Building a better testing experience for Workflows, our durable execution engine for multi-step applications

Cloudflare announces isolated, local testing capabilities for Workflows via the cloudflare:test module (with @cloudflare/vitest-pool-workers v0.9.0+), enabling developers to introspect workflow instances, mock step outcomes and events, disable sleeps, and assert intermediate results. The article details implementation using Miniflare/workerd, a Runner Worker, and RPC to Engine Durable Objects, and provides example test patterns for known and unknown instance IDs along with setup steps to get started.