From 43a97878ce14b72f0981164f87f2e35e14151312 Mon Sep 17 00:00:00 2001
From: Daniel Baumann <daniel.baumann@progress-linux.org>
Date: Sun, 7 Apr 2024 11:22:09 +0200
Subject: Adding upstream version 110.0.1.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
---
 .../beforematch-element-fragment-navigation.html   | 200 +++++++++++++++++++++
 .../editing/the-hidden-attribute/hidden-1-ref.html |   4 +
 .../editing/the-hidden-attribute/hidden-1a.html    |   8 +
 .../editing/the-hidden-attribute/hidden-1b.html    |  11 ++
 .../editing/the-hidden-attribute/hidden-1c.html    |  12 ++
 .../editing/the-hidden-attribute/hidden-1d.html    |  12 ++
 .../editing/the-hidden-attribute/hidden-1e.html    |  10 ++
 .../editing/the-hidden-attribute/hidden-1f.html    |  10 ++
 .../editing/the-hidden-attribute/hidden-1g.html    |  11 ++
 .../editing/the-hidden-attribute/hidden-2-ref.svg  |   7 +
 .../html/editing/the-hidden-attribute/hidden-2.svg |  12 ++
 .../editing/the-hidden-attribute/hidden-idl.html   |  49 +++++
 .../the-hidden-attribute/hidden-ua-stylesheet.html |  65 +++++++
 13 files changed, 411 insertions(+)
 create mode 100644 testing/web-platform/tests/html/editing/the-hidden-attribute/beforematch-element-fragment-navigation.html
 create mode 100644 testing/web-platform/tests/html/editing/the-hidden-attribute/hidden-1-ref.html
 create mode 100644 testing/web-platform/tests/html/editing/the-hidden-attribute/hidden-1a.html
 create mode 100644 testing/web-platform/tests/html/editing/the-hidden-attribute/hidden-1b.html
 create mode 100644 testing/web-platform/tests/html/editing/the-hidden-attribute/hidden-1c.html
 create mode 100644 testing/web-platform/tests/html/editing/the-hidden-attribute/hidden-1d.html
 create mode 100644 testing/web-platform/tests/html/editing/the-hidden-attribute/hidden-1e.html
 create mode 100644 testing/web-platform/tests/html/editing/the-hidden-attribute/hidden-1f.html
 create mode 100644 testing/web-platform/tests/html/editing/the-hidden-attribute/hidden-1g.html
 create mode 100644 testing/web-platform/tests/html/editing/the-hidden-attribute/hidden-2-ref.svg
 create mode 100644 testing/web-platform/tests/html/editing/the-hidden-attribute/hidden-2.svg
 create mode 100644 testing/web-platform/tests/html/editing/the-hidden-attribute/hidden-idl.html
 create mode 100644 testing/web-platform/tests/html/editing/the-hidden-attribute/hidden-ua-stylesheet.html

(limited to 'testing/web-platform/tests/html/editing/the-hidden-attribute')
diff --git a/testing/web-platform/tests/html/editing/the-hidden-attribute/beforematch-element-fragment-navigation.html b/testing/web-platform/tests/html/editing/the-hidden-attribute/beforematch-element-fragment-navigation.html
new file mode 100644
index 0000000000..812a55f318
--- /dev/null
+++ b/testing/web-platform/tests/html/editing/the-hidden-attribute/beforematch-element-fragment-navigation.html
@@ -0,0 +1,200 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<link rel="author" title="Joey Arhar" href="mailto:jarhar@chromium.org">
+<link rel="help" href="https://github.com/WICG/display-locking">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+
+<div id=parentid>
+  <div id=hiddenid>
+    <div id=childid>hello</div>
+  </div>
+</div>
+
+<div id=spacer style="height:4000px">spacer</div>
+
+<script>
+test(() => {
+  window.location.hash = '';
+  hiddenid.hidden = 'until-found';
+  window.location.hash = '#hiddenid';
+  assert_false(hiddenid.hasAttribute('hidden'));
+}, 'Verifies that fragment navigation reveals hidden=until-found elements.');
+
+test(() => {
+  window.location.hash = '';
+  parentid.hidden = 'until-found';
+  hiddenid.hidden = 'until-found';
+  childid.hidden = 'until-found';
+  window.location.hash = 'childid';
+  assert_false(parentid.hasAttribute('hidden'), 'parentid should not have the hidden attribute.');
+  assert_false(hiddenid.hasAttribute('hidden'), 'hiddenid should not have the hidden attribute.');
