Testing Requirements

Use this skill when implementing features that need testing or modifying existing tests.

Checklist

Test Framework Setup

• Location: Create tests in __tests__/ folder next to source files
• Framework: Use Vitest + React Testing Library
• File naming: ComponentName.test.tsx or functionName.test.ts

Test Structure

• Test behavior, not implementation
  • What the code does, not how it does it
  • User-facing behavior and outcomes
  • API contracts and data flow
• Mock external dependencies
  • APIs and React Query hooks
  • Electron APIs via global.window.electronAPI
  • Socket.io events and handlers
  • Zustand stores (reset in beforeEach)
• Keep tests focused and readable
  • One concern per test
  • Clear test names describing behavior
  • Arrange-Act-Assert pattern

Common Testing Patterns

Socket Events - Capture handlers:

let handlers: Record<string, (data: unknown) => void> = {}
vi.mock('@/cores/sockets', () => ({
  useSocketEvent: (event, handler) => (handlers[event] = handler)
}))

// Trigger event in test
handlers[SocketEvents.DOWNLOAD_START]({ id: 'model-123' })

Zustand Stores:

import { renderHook, act } from '@testing-library/react'
import { useMyStore } from './useMyStore'

const { result } = renderHook(() => useMyStore())
act(() => result.current.setValue('new'))

React Query:

import { QueryClient, QueryClientProvider } from '@tanstack/react-query'

const queryClient = new QueryClient()
const wrapper = ({ children }) => (
  <QueryClientProvider client={queryClient}>{children}</QueryClientProvider>
)

render(<MyComponent />, { wrapper })

Coverage Goals

• Aim for 100% on critical paths
  • State management logic
  • Data flow and transformations
  • Business logic
• Run coverage: pnpm run test:coverage -- path/to/files
• Focus on behavior coverage, not just line coverage

Pre-Completion Verification

Before marking work complete, ALWAYS run:

• pnpm run type-check - TypeScript validation
• pnpm run lint - ESLint checks
• pnpm run format - Prettier formatting
• pnpm test -- path/to/test - Run specific tests

Testing Anti-Patterns to Avoid

❌ Don't test implementation details

• Example: Testing that socket.on was called 3 times
• Instead: Test that component responds correctly to events

❌ Don't use any type in tests

• Use proper types, unknown, or as unknown as Type

❌ Don't skip cleanup

• Always reset Zustand stores in beforeEach
• Clear mocks between tests