Managing Highly Concurrent, State-Dependent Playwright Sessions

Large-scale Playwright E2E load tests for stateful processes, such as login, cart, and checkout, on distributed CI/CD systems encounter significant challenges. Failed tests leave behind residual backend state, including logged-in users and partial carts, and also affect browser state, such as cookies. This contamination leads to flaky, hard-to-diagnose failures. The objective is to ensure absolute isolation and guarantee cleanup efficiently, without the need for a full browser restart for each test.

The solution involves utilizing Playwright's BrowserContext to isolate each test, ensuring no interference between concurrent sessions. This is achieved by creating a new BrowserContext in each testBeforeEach hook, providing a clean, incognito-like session for each test execution. TestBeforeEach and testAfterEach hooks are crucial for managing state.

In testBeforeEach, the context.close() method is used to tear down the isolated session, while in testAfterEach, backend state is cleaned up through targeted API calls (e.g., DELETE /api/user/{id}) using Playwright's request context. This comprehensive approach guarantees that each test starts with a pristine environment and ends with all state managed and removed, significantly reducing flakiness and failures in CI/CD pipelines.