+  assert_false(childid.hasAttribute('hidden'), 'childid should not have the hidden attribute.');
+}, 'Verifies that fragment navigation reveals all parent hidden=until-found elements.');
+
+test(() => {
+  window.location.hash = '';
+  hiddenid.hidden = 'until-found';
+  let beforematchFiredOnParent = false;
+  let beforematchFiredOnHidden = false;
+  let beforematchFiredOnChild = false;
+  parentid.onbeforematch = () => beforematchFiredOnParent = true;
+  hiddenid.onbeforematch = () => beforematchFiredOnHidden = true;
+  childid.onbeforematch = () => beforematchFiredOnChild = true;
+
+  window.location.hash = '#childid';
+  assert_true(beforematchFiredOnParent, 'beforematch should have been fired on parentid.');
+  assert_true(beforematchFiredOnHidden, 'beforematch should have been fired on hiddenid.');
+  assert_false(beforematchFiredOnChild, 'beforematch should not have been fired on childid.');
+}, 'Verifies that the beforematch event is fired synchronously and bubbles after fragment navigation.');
+
+test(t => {
+  window.location.hash = '';
+  window.scrollTo(0, 0);
+  assert_true(window.pageYOffset === 0, 'Scroll should reset at the beginning of the test.');
+
+  const target = document.createElement('div');
+  target.textContent = 'target';
+  target.id = 'target';
+  target.hidden = 'until-found';
+  document.body.appendChild(target);
+  const spacer = document.createElement('div');
+  spacer.style.height = '4000px';
+  t.add_cleanup(() => {
+    target.remove();
+    spacer.remove();
+  });
+
+  let beforematchCalled = false;
+  target.onbeforematch = () => {
+    assert_equals(window.pageYOffset, 0, 'scrolling should happen after beforematch is fired.');
+    beforematchCalled = true;
+    // Move the target down the page.
+    document.body.appendChild(spacer);
+    target.remove();
+    document.body.appendChild(target);
+  };
+
+  window.location.hash = '#target';
+  assert_true(beforematchCalled, 'The beforematch event should have been fired.');
+
+  const offsetAfterMatch = window.pageYOffset;
+  assert_not_equals(offsetAfterMatch, 0, 'Fragment navigation should have scrolled down the page to the target element.');
+  target.scrollIntoView();
+  assert_equals(offsetAfterMatch, window.pageYOffset, `The scroll after beforematch should be the same as scrolling directly to the element's final destination.`);
+}, 'Verifies that when a beforematch event handler moves a matching element, we scroll to its final location.');
+
+test(t => {
+  window.location.hash = '';
+  const foo = document.createElement('div');
+  foo.textContent = 'foo';
+  foo.id = 'foo';
+  foo.hidden = 'until-found';
+  document.body.appendChild(foo);
+
+  const bar = document.createElement('div');
+  bar.textContent = 'bar';
+  bar.id = 'bar';
+  bar.hidden = 'until-found';
+  document.body.appendChild(bar);
+
+  t.add_cleanup(() => {
+    foo.remove();
+    bar.remove();
+  });
+
+  let beforematchFiredOnFoo = false;
+  foo.onbeforematch = () => beforematchFiredOnFoo = true;
+  let beforematchFiredOnBar = false;
+  bar.onbeforematch = () => beforematchFiredOnBar = true;
+
+  window.location.hash = '#bar';
+
+  assert_false(beforematchFiredOnFoo, 'foo was not navigated to, so it should not get the beforematch event.');
+  assert_true(beforematchFiredOnBar, 'bar was navigated to, so it should get the beforematch event.');
+  assert_true(window.pageYOffset > 0, 'the page should be scrolled down to bar.');
+}, 'Verifies that the beforematch event is fired on the right element when there are multiple hidden=until-found elements.');
+
+test(t => {
+  window.location.hash = '';
+  window.scrollTo(0, 0);
+  assert_true(window.pageYOffset === 0, 'Scroll should reset at the beginning of the test.');
+
+  const div = document.createElement('div');
+  div.textContent = 'detach';
+  div.id = 'detach';
+  div.hidden = 'until-found';
+  document.body.appendChild(div);
+  t.add_cleanup(() => div.remove());
+
+  let beforematchCalled = false;
+  div.onbeforematch = () => {
