fontfaceset-update-after-stylesheet-change.html

<!DOCTYPE html>
<html>
<head id="head">
<meta charset="utf-8">
<link rel="author" title="Myles C. Maxfield" href="[email protected]">
<link rel="help" href="https://drafts.csswg.org/css-font-loading-3/#document-font-face-set">
<meta name="assert" content="Ensure that stylesheet changes are reflected in document.fonts." />
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<style id="style">
@font-face {
    font-family: "WebFont";
    src: url("resources/Rochester.otf") format("opentype");
}
</style>
</head>
<body>
<script>
test(function(t) {
    let fonts = document.fonts;
    assert_equals(fonts.size, 1);
    document.getElementById("head").removeChild(document.getElementById("style"));
    assert_equals(fonts.size, 0);
});
</script>
</body>
</html>

chromium/third_party/blink/web_tests/external/wpt/css/css-font-loading/fontfaceset-update-after-stylesheet-change.html