Configure the test harness
Configure Workers, test values, lifecycle hooks, and failure diagnostics.
← Workers / workers / testing
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.
Get started
View complete example
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
Prepare test state
Seed storage, mock outbound requests, and replace bindings.
Interact with Workers
Test routes, dispatch events, control Workflows, and assert logs.
Integrations
Use the test harness with MSW and Playwright.