+    div.remove();
+    beforematchCalled = true;
+  };
+
+  window.location.hash = '#detach';
+
+  assert_true(beforematchCalled, 'beforematch should be called when window.location.hash is set to #detach.');
+  assert_true(window.pageYOffset === 0, 'The page should not be scrolled down to where #detach used to be.');
+}, 'Verifies that no scrolling occurs when an element selected by the fragment identifier is detached by the beforematch event handler.');
+
+test(t => {
+  window.location.hash = '';
+  window.scrollTo(0, 0);
+  assert_true(window.pageYOffset === 0, 'Scroll should reset at the beginning of the test.');
+
+  const div = document.createElement('div');
+  div.textContent = 'displaynone';
+  div.id = 'displaynone';
+  div.hidden = 'until-found';
+  document.body.appendChild(div);
+  t.add_cleanup(() => div.remove());
+
+  let beforematchCalled = false;
+  div.addEventListener('beforematch', () => {
+    div.style = 'display: none';
+    beforematchCalled = true;
+  });
+
+  window.location.hash = '#displaynone';
+
+  assert_true(beforematchCalled, 'beforematch should be called when window.location.hash is set to #displaynone.');
+  assert_true(window.pageYOffset === 0, 'The page should not be scrolled down to where #displaynone used to be.');
+}, `No scrolling should occur when the beforematch event handler sets the target element's style to display: none.`);
+
+test(t => {
+  window.location.hash = '';
+  window.scrollTo(0, 0);
+  assert_true(window.pageYOffset === 0, 'Scroll should reset at the beginning of the test.');
+
+  const div = document.createElement('div');
+  div.textContent = 'visibilityhidden';
+  div.id = 'visibilityhidden';
+  div.hidden = 'until-found';
+  document.body.appendChild(div);
+  t.add_cleanup(() => div.remove());
+
+  let beforematchCalled = false;
+  div.addEventListener('beforematch', () => {
+    div.style = 'visibility: hidden';
+    beforematchCalled = true;
+  });
+
+  window.location.hash = '#visibilityhidden';
+
+  assert_true(beforematchCalled, 'beforematch should be called when window.location.hash is set to #visibilityhidden.');
+  assert_true(window.pageYOffset !== 0, 'The page should be scrolled down to where #visibilityhidden is.');
+}, `Scrolling should still occur when beforematch sets visiblity:hidden on the target element.`);
+
+test(t => {
+  window.location.hash = '';
+  const div = document.createElement('div');
+  div.id = 'target';
+  div.textContent = 'target';
+  document.body.appendChild(div);
+  t.add_cleanup(() => div.remove());
+  div.addEventListener('beforematch', t.unreached_func('beforematch should not be fired without hidden=until-found.'));
+  window.location.hash = '#target';
+}, 'Verifies that the beforematch event is not fired on elements without hidden=until-found.');
+</script>
diff --git a/testing/web-platform/tests/html/editing/the-hidden-attribute/hidden-1-ref.html b/testing/web-platform/tests/html/editing/the-hidden-attribute/hidden-1-ref.html
new file mode 100644
index 0000000000..7346ce919d
--- /dev/null
+++ b/testing/web-platform/tests/html/editing/the-hidden-attribute/hidden-1-ref.html
@@ -0,0 +1,4 @@
+<!doctype html>
+<title>The hidden attribute</title>
+<link rel=author title=Ms2ger href=mailto:Ms2ger@gmail.com>
+<p>This line should be visible.
diff --git a/testing/web-platform/tests/html/editing/the-hidden-attribute/hidden-1a.html b/testing/web-platform/tests/html/editing/the-hidden-attribute/hidden-1a.html
new file mode 100644
index 0000000000..036bfc88b5
--- /dev/null
+++ b/testing/web-platform/tests/html/editing/the-hidden-attribute/hidden-1a.html
@@ -0,0 +1,8 @@
+<!doctype html>
+<title>The hidden attribute</title>
+<link rel=match href=hidden-1-ref.html>
+<link rel=author title=Ms2ger href=mailto:Ms2ger@gmail.com>
+<link rel=help href=https://html.spec.whatwg.org/multipage/#the-hidden-attribute>
+<link rel=help href=https://html.spec.whatwg.org/multipage/#hidden-elements>
+<p>This line should be visible.
