What is the core principle of the Writing Tests skill?

The core principle is that test names should describe outcomes, not actions. It emphasizes that the test name is the specification, and assertions must exactly match the behavior described in the title.

Which testing libraries does this skill support?

While the principles are universal, this skill is specifically configured with support for Vitest and vitest-mock-extended.

How does this skill help with edge cases?

It provides systematic checklists for different data types—such as handling leap years for dates, Unicode for strings, or zero-values for numbers—ensuring no common failure point is overlooked.

BugMagnet is a popular exploratory testing assistant created by Gojko Adzic. This skill adapts those proven testing heuristics for use within the Claude Code environment.

Writing Tests

Name: Writing Tests
Author: jagreehal

byjagreehal

0•

Security & Testing

Implements rigorous testing principles and systematic edge case checklists to help developers write maintainable, outcome-driven test suites.

The Writing Tests skill transforms automated testing from a chore into a precise specification tool by applying the principles of BugMagnet by Gojko Adzic. It guides Claude to generate tests that focus on outcomes rather than actions, utilizing specific assertions and comprehensive edge case checklists for data types like strings, numbers, and collections. By enforcing patterns like 'outcome when condition' and 'one concept per test,' this skill ensures your test suites serve as living documentation while catching subtle bugs through systematic boundary analysis and domain constraint verification.

Key Features

01Outcome-driven test naming conventions following the [outcome] when [condition] pattern

02Robust patterns for testing Result types and error handling in TypeScript

03Comprehensive edge case checklists for numbers, strings, collections, and dates

04Standardized Arrange-Act-Assert (AAA) structure for readable test flows

050 GitHub stars

06Specific assertion guidance to catch actual bugs rather than just verifying types

Use Cases

01Refactoring brittle tests to decouple them from internal implementation details

02Expanding test coverage for legacy functions by identifying missing edge cases

03Drafting high-quality test cases during the RED phase of Test-Driven Development

What are Skills?·How to Install

Install with 🐟 Skill.Fish

npx skillfish add jagreehal/jagreehal-claude-skills writing-tests

For use in Claude.ai and ChatGPT

Download Skill