react-testing
Complete React testing system. PROACTIVELY activate for: (1) Vitest/Jest setup and configuration, (2) React Testing Library patterns, (3) Component testing with userEvent, (4) Custom hook testing with renderHook, (5) Mocking modules and components, (6) Async component testing, (7) Context and provider testing, (8) Accessibility testing with jest-axe. Provides: Test setup, query priority, user simulation, mock patterns, integration testing. Ensures reliable tests that focus on user behavior.
What this skill does
# React Testing Skill Use this skill for React tests that focus on user behavior: Vitest/Jest setup, Testing Library queries, user-event flows, async UI, hooks, providers, mocks, integration tests, accessibility checks, and media component tests. ## When to Use This Skill Use when the user asks for tasks covered by the frontmatter triggers, especially implementation guidance, debugging, architecture choices, production hardening, or performance-sensitive decisions in this domain. Start from this orchestrator, then load the focused reference file that matches the requested detail level. ## Core Workflow 1. Set up the runner and jsdom environment first, then centralize `@testing-library/jest-dom`, cleanup, and browser API mocks in test setup. 2. Write tests from the user perspective using role, label, text, placeholder, and display-value queries before falling back to test IDs. 3. Use `userEvent.setup()` for interactions and `waitFor` or findBy queries for async state changes. 4. Mock at module or network boundaries, not internal component state, and reset mocks between tests. 5. Create provider-aware render utilities for context, routers, query clients, themes, and other app-wide wrappers. 6. For media components, mock jsdom gaps such as `HTMLMediaElement.play`, `pause`, `load`, metadata properties, and IntersectionObserver. ## Key Gotchas - Avoid asserting implementation details such as component state; assert visible behavior and accessibility state. - `fireEvent` is lower-level than `userEvent`; prefer `userEvent` unless directly firing browser/media events is necessary. - Async assertions should wait for UI changes, not arbitrary timers. - jsdom does not implement real media playback, layout, or browser codecs; mock those APIs deliberately. - Provider state can leak between tests unless render utilities create fresh clients and cleanup runs after each test. ## Reference Map - [references/react-testing-complete-guide.md](references/react-testing-complete-guide.md) - Full original guide covering setup, component tests, forms, async components, hooks, context, mocks, integration tests, accessibility tests, testing utilities, and video/media testing. - [references/testing-recipes.md](references/testing-recipes.md) - Additional testing recipes already maintained for this skill. ## Response Guidance - Preserve the user's existing framework, library, and tooling choices unless there is a clear compatibility or performance reason to suggest an alternative. - Give copy-pasteable code only for the exact task at hand; otherwise point to the relevant reference section. - Call out tradeoffs, failure modes, and verification steps for production workflows. - Prefer accessible, maintainable, measurable solutions over clever micro-optimizations.
Related in Design
contribute
IncludedLocal-only OSS contribution command center. Auto-refreshes the user's in-flight PR and issue state on invoke so conversations start with full context — no need to brief Claude on what's in flight. Helps the user find issues to contribute to on GitHub, builds per-repo dossiers of what each upstream expects (CLA, DCO, branch convention, AI policy, draft-first, review bots, issue templates), runs deterministic gates before any external action so AI-assisted contributions don't reach maintainers as slop. State is markdown-only: candidate files at ~/.contribute-system/candidates/, repo dossiers at ~/.contribute-system/research/, append-only event log at ~/.contribute-system/log.jsonl. No database, no cloud calls. Use when the user asks about their PRs / issues / contributions, wants to find new work to take on, claim an issue, build/refresh a repo's dossier, or draft a Design Issue or PR. Trigger with "/contribute", "what's my PR status", "find a contribution", "claim issue X", "draft a Design Issue for Y", "refresh dossier for Z".
architectural-analysis
IncludedUser-triggered deep architectural analysis of a codebase or scoped subtree across eight modes — information architecture, data flow, integration points, UI surfaces, interaction patterns, data model, control flow, and failure modes. This skill should be used when the user asks to "diagram this codebase," "map the architecture," "show the data flow," "give me an ERD," "trace control flow," "find the integration points," "verify the layout pattern," "audit the UX architecture," or any similar request whose primary deliverable is mermaid diagrams plus cited reports under docs/architecture/. Dispatches haiku/sonnet sub-agents in parallel for per-mode exploration, then verifies every citation mechanically before any node lands in a diagram. Not for one-off prose explanations of code (use code-explanation) or for high-level system design from scratch (use system-design).
mcp
IncludedModel Context Protocol (MCP) server development and tool management. Languages: Python, TypeScript. Capabilities: build MCP servers, integrate external APIs, discover/execute MCP tools, manage multi-server configs, design agent-centric tools. Actions: create, build, integrate, discover, execute, configure MCP servers/tools. Keywords: MCP, Model Context Protocol, MCP server, MCP tool, stdio transport, SSE transport, tool discovery, resource provider, prompt template, external API integration, Gemini CLI MCP, Claude MCP, agent tools, tool execution, server config. Use when: building MCP servers, integrating external APIs as MCP tools, discovering available MCP tools, executing MCP capabilities, configuring multi-server setups, designing tools for AI agents.
react-native-skia
IncludedDesign, build, debug, and optimise high-polish animated graphics in React Native or Expo using @shopify/react-native-skia, Reanimated, and Gesture Handler. Use when the user wants canvas-driven UI, shaders, paths, rich text, image filters, sprite fields, Skottie, video frames, snapshots, web CanvasKit setup, or performance tuning for custom motion-heavy elements such as loaders, hero art, cards, charts, progress indicators, particle systems, or gesture-driven surfaces. Also use when the user asks for fluid, glow, glass, blob, parallax, 60fps/120fps, or GPU-friendly animated effects in React Native, even if they do not explicitly say "Skia". Do not use for ordinary form/layout work with standard views.
plaid
IncludedProduct Led AI Development — guides founders from idea to launched product. Six capabilities: Idea (discover a product idea), Validate (pressure-test the idea against fatal flaws, problem reality, competition, and 2-week MVP feasibility), Plan (vision intake + document generation), Design (translate image references into a design.md spec), Launch (go-to-market strategy), and Build (roadmap execution). Use when someone says "PLAID", "plaid idea", "help me find an idea", "product idea", "idea from my business", "idea from my expertise", "plaid validate", "validate my idea", "pressure-test", "is this idea good", "find fatal flaws", "validate the problem", "plan a product", "define my vision", "generate a PRD", "product strategy", "plaid design", "design from image", "translate image to design", "create design.md", "extract design tokens", "plaid launch", "go-to-market", "launch plan", "GTM strategy", "launch playbook", "plaid build", "build the app", "start building", or "execute the roadmap".
nextjs-framer-motion-animations
IncludedAdds production-safe Motion for React or Framer Motion animations to Next.js apps, including reveal, hover and tap micro-interactions, whileInView, stagger, AnimatePresence, layout and layoutId transitions, reorder, scroll-linked UI, and lightweight route-content transitions. Use when the user asks to add, refactor, or debug Motion or Framer Motion in App Router or Pages Router codebases, especially around server/client boundaries, reduced motion, LazyMotion, bundle size, hydration, or route transitions. Avoid for GSAP-style timelines, WebGL or 3D scenes, heavy scroll storytelling, or CSS-only effects unless Motion is explicitly requested.