+<p hidden>This line should not be visible.
diff --git a/testing/web-platform/tests/html/editing/the-hidden-attribute/hidden-1b.html b/testing/web-platform/tests/html/editing/the-hidden-attribute/hidden-1b.html
new file mode 100644
index 0000000000..3d8b05d349
--- /dev/null
+++ b/testing/web-platform/tests/html/editing/the-hidden-attribute/hidden-1b.html
@@ -0,0 +1,11 @@
+<!doctype html>
+<title>The hidden attribute</title>
+<link rel=match href=hidden-1-ref.html>
+<link rel=author title=Ms2ger href=mailto:Ms2ger@gmail.com>
+<link rel=help href=https://html.spec.whatwg.org/multipage/#the-hidden-attribute>
+<link rel=help href=https://html.spec.whatwg.org/multipage/#hidden-elements>
+<style>
+p { display: none; }
+[hidden] { display: block; }
+</style>
+<p hidden>This line should be visible.
diff --git a/testing/web-platform/tests/html/editing/the-hidden-attribute/hidden-1c.html b/testing/web-platform/tests/html/editing/the-hidden-attribute/hidden-1c.html
new file mode 100644
index 0000000000..8a8cc63c48
--- /dev/null
+++ b/testing/web-platform/tests/html/editing/the-hidden-attribute/hidden-1c.html
@@ -0,0 +1,12 @@
+<!doctype html>
+<title>The hidden attribute</title>
+<link rel=match href=hidden-1-ref.html>
+<link rel=author title=Ms2ger href=mailto:Ms2ger@gmail.com>
+<link rel=help href=https://html.spec.whatwg.org/multipage/#the-hidden-attribute>
+<link rel=help href=https://html.spec.whatwg.org/multipage/#hidden-elements>
+<p hidden>This line should be visible.
+<p>This line should not be visible.
+<script>
+document.getElementsByTagName("p")[0].hidden = false;
+document.getElementsByTagName("p")[1].hidden = true;
+</script>
diff --git a/testing/web-platform/tests/html/editing/the-hidden-attribute/hidden-1d.html b/testing/web-platform/tests/html/editing/the-hidden-attribute/hidden-1d.html
new file mode 100644
index 0000000000..e759148f22
--- /dev/null
+++ b/testing/web-platform/tests/html/editing/the-hidden-attribute/hidden-1d.html
@@ -0,0 +1,12 @@
+<!doctype html>
+<title>The hidden attribute</title>
+<link rel=match href=hidden-1-ref.html>
+<link rel=author title=Ms2ger href=mailto:Ms2ger@gmail.com>
+<link rel=help href=https://html.spec.whatwg.org/multipage/#the-hidden-attribute>
+<link rel=help href=https://html.spec.whatwg.org/multipage/#hidden-elements>
+<p hidden>This line should be visible.
+<p>This line should not be visible.
+<script>
+document.getElementsByTagName("p")[0].removeAttribute("hidden");
+document.getElementsByTagName("p")[1].setAttribute("hidden", "");
+</script>
diff --git a/testing/web-platform/tests/html/editing/the-hidden-attribute/hidden-1e.html b/testing/web-platform/tests/html/editing/the-hidden-attribute/hidden-1e.html
new file mode 100644
index 0000000000..2f3f3c617e
--- /dev/null
+++ b/testing/web-platform/tests/html/editing/the-hidden-attribute/hidden-1e.html
@@ -0,0 +1,10 @@
+<!doctype html>
+<title>The hidden attribute</title>
+<link rel=match href=hidden-1-ref.html>
+<link rel=author title=Ms2ger href=mailto:Ms2ger@gmail.com>
+<link rel=help href=https://html.spec.whatwg.org/multipage/#the-hidden-attribute>
+<link rel=help href=https://html.spec.whatwg.org/multipage/#hidden-elements>
+<style>
+p { display: block; }
+</style>
+<p hidden>This line should be visible.
diff --git a/testing/web-platform/tests/html/editing/the-hidden-attribute/hidden-1f.html b/testing/web-platform/tests/html/editing/the-hidden-attribute/hidden-1f.html
new file mode 100644
index 0000000000..6df30a6143
--- /dev/null
+++ b/testing/web-platform/tests/html/editing/the-hidden-attribute/hidden-1f.html
@@ -0,0 +1,10 @@
+<!doctype html>
+<title>The hidden attribute</title>
+<link rel=match href=hidden-1-ref.html>
+<link rel=author title=Ms2ger href=mailto:Ms2ger@gmail.com>
+<link rel=help href=https://html.spec.whatwg.org/multipage/#the-hidden-attribute>
+<link rel=help href=https://html.spec.whatwg.org/multipage/#hidden-elements>
+<style>
+p { display: block !important; }
+</style>
+<p hidden>This line should be visible.
