xp-practices

# Extreme Programming (XP) Practices <default_to_action> When applying XP practices: 1. START with practices that give immediate value 2. BUILD supporting practices gradually 3. ADAPT to your context 4. MEASURE results **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 ``` </default_to_action> ## 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) 1. **Passes all tests** - Works correctly 2. **Reveals intention** - Clear, expressive code 3. **No duplication** - DRY principle 4. **Fewest elements** - No speculative code --- ## Agent Integration ```typescript // 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 ```typescript 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-london-chicago/) - TDD deep dive - [refactoring-patterns](../refactoring-patterns/) - Safe refactoring - [pair-programming](../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.