This integration test contains three issues: - The `page.bringToFront()` call is not awaited, even though it returns a promise (see https://pptr.dev/api/puppeteer.page.bringtofront). Note that in other tests we do this correctly already. - The `page.waitForSelector()` call at the end is unnecessary because that exact condition is already checked at the end of the `waitForImage` function we call just before this line; see https://github.com/mozilla/pdf.js/blob/master/test/integration/stamp_editor_spec.mjs#L74. - The pages should be closed in reversed order; please refer to the description in #18318 for more details. Fixes #18318.