Agile Development Introduction

Introduction to Agile Development

• Rapid software development and delivery is now a key requirement
• Businesses operate in fast-changing environments, making stable software requirements difficult to achieve
• Software must evolve quickly to meet new business demands
• For projects needing thorough analysis (safety-critical systems), a plan-driven approach is still appropriate
• Agile development suits business systems that need rapid adaptability
• Agile methods prioritize producing functional software quickly through iterative cycles

Key Characteristics of Agile Approaches

• Specification, design, and implementation happen simultaneously
• Minimal detailed documentation with high-level user requirements
• Software is developed in increments with ongoing user and stakeholder feedback
• Tools for automated testing, configuration management, integration, and UI production support rapid development

Agile Methods Overview

• Agile methods are a type of incremental development
• Software releases occur in small, frequent increments (every 2-3 weeks)
• Customer involvement is crucial for rapid feedback and adapting to changes
• Agile development reduces formal documentation, favoring informal communication
• Design and implementation are central in agile methodologies
• Agile integrates requirements elicitation and testing into core development
• Plan-driven methods follow distinct stages with specific outputs

Plan-Driven vs. Agile: System Specification

• Plan-Driven: Iteration occurs within individual stages
• Plan-Driven: Formal documents guide stage transitions
• Plan-Driven: Evolving requirements lead to a formal specification document
• Agile: Iteration occurs across all activities
• Agile: Requirements and design are developed concurrently
• Agile prioritizes flexibility and coding, but includes design documentation and planned activities
• Agile may include creating system models and documentation within iterations

Historical Context of Agile

• 1980s/early 1990s: Software development focused on extensive planning, formal QA, and rigorous processes
• These processes were mainly for large-scale projects (aerospace and government)
• Plan-driven approaches suited complex, long-term projects with large, dispersed teams
• Applying these heavyweight approaches to smaller business systems resulted in overhead
• Excessive focus was spent on planning and documentation, reducing time for development/testing
• Inefficiencies led to more flexible methods, resulting in agile methods in the late 1990s

Agile Manifesto Values

• Individuals and interactions over processes and tools are prioritized
• Working software takes precedence over comprehensive documentation
• Customer collaboration is more important than contract negotiation
• Responding to change is valued over following a rigid plan
• Agile methods favor flexibility and responsiveness for software development

Agile Principles

• Customer involvement is essential throughout the development process
• Customers provide and prioritize new system requirements
• Customers evaluate system iterations
• Expect system requirements to change and design the system to adapt to new changes
• The software is developed incrementally, the customer specifies requirements for each
• Focus on simplicity in software development and the development process
• Actively work to eliminate project complexity where possible
• Recognize and utilize the skills of the development team
• Team members should develop their own work methods without prescriptive processes

Agile Method Applicability

• Promotes incremental software development and delivery, based on agile principles
• Product Development: Standard practice for software companies building small to medium products/apps
• Custom System Development: Suits organizations with actively involved customers and minimal constraints
• Agile practices are widely used for commercial and internal custom software projects

Challenges of Agile Methods

• Customer Engagement: Maintaining consistent customer involvement is challenging
• Not all customers have the time to stay engaged
• Team Suitability: Requires intense team involvement and collaboration
• Team members may struggle with high engagement levels
• Prioritization of Changes: Prioritizing changes can be complex with multiple stakeholders
• Differing priorities can create alignment issues
• Maintaining Simplicity: Achieving and maintaining simplicity requires extra effort
• Teams must continuously refine processes/designs
• Contractual Issues: Flexible nature of agile can complicate contract management
• Traditional contracts assume fixed scope

Factors for Choosing Agile or Plan-Driven

• Project choices depend on several factors
• Detail Requirements: Plan-driven needed
• Feedback and Delivery: Agile is suitable
• System Size: Agile is for small, co-located teams
• System Type: Plan-driven needed for complex systems with critical requirements
• System Lifetime: Long-lifetime systems require detailed documentation
• Technology: Agile relies on tools for managing evolving designs
• Team Organization: Detailed documents needed for distributed teams to coordinate
• Cultural Issues: Traditional cultures favor plan-based methods
• Team Skills/Regulation: Agile demands higher skill levels
• Safety-critical systems need detailed documentation

Extreme Programming (XP)

• Widely used agile methodology
• Introduced by Kent Beck in the late 1990s
• Enhance customer satisfaction, flexibility, and rapid iteration.
• New software versions are built frequently each day
• Increments delivered to customers every two weeks
• All tests are run for every build, ensuring high quality and reliability.

