tdd

Automate software behavior verification with test-driven development and red-green-refactor loops.

1|Updated Feb 22, 2026

Search Tags:#testing #tdd #refactor #integration-testing #software-quality #vertical-slices #tracer-bullet

Ready to run

npx skills add https://github.com/1337hero/claude-toolkit --skill tdd-1337hero

💬 Prompt for ChatGPT / Claude Chat▼

Please help me install this Agent Skill.
Skill: tdd
Source: https://github.com/1337hero/claude-toolkit/tree/main/skills/test-driven-development
Command: npx skills add https://github.com/1337hero/claude-toolkit --skill tdd-1337hero

SYSTEM DOCUMENTATION & REQUIREMENTS

What problem does it solve?

Test-driven development (TDD) helps developers ensure behavior by writing tests against public interfaces before implementing code, reducing fragility and guarding against refactors.

Core Features & Use Cases

Tracer bullets: write a single failing test that drives the minimal production code to pass.
Vertical slices: implement end-to-end behavior for one feature at a time, not isolated units.
Public-interface testing: verify observable behavior through public APIs, enabling safe refactors.
Guided workflows: follow planning, tracer bullet, incremental loop, and refactor steps to maintain discipline.

Quick Start

Write a single failing test for the desired behavior, implement the minimal code to pass, then refactor.

Frequently Asked Questions about tdd

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

FAQPage Schema

How do I apply test-driven development for feature development and bug fixes?▼

Test-driven development for feature development and bug fixes uses incremental red-green-refactor loops to verify software behavior. You write a failing test against a public interface, implement minimal code to pass, then refactor safely.

What is a tracer bullet in test-driven development?▼

A tracer bullet in test-driven development is a single failing test that drives the minimal production code needed to pass. It establishes end-to-end behavior early, guiding subsequent incremental red-green-refactor cycles for the feature.

How do I start writing tests against public interfaces for new features?▼

Writing tests against public interfaces starts with planning the desired behavior, writing a single failing tracer bullet test, implementing minimal code to pass, and refactoring. This guided workflow enforces testing observable behavior rather than internal implementation.

Does test-driven development work for end-to-end verification or only isolated unit testing?▼

Test-driven development works for end-to-end verification by implementing vertical slices of behavior rather than isolated unit tests. It enforces strict adherence to testing public interfaces, enabling safe refactors while maintaining software quality.

Why does test-driven development focus on testing public interfaces instead of internal code?▼

Test-driven development focuses on testing public interfaces because it verifies observable behavior without coupling tests to internal implementation details. This reduces fragility and guards against refactors by ensuring tests remain stable when internal code changes.