Welcome to my bug report!

To reproduce...

1. Run npm install
2. Run npm run build. This will run build.mjs and should log the following error:

Unexpected early exit. This happens when Promises returned by plugins cannot resolve. Unfinished hook action(s) on exit:
(vite:optimized-deps-build) load "/Users/benholmes/Sandbox/vite-server-build-simulaneously/node_modules/.vite/deps_build-dist/is-odd.js"

3. Head to build.mjs and uncomment "src/test-module.js." This should resolve the error.