What testing levels does this skill support?

It supports the entire testing pyramid, including unit tests for domain logic, integration tests for controllers and external dependencies, and E2E tests for critical user paths.

How does it improve test maintainability?

The skill enforces 'refactoring resistance' by focusing on observable behavior rather than implementation details, ensuring tests only fail when the actual business outcome changes.

Does it recommend specific mocking libraries?

It provides a framework for deciding *when* to mock (e.g., for unmanaged external dependencies) rather than dictating specific libraries, though it follows standard patterns for TypeScript/JavaScript by default.

Can it help me fix failing tests?

Yes, it includes a dedicated troubleshooting workflow to determine if a failure is due to a bug in the code, an error in the test, or an underlying design issue that requires refactoring.

Test-Driven Design (TDD) Expert

Name: Test-Driven Design (TDD) Expert
Author: Suntory-N-Water

bySuntory-N-Water

0•

Security & Testing

Guides the design, implementation, and review of high-value tests across unit, integration, and E2E layers using a behavior-focused workflow.

This skill transforms Claude into a senior test architect focused on maximizing the ROI of your test suite. It uses a rigorous framework where test value is calculated based on protection against regressions, resistance to refactoring, feedback speed, and maintainability. The skill leads you through a three-phase process: identifying critical test cases based on code complexity, implementing them using the Arrange-Act-Assert (AAA) pattern, and reviewing existing suites to prune fragile or implementation-coupled tests. By prioritizing observable behavior over internal details, it ensures your tests act as reliable documentation and safety nets rather than maintenance burdens.

Key Features

01Standardized implementation using the Arrange-Act-Assert (AAA) pattern and factory methods.

02Behavior-driven test case generation using descriptive, non-technical Japanese or English naming.

03Four-quadrant code classification to prioritize high-value domain logic for testing.

04Automated test suite reviews to identify and remove redundant or implementation-leaking tests.

050 GitHub stars

06Strategic dependency management with clear rules for when to use mocks vs. real implementations.

Use Cases

01Establishing a project-wide testing strategy that balances unit, integration, and E2E tests.

02Designing a robust test suite for complex business logic before writing the production code.

03Refactoring legacy tests to improve their resistance to false positives and implementation changes.

What are Skills?·How to Install

Install with 🐟 Skill.Fish

npx skillfish add suntory-n-water/suntory-n-water-marketplace test-driven-design

For use in Claude.ai and ChatGPT

Key Features

01Standardized implementation using the Arrange-Act-Assert (AAA) pattern and factory methods.

02Behavior-driven test case generation using descriptive, non-technical Japanese or English naming.

03Four-quadrant code classification to prioritize high-value domain logic for testing.

04Automated test suite reviews to identify and remove redundant or implementation-leaking tests.

050 GitHub stars

06Strategic dependency management with clear rules for when to use mocks vs. real implementations.

Use Cases

01Establishing a project-wide testing strategy that balances unit, integration, and E2E tests.

02Designing a robust test suite for complex business logic before writing the production code.

03Refactoring legacy tests to improve their resistance to false positives and implementation changes.