majiayu000 Extreme Programming (XP) Practices
Core XP Practices (Prioritized):
| Practice | Start Here | Why First |
|---|---|---|
| TDD | ✅ Yes | Foundation for everything |
| Continuous Integration | ✅ Yes | Fast feedback |
| Pair Programming | ✅ Yes | Knowledge sharing |
| Collective Ownership | After CI+TDD | Needs safety net |
| Small Releases | After CI | Infrastructure dependent |
Pairing Quick Start:
Driver-Navigator (Classic):
- Driver: Writes code
- Navigator: Reviews, thinks ahead
- Rotate every 20-30 min
Ping-Pong (with TDD):
A: Write failing test
B: Make test pass + refactor
B: Write next failing test
A: Make test pass + refactor
Quick Reference Card
The Five XP Values
| Value | Meaning | Practice |
|---|---|---|
| Communication | Everyone knows what everyone does | Daily standups, pairing |
| Simplicity | Simplest thing that works | YAGNI, small design |
| Feedback | Get feedback early and often | TDD, CI, short iterations |
| Courage | Tell truth, adapt | Refactor, admit mistakes |
| Respect | Everyone contributes value | Sustainable pace, pairing |
Core Practices
| Practice | Description | Benefit |
|---|---|---|
| Pair Programming | Two devs, one workstation | Quality + knowledge sharing |
| TDD | Red-Green-Refactor | Confidence + design |
| CI | Integrate multiple times/day | Fast feedback |
| Collective Ownership | Anyone can change anything | No bottlenecks |
| Sustainable Pace | 40-hour weeks | Long-term productivity |
| Small Releases | Ship frequently | Risk reduction |
Pair Programming
When to Pair
| Context | Pair? | Why |
|---|---|---|
| Complex/risky code | ✅ Always | Needs multiple perspectives |
| New technology | ✅ Always | Learning accelerator |
| Onboarding | ✅ Always | Knowledge transfer |
| Critical bugs | ✅ Always | Two heads better |
| Simple tasks | ❌ Skip | Not worth overhead |
| Research spikes | ❌ Skip | Pair to discuss findings |
Pairing Dos and Don'ts
Do:
- ✅ Switch roles every 20-30 min
- ✅ Take breaks together
- ✅ Think out loud
- ✅ Ask questions
- ✅ Keep sessions 2-4 hours max
Don't:
- ❌ Grab keyboard without asking
- ❌ Check phone while pairing
- ❌ Dominate conversation
- ❌ Pair all day (exhausting)
Ensemble (Mob) Programming
Setup: 3+ developers, one screen, rotating driver
[Screen]
↓
[Driver] ← Directions from navigators
↑
[Navigator 1] [Navigator 2] [Navigator 3]
Rotation: Driver switches every 5-10 min
Best for:
- Complex problem solving
- Architectural decisions
- Learning new frameworks
- Resolving blockers
Continuous Integration
CI Workflow:
1. Pull latest from main
2. Make small change (<2 hrs work)
3. Run tests locally (all pass)
4. Commit and push
5. CI runs tests automatically
6. If fail → fix immediately
Best Practices:
- Commit frequently (small changes)
- Keep build fast (<10 min)
- Fix broken builds immediately
- Never commit to broken build
Four Rules of Simple Design
(In priority order)
- Passes all tests - Works correctly
- Reveals intention - Clear, expressive code
- No duplication - DRY principle
- Fewest elements - No speculative code
Agent Integration
// Agent-human pair testing
const charter = "Test payment edge cases";
const tests = await Task("Generate Tests", { charter }, "qe-test-generator");
const reviewed = await human.review(tests);
await Task("Implement", { tests: reviewed }, "qe-test-generator");
// Continuous integration with agents
await Task("Risk Analysis", { prDiff }, "qe-regression-risk-analyzer");
await Task("Generate Tests", { changes: prDiff }, "qe-test-generator");
await Task("Execute Tests", { scope: 'affected' }, "qe-test-executor");
// Sustainable pace: agents handle grunt work
const agentWork = ['regression', 'data-generation', 'coverage-analysis'];
const humanWork = ['exploratory', 'risk-assessment', 'strategy'];
Agent Coordination Hints
Memory Namespace
aqe/xp-practices/
├── pairing-sessions/* - Pair/ensemble session logs
├── ci-metrics/* - CI health metrics
├── velocity/* - Team velocity data
└── retrospectives/* - XP retrospective notes
Fleet Coordination
const xpFleet = await FleetManager.coordinate({
strategy: 'xp-workflow',
agents: [
'qe-test-generator', // TDD support
'qe-test-executor', // CI integration
'qe-code-reviewer' // Collective ownership
],
topology: 'parallel'
});
Common Objections
| Objection | Response |
|---|---|
| "Pairing is 2x slower" | 15% slower writing, 15% fewer bugs, net positive |
| "No time for TDD" | Debugging takes longer than testing |
| "CI is hard to setup" | Start simple: one action, one test |
| "Collective ownership = chaos" | Only without tests + CI |
Related Skills
- tdd-london-chicago - TDD deep dive
- refactoring-patterns - Safe refactoring
- pair-programming - AI-assisted pairing
Remember
XP practices work as a system. Don't cherry-pick randomly:
- TDD enables collective ownership
- CI enables small releases
- Pairing enables collective ownership
- Sustainable pace enables everything
With Agents: Agents amplify XP. Pair humans with agents. Agents handle repetitive work, humans provide judgment and creativity.