Integration test harness
createTestHarness() is a Wrangler API for integration testing from any Node.js test runner. It runs one or more Workers from Wrangler projects or Vite projects that use the Cloudflare Vite plugin.
Features
- Runs production build output from Wrangler or the Cloudflare Vite plugin
- Dispatches requests and events to one or more Workers
- Provides access to bindings and local storage from tests
- Captures logs and diagnostic output from the Workers runtime
Guides
Configure Workers, test values, lifecycle hooks, and failure diagnostics.
Seed storage, mock outbound requests, and replace bindings.
Test routes, dispatch events, control Workflows, and assert logs.
Use the test harness with MSW and Playwright.