characterization-testing

Name: characterization-testing
Availability: InStock
Author: 3balljuggleryu

Generate characterization tests for ViewModels, Repositories, Services, and Widgets.

Updated Nov 2, 2025

Search Tags:#testing #refactoring #legacy code #characterization tests #golden tests #approval tests

Ready to run

npx skills add https://github.com/3balljugglerYu/ai_coordinate --skill characterization-testing-3balljuggleryu

💬 Prompt for ChatGPT / Claude Chat▼

Please help me install this Agent Skill.
Skill: characterization-testing
Source: https://github.com/3balljugglerYu/ai_coordinate/tree/main/.agents/skills/characterization-testing
Command: npx skills add https://github.com/3balljugglerYu/ai_coordinate --skill characterization-testing-3balljuggleryu

SYSTEM DOCUMENTATION & REQUIREMENTS

💡 This Skill includes scripts (resource) and references (resource) components.

What problem does it solve?

This Skill addresses the dilemma of refactoring legacy code by creating characterization tests that capture its current, often undocumented, behavior, providing a safety net for changes.

Core Features & Use Cases

Automated Test Generation: Creates characterization tests for ViewModels, Repositories, Services, and Widgets.
Behavioral Snapshotting: Captures existing code behavior using ApprovalTests or Golden Tests.
Refactoring Safety Net: Enables confident refactoring by ensuring current behavior is preserved or intentionally changed.
Use Case: Before refactoring a complex authentication module, use this Skill to generate tests that document its current sign-in, sign-up, and error handling behaviors.

Quick Start

Use the characterization-testing skill to create tests for the AuthViewModel class.

Frequently Asked Questions about characterization-testing

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

FAQPage Schema

How do I capture existing behavior before refactoring legacy code?▼

Characterization tests capture the current behavior of legacy code before refactoring by generating behavioral snapshots. This creates a safety net that ensures refactoring efforts do not introduce regressions or unintentionally change pre-refactoring states.

What is the best way to create golden tests for ViewModels and Repositories?▼

Generating golden tests for ViewModels, Repositories, Services, and Widgets uses ApprovalTests for deterministic snapshotting. This approach documents the exact current outputs of these components, locking them into verified states before any code modifications begin.

How do I use ApprovalTests to document undocumented code behavior?▼

ApprovalTests document undocumented code behavior by snapshotting the outputs of existing execution paths. This method captures the actual current state of complex modules, such as authentication flows, without requiring prior knowledge of the intended design.

Can I generate characterization tests for Widget components?▼

Yes, you can generate characterization tests for Widget components alongside ViewModels, Repositories, and Services. The automated test generation captures the deterministic rendering and interaction behaviors of these UI elements before you begin refactoring.

When do I need characterization tests instead of standard unit tests?▼

You need characterization tests instead of standard unit tests when refactoring legacy code with undocumented behavior. They focus on capturing what the code currently does rather than what it should do, providing a safety net for complex modules where expected behavior is unknown.

Does characterization testing work for complex authentication modules?▼

Characterization testing works for complex authentication modules by generating tests that document current sign-in, sign-up, and error handling behaviors. This captures the existing authentication logic precisely, ensuring refactoring efforts preserve pre-refactoring states without introducing regressions.