E2E + Visual Testing
for React Apps.

Common questions for React developers

How do I E2E test a React app in a real browser without writing Playwright code?

Run Lastest, point it at your React app (CRA, Vite, Next.js, Remix, any React stack), click through your flow once, and Lastest generates deterministic Playwright code with 7-layer self-healing selectors and a visual baseline. Replays run on every commit for $0, with zero AI tokens. No test DSL, no Page Object Model, no Playwright docs.

Why do React Testing Library tests pass while my React app is visibly broken?

React Testing Library renders components in JSDOM: no real browser, no real layout, no real routing. State management bugs from Redux, Zustand, or React Query, and visual regressions from Tailwind class swaps both pass JSDOM and break in production. Lastest tests the running app in a real browser and adds a visual diff layer that catches both.

Component refactors keep breaking my selectors. How does Lastest survive that?

Every recorded action gets seven selector candidates: data-testid, id, ARIA role, aria-label, text content, CSS, and OCR. At replay time the runner walks the chain until one matches, so Tailwind class renames, component rewrites, and styled-components migrations usually pass untouched. If everything breaks, AI Test Fixing proposes a patch you approve in one click.

Does Lastest work with React Router, TanStack Router, or Next.js App Router?

Yes, all of them. Lastest tests the running application, not the routing library, so client-side route transitions, server components, suspense boundaries, and parallel routes all work. The recorder captures SPA navigation without page reloads, which is exactly what React Router and TanStack Router emit.

How do I test Redux, Zustand, or React Query state in E2E tests?

You don't need to mock state. Lastest drives the real React app the way a user does: it triggers the component that dispatches the Redux action, renders the resulting UI, and asserts on what shows up on screen. State management bugs that only fire on real network or hydration timing get caught, instead of being mocked away.

How does Lastest handle React 18 / React 19 hydration and concurrent rendering?

Lastest auto-waits for network quiescence and DOM stability before each action, so concurrent rendering, suspense fallbacks, and useTransition updates settle before the test asserts. Hydration mismatches that only appear after the client takes over (one of the most common React 18+ bugs) show up as visual diffs against the SSR baseline.

Will Lastest work with my existing Vitest or Jest unit tests?

Yes, Lastest is additive. Keep your unit tests for component logic and pure functions; use Lastest for the integration seams unit tests cannot reach: routing, real network, real layout, real visual rendering. Most React teams keep Vitest for component-level coverage and add Lastest for the 5-10 critical end-to-end flows.