`toHaveValue` fails to find value for `scrollbar` and `separator` roles

[JoshuaKGoldberg]

• @testing-library/jest-dom version: 6.9.1
• node version: 26
• jest (or vitest) version: n/a
• npm (or yarn) version: n/a

Relevant code or config:

const dom = new JSDOM(`
  <div role="meter"       aria-label="Disk"           aria-valuenow="120"></div>
  <div role="progressbar" aria-label="Upload"         aria-valuenow="120"></div>
  <div role="scrollbar"   aria-label="Scroll"         aria-valuenow="120" aria-controls="panel" tabindex="0"></div>
  <div role="separator"   aria-label="Resize panels"  aria-valuenow="120" tabindex="0"></div>
  <div role="slider"      aria-label="Volume"         aria-valuenow="120" tabindex="0"></div>
  <div role="spinbutton"  aria-label="Quantity"       aria-valuenow="120" tabindex="0"></div>
`);

for (const role of ['meter', 'progressbar', 'scrollbar', 'separator', 'slider', 'spinButton']) {
  const element = dom.window.document.querySelector(`[role="${role}"]`);
  expect(element).toHaveValue(120);
}

What you did:

That should all pass, as the aria-valuenow values are all 120.

What happened:

• Pass: meter, progressbar, slider, spinbutton
• Fail: scrollbar, separator

Reproduction:

https://github.com/JoshuaKGoldberg/repros/tree/testing-library-jest-dom-aria-valuenow-roles

Problem description:

Per the WAI-ARIA spec, scrollbar and separator should be supported.

• https://developer.mozilla.org/en-US/docs/Web/Accessibility/ARIA/Reference/Roles/scrollbar_role
• https://developer.mozilla.org/en-US/docs/Web/Accessibility/ARIA/Reference/Roles/separator_role

Suggested solution:

#736 🤗