Merging upstream version 125.0.1.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

98 files changed, 1426 insertions, 594 deletions

diff --git a/accessible/tests/browser/atk/browser_role.js b/accessible/tests/browser/atk/browser_role.js
index 7b870b3337..47cc5ef28f 100644
--- a/accessible/tests/browser/atk/browser_role.js
+++ b/accessible/tests/browser/atk/browser_role.js
@@ -11,7 +11,7 @@ addAccessibleTask(
   `
 <p id="p">p</p>
   `,
-  async function (browser, docAcc) {
+  async function () {
     let role = await runPython(`
       global doc
       doc = getDoc()
diff --git a/accessible/tests/browser/atk/browser_table.js b/accessible/tests/browser/atk/browser_table.js
index 98b3270465..55452709e8 100644
--- a/accessible/tests/browser/atk/browser_table.js
+++ b/accessible/tests/browser/atk/browser_table.js
@@ -20,7 +20,7 @@ addAccessibleTask(
   </tr>
 </table>
   `,
-  async function (browser, docAcc) {
+  async function () {
     let result = await runPython(`
       global doc
       doc = getDoc()
diff --git a/accessible/tests/browser/bounds/browser_accessible_moved.js b/accessible/tests/browser/bounds/browser_accessible_moved.js
index 307c680000..a62f7ad8d0 100644
--- a/accessible/tests/browser/bounds/browser_accessible_moved.js
+++ b/accessible/tests/browser/bounds/browser_accessible_moved.js
@@ -12,10 +12,10 @@ function assertBoundsNonZero(acc) {
   let width = {};
   let height = {};
   acc.getBounds(x, y, width, height);
-  ok(x.value > 0, "x is non-0");
-  ok(y.value > 0, "y is non-0");
-  ok(width.value > 0, "width is non-0");
-  ok(height.value > 0, "height is non-0");
+  Assert.greater(x.value, 0, "x is non-0");
+  Assert.greater(y.value, 0, "y is non-0");
+  Assert.greater(width.value, 0, "width is non-0");
+  Assert.greater(height.value, 0, "height is non-0");
 }
 
 /**
diff --git a/accessible/tests/browser/bounds/browser_caret_rect.js b/accessible/tests/browser/bounds/browser_caret_rect.js
index ac0ee3aa50..9f5cac33a5 100644
--- a/accessible/tests/browser/bounds/browser_caret_rect.js
+++ b/accessible/tests/browser/bounds/browser_caret_rect.js
@@ -46,7 +46,7 @@ async function testCaretRect(browser, docAcc, id, offset) {
   );
   const [caretX, caretY, caretW, caretH] = await getCaretRect(browser, id);
   if (atEnd) {
-    ok(caretX > charX.value, "Caret x after last character x");
+    Assert.greater(caretX, charX.value, "Caret x after last character x");
   } else {
     is(caretX, charX.value, "Caret x same as character x");
   }
diff --git a/accessible/tests/browser/bounds/browser_test_display_contents.js b/accessible/tests/browser/bounds/browser_test_display_contents.js
index db1bfce178..4111ac5a81 100644
--- a/accessible/tests/browser/bounds/browser_test_display_contents.js
+++ b/accessible/tests/browser/bounds/browser_test_display_contents.js
@@ -16,7 +16,11 @@ async function testContentBounds(browser, acc) {
   is(x, expectedX, "Wrong x coordinate of " + prettyAccName);
   is(y, expectedY, "Wrong y coordinate of " + prettyAccName);
   is(width, expectedWidth, "Wrong width of " + prettyAccName);
-  ok(height >= expectedHeight, "Wrong height of " + prettyAccName);
+  Assert.greaterOrEqual(
+    height,
+    expectedHeight,
+    "Wrong height of " + prettyAccName
+  );
 }
 
 async function runTests(browser, accDoc) {
diff --git a/accessible/tests/browser/bounds/browser_test_iframe_transform.js b/accessible/tests/browser/bounds/browser_test_iframe_transform.js
index a44ab75faf..015d466da9 100644
--- a/accessible/tests/browser/bounds/browser_test_iframe_transform.js
+++ b/accessible/tests/browser/bounds/browser_test_iframe_transform.js
@@ -68,7 +68,7 @@ function testBoundsWithOffset(browser, iframeDocAcc, id, domElmBounds, offset) {
 
 addAccessibleTask(
   `<div id='${ELEM_ID}'>hello world</div>`,
-  async function (browser, iframeDocAcc, contentDocAcc) {
+  async function (browser, iframeDocAcc) {
     ok(iframeDocAcc, "IFRAME document accessible is present");
 
     await testBoundsWithContent(iframeDocAcc, ELEM_ID, browser);
@@ -143,7 +143,7 @@ addAccessibleTask(
  */
 addAccessibleTask(
   `<div id="div" style="width: 30px; height: 30px"></div>`,
-  async function (browser, accDoc, foo) {
+  async function (browser, accDoc) {
     const docWidth = () => {
       let width = {};
       accDoc.getBounds({}, {}, width, {});
diff --git a/accessible/tests/browser/bounds/browser_test_simple_transform.js b/accessible/tests/browser/bounds/browser_test_simple_transform.js
index 7197968b40..b5cb983e72 100644
--- a/accessible/tests/browser/bounds/browser_test_simple_transform.js
+++ b/accessible/tests/browser/bounds/browser_test_simple_transform.js
@@ -9,7 +9,7 @@ loadScripts({ name: "role.js", dir: MOCHITESTS_DIR });
 // test basic translation
 addAccessibleTask(
   `<p id="translate">hello world</p>`,
-  async function (browser, iframeDocAcc, contentDocAcc) {
+  async function (browser, iframeDocAcc) {
     ok(iframeDocAcc, "IFRAME document accessible is present");
     await testBoundsWithContent(iframeDocAcc, "translate", browser);
 
@@ -42,7 +42,7 @@ addAccessibleTask(
 // test basic rotation
 addAccessibleTask(
   `<p id="rotate">hello world</p>`,
-  async function (browser, iframeDocAcc, contentDocAcc) {
+  async function (browser, iframeDocAcc) {
     ok(iframeDocAcc, "IFRAME document accessible is present");
     await testBoundsWithContent(iframeDocAcc, "rotate", browser);
 
@@ -60,7 +60,7 @@ addAccessibleTask(
 // test basic scale
 addAccessibleTask(
   `<p id="scale">hello world</p>`,
-  async function (browser, iframeDocAcc, contentDocAcc) {
+  async function (browser, iframeDocAcc) {
     ok(iframeDocAcc, "IFRAME document accessible is present");
     await testBoundsWithContent(iframeDocAcc, "scale", browser);
 
diff --git a/accessible/tests/browser/bounds/browser_test_zoom.js b/accessible/tests/browser/bounds/browser_test_zoom.js
index ac84e485a4..1af84d61d8 100644
--- a/accessible/tests/browser/bounds/browser_test_zoom.js
+++ b/accessible/tests/browser/bounds/browser_test_zoom.js
@@ -16,7 +16,11 @@ async function testContentBounds(browser, acc) {
   is(x, expectedX, "Wrong x coordinate of " + prettyAccName);
   is(y, expectedY, "Wrong y coordinate of " + prettyAccName);
   is(width, expectedWidth, "Wrong width of " + prettyAccName);
-  ok(height >= expectedHeight, "Wrong height of " + prettyAccName);
+  Assert.greaterOrEqual(
+    height,
+    expectedHeight,
+    "Wrong height of " + prettyAccName
+  );
 }
 
