What is the 'Seam Model' mentioned in this skill?

A seam is a place in your code where you can alter behavior without editing the source file. This skill helps identify Object Seams and Link Seams to inject test doubles effectively.

Does this skill work with modern languages like TypeScript?

Yes, while the patterns are derived from classic software engineering principles, the skill includes modern implementations and examples for TypeScript and other object-oriented languages.

What are characterization tests?

Characterization tests are used to document the actual current behavior of a system rather than its intended behavior. They provide a safety net that ensures existing functionality is preserved during refactoring.

How does this skill help with legacy code?

It provides specific patterns for the 'Testing Dilemma,' helping you identify seams to break dependencies and make code testable without introducing bugs in the process.

When should I use the Sprout Method vs. Wrap Method?

Use the Sprout Method when adding a new feature that can be isolated into a new, tested function. Use the Wrap Method when you need to add behavior that should execute before or after an existing untestable method.

Testing Patterns & Refactoring

Name: Testing Patterns & Refactoring
Author: joelhooks

byjoelhooks

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359

セキュリティとテスト

Implements industry-standard patterns for breaking dependencies, adding tests to legacy code, and performing safe refactoring.

概要

This skill equips Claude with specialized strategies for managing untested or legacy codebases based on Michael Feathers' proven methodologies. It provides a structured framework for identifying 'seams' where behavior can be altered without source changes, creating characterization tests to document existing logic, and breaking tight dependencies through techniques like interface extraction and constructor parameterization. By following these patterns, developers can safely navigate the 'Testing Dilemma'—the need to change code to add tests vs. the need for tests to change code safely—ensuring high-quality software evolution with minimal regression risk.

主な機能

Automated strategies for breaking dependencies via Interface Extraction and Subclassing
Identification of Object, Link, and Preprocessing seams for test isolation
Characterization testing workflows to document and preserve existing behavior
Safe feature addition techniques including Sprout Method and Wrap Class
359 GitHub stars
Advanced heuristics for finding Pinch Points and Interception Points in complex logic

ユースケース

Refactoring complex, mission-critical logic that currently lacks any test coverage
Safely implementing new features in large, unfamiliar codebases while maintaining existing functionality
Adding unit tests to a legacy codebase with hard-to-instantiate classes or global state

概要

主な機能

Automated strategies for breaking dependencies via Interface Extraction and Subclassing
Identification of Object, Link, and Preprocessing seams for test isolation
Characterization testing workflows to document and preserve existing behavior
Safe feature addition techniques including Sprout Method and Wrap Class
359 GitHub stars
Advanced heuristics for finding Pinch Points and Interception Points in complex logic

ユースケース

Refactoring complex, mission-critical logic that currently lacks any test coverage
Safely implementing new features in large, unfamiliar codebases while maintaining existing functionality
Adding unit tests to a legacy codebase with hard-to-instantiate classes or global state