While bUnit tests components in isolation, Playwright verifies that your entire app works correctly in a real browser.
Playwright can run your Blazor app in Chromium, Firefox, and WebKit simultaneously. It finds real-world issues that bUnit can't, like CSS layout breaks, JS Interop failures, or SignalR connection drops on specific browsers.
In an E2E test, you run your real API and real DB (via Testcontainers). You verify the full 'User Journey': Login -> View Products -> Add to Cart -> Checkout. This is the ultimate 'Sleep-at-night' assurance for a senior architect.
Q: "Playwright or Selenium for Blazor?"
Architect Answer: "Playwright. It has much better support for modern SPAs. It has built-in **Auto-Waiting**, so your tests don't fail just because the SignalR update took 50ms longer than usual. It also supports **Trace Viewing**, which gives you a full video and console log of every test failure in your CI/CD pipeline."