E2E tests broken on Node 22+: import assert syntax, EADDRINUSE port collisions, missing html-webpack-plugin

[pedrotainha]

Description

Running test:e2e-serve on Node 22+ results in 5 out of 12 test suites failing. The failures are caused by four independent issues in the examples and test infrastructure:

1. Deprecated import ... assert { type: 'json' } syntax (3 suites)

Several rollup-based examples use the deprecated Import Assertions syntax:

import pkg from './package.json' assert { type: 'json' }

Node 22+ removed support for assert in favor of the Import Attributes syntax (with keyword). This causes:

SyntaxError: Unexpected identifier 'assert'

Affected files (6):

• packages/examples/simple-react-systemjs/host-systemjs/rollup.config.mjs
• packages/examples/simple-react-systemjs/remote-systemjs/rollup.config.mjs
• packages/examples/basic-host-remote/rollup-host/rollup.config.mjs
• packages/examples/simple-react-webpack/host/rollup.config.mjs
• packages/examples/simple-react-esm/host-esm/rollup.config.mjs
• packages/examples/simple-react-esm/remote-esm/rollup.config.mjs

2. Port collisions between sequential E2E tests (4 suites)

All examples hardcode the same ports (5000/5001). Tests run sequentially via threads: false, but kill-port in afterAll doesn't always free the port before the next test starts, causing:

Error: listen EADDRINUSE: address already in use 0.0.0.0:5000

Affected examples: webpack-host, simple-react-systemjs, basic-host-remote, simple-react-webpack

3. Server readiness race condition (1 suite)

vue3-advanced-demo times out (60s) because pnpm run serve is spawned without await and page.goto() is called before the Vite preview server is actually listening.

4. Missing html-webpack-plugin dependency (1 suite)

simple-react-webpack/remote/webpack.config.js requires html-webpack-plugin but it's not listed in devDependencies:

Error: Cannot find module 'html-webpack-plugin'

Before / After

Metric	Before	After
Test suites passed	6/12	11/12
Test suites failed	5/12	0/12
Test suites skipped	1/12	1/12

(vue2-demo remains skipped — pre-existing, unrelated)

Environment

• Node: 22+ (tested on 24.14.0)
• vite-plugin-federation: 1.4.1 (main branch)
• OS: macOS, Linux