diff --git a/testing/web-platform/tests/html/editing/the-hidden-attribute/hidden-1g.html b/testing/web-platform/tests/html/editing/the-hidden-attribute/hidden-1g.html
new file mode 100644
index 0000000000..849d61fe1e
--- /dev/null
+++ b/testing/web-platform/tests/html/editing/the-hidden-attribute/hidden-1g.html
@@ -0,0 +1,11 @@
+<!doctype html>
+<title>The hidden attribute</title>
+<link rel=match href=hidden-1-ref.html>
+<link rel=author title=Ms2ger href=mailto:Ms2ger@gmail.com>
+<link rel=help href=https://html.spec.whatwg.org/multipage/#the-hidden-attribute>
+<link rel=help href=https://html.spec.whatwg.org/multipage/#hidden-elements>
+<p>This line should be visible.
+<p hidden=hidden>This line should not be visible.
+<p hidden=blue>This line should not be visible.
+<p hidden=true>This line should not be visible.
+<p hidden=false>This line should not be visible.
diff --git a/testing/web-platform/tests/html/editing/the-hidden-attribute/hidden-2-ref.svg b/testing/web-platform/tests/html/editing/the-hidden-attribute/hidden-2-ref.svg
new file mode 100644
index 0000000000..10931bfcab
--- /dev/null
+++ b/testing/web-platform/tests/html/editing/the-hidden-attribute/hidden-2-ref.svg
@@ -0,0 +1,7 @@
+<svg xmlns="http://www.w3.org/2000/svg" height="20" width="20">
+<metadata>
+  <link xmlns="http://www.w3.org/1999/xhtml" rel="author" title="Ms2ger"
+        href="mailto:Ms2ger@gmail.com"/>
+</metadata>
+<rect height="20" width="20"/>
+</svg>
diff --git a/testing/web-platform/tests/html/editing/the-hidden-attribute/hidden-2.svg b/testing/web-platform/tests/html/editing/the-hidden-attribute/hidden-2.svg
new file mode 100644
index 0000000000..a5f08f6b27
--- /dev/null
+++ b/testing/web-platform/tests/html/editing/the-hidden-attribute/hidden-2.svg
@@ -0,0 +1,12 @@
+<svg xmlns="http://www.w3.org/2000/svg" height="20" width="20">
+<metadata>
+  <link xmlns="http://www.w3.org/1999/xhtml" rel="match" href="hidden-2-ref.svg" />
+  <link xmlns="http://www.w3.org/1999/xhtml" rel="author" title="Ms2ger"
+        href="mailto:Ms2ger@gmail.com"/>
+  <link xmlns="http://www.w3.org/1999/xhtml" rel="help"
+        href="https://html.spec.whatwg.org/multipage/#the-hidden-attribute"/>
+  <link xmlns="http://www.w3.org/1999/xhtml" rel="help"
+        href="https://html.spec.whatwg.org/multipage/#hidden-elements"/>
+</metadata>
+<rect hidden="" height="20" width="20"/>
+</svg>
diff --git a/testing/web-platform/tests/html/editing/the-hidden-attribute/hidden-idl.html b/testing/web-platform/tests/html/editing/the-hidden-attribute/hidden-idl.html
new file mode 100644
index 0000000000..331b63f93f
--- /dev/null
+++ b/testing/web-platform/tests/html/editing/the-hidden-attribute/hidden-idl.html
@@ -0,0 +1,49 @@
+<!DOCTYPE html>
+<link rel=author href="mailto:jarhar@chromium.org">
+<link rel=help href="https://github.com/whatwg/html/pull/7475">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+
+<div>hello</div>
+<script>
+const div = document.querySelector('div');
+
+function runPropertyTest(assignedValue, expectedValue, expectedAttribute) {
+  test(() => {
+    div.hidden = assignedValue;
+    assert_equals(div.hidden, expectedValue,
+      `div.hidden = ${JSON.stringify(assignedValue)} should return ${JSON.stringify(expectedValue)}`);
+    assert_equals(div.getAttribute('hidden'), expectedAttribute,
+      `div.hidden = ${JSON.stringify(assignedValue)} should set the hidden attribute to ${JSON.stringify(expectedAttribute)}`);
+  }, `div.hidden = ${Number.isNaN(assignedValue) ? 'NaN' : JSON.stringify(assignedValue)}`);
+}
+
+function runAttributeTest(assignedAttribute, expectedValue) {
