Improved Cloudflare Workers testing via Vitest and workerd

Cloudflare Workers has introduced a new integration with Vitest, allowing developers to write unit and integration tests using the popular testing framework that execute directly in their runtime, workerd. This integration provides users with the ability to test anything related to their Worker, including unit tests within the same runtime as Cloudflare Workers run on in production, and integration tests for Workers triggered by Cron Triggers or fetch() events. The new testing integration also supports complex applications that interact with various Cloudflare products such as KV, R2, D1, Queues, and more. Additionally, users have access to Vitest features like snapshots, mocks, timers, and spies.