Why test at layer boundaries?

Testing at boundaries ensures you are verifying the contract and behavior of a component without becoming coupled to its internal implementation details, making refactoring easier.

What is Stub-Driven TDD?

Stub-Driven TDD is a workflow where you first define function signatures (stubs), write failing tests against those signatures, implement the logic, and finally refactor for clean code.

Does this skill work with FastAPI?

Yes, it includes specific patterns for the Router layer, utilizing FastAPI's TestClient to validate status codes, request validation, and response serialization.

How does it handle database testing?

The skill promotes Repository layer testing using real test database fixtures (like in-memory SQLite) rather than mocking the database, ensuring query logic is actually verified.

Python Testing & Stub-Driven TDD

Name: Python Testing & Stub-Driven TDD
Author: martinffx

bymartinffx

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Security & Testing

Implements professional TDD workflows and layer boundary testing patterns for Python applications using pytest.

This skill equips Claude with a robust architectural approach to Python testing, prioritizing 'Stub-Driven TDD' to ensure code quality from the first line. By focusing on layer boundaries—specifically Entities, Services, Repositories, and Routers—the skill guides the development of decoupled, maintainable test suites. It provides structured patterns for mocking dependencies, verifying business logic, and conducting integration tests with real databases, ensuring that every component of a Python backend is thoroughly validated before implementation.

Key Features

01Layer boundary testing for clean architectural separation

02Service orchestration testing with advanced mocking strategies

03Repository integration testing with real database fixtures

046 GitHub stars

05FastAPI and Router testing using TestClient patterns

06Stub-Driven TDD workflow (Stub -> Test -> Implement -> Refactor)

Use Cases

01Building a new Python backend service using a strict Test-Driven Development approach

02Implementing comprehensive integration tests for database layers and REST APIs

03Refactoring legacy Python codebases by establishing clear boundaries and unit tests

What are Skills?·How to Install

Install with 🐟 Skill.Fish

npx skillfish add martinffx/claude-code-atelier atelier-python-testing

For use in Claude.ai and ChatGPT

Download Skill