reviewing-vitest-config

djankies's avatarfrom djankies

Review Vitest configuration for deprecated patterns and best practices. Use when reviewing test configuration or vitest setup.

⭐0stars🔀0forks📁View on GitHub🕐Updated Nov 25, 2025
[Testing and QA]

When & Why to Use This Skill

This Claude skill automates the technical review of Vitest configuration files to ensure compliance with Vitest 4.x best practices. It proactively identifies deprecated patterns—such as obsolete thread management and coverage settings—and provides actionable remediation steps to optimize test execution performance and maintainability.

Use Cases

  • Migrating projects to Vitest 4.x by automatically detecting and replacing deprecated configuration keys like maxThreads, singleThread, and legacy coverage options.
  • Standardizing testing environments across monorepos by validating that all workspace and project configurations follow the latest recommended patterns.
  • Optimizing CI/CD pipeline performance by ensuring efficient worker allocation and pool configuration in vitest.config.ts.
  • Troubleshooting browser-based testing setups by verifying correct package imports and provider function calls for Playwright or WebdriverIO integrations.
namereviewing-vitest-config
descriptionReview Vitest configuration for deprecated patterns and best practices. Use when reviewing test configuration or vitest setup.
reviewtrue
allowed-tools[Read, Grep, Glob]

Reviewing Vitest Config

This review skill validates Vitest configurations for deprecated patterns and best practices specific to Vitest 4.x.

Review Scope

This skill reviews:

  1. Pool configuration options
  2. Coverage configuration
  3. Workspace/project setup
  4. Browser mode configuration
  5. Dependency configuration
  6. Reporter configuration
  7. Import paths in test files

Quick Review Checklist

Pool Configuration

  • No maxThreads or maxForks (use maxWorkers)
  • No singleThread or singleFork (use maxWorkers: 1, isolate: false)
  • No nested poolOptions (flatten to top-level)

Coverage Configuration

  • Has explicit coverage.include patterns
  • No coverage.ignoreEmptyLines
  • No coverage.all
  • No coverage.extensions

Workspace/Projects

  • No defineWorkspace (use defineConfig with projects)
  • No poolMatchGlobs or environmentMatchGlobs

Browser Mode

  • Provider imported from package
  • Provider is function call: playwright()
  • Uses instances array, not browser.name
  • Test files use vitest/browser, not @vitest/browser/context

Dependencies

  • Dependencies under server.deps, not top-level deps

Other

  • No reporters: ['basic'] (use default + summary: false)
  • No VITE_NODE_DEPS_MODULE_DIRECTORIES in env
  • No vitest/execute imports

Common Issues

Issue: maxThreads/maxForks Used

Finding:

test: {
  maxThreads: 4,
}

Severity: Critical

Remediation:

test: {
  maxWorkers: 4,
}

Issue: Missing coverage.include

Finding:

coverage: {
  provider: 'v8',
}

Severity: Critical

Remediation:

coverage: {
  provider: 'v8',
  include: ['src/**/*.{ts,tsx}'],
}

Issue: defineWorkspace Used

Finding:

import { defineWorkspace } from 'vitest/config';

export default defineWorkspace([...]);

Severity: Critical

Remediation:

import { defineConfig } from 'vitest/config';

export default defineConfig({
  test: {
    projects: [...],
  },
});

Issue: Wrong Browser Import

Finding:

import { page } from '@vitest/browser/context';

Severity: Critical

Remediation:

import { page } from 'vitest/browser';

Issue: Browser Provider Not Function

Finding:

browser: {
  provider: 'playwright',
  name: 'chromium',
}

Severity: Critical

Remediation:

import { playwright } from '@vitest/browser-playwright';

browser: {
  provider: playwright(),
  instances: [{ browser: 'chromium' }],
}

Issue: deps Not Under server

Finding:

test: {
  deps: {
    inline: ['vue'],
  },
}

Severity: Deprecated

Remediation:

test: {
  server: {
    deps: {
      inline: ['vue'],
    },
  },
}

Review Workflow

Step 1: Find Config Files

glob "vitest.config.{ts,js,mts,mjs}"
glob "vite.config.{ts,js,mts,mjs}"

Step 2: Check Pool Options

Search for deprecated options:

grep -E "(maxThreads|maxForks|singleThread|poolOptions)" vitest.config.ts

Step 3: Check Coverage

Verify include patterns:

grep -A 10 "coverage:" vitest.config.ts | grep "include:"

Step 4: Check Workspace

Search for deprecated workspace:

grep "defineWorkspace" vitest.config.ts

Step 5: Check Browser Mode

Verify provider and instances:

grep -A 5 "browser:" vitest.config.ts

Step 6: Check Test Files

Find wrong imports:

grep -r "@vitest/browser/context" tests/

For detailed review workflow, see references/review-workflow.md

Review Output Format

# Vitest Configuration Review

## Summary
- Config files reviewed: X
- Test files reviewed: Y
- Critical issues: Z
- Deprecated patterns: W
- Best practice suggestions: V

## Critical Issues

### 1. [File]: [Issue]
**Pattern:** [Code snippet]
**Problem:** [Description]
**Remediation:** [Fix]

## Deprecated Patterns

### 1. [File]: [Issue]
**Pattern:** [Code snippet]
**Problem:** [Description]
**Remediation:** [Fix]

## Best Practices

### 1. [File]: [Suggestion]
**Current:** [Code snippet]
**Suggestion:** [Improvement]

For reviewing test quality beyond configuration, use the reviewing-test-quality skill for patterns on coverage, React 19 APIs, and anti-patterns.

References

For detailed information:

For migration guide, see @vitest-4/skills/migrating-to-vitest-4

For configuration patterns, see @vitest-4/skills/configuring-vitest-4

For complete API reference, see @vitest-4/knowledge/vitest-4-comprehensive.md