 async function runTests(browser, accDoc) {
diff --git a/accessible/tests/browser/bounds/browser_zero_area.js b/accessible/tests/browser/bounds/browser_zero_area.js
index c0f9db2673..80954fbd1a 100644
--- a/accessible/tests/browser/bounds/browser_zero_area.js
+++ b/accessible/tests/browser/bounds/browser_zero_area.js
@@ -67,10 +67,10 @@ addAccessibleTask(
     const radio = findAccessibleChildByID(accDoc, "radio");
     const contentDPR = await getContentDPR(browser);
     const [x, y, width, height] = getBounds(radio, contentDPR);
-    ok(x < 0, "X coordinate should be negative");
-    ok(y > 0, "Y coordinate should be positive");
-    ok(width > 0, "Width should be positive");
-    ok(height > 0, "Height should be positive");
+    Assert.less(x, 0, "X coordinate should be negative");
+    Assert.greater(y, 0, "Y coordinate should be positive");
+    Assert.greater(width, 0, "Width should be positive");
+    Assert.greater(height, 0, "Height should be positive");
     // Note: the exact values of x, y, width, and height
     // are inconsistent with the DOM element values of those
     // fields, so we don't check our bounds against them with
diff --git a/accessible/tests/browser/browser_shutdown_acc_reference.js b/accessible/tests/browser/browser_shutdown_acc_reference.js
index 1768095f94..975eab55a0 100644
--- a/accessible/tests/browser/browser_shutdown_acc_reference.js
+++ b/accessible/tests/browser/browser_shutdown_acc_reference.js
@@ -36,7 +36,7 @@ add_task(async function () {
   const [a11yShutdownObserver, a11yShutdownPromise] = shutdownAccService();
   await a11yShutdownObserver;
   const a11yShutdown = new Promise((resolve, reject) =>
-    a11yShutdownPromise.then(flag =>
+    a11yShutdownPromise.then(() =>
       canShutdown
         ? resolve()
         : reject("Accessible service was shut down incorrectly")
diff --git a/accessible/tests/browser/browser_shutdown_doc_acc_reference.js b/accessible/tests/browser/browser_shutdown_doc_acc_reference.js
index 8f7bf6d423..7d999d7d13 100644
--- a/accessible/tests/browser/browser_shutdown_doc_acc_reference.js
+++ b/accessible/tests/browser/browser_shutdown_doc_acc_reference.js
@@ -28,7 +28,7 @@ add_task(async function () {
   const [a11yShutdownObserver, a11yShutdownPromise] = shutdownAccService();
   await a11yShutdownObserver;
   const a11yShutdown = new Promise((resolve, reject) =>
-    a11yShutdownPromise.then(flag =>
+    a11yShutdownPromise.then(() =>
       canShutdown
         ? resolve()
         : reject("Accessible service was shut down incorrectly")
diff --git a/accessible/tests/browser/browser_shutdown_multi_acc_reference_doc.js b/accessible/tests/browser/browser_shutdown_multi_acc_reference_doc.js
index 273fc7175d..1200e02116 100644
--- a/accessible/tests/browser/browser_shutdown_multi_acc_reference_doc.js
+++ b/accessible/tests/browser/browser_shutdown_multi_acc_reference_doc.js
@@ -39,7 +39,7 @@ add_task(async function () {
   const [a11yShutdownObserver, a11yShutdownPromise] = shutdownAccService();
   await a11yShutdownObserver;
   const a11yShutdown = new Promise((resolve, reject) =>
-    a11yShutdownPromise.then(flag =>
+    a11yShutdownPromise.then(() =>
       canShutdown
         ? resolve()
         : reject("Accessible service was shut down incorrectly")
diff --git a/accessible/tests/browser/browser_shutdown_multi_acc_reference_obj.js b/accessible/tests/browser/browser_shutdown_multi_acc_reference_obj.js
index af21b3dc4c..346aa9b6c4 100644
--- a/accessible/tests/browser/browser_shutdown_multi_acc_reference_obj.js
+++ b/accessible/tests/browser/browser_shutdown_multi_acc_reference_obj.js
@@ -39,7 +39,7 @@ add_task(async function () {
   const [a11yShutdownObserver, a11yShutdownPromise] = shutdownAccService();
   await a11yShutdownObserver;
   const a11yShutdown = new Promise((resolve, reject) =>
-    a11yShutdownPromise.then(flag =>
+    a11yShutdownPromise.then(() =>
       canShutdown
         ? resolve()
         : reject("Accessible service was shut down incorrectly")
diff --git a/accessible/tests/browser/browser_shutdown_multi_proxy_acc_reference_doc.js b/accessible/tests/browser/browser_shutdown_multi_proxy_acc_reference_doc.js
index e4091c5216..84429cf077 100644
--- a/accessible/tests/browser/browser_shutdown_multi_proxy_acc_reference_doc.js
+++ b/accessible/tests/browser/browser_shutdown_multi_proxy_acc_reference_doc.js
@@ -30,7 +30,7 @@ add_task(async function () {
         <body id="body"><div id="div"></div></body>
       </html>`,
     },
-    async function (browser) {
+    async function () {
       let docLoadedEvent = await docLoaded;
       let docAcc = docLoadedEvent.accessibleDocument;
       ok(docAcc, "Accessible document proxy is created");
@@ -46,7 +46,7 @@ add_task(async function () {
       const [a11yShutdownObserver, a11yShutdownPromise] = shutdownAccService();
       await a11yShutdownObserver;
       const a11yShutdown = new Promise((resolve, reject) =>
-        a11yShutdownPromise.then(flag =>
+        a11yShutdownPromise.then(() =>
           canShutdown
             ? resolve()
             : reject("Accessible service was shut down incorrectly")
diff --git a/accessible/tests/browser/browser_shutdown_multi_proxy_acc_reference_obj.js b/accessible/tests/browser/browser_shutdown_multi_proxy_acc_reference_obj.js
index f6eca362b0..b7356f3e6f 100644
--- a/accessible/tests/browser/browser_shutdown_multi_proxy_acc_reference_obj.js
+++ b/accessible/tests/browser/browser_shutdown_multi_proxy_acc_reference_obj.js
@@ -30,7 +30,7 @@ add_task(async function () {
         <body id="body"><div id="div"></div></body>
       </html>`,
     },
-    async function (browser) {
+    async function () {
       let docLoadedEvent = await docLoaded;
       let docAcc = docLoadedEvent.accessibleDocument;
       ok(docAcc, "Accessible document proxy is created");
@@ -46,7 +46,7 @@ add_task(async function () {
       const [a11yShutdownObserver, a11yShutdownPromise] = shutdownAccService();
       await a11yShutdownObserver;
       const a11yShutdown = new Promise((resolve, reject) =>
-        a11yShutdownPromise.then(flag =>
+        a11yShutdownPromise.then(() =>
           canShutdown
             ? resolve()
             : reject("Accessible service was shut down incorrectly")
diff --git a/accessible/tests/browser/browser_shutdown_multi_reference.js b/accessible/tests/browser/browser_shutdown_multi_reference.js
index a92f6faf61..49ee822afa 100644
--- a/accessible/tests/browser/browser_shutdown_multi_reference.js
+++ b/accessible/tests/browser/browser_shutdown_multi_reference.js
@@ -31,7 +31,7 @@ add_task(async function () {
   const [a11yShutdownObserver, a11yShutdownPromise] = shutdownAccService();
   await a11yShutdownObserver;
   const a11yShutdown = new Promise((resolve, reject) =>
-    a11yShutdownPromise.then(flag =>
+    a11yShutdownPromise.then(() =>
       canShutdown
         ? resolve()
         : reject("Accessible service was shut down incorrectly")
diff --git a/accessible/tests/browser/browser_shutdown_parent_own_reference.js b/accessible/tests/browser/browser_shutdown_parent_own_reference.js
index 472e977626..ffbe33f137 100644
--- a/accessible/tests/browser/browser_shutdown_parent_own_reference.js
+++ b/accessible/tests/browser/browser_shutdown_parent_own_reference.js
@@ -61,7 +61,7 @@ add_task(async function () {
         shutdownAccService(browser);
       await contentA11yShutdownObserver;
       const contentA11yShutdown = new Promise((resolve, reject) =>
-        contentA11yShutdownPromise.then(flag =>
+        contentA11yShutdownPromise.then(() =>
           contentCanShutdown
             ? resolve()
             : reject("Accessible service was shut down incorrectly")
diff --git a/accessible/tests/browser/browser_shutdown_proxy_acc_reference.js b/accessible/tests/browser/browser_shutdown_proxy_acc_reference.js
index 7144cff019..47fa47da53 100644
--- a/accessible/tests/browser/browser_shutdown_proxy_acc_reference.js
+++ b/accessible/tests/browser/browser_shutdown_proxy_acc_reference.js
@@ -41,7 +41,7 @@ add_task(async function () {
       const [a11yShutdownObserver, a11yShutdownPromise] = shutdownAccService();
       await a11yShutdownObserver;
       const a11yShutdown = new Promise((resolve, reject) =>
-        a11yShutdownPromise.then(flag =>
+        a11yShutdownPromise.then(() =>
           canShutdown
             ? resolve()
             : reject("Accessible service was shut down incorrectly")
diff --git a/accessible/tests/browser/browser_shutdown_proxy_doc_acc_reference.js b/accessible/tests/browser/browser_shutdown_proxy_doc_acc_reference.js
index 6d4ad71f1e..72a424b21f 100644
--- a/accessible/tests/browser/browser_shutdown_proxy_doc_acc_reference.js
+++ b/accessible/tests/browser/browser_shutdown_proxy_doc_acc_reference.js
@@ -30,7 +30,7 @@ add_task(async function () {
         <body id="body"></body>
       </html>`,
     },
-    async function (browser) {
+    async function () {
       let docLoadedEvent = await docLoaded;
       let docAcc = docLoadedEvent.accessibleDocument;
       ok(docAcc, "Accessible document proxy is created");
@@ -43,7 +43,7 @@ add_task(async function () {
       const [a11yShutdownObserver, a11yShutdownPromise] = shutdownAccService();
       await a11yShutdownObserver;
       const a11yShutdown = new Promise((resolve, reject) =>
-        a11yShutdownPromise.then(flag =>
+        a11yShutdownPromise.then(() =>
           canShutdown
             ? resolve()
             : reject("Accessible service was shut down incorrectly")
diff --git a/accessible/tests/browser/browser_shutdown_remote_own_reference.js b/accessible/tests/browser/browser_shutdown_remote_own_reference.js
index a30d191b53..83c68689b7 100644
--- a/accessible/tests/browser/browser_shutdown_remote_own_reference.js
+++ b/accessible/tests/browser/browser_shutdown_remote_own_reference.js
@@ -108,7 +108,7 @@ add_task(async function () {
       const [contentA11yShutdownObserver, contentA11yShutdownPromise] =
         shutdownAccService(browser);
       const contentA11yShutdown = new Promise((resolve, reject) =>
-        contentA11yShutdownPromise.then(flag =>
+        contentA11yShutdownPromise.then(() =>
           contentCanShutdown
             ? resolve()
             : reject("Accessible service was shut down incorrectly")
diff --git a/accessible/tests/browser/e10s/browser.toml b/accessible/tests/browser/e10s/browser.toml
index dfac6b5219..914f839993 100644
--- a/accessible/tests/browser/e10s/browser.toml
+++ b/accessible/tests/browser/e10s/browser.toml
@@ -18,9 +18,12 @@ support-files = [
 ]
 prefs = [
   "javascript.options.asyncstack_capture_debuggee_only=false",
-  "dom.element.popover.enabled=true"
+  "dom.element.popover.enabled=true",
+  "accessibility.ARIAElementReflection.enabled=true"
 ]
 
+["browser_aria_activedescendant.js"]
+
 # Caching tests
 ["browser_caching_actions.js"]
 
