When should the Refactor step be performed?

Refactoring is performed only after all tests are green. It is an optional step to improve code quality, and all tests must be re-run immediately after to ensure no regressions.

Does it support languages other than Python?

While it includes specific patterns for Python and pytest, the workflow logic is language-agnostic and can be extended to any programming language.

What is the mandatory RED phase in this TDD skill?

The RED phase requires you to write a single test and run it in isolation to verify that it fails before writing any implementation code. This prevents false positives.

How does the skill track development progress?

It uses a standardized marking system in a SPEC.md file, using tags like [U][O] for unit tests and [U][X] for completed implementation to visualize coverage.

What is the difference between unit and acceptance tests in this skill?

Unit tests focus on individual functions in isolation, while acceptance tests verify complete user features and business requirements from an end-to-end perspective.

Test-Driven Development

Name: Test-Driven Development
Author: craigtkhill

bycraigtkhill

Security & Testing

Enforces a rigorous Red-Green-Refactor workflow to ensure high-quality, tested code through the Spec-Test-Driven Development process.

About

The Test-Driven Development (TDD) skill integrates a structured Spec-Test-Driven Development (STDD) methodology into Claude Code, ensuring every line of code is justified by a requirement and verified by a test. It guides users through a strict cycle: writing a single failing test (RED), implementing the absolute minimum code to pass (GREEN), verifying the entire suite to prevent regressions, and performing safe refactoring. With specialized support for Python and pytest patterns, plus a system for tracking progress via SPEC.md markers, this skill transforms Claude into a disciplined software engineer that prioritizes reliability and maintainability.

Key Features

Isolated test execution and full-suite verification
Clear distinction between unit, acceptance, and integration tests
Python-specific pytest patterns and implementation guides
Enforced RED-GREEN-REFACTOR workflow cycle
0 GitHub stars
SPEC.md requirement and implementation tracking markers

Use Cases

Implementing complex features directly from technical specifications
Refactoring legacy codebases safely using the RED-GREEN cycle
Building robust Python microservices with high test coverage

About

Key Features

Isolated test execution and full-suite verification
Clear distinction between unit, acceptance, and integration tests
Python-specific pytest patterns and implementation guides
Enforced RED-GREEN-REFACTOR workflow cycle
0 GitHub stars
SPEC.md requirement and implementation tracking markers

Use Cases

Implementing complex features directly from technical specifications
Refactoring legacy codebases safely using the RED-GREEN cycle
Building robust Python microservices with high test coverage