name: vitest-feature-protector description: Generate Vitest unit tests for new features/components to prevent regressions

Vitest Feature Protector

Automatically creates Vitest test templates when new features or components are added.

When to use this skill

• A new React/Vue component is created
• A new feature module is added
• Existing code needs test coverage
• User explicitly asks to "generate tests" or "create unit tests"

How to use it

1. Identify the target

   • Get the feature/component name and file path
   • Determine type: component, utility function, or feature logic

2. Generate test template

   // For React components
   import { describe, it, expect } from 'vitest'
   import { render, screen } from '@testing-library/react'
   import { ComponentName } from './ComponentName'

   describe('ComponentName', () => {
     it('should render without errors', () => {
       render(<ComponentName />)
       expect(screen.getByRole('...').toBeInTheDocument()
     })
     
     it('should handle props correctly', () => {
       // TODO: Test props
     })
   })

3. File placement

   • Components → tests/components/ComponentName.test.tsx
   • Features → tests/features/FeatureName.test.ts
   • Utils → tests/utils/UtilName.test.ts

4. Follow conventions

   • Use describe() for grouping
   • Use it('should...') for test cases
   • Include at least: render test, props test, interaction test
   • Add TODO comments for edge cases

5. Remind user to

   • Run npm test before committing
   • Check test coverage with npm run test:coverage

Examples

User request: "Create a Button component"

Agent response:

// src/components/Button.tsx
export function Button({ label, onClick }) { ... }

// tests/components/Button.test.tsx
import { describe, it, expect, vi } from 'vitest'
import { render, screen, fireEvent } from '@testing-library/react'
import { Button } from '@/components/Button'

describe('Button', () => {
  it('should render with label', () => {
    render(<Button label="Click me" onClick={() => {}} />)
    expect(screen.getByText('Click me')).toBeInTheDocument()
  })

  it('should call onClick when clicked', () => {
    const handleClick = vi.fn()
    render(<Button label="Click" onClick={handleClick} />)
    fireEvent.click(screen.getByText('Click'))
    expect(handleClick).toHaveBeenCalledOnce()
  })
})

Notes

• Don't generate tests for third-party libraries
• Skip tests if user explicitly says "no tests needed"
• Prefer Testing Library queries in this order: getByRole > getByLabelText > getByText