# Vitest Expert

> Use when implementing vitest functionality with production-grade patterns and safeguards.

- Skill: `0xharryriddle/vitest-expert` (Agent Skill)
- Install (CLI): `npx skillmds@latest add 0xharryriddle/vitest-expert`
- Raw SKILL.md: https://api.skillmd.com/api/skills/0xharryriddle/vitest-expert/raw
- Safety review: pending (external: skill-scanner PASS, skillspector PASS)
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Coding & Dev Tools
- Author: 0xharryriddle (https://skillmd.com/u/0xharryriddle)
- Updated: 2026-09-08
- Page: https://skillmd.com/skills/0xharryriddle/vitest-expert

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# Vitest Expert

## Focus Areas

- Mastery of Vitest API and configuration
- Writing unit tests for JavaScript and TypeScript
- Asynchronous test handling and assertions
- Mocking and spying on modules and functions
- Test setup and teardown with hooks
- Grouping and organizing related tests
- Handling test environments and global variables
- Configuring Vitest for different environments
- Integrating Vitest with CI/CD pipelines
- Debugging tests effectively within Vitest

## Approach

- Use `describe` blocks to group related tests logically
- Prefer `async/await` for handling asynchronous code
- Use `beforeEach` and `afterEach` hooks for setup/teardown
- Mock external dependencies to isolate test subjects
- Utilize Vitest's snapshot testing for UI components
- Leverage Vitest's built-in assertions for clarity
- Configure Vitest to run specific test files or directories
- Use `.only` and `.skip` to focus on specific tests
- Integrate Vitest seamlessly with version control hooks
- Maintain a separate vitest.config.js for test-specific configuration

## Quality Checklist

- All tests should be deterministic and stable
- Ensure high coverage with meaningful tests
- Avoid testing implementation details; focus on behavior
- Provide clear and descriptive test names
- Regularly refactor tests to remove duplication
- Continuously review and update mocks and stubs
- Optimize test run times without sacrificing coverage
- Consistently review and prune outdated tests
- Ensure compatibility with multiple Node.js versions
- Document test rationale and methodology clearly

## Output

- A comprehensive suite of tests covering all critical paths
- Structured test files with logical organization
- Detailed test reports with coverage metrics
- Maintained and updated vitest snapshots
- Clean test directory with no orphan or obsolete files
- Documented test cases with clear descriptions
- Efficient execution with minimal global side effects
- Configuration files for customizing test environments
- Established CI/CD workflows for automated testing
- Secure and isolated testing environments for reliability