diff --git a/accessible/tests/browser/e10s/browser_aria_activedescendant.js b/accessible/tests/browser/e10s/browser_aria_activedescendant.js
new file mode 100644
index 0000000000..f58c5aab39
--- /dev/null
+++ b/accessible/tests/browser/e10s/browser_aria_activedescendant.js
@@ -0,0 +1,485 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+"use strict";
+
+/* import-globals-from ../../mochitest/role.js */
+/* import-globals-from ../../mochitest/states.js */
+loadScripts(
+  { name: "role.js", dir: MOCHITESTS_DIR },
+  { name: "states.js", dir: MOCHITESTS_DIR }
+);
+
+async function synthFocus(browser, container, item) {
+  let focusPromise = waitForEvent(EVENT_FOCUS, item);
+  await invokeContentTask(browser, [container], _container => {
+    let elm = (
+      content.document._testGetElementById || content.document.getElementById
+    ).bind(content.document)(_container);
+    elm.focus();
+  });
+  await focusPromise;
+}
+
+async function changeARIAActiveDescendant(
+  browser,
+  container,
+  itemId,
+  prevItemId,
+  elementReflection
+) {
+  let expectedEvents = [[EVENT_FOCUS, itemId]];
+
+  if (prevItemId) {
+    info("A state change of the previous item precedes the new one.");
+    expectedEvents.push(
+      stateChangeEventArgs(prevItemId, EXT_STATE_ACTIVE, false, true)
+    );
+  }
+
+  expectedEvents.push(
+    stateChangeEventArgs(itemId, EXT_STATE_ACTIVE, true, true)
+  );
+
+  let expectedPromise = waitForEvents(expectedEvents);
+  await invokeContentTask(
+    browser,
+    [container, itemId, elementReflection],
+    (_container, _itemId, _elementReflection) => {
+      let getElm = (
+        content.document._testGetElementById || content.document.getElementById
+      ).bind(content.document);
+      let elm = getElm(_container);
+      if (_elementReflection) {
+        elm.ariaActiveDescendantElement = getElm(_itemId);
+      } else {
+        elm.setAttribute("aria-activedescendant", _itemId);
+      }
+    }
+  );
+
+  await expectedPromise;
+}
+
+async function clearARIAActiveDescendant(
+  browser,
+  container,
+  prevItemId,
+  defaultId,
+  elementReflection
+) {
+  let expectedEvents = [[EVENT_FOCUS, defaultId || container]];
+  if (prevItemId) {
+    expectedEvents.push(
+      stateChangeEventArgs(prevItemId, EXT_STATE_ACTIVE, false, true)
+    );
+  }
+
+  if (defaultId) {
+    expectedEvents.push(
+      stateChangeEventArgs(defaultId, EXT_STATE_ACTIVE, true, true)
+    );
+  }
+
+  let expectedPromise = waitForEvents(expectedEvents);
+  await invokeContentTask(
+    browser,
+    [container, elementReflection],
+    (_container, _elementReflection) => {
+      let elm = (
+        content.document._testGetElementById || content.document.getElementById
+      ).bind(content.document)(_container);
+      if (_elementReflection) {
+        elm.ariaActiveDescendantElement = null;
+      } else {
+        elm.removeAttribute("aria-activedescendant");
+      }
+    }
+  );
+
+  await expectedPromise;
+}
+
+async function insertItemNFocus(
+  browser,
+  container,
+  newItemID,
+  prevItemId,
+  elementReflection
+) {
+  let expectedEvents = [
+    [EVENT_SHOW, newItemID],
+    [EVENT_FOCUS, newItemID],
+  ];
+
+  if (prevItemId) {
+    info("A state change of the previous item precedes the new one.");
+    expectedEvents.push(
+      stateChangeEventArgs(prevItemId, EXT_STATE_ACTIVE, false, true)
+    );
+  }
+
+  expectedEvents.push(
+    stateChangeEventArgs(newItemID, EXT_STATE_ACTIVE, true, true)
+  );
+
+  let expectedPromise = waitForEvents(expectedEvents);
+
+  await invokeContentTask(
+    browser,
+    [container, newItemID, elementReflection],
+    (_container, _newItemID, _elementReflection) => {
+      let elm = (
+        content.document._testGetElementById || content.document.getElementById
+      ).bind(content.document)(_container);
+      let itemElm = content.document.createElement("div");
+      itemElm.setAttribute("id", _newItemID);
+      itemElm.setAttribute("role", "listitem");
+      itemElm.textContent = _newItemID;
+      elm.appendChild(itemElm);
+      if (_elementReflection) {
+        elm.ariaActiveDescendantElement = itemElm;
+      } else {
+        elm.setAttribute("aria-activedescendant", _newItemID);
+      }
+    }
+  );
+
+  await expectedPromise;
+}
+
+async function moveARIAActiveDescendantID(browser, fromID, toID) {
+  let expectedEvents = [
+    [EVENT_FOCUS, toID],
+    stateChangeEventArgs(toID, EXT_STATE_ACTIVE, true, true),
+  ];
+
+  let expectedPromise = waitForEvents(expectedEvents);
+  await invokeContentTask(browser, [fromID, toID], (_fromID, _toID) => {
+    let orig = (
+      content.document._testGetElementById || content.document.getElementById
+    ).bind(content.document)(_toID);
+    if (orig) {
+      orig.id = "";
+    }
+    (
+      content.document._testGetElementById || content.document.getElementById
+    ).bind(content.document)(_fromID).id = _toID;
+  });
+  await expectedPromise;
+}
+
+async function changeARIAActiveDescendantInvalid(
+  browser,
+  container,
+  invalidID = "invalid",
+  prevItemId = null
+) {
+  let expectedEvents = [[EVENT_FOCUS, container]];
+  if (prevItemId) {
+    expectedEvents.push(
+      stateChangeEventArgs(prevItemId, EXT_STATE_ACTIVE, false, true)
+    );
+  }
+
+  let expectedPromise = waitForEvents(expectedEvents);
+  await invokeContentTask(
+    browser,
+    [container, invalidID],
+    (_container, _invalidID) => {
+      let elm = (
+        content.document._testGetElementById || content.document.getElementById
+      ).bind(content.document)(_container);
+      elm.setAttribute("aria-activedescendant", _invalidID);
+    }
+  );
+
+  await expectedPromise;
+}
+
+const LISTBOX_MARKUP = `
+<div role="listbox" aria-activedescendant="item1" id="listbox" tabindex="1"
+aria-owns="item3">
+<div role="listitem" id="item1">item1</div>
+<div role="listitem" id="item2">item2</div>
+<div role="listitem" id="roaming" data-id="roaming">roaming</div>
+<div role="listitem" id="roaming2" data-id="roaming2">roaming2</div>
+</div>
+<div role="listitem" id="item3">item3</div>
+<div role="combobox" id="combobox">
+<input id="combobox_entry">
+<ul>
+  <li role="option" id="combobox_option1">option1</li>
+  <li role="option" id="combobox_option2">option2</li>
+</ul>
+</div>`;
+
+async function basicListboxTest(browser, elementReflection) {
+  await synthFocus(browser, "listbox", "item1");
+  await changeARIAActiveDescendant(
+    browser,
+    "listbox",
+    "item2",
+    "item1",
+    elementReflection
+  );
+  await changeARIAActiveDescendant(
+    browser,
+    "listbox",
+    "item3",
+    "item2",
+    elementReflection
+  );
+
+  info("Focus out of listbox");
+  await synthFocus(browser, "combobox_entry", "combobox_entry");
+  await changeARIAActiveDescendant(
+    browser,
+    "combobox",
+    "combobox_option2",
+    null,
+    elementReflection
+  );
+  await changeARIAActiveDescendant(
+    browser,
+    "combobox",
+    "combobox_option1",
+    null,
+    elementReflection
+  );
+
+  info("Focus back in listbox");
+  await synthFocus(browser, "listbox", "item3");
+  await insertItemNFocus(
+    browser,
+    "listbox",
+    "item4",
+    "item3",
+    elementReflection
+  );
+
+  await clearARIAActiveDescendant(
+    browser,
+    "listbox",
+    "item4",
+    null,
+    elementReflection
+  );
+  await changeARIAActiveDescendant(
+    browser,
+    "listbox",
+    "item1",
+    null,
+    elementReflection
+  );
+}
+
+addAccessibleTask(
+  LISTBOX_MARKUP,
+  async function (browser, docAcc) {
+    info("Test aria-activedescendant content attribute");
+    await basicListboxTest(browser, false);
+
+    await changeARIAActiveDescendantInvalid(
+      browser,
+      "listbox",
+      "invalid",
+      "item1"
+    );
+
+    await changeARIAActiveDescendant(browser, "listbox", "roaming");
+    await moveARIAActiveDescendantID(browser, "roaming2", "roaming");
+    await changeARIAActiveDescendantInvalid(
+      browser,
+      "listbox",
+      "roaming3",
+      "roaming"
+    );
+    await moveARIAActiveDescendantID(browser, "roaming", "roaming3");
+  },
+  { topLevel: true, chrome: true }
+);
+
+addAccessibleTask(
+  LISTBOX_MARKUP,
+  async function (browser, docAcc) {
+    info("Test ariaActiveDescendantElement element reflection");
+    await basicListboxTest(browser, true);
+  },
+  { topLevel: true, chrome: true }
+);
+
+addAccessibleTask(
+  `
+<input id="activedesc_nondesc_input" aria-activedescendant="activedesc_nondesc_option">
+<div role="listbox">
+  <div role="option" id="activedesc_nondesc_option">option</div>
+</div>`,
+  async function (browser, docAcc) {
+    info("Test aria-activedescendant non-descendant");
+    await synthFocus(
+      browser,
+      "activedesc_nondesc_input",
+      "activedesc_nondesc_option"
+    );
+  },
+  { topLevel: true, chrome: true }
+);
+
+addAccessibleTask(
+  `
+<div id="shadow"></div>
+<script>
+  let host = document.getElementById("shadow");
+  let shadow = host.attachShadow({mode: "open"});
+  let listbox = document.createElement("div");
+  listbox.id = "shadowListbox";
+  listbox.setAttribute("role", "listbox");
+  listbox.setAttribute("tabindex", "0");
+  shadow.appendChild(listbox);
+  let item = document.createElement("div");
+  item.id = "shadowItem1";
+  item.setAttribute("role", "option");
+  listbox.appendChild(item);
+  listbox.setAttribute("aria-activedescendant", "shadowItem1");
+  item = document.createElement("div");
+  item.id = "shadowItem2";
+  item.setAttribute("role", "option");
+  listbox.appendChild(item);
+</script>`,
+  async function (browser, docAcc) {
+    info("Test aria-activedescendant in shadow root");
+    // We want to retrieve elements using their IDs inside the shadow root, so
+    // we define a custom get element by ID method that our utility functions
+    // above call into if it exists.
+    await invokeContentTask(browser, [], () => {
+      content.document._testGetElementById = id =>
+        content.document.getElementById("shadow").shadowRoot.getElementById(id);
+    });
+
+    await synthFocus(browser, "shadowListbox", "shadowItem1");
+    await changeARIAActiveDescendant(
+      browser,
+      "shadowListbox",
+      "shadowItem2",
+      "shadowItem1"
+    );
+    info("Do it again with element reflection");
+    await changeARIAActiveDescendant(
+      browser,
+      "shadowListbox",
+      "shadowItem1",
+      "shadowItem2",
+      true
+    );
+  },
+  { topLevel: true, chrome: true }
+);
+
+addAccessibleTask(
+  `
+<div id="comboboxWithHiddenList" tabindex="0" role="combobox" aria-owns="hiddenList">
+</div>
+<div id="hiddenList" hidden role="listbox">
+  <div id="hiddenListOption" role="option"></div>
+</div>`,
+  async function (browser, docAcc) {
+    info("Test simultaneous insertion, relocation and aria-activedescendant");
+    await synthFocus(
+      browser,
+      "comboboxWithHiddenList",
+      "comboboxWithHiddenList"
+    );
+
+    testStates(
+      findAccessibleChildByID(docAcc, "comboboxWithHiddenList"),
+      STATE_FOCUSED
+    );
+    let evtProm = Promise.all([
+      waitForEvent(EVENT_FOCUS, "hiddenListOption"),
+      waitForStateChange("hiddenListOption", EXT_STATE_ACTIVE, true, true),
+    ]);
+    await invokeContentTask(browser, [], () => {
+      info("hiddenList is owned, so unhiding causes insertion and relocation.");
+      (
+        content.document._testGetElementById || content.document.getElementById
+      ).bind(content.document)("hiddenList").hidden = false;
+      content.document
+        .getElementById("comboboxWithHiddenList")
+        .setAttribute("aria-activedescendant", "hiddenListOption");
+    });
+    await evtProm;
+    testStates(
+      findAccessibleChildByID(docAcc, "hiddenListOption"),
+      STATE_FOCUSED
+    );
+  },
+  { topLevel: true, chrome: true }
+);
+
+addAccessibleTask(
+  `
+<custom-listbox id="custom-listbox1">
+  <div role="listitem" id="l1_1"></div>
+  <div role="listitem" id="l1_2"></div>
+  <div role="listitem" id="l1_3"></div>
+</custom-listbox>
+
+<custom-listbox id="custom-listbox2" aria-activedescendant="l2_1">
+  <div role="listitem" id="l2_1"></div>
+  <div role="listitem" id="l2_2"></div>
+  <div role="listitem" id="l2_3"></div>
+</custom-listbox>
+
+<script>
+customElements.define("custom-listbox",
+  class extends HTMLElement {
+    constructor() {
+      super();
+      this.tabIndex = "0"
+      this._internals = this.attachInternals();
+      this._internals.role = "listbox";
+      this._internals.ariaActiveDescendantElement = this.lastElementChild;
+    }
+    get internals() {
+      return this._internals;
+    }
+  }
+);
+</script>`,
+  async function (browser, docAcc) {
+    await synthFocus(browser, "custom-listbox1", "l1_3");
+
+    let evtProm = Promise.all([
+      waitForEvent(EVENT_FOCUS, "l1_2"),
+      waitForStateChange("l1_3", EXT_STATE_ACTIVE, false, true),
+      waitForStateChange("l1_2", EXT_STATE_ACTIVE, true, true),
+    ]);
+
+    await invokeContentTask(browser, [], () => {
+      content.document.getElementById(
+        "custom-listbox1"
+      ).internals.ariaActiveDescendantElement =
+        content.document.getElementById("l1_2");
+    });
+
+    await evtProm;
+
+    evtProm = Promise.all([
+      waitForEvent(EVENT_FOCUS, "custom-listbox1"),
+      waitForStateChange("l1_2", EXT_STATE_ACTIVE, false, true),
+    ]);
+
+    await invokeContentTask(browser, [], () => {
+      content.document.getElementById(
+        "custom-listbox1"
+      ).internals.ariaActiveDescendantElement = null;
+    });
+
+    await evtProm;
+
+    await synthFocus(browser, "custom-listbox2", "l2_1");
+    await clearARIAActiveDescendant(browser, "custom-listbox2", "l2_1", "l2_3");
+  }
+);
diff --git a/accessible/tests/browser/e10s/browser_caching_attributes.js b/accessible/tests/browser/e10s/browser_caching_attributes.js
index 139015061f..7a1f90ec13 100644
--- a/accessible/tests/browser/e10s/browser_caching_attributes.js
+++ b/accessible/tests/browser/e10s/browser_caching_attributes.js
@@ -733,7 +733,7 @@ addAccessibleTask(
  */
 addAccessibleTask(
   `<div id="popover" popover>popover</div>`,
-  async function testIspopup(browser, docAcc) {
+  async function testIspopup(browser) {
     info("Showing popover");
     let shown = waitForEvent(EVENT_SHOW, "popover");
     await invokeContentTask(browser, [], () => {
diff --git a/accessible/tests/browser/e10s/browser_caching_large_update.js b/accessible/tests/browser/e10s/browser_caching_large_update.js
index ccf8a86921..9a36ac7326 100644
--- a/accessible/tests/browser/e10s/browser_caching_large_update.js
+++ b/accessible/tests/browser/e10s/browser_caching_large_update.js
@@ -8,59 +8,56 @@
  * Test a large update which adds many thousands of Accessibles with a
  * lot of content in each.
  */
-addAccessibleTask(
-  `<main id="main" hidden></main>`,
-  async function (browser, docAcc) {
-    let shown = waitForEvent(EVENT_SHOW, "main");
-    await invokeContentTask(browser, [], () => {
-      // Make a long string.
-      let text = "";
-      for (let i = 0; i < 100; ++i) {
-        text += "a";
-      }
-      // Create lots of nodes which include the long string.
-      const contMain = content.document.getElementById("main");
-      // 15000 children of main.
-      for (let w = 0; w < 15000; ++w) {
-        // Each of those goes 9 deep.
-        let parent = contMain;
-        for (let d = 0; d < 10; ++d) {
-          const div = content.document.createElement("div");
-          div.setAttribute("aria-label", `${w} ${d} ${text}`);
-          parent.append(div);
-          parent = div;
-        }
-      }
-      contMain.hidden = false;
-    });
-    const main = (await shown).accessible;
-    is(main.childCount, 15000, "main has correct number of children");
-
-    // We don't want to output passes for every check, since that would output
-    // hundreds of thousands of lines, which slows the test to a crawl. Instead,
-    // output any failures and keep track of overall success/failure.
-    let treeOk = true;
-    function check(val, msg) {
-      if (!val) {
-        ok(false, msg);
-        treeOk = false;
-      }
+addAccessibleTask(`<main id="main" hidden></main>`, async function (browser) {
+  let shown = waitForEvent(EVENT_SHOW, "main");
+  await invokeContentTask(browser, [], () => {
+    // Make a long string.
+    let text = "";
+    for (let i = 0; i < 100; ++i) {
+      text += "a";
     }
-
-    info("Checking tree");
+    // Create lots of nodes which include the long string.
+    const contMain = content.document.getElementById("main");
+    // 15000 children of main.
     for (let w = 0; w < 15000; ++w) {
-      let acc = main.getChildAt(w);
-      let parent = main;
+      // Each of those goes 9 deep.
+      let parent = contMain;
       for (let d = 0; d < 10; ++d) {
-        check(acc, `Got child ${w} depth ${d}`);
-        const name = `${w} ${d}`;
-        check(acc.name.startsWith(name + " "), `${name}: correct name`);
-        check(acc.parent == parent, `${name}: correct parent`);
-        parent = acc;
-        acc = acc.firstChild;
+        const div = content.document.createElement("div");
+        div.setAttribute("aria-label", `${w} ${d} ${text}`);
+        parent.append(div);
+        parent = div;
       }
     }
-    // check() sets treeOk to false for any failure.
-    ok(treeOk, "Tree is correct");
+    contMain.hidden = false;
+  });
+  const main = (await shown).accessible;
+  is(main.childCount, 15000, "main has correct number of children");
+
+  // We don't want to output passes for every check, since that would output
+  // hundreds of thousands of lines, which slows the test to a crawl. Instead,
+  // output any failures and keep track of overall success/failure.
+  let treeOk = true;
+  function check(val, msg) {
+    if (!val) {
+      ok(false, msg);
+      treeOk = false;
+    }
+  }
+
+  info("Checking tree");
+  for (let w = 0; w < 15000; ++w) {
+    let acc = main.getChildAt(w);
+    let parent = main;
+    for (let d = 0; d < 10; ++d) {
+      check(acc, `Got child ${w} depth ${d}`);
+      const name = `${w} ${d}`;
+      check(acc.name.startsWith(name + " "), `${name}: correct name`);
+      check(acc.parent == parent, `${name}: correct parent`);
+      parent = acc;
+      acc = acc.firstChild;
+    }
   }
-);
+  // check() sets treeOk to false for any failure.
+  ok(treeOk, "Tree is correct");
+});
diff --git a/accessible/tests/browser/e10s/browser_caching_name.js b/accessible/tests/browser/e10s/browser_caching_name.js
index 55f506b85a..383d268d7d 100644
--- a/accessible/tests/browser/e10s/browser_caching_name.js
+++ b/accessible/tests/browser/e10s/browser_caching_name.js
@@ -477,7 +477,7 @@ markupTests.forEach(({ id, ruleset, markup, expected }) =>
     markup,
     async function (browser, accDoc) {
       const observer = {
-        observe(subject, topic, data) {
+        observe(subject) {
           const event = subject.QueryInterface(nsIAccessibleEvent);
           console.log(eventToString(event));
         },
diff --git a/accessible/tests/browser/e10s/browser_caching_relations_002.js b/accessible/tests/browser/e10s/browser_caching_relations_002.js
index 072656eb5e..61d92ba4ac 100644
--- a/accessible/tests/browser/e10s/browser_caching_relations_002.js
+++ b/accessible/tests/browser/e10s/browser_caching_relations_002.js
@@ -293,7 +293,7 @@ addAccessibleTask(
 );
 
