陌讯skills聚合平台

test-driven-development

📁 oakoss/agent-skills 📅 2 days ago
8
总安装量
6
周安装量
#33703
全站排名
安装命令
npx skills add https://github.com/oakoss/agent-skills --skill test-driven-development

Agent 安装分布

claude-code 6
opencode 5
github-copilot 5
codex 5
kimi-cli 5
gemini-cli 5

Skill 文档

Test-Driven Development

Write one failing test that describes the next behavior, write the minimal code to pass it, then refactor while green. Every production change starts with a test that proves the need exists. This is the discipline within each vertical slice — not framework syntax, but when and why to write tests.

Skip for exploratory prototyping, config-only changes (environment variables, feature flags), visual/CSS-only tweaks, and one-off scripts that won’t be maintained.

Quick Reference — TDD Cycle

Phase Action Rule
RED Write one test that fails for the right reason No production code without a failing test
GREEN Write the simplest code that makes the test pass Resist the urge to generalize prematurely
REFACTOR Improve structure while all tests stay green Never change behavior and structure at once

Quick Reference — Principles

Principle Practice
One test at a time Complete the full red-green-refactor cycle before writing the next test
Behavior over implementation Test what code does, not how it does it; assert outputs and side effects
Vertical slices TDD one end-to-end behavior at a time, not one layer at a time
Mock at boundaries Mock I/O, network, filesystem, clock. Never mock internal collaborators
Deep modules Design small interfaces with rich internals; fewer tests cover more behavior
Refactor only when green All tests pass before touching structure; refactoring under red hides new bugs
Design through tests The first test IS the API design decision; awkward tests signal awkward interfaces
Failing test for every bug Reproduce the bug as a failing test before writing the fix

Planning Before Coding

Step Action Output
1 Identify behaviors List of observable behaviors the feature must exhibit
2 Order by dependency Sequence where each test builds on prior passing tests
3 Design the interface Function signatures, parameter types, return types
4 Identify mock boundaries External dependencies that need test doubles

Common Mistakes

Mistake Correct Pattern
Writing all tests first One test at a time. Complete the cycle before starting the next
Testing private methods Test through the public interface; private methods are implementation detail
Mocking internal collaborators Only mock at I/O boundaries; trust your own code
Writing code before a failing test RED first. The failing test proves the behavior is missing
Refactoring while tests are red Get to GREEN first, then refactor with confidence
Tests coupled to call sequences Assert on outputs and state, not on which internal methods were called
Skipping the refactor phase GREEN is not done. Clean up duplication and naming before moving on
Hardcoding expected values Use triangulation: add a second test case to force the general solution
One giant test per feature One test per behavior — small, focused, independently meaningful

Delegation

  • Slice decomposition: If the tracer-bullets skill is available, use it to decompose features into vertical slices before applying TDD within each slice
  • Test framework syntax: Delegate framework-specific patterns to vitest-testing, e2e-testing, or api-testing skills
  • Feature planning: If the plan-first-development skill is available, use it for upfront planning before entering the TDD cycle
  • Individual TDD cycles: Delegate each red-green-refactor cycle to a Task subagent to keep context focused

References

  • Test Quality — good vs bad tests, what to test, naming, triangulation, refactoring signals
  • Mocking Boundaries — boundary rule, test doubles, dependency injection, anti-patterns
  • Design for Testability — deep modules, interface-first design, pure functions, computation vs I/O
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