javascript-testing-patterns

Quick Review

This is a high-quality, comprehensive JavaScript testing skill. The description clearly articulates when to use the skill (test setup, TDD, mocking, etc.), making it easy for a CLI agent to invoke appropriately. The skill provides extensive task knowledge with concrete, production-ready code examples covering Jest/Vitest setup, unit testing, mocking patterns, integration testing, React Testing Library, fixtures, and best practices. The structure is logical with clear sections, though it is quite lengthy in a single file (could benefit from splitting into separate pattern files for very large teams, but acceptable as-is). The novelty score is moderate: while testing patterns are well-established, consolidating best practices for modern tools (Vitest, Testing Library) with TypeScript examples and dependency injection patterns provides meaningful value over a CLI agent attempting to implement testing from scratch, especially for maintaining consistency across a codebase. The skill would significantly reduce token usage and improve test quality for JavaScript/TypeScript projects.