 /**
- * Test details relations on popovers and their invokers.
+ * Test details relations for the popovertarget content attribute.
  */
 addAccessibleTask(
   `
@@ -304,7 +304,7 @@ addAccessibleTask(
 <div id="popover" popover>popover</div>
 <div id="details">details</div>
   `,
-  async function testPopover(browser, docAcc) {
+  async function testPopoverContent(browser, docAcc) {
     // The popover is hidden, so nothing should be referring to it.
     const hide = findAccessibleChildByID(docAcc, "hide");
     await testCachedRelation(hide, RELATION_DETAILS, []);
@@ -330,7 +330,7 @@ addAccessibleTask(
     await testCachedRelation(toggleSibling, RELATION_DETAILS, []);
     await testCachedRelation(popover, RELATION_DETAILS_FOR, toggle1);
 
-    info("Setting toggle2 popovertargetaction");
+    info("Setting toggle2 popovertarget");
     await invokeSetAttribute(browser, "toggle2", "popovertarget", "popover");
     await testCachedRelation(toggle2, RELATION_DETAILS, popover);
     await testCachedRelation(popover, RELATION_DETAILS_FOR, [toggle1, toggle2]);
@@ -364,3 +364,106 @@ addAccessibleTask(
   },
   { chrome: false, topLevel: true }
 );
+
+/**
+ * Test details relations for the popoverTargetElement WebIDL attribute.
+ */
+addAccessibleTask(
+  `
+<button id="toggle1">toggle1</button>
+<button id="toggle2">toggle2</button>
+between
+<div id="popover1" popover>popover1</div>
+<button id="toggle3">toggle3</button>
+<div id="shadowHost"><template shadowrootmode="open">
+  <button id="toggle4">toggle4</button>
+  between
+  <div id="popover2" popover>popover2</div>
+  <button id="toggle5">toggle5</button>
+</template></div>
+<script>
+  const toggle1 = document.getElementById("toggle1");
+  const popover1 = document.getElementById("popover1");
+  toggle1.popoverTargetElement = popover1;
+  const toggle3 = document.getElementById("toggle3");
+  const shadow = document.getElementById("shadowHost").shadowRoot;
+  const toggle4 = shadow.getElementById("toggle4");
+  const popover2 = shadow.getElementById("popover2");
+  toggle3.popoverTargetElement = popover2;
+  toggle4.popoverTargetElement = popover2;
+  const toggle5 = shadow.getElementById("toggle5");
+  toggle5.popoverTargetElement = popover1;
+</script>
+  `,
+  async function testPopoverIdl(browser, docAcc) {
+    // No popover is showing, so there shouldn't be any details relations.
+    const toggle1 = findAccessibleChildByID(docAcc, "toggle1");
+    await testCachedRelation(toggle1, RELATION_DETAILS, []);
+    const toggle2 = findAccessibleChildByID(docAcc, "toggle2");
+    await testCachedRelation(toggle2, RELATION_DETAILS, []);
+    const toggle3 = findAccessibleChildByID(docAcc, "toggle3");
+    await testCachedRelation(toggle3, RELATION_DETAILS, []);
+    const toggle4 = findAccessibleChildByID(docAcc, "toggle4");
+    await testCachedRelation(toggle4, RELATION_DETAILS, []);
+    const toggle5 = findAccessibleChildByID(docAcc, "toggle5");
+    await testCachedRelation(toggle5, RELATION_DETAILS, []);
+
+    info("Showing popover1");
+    let shown = waitForEvent(EVENT_SHOW, "popover1");
+    toggle1.doAction(0);
+    const popover1 = (await shown).accessible;
+    await testCachedRelation(toggle1, RELATION_DETAILS, popover1);
+    // toggle5 is inside the shadow DOM and popover1 is outside, so the target
+    // is valid.
+    await testCachedRelation(toggle5, RELATION_DETAILS, popover1);
+    await testCachedRelation(popover1, RELATION_DETAILS_FOR, [
+      toggle1,
+      toggle5,
+    ]);
+    info("Setting toggle2's popover target to popover1");
+    await invokeContentTask(browser, [], () => {
+      const toggle2Dom = content.document.getElementById("toggle2");
+      const popover1Dom = content.document.getElementById("popover1");
+      toggle2Dom.popoverTargetElement = popover1Dom;
+    });
+    await testCachedRelation(toggle2, RELATION_DETAILS, popover1);
+    await testCachedRelation(popover1, RELATION_DETAILS_FOR, [
+      toggle1,
+      toggle2,
+      toggle5,
+    ]);
+    info("Clearing toggle2's popover target");
+    await invokeContentTask(browser, [], () => {
+      const toggle2Dom = content.document.getElementById("toggle2");
+      toggle2Dom.popoverTargetElement = null;
+    });
+    await testCachedRelation(toggle2, RELATION_DETAILS, []);
+    await testCachedRelation(popover1, RELATION_DETAILS_FOR, [
+      toggle1,
+      toggle5,
+    ]);
+    info("Hiding popover1");
+    let hidden = waitForEvent(EVENT_HIDE, popover1);
+    toggle1.doAction(0);
+    await hidden;
+    await testCachedRelation(toggle1, RELATION_DETAILS, []);
+    await testCachedRelation(toggle2, RELATION_DETAILS, []);
+    await testCachedRelation(toggle5, RELATION_DETAILS, []);
+
+    info("Showing popover2");
+    shown = waitForEvent(EVENT_SHOW, "popover2");
+    toggle4.doAction(0);
+    const popover2 = (await shown).accessible;
+    // toggle4 is in the same shadow DOM as popover2.
+    await testCachedRelation(toggle4, RELATION_DETAILS, popover2);
+    // toggle3 is outside popover2's shadow DOM, so the target isn't valid.
+    await testCachedRelation(toggle3, RELATION_DETAILS, []);
+    await testCachedRelation(popover2, RELATION_DETAILS_FOR, [toggle4]);
+    info("Hiding popover2");
+    hidden = waitForEvent(EVENT_HIDE, popover2);
+    toggle4.doAction(0);
+    await hidden;
+    await testCachedRelation(toggle4, RELATION_DETAILS, []);
+  },
+  { chrome: true, topLevel: true }
+);
diff --git a/accessible/tests/browser/e10s/browser_caching_states.js b/accessible/tests/browser/e10s/browser_caching_states.js
index 37f8c46966..7292228f25 100644
--- a/accessible/tests/browser/e10s/browser_caching_states.js
+++ b/accessible/tests/browser/e10s/browser_caching_states.js
@@ -3,6 +3,7 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 "use strict";
+requestLongerTimeout(2);
 
 /* import-globals-from ../../mochitest/role.js */
 /* import-globals-from ../../mochitest/states.js */
@@ -484,7 +485,7 @@ addAccessibleTask(
 );
 