XP and Agile Principles

• Aligns closely with agile principles
• Supports incremental development through frequent releases
• Enables ongoing user feedback and adaptation
• Pair Programming: Two developers work together, fostering collaboration quality
• Collective Ownership: All team members share the codebase, encouraging shared ownership
• Avoiding Long Hours: XP advocates for sustainable work practices
• Support for Change in XP
• Maintaining Simplicity: XP emphasizes design simplicity through constant refactoring

Extreme Programming Practices

• Pairs of developers check each other's work, provides support
• Refactor code continuously
• Design is carried out to current requirements only
• Deliver the minimal useful functionality
• Releases adds incrementally
• Overtime is not acceptable
• Code is tested for functionality before implementation

Requirements in XP

• Managed collaboratively and flexibly through customer involvement
• Customer is an essential part of the XP team
• User Stories: Brief descriptions of user interactions
• Story Cards and Task Breakdown: User stories are broken down into specific tasks
• Prioritization and Scheduling involves setting deadlines

Refactoring

• Constant code refactoring is advocated
• Continuous efforts to improve code structure and readability
• Involves making incremental improvements, preventing software structure degradation

Testing in XP

• Integrates automated testing into development
• Development progresses only when all tests pass
• Feature Include: tests, development, and harness
• Test First: Writing programs to be executed correctly and automatically
• All previous and new tests are run when new updates aree added
• Requires customer involvement, they write tests, however time constraint can be an issue

Test Automation

• Independent tests are designed to simulate input submission
• Automation provides always-available tests and allows for quick fixes when new functionality is added

XP Testing Difficulties

• Can be incomplete as developers prefer coding over testing
• Can be impossible with complex inter-screen logic
• Test are difficult to complete, its hard to test every aspect of the system

Pair Programming

• Pair Programming involves two people working together on the same workstation to optimize code
• Review process, code enhancement and knowledge is distributed
• Collaboration between team member is ensured

Advantages of Pair Programming

• The team is held responsable rather than one team member
• Code is enhances by a constand code review process
• Facilitates refactoning to ensure consistent code enhancements

Scrum Methodology

• Manages iterative development
• Establishes general project objectives and design the software
• Project is finalized, the code is documented, and the project is closed

Key Roles of Scrum

• The product owner defines the product backlog and determines its features
• The scrum master enforces communication, and clears any impediments within the system
• The developers work together to deliver potentially any shippable product

Scrum: Events, Artefacts, and Framework

• Has the three roles, and a 15min sync meeting, plus reviews
• Priorized list of enhancements managed by the product owner, to be deleivered within a time constraint
• Incriment of deliverables from the Product backlog and all prior events

The Sprint Cycle

• fixed iterations that result in system releases
• Product backlog that indicates tasks
• The team is isolated from stakeholders
• Completed work is reviewed and presented

Teamwork in Scrum

• Scrum Master: facilitator arrangements within the system for all stakeholders
• Everyone in the team is syncronized after a daily meeting to ensure the project stays in scope

Scrum Benefits

• Smaller understandable peices
• Can handle any project requirement
• Better communication due to the visibility and collaboration between team member
• Costumer feed back ensures positive trust and culture

How To Scale Agile Methods

• Adapt to larger complex projects and locations
• Suited to small projects with good communication among team
• Need to mange mulitple developments with distributed teams
• Modification needed to processes to accommodate effective team collaboration

Large System Development Complexities

• Large Systems require seperate systems and multiple teams acors multiple locations
• Has to accomidate systems and rules from previous systems
• Lengthly periods and challanes to mainting the team

Scaling Out and Scaling Up

• Adapting agile to larger contexts:
• scaling is required because more people and resources are needed
• Agile fundamentals must be maintinaed to manage the changes
• Has to deliver constant testing because it is integrated

Scale Up to large system

• Coding is not enough, comprehesive design is imperative
• Communication is critical among team , regular progress updates are required
• System builds are essential when managine large systems

Challenges scaling out to companies

• Project mangers are hesitant due to preceived risks
• Compatability with standards and bureaucractoc rifts are common
• Variable skill set is a big issues
• Cultural resistance needs to be adressed