+  test(() => {
+    div.setAttribute('hidden', assignedAttribute);
+    assert_equals(div.hidden, expectedValue);
+  }, `div.setAttribute('hidden', ${JSON.stringify(assignedAttribute)}) should make div.hidden return ${JSON.stringify(expectedValue)}`);
+}
+
+runPropertyTest(false, false, null);
+runPropertyTest(true, true, '');
+runPropertyTest('foo', true, '');
+runPropertyTest('false', true, '');
+runPropertyTest('', false, null);
+
+runAttributeTest('false', true);
+runAttributeTest('foo', true);
+
+runPropertyTest('until-found', 'until-found', 'until-found');
+runPropertyTest('UNTIL-FOUND', 'until-found', 'until-found');
+runPropertyTest('UnTiL-FoUnD', 'until-found', 'until-found');
+runPropertyTest('unt\u0131l-found', true, '');
+runPropertyTest('unt\u0130l-found', true, '');
+
+runPropertyTest(null, false, null);
+runPropertyTest(undefined, false, null);
+
+runPropertyTest(1, true, '');
+runPropertyTest(0, false, null);
+runPropertyTest(NaN, false, null);
+</script>
diff --git a/testing/web-platform/tests/html/editing/the-hidden-attribute/hidden-ua-stylesheet.html b/testing/web-platform/tests/html/editing/the-hidden-attribute/hidden-ua-stylesheet.html
new file mode 100644
index 0000000000..913ecc037c
--- /dev/null
+++ b/testing/web-platform/tests/html/editing/the-hidden-attribute/hidden-ua-stylesheet.html
@@ -0,0 +1,65 @@
+<!DOCTYPE html>
+<link rel=author href="mailto:jarhar@chromium.org">
+<link rel=help href="https://html.spec.whatwg.org/multipage/rendering.html#hiddenCSS">
+<link rel=help href="https://github.com/whatwg/html/pull/7475#issuecomment-1069313217">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+
+<div id=div>hello world</div>
+<table id=table>
+  <colgroup id=colgroup>
+    <col id=col></col>
+  </colgroup>
+</table>
+
+<script>
+function testDisplayNone(description) {
+  test(() => {
+    assert_equals(getComputedStyle(div).display, 'none',
+        `${description} should make the div display:none.`);
+    assert_equals(getComputedStyle(div).contentVisibility, 'visible',
+        `${description} should not affect the div's content-visibility property.`);
+  }, description);
+}
+
+function testCVHidden(description) {
+  test(() => {
+    assert_equals(getComputedStyle(div).display, 'block',
+        `${description} should not affect the div's display property.`);
+    assert_equals(getComputedStyle(div).contentVisibility, 'hidden',
+        `${description} should make the div content-visibility:hidden.`);
+  }, description);
+}
+
+function testNormal(description) {
+  test(() => {
+    assert_equals(getComputedStyle(div).display, 'block',
+        `${description} should not affect the div's display property.`);
+    assert_equals(getComputedStyle(div).contentVisibility, 'visible',
+        `${description} should not affect the div's content-visibility property.`);
+  }, description);
+}
+
+test(() => {
+  div.removeAttribute('hidden');
+  testNormal(`div.removeAttribute('hidden')`);
+
+  div.setAttribute('hidden', '');
+  testDisplayNone(`div.setAttribute('hidden', '')`);
+
+  div.setAttribute('hidden', 'asdf');
+  testDisplayNone(`div.setAttribute('hidden', 'asdf')`);
+
+  div.setAttribute('hidden', 'until-found');
+  testCVHidden(`div.setAttribute('hidden', 'until-found')`);
+
+  div.setAttribute('hidden', 'UNTIL-FOUND');
+  testCVHidden(`div.setAttribute('hidden', 'UNTIL-FOUND')`);
+
+  div.setAttribute('hidden', 'UnTiL-FoUnD');
+  testCVHidden(`div.setAttribute('hidden', 'UnTiL-FoUnD')`);
+
+  div.setAttribute('hidden', '0');
+  testDisplayNone(`div.setAttribute('hidden', '0')`);
+});
+</script>
-- 
cgit v1.2.3