 /**
- * Test caching of the expanded state for popover target element.
+ * Test caching of the expanded state for the popovertarget content attribute.
  */
 addAccessibleTask(
   `
@@ -550,3 +551,157 @@ addAccessibleTask(
   },
   { chrome: true, topLevel: true, remoteIframe: true }
 );
+
+/**
+ * Test caching of the expanded state for the popoverTargetElement WebIDL
+ * attribute.
+ */
+addAccessibleTask(
+  `
+<button id="toggle1">toggle</button>
+<div id="popover1" popover>popover1</div>
+<button id="toggle2">toggle2</button>
+<button id="toggle3">toggle3</button>
+<div id="shadowHost"><template shadowrootmode="open">
+  <button id="toggle4">toggle4</button>
+  <div id="popover2" popover>popover2</div>
+  <button id="toggle5">toggle5</button>
+</template></div>
+<script>
+  const toggle1 = document.getElementById("toggle1");
+  const popover1 = document.getElementById("popover1");
+  toggle1.popoverTargetElement = popover1;
+  const toggle3 = document.getElementById("toggle3");
+  const shadow = document.getElementById("shadowHost").shadowRoot;
+  const toggle4 = shadow.getElementById("toggle4");
+  const popover2 = shadow.getElementById("popover2");
+  toggle3.popoverTargetElement = popover2;
+  toggle4.popoverTargetElement = popover2;
+  const toggle5 = shadow.getElementById("toggle5");
+  toggle5.popoverTargetElement = popover1;
+</script>
+  `,
+  async function (browser, docAcc) {
+    const toggle1 = findAccessibleChildByID(docAcc, "toggle1");
+    // toggle1's popover target is set and connected to the document.
+    testStates(toggle1, STATE_COLLAPSED);
+
+    const toggle2 = findAccessibleChildByID(docAcc, "toggle2");
+    // toggle2's popover target isn't set yet.
+    testStates(
+      toggle2,
+      0,
+      0,
+      STATE_EXPANDED | STATE_COLLAPSED,
+      EXT_STATE_EXPANDABLE
+    );
+    info("Setting toggle2's popoverTargetElement");
+    let changed = waitForStateChange(toggle2, EXT_STATE_EXPANDABLE, true, true);
+    await invokeContentTask(browser, [], () => {
+      const toggle2Dom = content.document.getElementById("toggle2");
+      const popover1 = content.document.getElementById("popover1");
+      toggle2Dom.popoverTargetElement = popover1;
+    });
+    await changed;
+    testStates(toggle2, STATE_COLLAPSED);
+
+    const toggle5 = findAccessibleChildByID(docAcc, "toggle5");
+    // toggle5 is inside the shadow DOM and popover1 is outside, so the target
+    // is valid.
+    testStates(toggle5, STATE_COLLAPSED);
+
+    // Changes to the popover should fire events on all invokers.
+    const changeEvents = [
+      [EVENT_STATE_CHANGE, toggle1],
+      [EVENT_STATE_CHANGE, toggle2],
+      [EVENT_STATE_CHANGE, toggle5],
+    ];
+    info("Showing popover1");
+    changed = waitForEvents(changeEvents);
+    toggle1.doAction(0);
+    await changed;
+    testStates(toggle1, STATE_EXPANDED);
+    testStates(toggle2, STATE_EXPANDED);
+
+    info("Hiding popover1");
+    changed = waitForEvents(changeEvents);
+    toggle1.doAction(0);
+    await changed;
+    testStates(toggle1, STATE_COLLAPSED);
+    testStates(toggle2, STATE_COLLAPSED);
+
+    info("Clearing toggle1's popover target");
+    changed = waitForStateChange(toggle1, EXT_STATE_EXPANDABLE, false, true);
+    await invokeContentTask(browser, [], () => {
+      const toggle1Dom = content.document.getElementById("toggle1");
+      toggle1Dom.popoverTargetElement = null;
+    });
+    await changed;
+    testStates(
+      toggle1,
+      0,
+      0,
+      STATE_EXPANDED | STATE_COLLAPSED,
+      EXT_STATE_EXPANDABLE
+    );
+
+    info("Setting toggle2's popover target to a disconnected node");
+    changed = waitForStateChange(toggle2, EXT_STATE_EXPANDABLE, false, true);
+    await invokeContentTask(browser, [], () => {
+      const toggle2Dom = content.document.getElementById("toggle2");
+      const popover3 = content.document.createElement("div");
+      popover3.popover = "auto";
+      popover3.textContent = "popover3";
+      // We don't append popover3 anywhere, so it is disconnected.
+      toggle2Dom.popoverTargetElement = popover3;
+    });
+    await changed;
+    testStates(
+      toggle2,
+      0,
+      0,
+      STATE_EXPANDED | STATE_COLLAPSED,
+      EXT_STATE_EXPANDABLE
+    );
+
+    const toggle3 = findAccessibleChildByID(docAcc, "toggle3");
+    // toggle3 is outside popover2's shadow DOM, so the target isn't valid.
+    testStates(
+      toggle3,
+      0,
+      0,
+      STATE_EXPANDED | STATE_COLLAPSED,
+      EXT_STATE_EXPANDABLE
+    );
+    const toggle4 = findAccessibleChildByID(docAcc, "toggle4");
+    // toggle4 is in the same shadow DOM as popover2.
+    testStates(toggle4, STATE_COLLAPSED);
+  },
+  { chrome: true, topLevel: true }
+);
+
+/**
+ * Test the mixed state of indeterminate HTML checkboxes.
+ */
+addAccessibleTask(
+  `<input type="checkbox" id="checkbox">`,
+  async function testHTMLCheckboxMixed(browser, docAcc) {
+    const checkbox = findAccessibleChildByID(docAcc, "checkbox");
+    testStates(checkbox, 0, 0, STATE_MIXED);
+    info("Setting indeterminate on checkbox");
+    let changed = waitForStateChange(checkbox, STATE_MIXED, true);
+    await invokeContentTask(browser, [], () => {
+      content.document.getElementById("checkbox").indeterminate = true;
+    });
+    await changed;
+    testStates(checkbox, STATE_MIXED);
+    info("Clearing indeterminate on checkbox");
+    changed = waitForStateChange(checkbox, STATE_MIXED, false);
+    await invokeContentTask(browser, [], () => {
+      content.document.getElementById("checkbox").indeterminate = false;
+    });
+    await changed;
+    testStates(checkbox, 0, 0, STATE_MIXED);
+  },
+  { chrome: true, topLevel: true, iframe: true, remoteIframe: true }
+);
diff --git a/accessible/tests/browser/e10s/browser_caching_table.js b/accessible/tests/browser/e10s/browser_caching_table.js
index 9c8bcb9616..0329e6411b 100644
--- a/accessible/tests/browser/e10s/browser_caching_table.js
+++ b/accessible/tests/browser/e10s/browser_caching_table.js
@@ -482,7 +482,7 @@ addAccessibleTask(
  */
 addAccessibleTask(
   `<table><tr id="tr"></tr></table>`,
-  async function (browser, docAcc) {
+  async function (browser) {
     let reordered = waitForEvent(EVENT_REORDER, "tr");
     await invokeContentTask(browser, [], () => {
       const iframe = content.document.createElement("iframe");
diff --git a/accessible/tests/browser/e10s/browser_caching_text_bounds.js b/accessible/tests/browser/e10s/browser_caching_text_bounds.js
index 3e37bf7490..486e28df53 100644
--- a/accessible/tests/browser/e10s/browser_caching_text_bounds.js
+++ b/accessible/tests/browser/e10s/browser_caching_text_bounds.js
@@ -138,9 +138,13 @@ async function testLineWithNonRenderedSpace(docAcc, browser, id, length) {
     const w = {};
     const h = {};
     acc.getCharacterExtents(offset, x, y, w, h, COORDTYPE_SCREEN_RELATIVE);
-    ok(x.value > prevX, `${id}: offset ${offset} x is larger (${x.value})`);
+    Assert.greater(
+      x.value,
+      prevX,
+      `${id}: offset ${offset} x is larger (${x.value})`
+    );
     prevX = x.value;
-    ok(w.value > 0, `${id}: offset ${offset} width > 0`);
+    Assert.greater(w.value, 0, `${id}: offset ${offset} width > 0`);
   }
 }
 
@@ -566,7 +570,11 @@ c</textarea>
       {},
       COORDTYPE_SCREEN_RELATIVE
     );
-    ok(newY.value < oldY.value, "y coordinate smaller after scrolling down");
+    Assert.less(
+      newY.value,
+      oldY.value,
+      "y coordinate smaller after scrolling down"
+    );
   },
   { chrome: true, topLevel: true, iframe: !true }
 );
diff --git a/accessible/tests/browser/e10s/browser_file_input.js b/accessible/tests/browser/e10s/browser_file_input.js
index 238e48740e..4c68e8e6da 100644
--- a/accessible/tests/browser/e10s/browser_file_input.js
+++ b/accessible/tests/browser/e10s/browser_file_input.js
@@ -34,7 +34,7 @@ addAccessibleTask(
     function chooseFile(id) {
       return invokeContentTask(browser, [id], contentId => {
         const MockFilePicker = content.SpecialPowers.MockFilePicker;
-        MockFilePicker.init(content);
+        MockFilePicker.init(content.browsingContext);
         MockFilePicker.useBlobFile();
         MockFilePicker.returnValue = MockFilePicker.returnOK;
         const input = content.document.getElementById(contentId);
diff --git a/accessible/tests/browser/e10s/browser_treeupdate_select_dropdown.js b/accessible/tests/browser/e10s/browser_treeupdate_select_dropdown.js
index a82fc4c04d..8ccbe58751 100644
--- a/accessible/tests/browser/e10s/browser_treeupdate_select_dropdown.js
+++ b/accessible/tests/browser/e10s/browser_treeupdate_select_dropdown.js
@@ -24,7 +24,7 @@ const snippet = `
 
 addAccessibleTask(
   snippet,
-  async function (browser, accDoc) {
+  async function (browser) {
     await invokeFocus(browser, "select");
     // Expand the select. A dropdown item should get focus.
     // Note that the dropdown is rendered in the parent process.
diff --git a/accessible/tests/browser/events/browser_test_docload.js b/accessible/tests/browser/events/browser_test_docload.js
index 78ac77fd8c..12076b3002 100644
--- a/accessible/tests/browser/events/browser_test_docload.js
+++ b/accessible/tests/browser/events/browser_test_docload.js
@@ -30,7 +30,7 @@ function urlChecker(url) {
   };
 }
 
-async function runTests(browser, accDoc) {
+async function runTests(browser) {
   let onLoadEvents = waitForEvents({
     expected: [
       [EVENT_REORDER, getAccessible(browser)],
diff --git a/accessible/tests/browser/events/browser_test_focus_browserui.js b/accessible/tests/browser/events/browser_test_focus_browserui.js
index 969d336c74..2f67cb3681 100644
--- a/accessible/tests/browser/events/browser_test_focus_browserui.js
+++ b/accessible/tests/browser/events/browser_test_focus_browserui.js
@@ -11,7 +11,7 @@ loadScripts(
   { name: "role.js", dir: MOCHITESTS_DIR }
 );
 
-async function runTests(browser, accDoc) {
+async function runTests(browser) {
   await SpecialPowers.pushPrefEnv({
     // If Fission is disabled, the pref is no-op.
     set: [["fission.bfcacheInParent", true]],
diff --git a/accessible/tests/browser/events/browser_test_focus_dialog.js b/accessible/tests/browser/events/browser_test_focus_dialog.js
index 71485a678d..03a1b82dc1 100644
--- a/accessible/tests/browser/events/browser_test_focus_dialog.js
+++ b/accessible/tests/browser/events/browser_test_focus_dialog.js
@@ -11,7 +11,7 @@ loadScripts(
   { name: "role.js", dir: MOCHITESTS_DIR }
 );
 
