XP Testing: Test-Driven Development and User Involvement

Testing in XP

• XP uses an approach where programs are tested after every change
• XP testing features include test-first development, incremental test development from scenarios, user involvement, and automated testing frameworks

Test-First Development

• Tests are written before code to clarify implementation requirements
• Tests are written as programs, enabling automatic execution
• Each test contains a check to verify correct execution
• Testing frameworks like Junit are commonly used for testing
• All previous and new tests are run automatically to ensure new functionality doesn't introduce errors

User Involvement

• The customer helps develop acceptance tests for implementing stories in the next system release
• The customer, as part of the team, writes tests as development advances

Pair Programming

• Programmers work together in pairs at one workstation to develop code
• Helps develop common code ownership and knowledge sharing across the team
• Serves as an informal review process
• Encourages refactoring for the benefit of the entire team
• Development productivity in pair programming is similar to that of two people working independently
• Pair programming is not inefficient, as a pair may be more efficient than two programmers working separately
• The advantages of pair programming are supporting collective ownership and responsibility, acting as an informal review process and supporting software refactoring
• Individuals are not held solely responsible, with the team being collectively responsible for resolving problems

Scrum Approach

• Software project managers are responsible for ensuring software is delivered on time and within the defined budget
• A plan-driven approach is typically used, where managers create a project plan with deliverables, timelines, and roles
• Agile project management requires an approach adapted to incremental development methods
• Scrum is an agile method focused on managing iterative development
• Scrum includes three phases: an initial outline planning phase, sprint cycles, and a project closure phase
• During sprint cycles, each cycle develops an increment of the system
• Sprints are fixed length, typically 2-4 weeks, corresponding with the development of a release
• The starting point for planning is the product backlog which is a list of work to be done on the project
• The selection phase involves the project team and the customer selecting features and functionality
• Once agreed, the team organizes to develop the software, isolated from the customer with communications through the 'Scrum master'
• The Scrum master protects the development team from distractions
• The completed work is reviewed and presented to stakeholders at the end of each sprint, before the next cycle begins
• The 'Scrum master' facilitates meetings, tracks the backlog, records decisions, measures progress, and communicates with customers and management
• The team attends short daily meetings to share information, progress, problems, and plans for the following day
• Advantages of Scrum are breaking down the product into chunks, unstable requirements do not hold up progress, customers give feedback and see delivery, and a positive culture is created