AgentSkillsCN

tdd-refactor-phase

引导经验丰富的开发者顺利通过 TDD 循环中的“重构”阶段——在保持测试通过的前提下，不断提升代码质量。

SKILL.md
--- frontmatter
name: tdd-refactor-phase
description: Guide experienced developers through REFACTOR phase of TDD cycle - improving code quality while maintaining green tests
license: Complete terms in LICENSE.txt

TDD REFACTOR Phase

Version: {{VERSION}}

When to Use

  • •GREEN phase complete with passing test
  • •Proceeding autonomously from GREEN phase
  • •Code works but could be improved

REFACTOR Phase Objectives

  1. •Improve code quality - Make code cleaner, more maintainable
  2. •Keep tests green - Ensure all improvements maintain functionality

Refactoring IS

  • •Improving code structure without changing behavior
  • •Making code more readable
  • •Eliminating duplication
  • •Simplifying complex logic

Refactoring IS NOT

  • •Adding new features
  • •Changing tested behavior
  • •Breaking tests to "improve" code

Workflow

Step 1: Analyze Refactoring Opportunities

Identify:

  • •Code duplication
  • •Long or complex functions
  • •Unclear variable/function names
  • •Complex conditional logic
  • •Magic numbers/strings

Step 2: Evaluate Suggestions

Refactor Now:

  • •Clear improvement
  • •Low risk, high value
  • •Won't over-engineer

Skip Refactoring:

  • •Premature abstraction
  • •Risk > reward
  • •Code already clear enough

Step 3: Apply Refactoring (if approved)

code
TASK: [Brief description]

STEP 1: [Open implementation file]
STEP 2: [Navigate to code]
STEP 3: [Apply refactored code]
STEP 4: [Explanation of improvement]
STEP 5: [Save file]
STEP 6: [Run full test suite]
STEP 7: [Verify ALL tests still PASS]
STEP 8: [Report back: All tests green?]

Step 4: Verify Tests Remain Green

If any test fails:

  1. •Rollback immediately
  2. •Keep tests green
  3. •Try smaller refactoring

Best Practices

Refactor in Small Steps

code
1. Extract one variable -> Run tests
2. Rename one function -> Run tests
3. Extract one function -> Run tests

One Refactoring at a Time

Focus on one improvement, then run tests.

Golden Rule

code
Tests must ALWAYS be green after refactoring.
If refactoring breaks tests -> ROLLBACK

Common Refactorings

RefactoringBeforeAfter
Extract VariableExpression embeddedWell-named variable
Extract FunctionLong functionSmaller focused functions
RenameUnclear namesNames express intent
Eliminate DuplicationSame code multiple placesSingle function
Simplify ConditionalNested conditionsGuard clauses

When to Skip Refactoring

  1. •Premature Abstraction - Only one use of code
  2. •Code Already Clear - Current code is good enough
  3. •High Risk, Low Value - Not worth risk
  4. •Over-Engineering - Adds design patterns prematurely

Rollback Procedures

  1. •Rollback changes (git checkout or undo)
  2. •Verify tests return to green
  3. •Options: Try smaller, skip, or investigate

Checklist Before Next Feature

  • • Code analyzed for refactoring opportunities
  • • Suggestions evaluated
  • • If refactoring applied: All tests PASS
  • • If skipped: Valid reason documented

Resources

  • •resources/refactor-checklist.md
  • •resources/common-refactorings.md
  • •resources/when-to-skip-refactoring.md

End of TDD REFACTOR Phase Skill