-async function runTests(browser, accDoc) {
+async function runTests(browser) {
   let onFocus = waitForEvent(EVENT_FOCUS, "button");
   await SpecialPowers.spawn(browser, [], () => {
     content.document.getElementById("button").focus();
diff --git a/accessible/tests/browser/events/browser_test_focus_urlbar.js b/accessible/tests/browser/events/browser_test_focus_urlbar.js
index 68b2b07f3c..647b837e9f 100644
--- a/accessible/tests/browser/events/browser_test_focus_urlbar.js
+++ b/accessible/tests/browser/events/browser_test_focus_urlbar.js
@@ -68,10 +68,10 @@ class TipTestProvider extends UrlbarProvider {
   get type() {
     return UrlbarUtils.PROVIDER_TYPE.PROFILE;
   }
-  isActive(context) {
+  isActive() {
     return true;
   }
-  isRestricting(context) {
+  isRestricting() {
     return true;
   }
   async startQuery(context, addCallback) {
diff --git a/accessible/tests/browser/events/browser_test_scrolling.js b/accessible/tests/browser/events/browser_test_scrolling.js
index 9678ee767b..d9425721bf 100644
--- a/accessible/tests/browser/events/browser_test_scrolling.js
+++ b/accessible/tests/browser/events/browser_test_scrolling.js
@@ -25,13 +25,15 @@ c</textarea>
     });
     let [scrollEvent1, scrollEndEvent1] = await onScrolling;
     scrollEvent1.QueryInterface(nsIAccessibleScrollingEvent);
-    ok(
-      scrollEvent1.maxScrollY >= scrollEvent1.scrollY,
+    Assert.greaterOrEqual(
+      scrollEvent1.maxScrollY,
+      scrollEvent1.scrollY,
       "scrollY is within max"
     );
     scrollEndEvent1.QueryInterface(nsIAccessibleScrollingEvent);
-    ok(
-      scrollEndEvent1.maxScrollY >= scrollEndEvent1.scrollY,
+    Assert.greaterOrEqual(
+      scrollEndEvent1.maxScrollY,
+      scrollEndEvent1.scrollY,
       "scrollY is within max"
     );
 
@@ -44,13 +46,15 @@ c</textarea>
     });
     let [scrollEvent2, scrollEndEvent2] = await onScrolling;
     scrollEvent2.QueryInterface(nsIAccessibleScrollingEvent);
-    ok(
-      scrollEvent2.scrollY > scrollEvent1.scrollY,
+    Assert.greater(
+      scrollEvent2.scrollY,
+      scrollEvent1.scrollY,
       `${scrollEvent2.scrollY} > ${scrollEvent1.scrollY}`
     );
     scrollEndEvent2.QueryInterface(nsIAccessibleScrollingEvent);
-    ok(
-      scrollEndEvent2.maxScrollY >= scrollEndEvent2.scrollY,
+    Assert.greaterOrEqual(
+      scrollEndEvent2.maxScrollY,
+      scrollEndEvent2.scrollY,
       "scrollY is within max"
     );
 
@@ -63,17 +67,20 @@ c</textarea>
     });
     let [scrollEvent3, scrollEndEvent3] = await onScrolling;
     scrollEvent3.QueryInterface(nsIAccessibleScrollingEvent);
-    ok(
-      scrollEvent3.maxScrollX >= scrollEvent3.scrollX,
+    Assert.greaterOrEqual(
+      scrollEvent3.maxScrollX,
+      scrollEvent3.scrollX,
       "scrollX is within max"
     );
     scrollEndEvent3.QueryInterface(nsIAccessibleScrollingEvent);
-    ok(
-      scrollEndEvent3.maxScrollX >= scrollEndEvent3.scrollX,
+    Assert.greaterOrEqual(
+      scrollEndEvent3.maxScrollX,
+      scrollEndEvent3.scrollX,
       "scrollY is within max"
     );
-    ok(
-      scrollEvent3.scrollX > scrollEvent2.scrollX,
+    Assert.greater(
+      scrollEvent3.scrollX,
+      scrollEvent2.scrollX,
       `${scrollEvent3.scrollX} > ${scrollEvent2.scrollX}`
     );
 
@@ -87,13 +94,15 @@ c</textarea>
     });
     let [scrollEvent4, scrollEndEvent4] = await onScrolling;
     scrollEvent4.QueryInterface(nsIAccessibleScrollingEvent);
-    ok(
-      scrollEvent4.maxScrollY >= scrollEvent4.scrollY,
+    Assert.greaterOrEqual(
+      scrollEvent4.maxScrollY,
+      scrollEvent4.scrollY,
       "scrollY is within max"
     );
     scrollEndEvent4.QueryInterface(nsIAccessibleScrollingEvent);
-    ok(
-      scrollEndEvent4.maxScrollY >= scrollEndEvent4.scrollY,
+    Assert.greaterOrEqual(
+      scrollEndEvent4.maxScrollY,
+      scrollEndEvent4.scrollY,
       "scrollY is within max"
     );
 
@@ -119,7 +128,7 @@ addAccessibleTask(
     <p>b</p>
     <p id="c">c</p>
   `,
-  async function (browser, accDoc) {
+  async function (browser) {
     let onScrollingStart = waitForEvent(EVENT_SCROLLING_START, "c");
     await SpecialPowers.spawn(browser, [], () => {
       content.location.hash = "#c";
@@ -137,7 +146,7 @@ addAccessibleTask(
   <h1 style="height: 300%;" id="inside-scrollable">test</h1>
 </div>
   `,
-  async function (browser, accDoc) {
+  async function (browser) {
     let onScrollingStart = waitForEvent(
       EVENT_SCROLLING_START,
       "inside-scrollable"
diff --git a/accessible/tests/browser/mac/browser_app.js b/accessible/tests/browser/mac/browser_app.js
index bedefae440..e7e18b5ddd 100644
--- a/accessible/tests/browser/mac/browser_app.js
+++ b/accessible/tests/browser/mac/browser_app.js
@@ -138,7 +138,7 @@ add_task(async () => {
       gBrowser,
       url: "about:license",
     },
-    async browser => {
+    async () => {
       let root = await getMacAccessible(document);
       let rootChildCount = () => root.getAttributeValue("AXChildren").length;
 
@@ -206,8 +206,10 @@ add_task(async () => {
       is(rootChildCount(), baseRootChildCount + 1, "Root has another child");
 
       // Close popup
+      let hide = waitForMacEvent("AXUIElementDestroyed");
       EventUtils.synthesizeKey("KEY_Escape");
       await BrowserTestUtils.waitForPopupEvent(identityPopup, "hidden");
+      await hide;
 
       // We're back to the base child count
       is(rootChildCount(), baseRootChildCount, "Root has the base child count");
@@ -225,7 +227,7 @@ add_task(async () => {
       // eslint-disable-next-line @microsoft/sdl/no-insecure-url
       url: "http://example.com",
     },
-    async browser => {
+    async () => {
       let input = await getMacAccessible("urlbar-input");
       is(
         input.getAttributeValue("AXValue"),
@@ -238,6 +240,38 @@ add_task(async () => {
 });
 
 /**
+ * Tests attributed text in nav bar has no invisible AXAttachments
+ */
+add_task(async () => {
+  await BrowserTestUtils.withNewTab(
+    {
+      gBrowser,
+      // eslint-disable-next-line @microsoft/sdl/no-insecure-url
+      url: "http://example.com",
+    },
+    async () => {
+      let root = await getMacAccessible(document);
+      let navBar = await getMacAccessible("nav-bar");
+      let elemRange = root.getParameterizedAttributeValue(
+        "AXTextMarkerRangeForUIElement",
+        navBar
+      );
+      let attributedString = root.getParameterizedAttributeValue(
+        "AXAttributedStringForTextMarkerRange",
+        elemRange
+      );
+      let attachmentRoles = attributedString.map(s =>
+        s.AXAttachment ? s.AXAttachment.getAttributeValue("AXRole") : null
+      );
+      ok(
+        !attachmentRoles.includes("AXMenu"),
+        "Collapsed menu should be embedded in attributed text"
+      );
+    }
+  );
+});
+
+/**
  * Test context menu
  */
 add_task(async () => {
diff --git a/accessible/tests/browser/mac/browser_bounds.js b/accessible/tests/browser/mac/browser_bounds.js
index 09343d7c9d..bc7939cfe0 100644
--- a/accessible/tests/browser/mac/browser_bounds.js
+++ b/accessible/tests/browser/mac/browser_bounds.js
@@ -21,22 +21,26 @@ addAccessibleTask(
     // test them here instead of calling AXFrame directly.
     const [helloWidth, helloHeight] = hello.getAttributeValue("AXSize");
     const [worldWidth, worldHeight] = world.getAttributeValue("AXSize");
-    ok(helloWidth > 0, "Hello has a positive width");
-    ok(helloHeight > 0, "Hello has a positive height");
-    ok(worldWidth > 0, "World has a positive width");
-    ok(worldHeight > 0, "World has a positive height");
-    ok(helloHeight < worldHeight, "Hello has a smaller height than world");
-    ok(helloWidth < worldWidth, "Hello has a smaller width than world");
+    Assert.greater(helloWidth, 0, "Hello has a positive width");
+    Assert.greater(helloHeight, 0, "Hello has a positive height");
+    Assert.greater(worldWidth, 0, "World has a positive width");
+    Assert.greater(worldHeight, 0, "World has a positive height");
+    Assert.less(
+      helloHeight,
+      worldHeight,
+      "Hello has a smaller height than world"
+    );
+    Assert.less(helloWidth, worldWidth, "Hello has a smaller width than world");
 
     // Note: these are mac screen coords, so our origin is bottom left
     const [helloX, helloY] = hello.getAttributeValue("AXPosition");
     const [worldX, worldY] = world.getAttributeValue("AXPosition");
-    ok(helloX > 0, "Hello has a positive X");
-    ok(helloY > 0, "Hello has a positive Y");
-    ok(worldX > 0, "World has a positive X");
-    ok(worldY > 0, "World has a positive Y");
-    ok(helloY > worldY, "Hello has a larger Y than world");
-    ok(helloX == worldX, "Hello and world have the same X");
+    Assert.greater(helloX, 0, "Hello has a positive X");
+    Assert.greater(helloY, 0, "Hello has a positive Y");
+    Assert.greater(worldX, 0, "World has a positive X");
+    Assert.greater(worldY, 0, "World has a positive Y");
+    Assert.greater(helloY, worldY, "Hello has a larger Y than world");
+    Assert.equal(helloX, worldX, "Hello and world have the same X");
   }
 );
 
@@ -57,21 +61,25 @@ addAccessibleTask(
     // test them here instead of calling AXFrame directly.
     const [helloWidth, helloHeight] = hello.getAttributeValue("AXSize");
     const [worldWidth, worldHeight] = world.getAttributeValue("AXSize");
-    ok(helloWidth > 0, "Hello has a positive width");
-    ok(helloHeight > 0, "Hello has a positive height");
-    ok(worldWidth > 0, "World has a positive width");
-    ok(worldHeight > 0, "World has a positive height");
-    ok(helloHeight < worldHeight, "Hello has a smaller height than world");
-    ok(helloWidth < worldWidth, "Hello has a smaller width than world");
+    Assert.greater(helloWidth, 0, "Hello has a positive width");
+    Assert.greater(helloHeight, 0, "Hello has a positive height");
+    Assert.greater(worldWidth, 0, "World has a positive width");
+    Assert.greater(worldHeight, 0, "World has a positive height");
+    Assert.less(
+      helloHeight,
+      worldHeight,
+      "Hello has a smaller height than world"
+    );
+    Assert.less(helloWidth, worldWidth, "Hello has a smaller width than world");
 
