nextjs-testing

To test Next.js Server Components, apply patterns that evaluate them within their rendering context rather than in isolation. This approach uses Vitest or Jest configurations to handle Server Component execution and verify output directly.

Configuring Vitest for a Next.js application involves setting up the environment to handle both server and client component boundaries. You combine Vitest with React Testing Library for client layers and define specific test layers for robust coverage.

Yes, you can test Next.js Server Actions and Route Handlers as pure functions. This strategy abstracts network and framework overhead, allowing Vitest or Jest to execute and validate their logic directly without running a live server.

Playwright works for end-to-end testing of Next.js React Server Components. You set up Playwright to run integration and e2e tests across your application, validating the full rendering and interaction lifecycle of RSC.

Use MSW for network mocks in Next.js testing when you need to intercept and simulate API requests during client or integration tests. It isolates component behavior by controlling network responses across server and client layers.

Next.js tests fail with React Testing Library on Server Components because RSCs cannot run in isolation like client components. You must choose the correct test layer, using specific configurations to evaluate Server Components properly.