Test Automation
XState v5 models application behavior as explicit state machines. Every state transition is predictable, every guard condition is explicit, and every side effect is an actor. This makes XState code highly testable — if you follow the right patterns. This guide covers testing XState v5 machines: transition testing, guard testing, actor
Test Automation
Jotai is a primitive, flexible state management library built on atoms. Each atom is an independent piece of state, and atoms can derive from other atoms — synchronously or asynchronously. Testing Jotai requires understanding how to provide atom state in tests and how to handle async atoms with Suspense. Setup npm
Test Automation
NativeWind v4 brings Tailwind CSS utility classes to React Native using a compiler that converts className strings into StyleSheet-compatible styles. Testing NativeWind components requires understanding what the compiler produces and how to assert it. This guide covers NativeWind v4 testing: className-based assertions, dark mode switching, responsive breakpoints, and custom theme
Test Automation
React Native's New Architecture — Fabric renderer, JSI (JavaScript Interface), and TurboModules — changes how native modules communicate with JavaScript. For testing, the key impact is that TurboModules use synchronous JSI calls instead of asynchronous bridge messages, and Fabric renders components differently from the legacy renderer. This guide covers testing
Test Automation
Maestro is a mobile E2E testing framework that drives your app through real gestures on a simulator or device. For Expo Router apps, Maestro tests the full navigation stack — deep links, tab switching, modal presentation, auth redirects — without needing to instrument your app code. This guide covers E2E testing Expo
Test Automation
Expo Router brings file-based routing to React Native with full TypeScript support. Each file in your app/ directory maps to a route, layouts wrap segments, and tabs and modals are first-class patterns. Testing all of this requires understanding what Expo Router provides and what you need to verify yourself. This
Test Automation
EAS Build creates native iOS and Android builds in the cloud. For testing, EAS provides three distinct opportunities: preview builds for QA teams, build-time validation of native plugins, and production-equivalent builds for E2E testing. This guide covers testing strategies across the EAS Build pipeline: structuring build profiles, validating environment configs,
Test Automation
TanStack Router is a fully type-safe router for React with built-in route loaders, search parameter validation, and nested layouts. Its type-first design means bugs often show up at build time — but runtime behaviour like data loading, access guards, and navigation still needs tests. This guide covers unit and integration testing
Test Automation
TanStack Query v5 handles server state — fetching, caching, synchronizing, and updating data from your API. Every meaningful UI state it manages (loading, error, success, stale, refetching) is a testing opportunity. This guide covers testing TanStack Query v5: custom query and mutation hooks, cache invalidation, optimistic updates, and offline mode behaviour.
Test Automation
Mock Service Worker (MSW) v2 intercepts HTTP requests at the network level, making it the best tool for testing TanStack Query hooks. Instead of mocking fetch directly (brittle, error-prone), MSW lets you define realistic API handlers that work across unit tests, integration tests, and the browser. This guide covers MSW
Test Automation
TanStack Router SPAs use client-side navigation — no full page reloads, history managed by the router, search params validated by Zod. Playwright handles all of this well, but you need to account for how the SPA manages state and URL. This guide covers Playwright E2E testing for TanStack Router: client-side navigation,
Test Automation
TanStack Form is a headless form library with built-in TypeScript support, field-level validation, async submission, and field arrays. Its headless design means your tests interact with real DOM elements through the form library's state — which makes Testing Library an ideal fit. This guide covers testing TanStack Form: field