     // Note: these are mac screen coords, so our origin is bottom left
     const [helloX, helloY] = hello.getAttributeValue("AXPosition");
     const [worldX, worldY] = world.getAttributeValue("AXPosition");
-    ok(helloX < 0, "Hello has a negative X");
-    ok(helloY > 0, "Hello has a positive Y");
-    ok(worldX < 0, "World has a negative X");
-    ok(worldY > 0, "World has a positive Y");
-    ok(helloY > worldY, "Hello has a larger Y than world");
-    ok(helloX == worldX, "Hello and world have the same X");
+    Assert.less(helloX, 0, "Hello has a negative X");
+    Assert.greater(helloY, 0, "Hello has a positive Y");
+    Assert.less(worldX, 0, "World has a negative X");
+    Assert.greater(worldY, 0, "World has a positive Y");
+    Assert.greater(helloY, worldY, "Hello has a larger Y than world");
+    Assert.equal(helloX, worldX, "Hello and world have the same X");
   }
 );
diff --git a/accessible/tests/browser/mac/browser_live_regions.js b/accessible/tests/browser/mac/browser_live_regions.js
index 10a03120f8..aa07f003df 100644
--- a/accessible/tests/browser/mac/browser_live_regions.js
+++ b/accessible/tests/browser/mac/browser_live_regions.js
@@ -131,7 +131,7 @@ addAccessibleTask(
   <button id="button" aria-label="Start"></button>
   </div>
   `,
-  async (browser, accDoc) => {
+  async browser => {
     let liveRegionChanged = waitForMacEvent("AXLiveRegionChanged", "live");
     await SpecialPowers.spawn(browser, [], () => {
       content.document.getElementById("time").textContent = "4:56pm";
diff --git a/accessible/tests/browser/mac/browser_menulist.js b/accessible/tests/browser/mac/browser_menulist.js
index b26a0be782..3b0fe8b210 100644
--- a/accessible/tests/browser/mac/browser_menulist.js
+++ b/accessible/tests/browser/mac/browser_menulist.js
@@ -74,7 +74,7 @@ addAccessibleTask(
       "First menu item is selected"
     );
     // focus the second item, and verify it is selected
-    event = waitForMacEvent("AXFocusedUIElementChanged", (iface, data) => {
+    event = waitForMacEvent("AXFocusedUIElementChanged", iface => {
       try {
         return iface.getAttributeValue("AXTitle") == "100%";
       } catch (e) {
diff --git a/accessible/tests/browser/mac/browser_roles_elements.js b/accessible/tests/browser/mac/browser_roles_elements.js
index 791598fed6..b6049e7afd 100644
--- a/accessible/tests/browser/mac/browser_roles_elements.js
+++ b/accessible/tests/browser/mac/browser_roles_elements.js
@@ -47,6 +47,7 @@ addAccessibleTask(
   <div id="complementary" role="complementary"></div>
   <div id="contentinfo" role="contentinfo"></div>
   <div id="form" role="form"></div>
+  <div id="form_label" aria-label="form" role="form"></div>
   <div id="main" role="main"></div>
   <div id="navigation" role="navigation"></div>
   <div id="search" role="search"></div>
@@ -149,7 +150,8 @@ addAccessibleTask(
       "AXLandmarkComplementary"
     );
     testRoleAndSubRole(accDoc, "contentinfo", null, "AXLandmarkContentInfo");
-    testRoleAndSubRole(accDoc, "form", null, "AXLandmarkForm");
+    testRoleAndSubRole(accDoc, "form", null, "AXApplicationGroup");
+    testRoleAndSubRole(accDoc, "form_label", null, "AXLandmarkForm");
     testRoleAndSubRole(accDoc, "main", null, "AXLandmarkMain");
     testRoleAndSubRole(accDoc, "navigation", null, "AXLandmarkNavigation");
     testRoleAndSubRole(accDoc, "search", null, "AXLandmarkSearch");
diff --git a/accessible/tests/browser/mac/browser_rotor.js b/accessible/tests/browser/mac/browser_rotor.js
index 3f13506757..87ac40592d 100644
--- a/accessible/tests/browser/mac/browser_rotor.js
+++ b/accessible/tests/browser/mac/browser_rotor.js
@@ -269,7 +269,7 @@ addAccessibleTask(
       "AXUIElementCountForSearchPredicate",
       NSDictionary(searchPred)
     );
-    is(4, tableCount, "Found four tables");
+    is(tableCount, 3, "Found three tables");
 
     const tables = webArea.getParameterizedAttributeValue(
       "AXUIElementsForSearchPredicate",
@@ -278,7 +278,6 @@ addAccessibleTask(
     const shapes = getNativeInterface(accDoc, "shapes");
     const food = getNativeInterface(accDoc, "food");
     const ariaTable = getNativeInterface(accDoc, "ariaTable");
-    const grid = getNativeInterface(accDoc, "grid");
 
     is(
       shapes.getAttributeValue("AXColumnCount"),
@@ -295,11 +294,6 @@ addAccessibleTask(
       tables[2].getAttributeValue("AXColumnCount"),
       "Found correct third table"
     );
-    is(
-      grid.getAttributeValue("AXColumnCount"),
-      tables[3].getAttributeValue("AXColumnCount"),
-      "Found correct fourth table"
-    );
   }
 );
 
diff --git a/accessible/tests/browser/mac/browser_text_leaf.js b/accessible/tests/browser/mac/browser_text_leaf.js
index 21deed6212..c65e8c6ebe 100644
--- a/accessible/tests/browser/mac/browser_text_leaf.js
+++ b/accessible/tests/browser/mac/browser_text_leaf.js
@@ -77,7 +77,11 @@ addAccessibleTask(
       NSRange(3, 8)
     );
 
-    ok(smallBounds.size[0] < largeBounds.size[0], "longer range is wider");
+    Assert.less(
+      smallBounds.size[0],
+      largeBounds.size[0],
+      "longer range is wider"
+    );
   },
   { chrome: true, iframe: true, remoteIframe: true }
 );
diff --git a/accessible/tests/browser/mac/browser_text_selection.js b/accessible/tests/browser/mac/browser_text_selection.js
index a914adba8e..7e2145631c 100644
--- a/accessible/tests/browser/mac/browser_text_selection.js
+++ b/accessible/tests/browser/mac/browser_text_selection.js
@@ -82,7 +82,7 @@ addAccessibleTask(
   Hello <a href="#" id="link">World</a>,
   I <a href="#" style="user-select: none;" id="unselectable_link">love</a>
   <button id="button">you</button></p>`,
-  async (browser, accDoc) => {
+  async browser => {
     // Set up an AXSelectedTextChanged listener here. It will get resolved
     // on the first non-root event it encounters, so if we test its data at the end
     // of this test it will show us the first text-selectable object that was focused,
diff --git a/accessible/tests/browser/mac/browser_toggle_radio_check.js b/accessible/tests/browser/mac/browser_toggle_radio_check.js
index 1695d73b0d..f9094ac3d7 100644
--- a/accessible/tests/browser/mac/browser_toggle_radio_check.js
+++ b/accessible/tests/browser/mac/browser_toggle_radio_check.js
@@ -128,7 +128,7 @@ addAccessibleTask(
 
     // Changing from checked to mixed fires two events. Make sure we wait until
     // the second so we're asserting based on the latest state.
-    evt = waitForMacEvent("AXValueChanged", (iface, data) => {
+    evt = waitForMacEvent("AXValueChanged", iface => {
       return (
         iface.getAttributeValue("AXDOMIdentifier") == "checkbox" &&
         iface.getAttributeValue("AXValue") == 2
diff --git a/accessible/tests/browser/mac/browser_webarea.js b/accessible/tests/browser/mac/browser_webarea.js
index ac6122de14..4872c58845 100644
--- a/accessible/tests/browser/mac/browser_webarea.js
+++ b/accessible/tests/browser/mac/browser_webarea.js
@@ -8,8 +8,8 @@
 loadScripts({ name: "role.js", dir: MOCHITESTS_DIR });
 
 // Test web area role and AXLoadComplete event
-addAccessibleTask(``, async (browser, accDoc) => {
-  let evt = waitForMacEvent("AXLoadComplete", (iface, data) => {
+addAccessibleTask(``, async browser => {
+  let evt = waitForMacEvent("AXLoadComplete", iface => {
     return iface.getAttributeValue("AXDescription") == "webarea test";
   });
   await SpecialPowers.spawn(browser, [], () => {
@@ -29,16 +29,16 @@ addAccessibleTask(``, async (browser, accDoc) => {
 });
 
 // Test iframe web area role and AXLayoutComplete event
-addAccessibleTask(`<title>webarea test</title>`, async (browser, accDoc) => {
+addAccessibleTask(`<title>webarea test</title>`, async browser => {
   // If the iframe loads before the top level document finishes loading, we'll
   // get both an AXLayoutComplete event for the iframe and an AXLoadComplete
   // event for the document. Otherwise, if the iframe loads after the
   // document, we'll get one AXLoadComplete event.
   let eventPromise = Promise.race([
-    waitForMacEvent("AXLayoutComplete", (iface, data) => {
+    waitForMacEvent("AXLayoutComplete", iface => {
       return iface.getAttributeValue("AXDescription") == "iframe document";
     }),
-    waitForMacEvent("AXLoadComplete", (iface, data) => {
+    waitForMacEvent("AXLoadComplete", iface => {
       return iface.getAttributeValue("AXDescription") == "webarea test";
     }),
   ]);
diff --git a/accessible/tests/browser/scroll/browser_test_scroll_bounds.js b/accessible/tests/browser/scroll/browser_test_scroll_bounds.js
index 31de002cda..33a99266db 100644
--- a/accessible/tests/browser/scroll/browser_test_scroll_bounds.js
+++ b/accessible/tests/browser/scroll/browser_test_scroll_bounds.js
@@ -238,7 +238,11 @@ addAccessibleTask(
       newTopBounds[0],
       "x of non-fixed element remains accurate."
     );
-    ok(newTopBounds[1] < 0, "y coordinate shows item scrolled off page");
+    Assert.less(
+      newTopBounds[1],
+      0,
+      "y coordinate shows item scrolled off page"
+    );
     is(
       origTopBounds[2],
       newTopBounds[2],
@@ -254,7 +258,11 @@ addAccessibleTask(
       newDBounds[0],
       "x of non-fixed container element remains accurate."
     );
-    ok(newDBounds[1] < 0, "y coordinate shows container scrolled off page");
+    Assert.less(
+      newDBounds[1],
+      0,
+      "y coordinate shows container scrolled off page"
+    );
     // Removing the position styling on this acc causes it to be bound by
     // its parent's bounding box, which alters its width as a block element.
     // We don't particularly care about width in this test, so skip it.
@@ -481,7 +489,7 @@ addAccessibleTask(
         newBounds[0],
         `x coord of non-sticky element remains accurate.`
       );
-      ok(newBounds[1] < 0, "y coordinate shows item scrolled off page");
+      Assert.less(newBounds[1], 0, "y coordinate shows item scrolled off page");
 
