Test runner times out when assertions fail with DOM elements

[mkutny]

This test times out instead of failing:

import { fixture, expect } from '@open-wc/testing';

it('fails with DOM element', async () => {
  const element = await fixture(`<h1>Title</h1>`);
  expect(element).to.be.true; // Will cause timeout
});

I launch it as npx web-test-runner test/minimal-timeout.test.js --node-resolve

Running this test in a --watch mode in a custom browser (M) fails as expected.

However, running it in Chromium (D) logs these errors in the browser's console:
Uncaught (in promise) DataCloneError: Failed to execute 'structuredClone' on 'Window': HTMLHeadingElement object could not be cloned.

And the next error log is:

autorun.js:1 Uncaught (in promise) DataCloneError: Failed to execute 'structuredClone' on 'Window': HTMLHeadingElement object could not be cloned.
    at stable (__web-dev-server__web-socket.js:23:24)
    at sendMessage (__web-dev-server__web-socket.js:171:20)
stable	@	__web-dev-server__web-socket.js:23
sendMessage	@	__web-dev-server__web-socket.js:171

What would be a workaround to assert DOM elements while this issue is open?

[web-padawan]

Related to #2771. You can try using polyfill as a workaround, see #2802 (comment)

[mkutny]

@web-padawan , thanks so much, Serhii!