skills.rest
marjorg
marjorgCOMMUNITY
Explore all skills by this author →
WebsiteGitHub

test-driven-development

Guides implementation of code changes using the red-green-refactor test-driven development cycle.

1|Updated Mar 2, 2025
Search Tags:#code quality#unit tests#testing#tdd#bug fixing#red-green-refactor#test pyramid
One-click install
npx skills add https://github.com/marjorg/setup --skill test-driven-development-marjorg
Or copy as Structured Prompt for Agent▼
Please help me install this Agent Skill.
Skill: test-driven-development
Source: https://github.com/marjorg/setup/tree/main/home/.agents/skills/test-driven-development
Command: npx skills add https://github.com/marjorg/setup --skill test-driven-development-marjorg

SYSTEM DOCUMENTATION & REQUIREMENTS

What problem does it solve? Code changes made without tests are unverified, and bug fixes without reproduction tests can silently regress. This Skill enforces a disciplined workflow where every behavior change is proven by a failing-then-passing test before it is considered done. ## Core Features & Use Cases - Red-Green-Refactor Cycle: Write a failing test first, implement the minimal code to pass it, then refactor with tests as a safety net. - Prove-It Pattern for Bug Fixes: Reproduce any reported bug with a failing test before attempting a fix, guaranteeing the fix actually works. - Stack Discovery: Detects the repository's own test framework and commands (npm, Gradle, pytest, Cargo, Go) instead of assuming defaults. - Use Case: A bug report says completing a task doesn't set its timestamp. The Skill guides you to write a failing reproduction test, implement the fix, confirm the test passes, and run the full suite to catch regressions. ## Quick Start Ask the agent to implement a new feature or fix a bug using test-driven development with a failing test written first.

Frequently Asked Questions about test-driven-development

High-intent search queries and answers about installing and using this skill.

FAQPage Schema
How do I practice test-driven development when fixing a bug?▼

Write a test that reproduces the bug first and confirm it fails, then implement the fix and confirm the test passes. Finally run the full test suite to verify no regressions were introduced.

What is the red-green-refactor cycle in TDD?▼

Red means writing a test that fails because the behavior doesn't exist yet. Green means writing the minimal code to make it pass. Refactor means cleaning up the implementation while keeping all tests passing.

Should I use mocks or real implementations in unit tests?▼

Prefer real implementations first, then fakes, stubs, and mocks last. Mock only when the real dependency is too slow, non-deterministic, or has uncontrollable side effects like external APIs or email sending.

When should I not write tests for a change?▼

Skip tests only for pure configuration changes, documentation updates, or static content with no behavioral impact. Any change to logic, behavior, or edge case handling should have a corresponding test.

Why do my tests break every time I refactor code?▼

Tests that verify internal method calls or implementation details break during refactoring even when behavior is unchanged. Assert on inputs and outputs (state) instead of interaction sequences to make tests resilient.

Related Skills

Explore More Software Engineering Skills→
iamsteveholmesiamsteveholmes

build-scanner

Scan project repositories to generate a structured technology profile from build files.

Community
Intermediate
The-Vibe-CompanyThe-Vibe-Company
2.4k

implement

Implement work from a spec or tickets using TDD and code review.

Official
Basic
pyoclawpyoclaw

browser-testing-with-devtools

Inspect DOM, console, network, and performance traces via Chrome DevTools MCP.

Community
Advanced
AZANIRAZANIR
2

qa-manual-test-designer

Design manual test cases and exploratory testing charters using specification-based techniques.

Community
Intermediate