value • For a few months-long project, there may be 50-100 user stories

34. SW Process Engineering Agile Methods Overview Extreme Programming Practices XP Process Conclusion Planning Game (2) • Moves (cont’d) • Story estimation • Each user story is assigned a cost by the developer • Cost is measured in ideal development weeks (1-3 person weeks) • No interruptions, know exactly what to do • A story is split by the customer if it takes longer than 3 weeks to implement • Estimate risk (high, medium, low) • Commitment • Customer and developer decide which user stories constitute the next release • Value and risk first • Developer orders the user stories of the next release so that more valuable or riskier stories are moved earlier in the schedule

35. Stand up meeting Iteration Backlog Product Release SW Process Engineering Agile Methods Overview Extreme Programming Practices XP Process Conclusion Backlog • To keep track of what needs to be done • Prioritized – value and risk • May contain user stories • Requirements

36. SW Process Engineering Agile Methods Overview Extreme Programming Practices XP Process Conclusion System Metaphor • Overall theme to which developers and clients can relate • The system is built around one (or more) metaphors • If the metaphor is well chosen, it leads to design approaches, class names, better communication... • The computer is like an office desk. • Selecting items is like filling a shopping cart

37. SW Process Engineering Agile Methods Overview Extreme Programming Practices XP Process Conclusion Frequent Releases • Highly iterative development process – release cycle of up to 3 months – iterations of up to 3 weeks • Short cycles during which the four phases take place in parallel • Functional system delivered at the end of each cycle • Frequent feedback from the customer • In each iteration the selected user stories are implemented • Each user story is split into programming tasks of 1-3 days

38. SW Process Engineering Agile Methods Overview Extreme Programming Practices XP Process Conclusion Spike Solution • Need a mutual understanding of architecture • XP does not do a BigDesignUpFront • No architecture phase • Architectural Spike • Very simple program to test out solutions for tough technical or design problems – a throwaway prototype

39. SW Process Engineering Agile Methods Overview Extreme Programming Practices XP Process Conclusion Pair Programming (1) • Pairs change continuously (few times during a day) • Every programmer knows all aspects of the system • A programmer can be easily replaced in the middle of the project

40. SW Process Engineering Agile Methods Overview Extreme Programming Practices XP Process Conclusion Pair Programming (2) • May cost 10-15% more than standalone programming • Code is simpler (fewer lines of code) with fewer defects (15%) • Ensures continuous code inspection

41. SW Process Engineering Agile Methods Overview Extreme Programming Practices XP Process Conclusion Other Practices (FYI) • Simple Design: Do the simplest thing that could possibly work • Tests: Automated tests developed prior to implementation: acceptance (from users) and unit (from developers) • Refactoring: to make the code and architecture simpler • Collective Code Ownership: Any programmer can (actually should) change any of the code at any time in order to make it simpler/better • Continuous Integration: Daily integration at least, at each commit if possible. A working, tested system is always available • 40 Hour Week: Overtime is defined as time in the office when you do not want to be there. Schedule wisely. Keep people happy and balanced • Coding Standards: Make pair programming and collective code ownership easier (naming, formatting…) • Stand Up Meeting: At the beginning of the day, 15min long, standing up. Commitments in front of your peers, not about problem solving

42. SW Process Engineering Agile Methods Overview Extreme Programming Practices XP Process Conclusion XP Practices Revisited • XP practices are not new • They are supposed to be used all together to get the full value of the approach • The practices work together to create synergy • The full value of XP will not come until all the practices are in place. Many of the practices can be adopted piecemeal, but their effects will be multiplied when they are in place together.1 [1] Ken Beck

43. SW Process Engineering Agile Methods Overview Extreme Programming Practices XP Process Conclusion XP Process – Overview Sources: http://www.extremeprogramming.org/ https://eternalsunshineoftheismind.wordpress.com/2013/03/04/extreme-programming-xp-method-of-developing-i-s/

44. SW Process Engineering Agile Methods Overview Extreme Programming Practices XP Process Conclusion XP Process – Details of one “Iteration” Source: http://www.extremeprogramming.org/

45. SW Process Engineering Agile Methods Overview Extreme Programming Practices XP Process Conclusion XP Process – Details of one “Development” Source: http://www.extremeprogramming.org/

46. SW Process Engineering Agile Methods Overview Extreme Programming Practices XP Process Conclusion XP Process – Details of one “Collective Code Ownership” Conclusion: an "agile" process does not mean that it is simple, or that it does not include roles / artifacts / activities!!! Source: http://www.extremeprogramming.org/

47. SW Process Engineering Agile Methods Overview Extreme Programming Practices XP Process Conclusion Lean Software Development • Another agile approach, adapted from the Toyota Production System • Several principles • Eliminate waste (what does not generate value) • E.g., unnecessary code or documents, bad requirements, avoidable repetitions, bureaucracy … • Optimize/See the whole (not just parts, and not just software) • Build quality/integrity in (work as intended, catch defects early) • Learn constantly (from customer feedback and from team) • Deliver fast (and steadily) • Respect people (and empower them) • Defer commitment (decide as late as possible, to gather knowledge) • Improve continuously (so, measure yourselves!) • Most are related to RE principles too!

48. SW Process Engineering Agile Methods Overview Extreme Programming Practices XP Process Conclusion Scrum • Scrum is an iterative, incremental framework for project management often seen in agile software development, a type of software engineering. http://en.wikipedia.org/wiki/Scrum_(development) • Scrum is a process skeleton that contains sets of practices and predefined roles (in addition to users/stakeholders): • ScrumMaster: maintains the processes (~ project manager) • Product Owner: represents the stakeholders and the business • Team: does the analysis, design, implementation, testing, etc.

49. SW Process Engineering Agile Methods Overview Extreme Programming Practices XP Process Conclusion Scrum Process: Roles, Activities, Artefacts

50. SW Process Engineering Agile Methods Overview Extreme Programming Practices XP Process Conclusion Scrum Product Owner • Responsible for: • Product backlog (voice of the customer) • Clarification of backlog items • Stakeholder analysis • Return on investment (value) • Prioritization of backlog (makes decisions) • Inspection of product increments (gathers feedback) • Capabilities • Project management • Communication • Business domain knowledge • Requirements engineering • Demanding! Certification available. [Susanne Muehlbauer, HOOD Group , RE 2011]