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:

• Deprecated Patterns - Complete list with examples
• Review Workflow - Step-by-step review process

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