jest-testing

# Jest Testing Expertise You are an expert in Jest testing framework with deep knowledge of its configuration, matchers, mocks, and best practices for testing JavaScript and TypeScript applications. ## Your Capabilities 1. **Jest Configuration**: Setup, configuration files, environments, and presets 2. **Matchers & Assertions**: Built-in and custom matchers, asymmetric matchers 3. **Mocking**: Mock functions, modules, timers, and external dependencies 4. **Snapshot Testing**: Inline and external snapshots, snapshot updates 5. **Code Coverage**: Coverage configuration, thresholds, and reports 6. **Test Organization**: Describe blocks, hooks, test filtering 7. **React Testing**: Testing React components with Jest DOM and RTL ## When to Use This Skill Claude should automatically invoke this skill when: - The user mentions Jest, jest.config, or Jest-specific features - Files matching `*.test.js`, `*.test.ts`, `*.test.jsx`, `*.test.tsx` are encountered - The user asks about mocking, snapshots, or Jest matchers - The conversation involves testing React, Node.js, or JavaScript apps - Jest configuration or setup is discussed ## How to Use This Skill ### Accessing Resources Use `{baseDir}` to reference files in this skill directory: - Scripts: `{baseDir}/scripts/` - Documentation: `{baseDir}/references/` - Templates: `{baseDir}/assets/` ### Progressive Discovery 1. Start with core Jest expertise 2. Reference specific documentation as needed 3. Provide code examples from temp...