       // Removing the position styling on this acc causes it to be bound by
       // its parent's bounding box, which alters its width as a block element.
diff --git a/accessible/tests/browser/scroll/browser_test_scroll_substring.js b/accessible/tests/browser/scroll/browser_test_scroll_substring.js
index e8426d00ca..031b8a5124 100644
--- a/accessible/tests/browser/scroll/browser_test_scroll_substring.js
+++ b/accessible/tests/browser/scroll/browser_test_scroll_substring.js
@@ -45,8 +45,9 @@ The only thing I found in the fridge was a dead dove in a bag.
       text.getCharacterExtents(7, {}, objY, {}, {}, COORDTYPE_SCREEN_RELATIVE);
       return objY.value;
     };
-    ok(
-      containerHeight < getCharY(),
+    Assert.less(
+      containerHeight,
+      getCharY(),
       "Character is outside of container bounds"
     );
     text.scrollSubstringTo(7, 8, SCROLL_TYPE_TOP_EDGE);
diff --git a/accessible/tests/browser/selectable/browser_test_select.js b/accessible/tests/browser/selectable/browser_test_select.js
index f86a371d81..6a51fd4f3b 100644
--- a/accessible/tests/browser/selectable/browser_test_select.js
+++ b/accessible/tests/browser/selectable/browser_test_select.js
@@ -313,7 +313,7 @@ addAccessibleTask(
   </select>
 </form>
   `,
-  async function (browser, docAcc) {
+  async function (browser) {
     let selected = waitForEvent(EVENT_SELECTION_WITHIN, "select");
     await invokeContentTask(browser, [], () => {
       const form = content.document.getElementById("form");
diff --git a/accessible/tests/browser/shared-head.js b/accessible/tests/browser/shared-head.js
index fe87a77765..c238a5a7a0 100644
--- a/accessible/tests/browser/shared-head.js
+++ b/accessible/tests/browser/shared-head.js
@@ -830,7 +830,7 @@ const CACHE_WAIT_TIMEOUT_MS = 5000;
  * be used to record a pass or fail in the test.
  */
 function untilCacheCondition(conditionFunc, argsFunc) {
-  return new Promise((resolve, reject) => {
+  return new Promise(resolve => {
     let args = argsFunc();
     if (conditionFunc(...args)) {
       resolve(args);
@@ -838,7 +838,7 @@ function untilCacheCondition(conditionFunc, argsFunc) {
     }
 
     let cacheObserver = {
-      observe(subject) {
+      observe() {
         args = argsFunc();
         if (conditionFunc(...args)) {
           clearTimeout(this.timer);
@@ -945,7 +945,7 @@ function runPython(code) {
       "ws://mochi.test:8888/browser/accessible/tests/browser/python_runner"
     );
     if (gPythonSocket.readyState != WebSocket.OPEN) {
-      gPythonSocket.onopen = evt => {
+      gPythonSocket.onopen = () => {
         gPythonSocket.send(code);
         gPythonSocket.onopen = null;
       };
diff --git a/accessible/tests/browser/text/browser_text_paragraph_boundary.js b/accessible/tests/browser/text/browser_text_paragraph_boundary.js
index 04e64520e8..b206829398 100644
--- a/accessible/tests/browser/text/browser_text_paragraph_boundary.js
+++ b/accessible/tests/browser/text/browser_text_paragraph_boundary.js
@@ -8,7 +8,7 @@
 // boundary on an Accessible which has remote ProxyAccessible descendants.
 addAccessibleTask(
   `test`,
-  async function testParagraphBoundaryWithRemoteDescendants(browser, accDoc) {
+  async function testParagraphBoundaryWithRemoteDescendants() {
     const root = getRootAccessible(document).QueryInterface(
       Ci.nsIAccessibleText
     );
diff --git a/accessible/tests/browser/text/head.js b/accessible/tests/browser/text/head.js
index fa4b095892..72195ddbb0 100644
--- a/accessible/tests/browser/text/head.js
+++ b/accessible/tests/browser/text/head.js
@@ -142,7 +142,7 @@ function testBoundarySequence(
 // Editable text
 
 async function waitForCopy(browser) {
-  await BrowserTestUtils.waitForContentEvent(browser, "copy", false, evt => {
+  await BrowserTestUtils.waitForContentEvent(browser, "copy", false, () => {
     return true;
   });
 
diff --git a/accessible/tests/browser/tree/browser_aria_owns.js b/accessible/tests/browser/tree/browser_aria_owns.js
index 0ca55ed357..904597cc66 100644
--- a/accessible/tests/browser/tree/browser_aria_owns.js
+++ b/accessible/tests/browser/tree/browser_aria_owns.js
@@ -176,7 +176,7 @@ addAccessibleTask(
 addAccessibleTask(
   `
   <select id="container" aria-owns="boom" multiple></select>`,
-  async function (browser, accDoc) {
+  async function () {
     ok(true, "Did not crash");
   }
 );
diff --git a/accessible/tests/browser/tree/browser_browser_element.js b/accessible/tests/browser/tree/browser_browser_element.js
index 82be24d93c..d6ece6676e 100644
--- a/accessible/tests/browser/tree/browser_browser_element.js
+++ b/accessible/tests/browser/tree/browser_browser_element.js
@@ -8,7 +8,7 @@ loadScripts({ name: "role.js", dir: MOCHITESTS_DIR });
 
 // Test that the tree is correct for browser elements containing remote
 // documents.
-addAccessibleTask(`test`, async function (browser, docAcc) {
+addAccessibleTask(`test`, async function (browser) {
   // testAccessibleTree also verifies childCount, indexInParent and parent.
   testAccessibleTree(browser, {
     INTERNAL_FRAME: [{ DOCUMENT: [{ TEXT_LEAF: [] }] }],
diff --git a/accessible/tests/browser/tree/browser_lazy_tabs.js b/accessible/tests/browser/tree/browser_lazy_tabs.js
index f7aa9bdeb2..46e10d0bac 100644
--- a/accessible/tests/browser/tree/browser_lazy_tabs.js
+++ b/accessible/tests/browser/tree/browser_lazy_tabs.js
@@ -5,7 +5,7 @@
 
 // Test that lazy background tabs aren't unintentionally loaded when building
 // the a11y tree (bug 1700708).
-addAccessibleTask(``, async function (browser, accDoc) {
+addAccessibleTask(``, async function () {
   await SpecialPowers.pushPrefEnv({
     set: [["browser.sessionstore.restore_on_demand", true]],
   });
diff --git a/accessible/tests/browser/tree/browser_test_nsIAccessibleDocument_URL.js b/accessible/tests/browser/tree/browser_test_nsIAccessibleDocument_URL.js
index 623f2640f0..e6b55d0fd3 100644
--- a/accessible/tests/browser/tree/browser_test_nsIAccessibleDocument_URL.js
+++ b/accessible/tests/browser/tree/browser_test_nsIAccessibleDocument_URL.js
@@ -25,7 +25,7 @@ async function promiseEventDocumentLoadComplete(expectedURL) {
 add_task(async function testInDataURI() {
   const kURL = "data:text/html,Some text";
   const waitForDocumentLoadComplete = promiseEventDocumentLoadComplete("");
-  await BrowserTestUtils.withNewTab(kURL, async browser => {
+  await BrowserTestUtils.withNewTab(kURL, async () => {
     is(
       (await waitForDocumentLoadComplete).URL,
       "",
@@ -44,7 +44,7 @@ add_task(async function testInHTTPSURIContainingPrivateThings() {
     "https://example.com/browser/toolkit/content/tests/browser/file_empty.html?query=some#ref";
   const waitForDocumentLoadComplete =
     promiseEventDocumentLoadComplete(kURLWithoutUserPass);
-  await BrowserTestUtils.withNewTab(kURL, async browser => {
+  await BrowserTestUtils.withNewTab(kURL, async () => {
     is(
       (await waitForDocumentLoadComplete).URL,
       kURLWithoutUserPass,
diff --git a/accessible/tests/browser/windows/a11y_setup.py b/accessible/tests/browser/windows/a11y_setup.py
index d6dc19f0fb..726eea07a4 100644
--- a/accessible/tests/browser/windows/a11y_setup.py
+++ b/accessible/tests/browser/windows/a11y_setup.py
@@ -9,19 +9,28 @@ import ctypes
 import os
 from ctypes import POINTER, byref
 from ctypes.wintypes import BOOL, HWND, LPARAM, POINT  # noqa: F401
+from dataclasses import dataclass
 
+import comtypes.automation
 import comtypes.client
 import psutil
 from comtypes import COMError, IServiceProvider
 
+CHILDID_SELF = 0
+COWAIT_DEFAULT = 0
+EVENT_OBJECT_FOCUS = 0x8005
+GA_ROOT = 2
+NAVRELATION_EMBEDS = 0x1009
+OBJID_CLIENT = -4
+RPC_S_CALLPENDING = -2147417835
+WINEVENT_OUTOFCONTEXT = 0
+WM_CLOSE = 0x0010
+
 user32 = ctypes.windll.user32
 oleacc = ctypes.oledll.oleacc
 oleaccMod = comtypes.client.GetModule("oleacc.dll")
 IAccessible = oleaccMod.IAccessible
 del oleaccMod
-OBJID_CLIENT = -4
-CHILDID_SELF = 0
-NAVRELATION_EMBEDS = 0x1009
 # This is the path if running locally.
 ia2Tlb = os.path.join(
     os.getcwd(),
@@ -65,6 +74,13 @@ def AccessibleObjectFromWindow(hwnd, objectID=OBJID_CLIENT):
     return p
 
 
+def getWindowClass(hwnd):
+    MAX_CHARS = 257
+    buffer = ctypes.create_unicode_buffer(MAX_CHARS)
+    user32.GetClassNameW(hwnd, buffer, MAX_CHARS)
+    return buffer.value
+
+
 def getFirefoxHwnd():
     """Search all top level windows for the Firefox instance being
     tested.
@@ -78,9 +94,7 @@ def getFirefoxHwnd():
 
     @ctypes.WINFUNCTYPE(BOOL, HWND, LPARAM)
     def callback(hwnd, lParam):
-        name = ctypes.create_unicode_buffer(100)
-        user32.GetClassNameW(hwnd, name, 100)
-        if name.value != "MozillaWindowClass":
+        if getWindowClass(hwnd) != "MozillaWindowClass":
             return True
         pid = ctypes.wintypes.DWORD()
         user32.GetWindowThreadProcessId(hwnd, byref(pid))
@@ -127,6 +141,106 @@ def findIa2ByDomId(root, id):
             return descendant
 
 
+@dataclass
+class WinEvent:
+    event: int
+    hwnd: int
+    objectId: int
+    childId: int
+
+    def getIa2(self):
+        acc = ctypes.POINTER(IAccessible)()
+        child = comtypes.automation.VARIANT()
+        ctypes.oledll.oleacc.AccessibleObjectFromEvent(
+            self.hwnd,
+            self.objectId,
+            self.childId,
+            ctypes.byref(acc),
+            ctypes.byref(child),
+        )
+        if child.value != CHILDID_SELF:
+            # This isn't an IAccessible2 object.
+            return None
+        return toIa2(acc)
+
+
+class WaitForWinEvent:
+    """Wait for a win event, usually for IAccessible2.
+    This should be used as follows:
+    1. Create an instance to wait for the desired event.
+    2. Perform the action that should fire the event.
+    3. Call wait() on the instance you created in 1) to wait for the event.
+    """
+
+    def __init__(self, eventId, match):
+        """event is the event id to wait for.
+        match is either None to match any object, an str containing the DOM id
+        of the desired object, or a function taking a WinEvent which should
+        return True if this is the requested event.
+        """
+        self._matched = None
+        # A kernel event used to signal when we get the desired event.
+        self._signal = ctypes.windll.kernel32.CreateEventW(None, True, False, None)
+
+        # We define this as a nested function because it has to be a static
+        # function, but we need a reference to self.
+        @ctypes.WINFUNCTYPE(
+            None,
+            ctypes.wintypes.HANDLE,
+            ctypes.wintypes.DWORD,
+            ctypes.wintypes.HWND,
+            ctypes.wintypes.LONG,
+            ctypes.wintypes.LONG,
+            ctypes.wintypes.DWORD,
+            ctypes.wintypes.DWORD,
+        )
+        def winEventProc(hook, eventId, hwnd, objectId, childId, thread, time):
+            event = WinEvent(eventId, hwnd, objectId, childId)
+            if isinstance(match, str):
+                try:
+                    ia2 = event.getIa2()
+                    if f"id:{match};" in ia2.attributes:
+                        self._matched = event
+                except (comtypes.COMError, TypeError):
+                    pass
+            elif callable(match):
+                try:
+                    if match(event):
+                        self._matched = event
+                except Exception as e:
+                    self._matched = e
+            if self._matched:
+                ctypes.windll.kernel32.SetEvent(self._signal)
+
+        self._hook = user32.SetWinEventHook(
+            eventId, eventId, None, winEventProc, 0, 0, WINEVENT_OUTOFCONTEXT
+        )
+        # Hold a reference to winEventProc so it doesn't get destroyed.
+        self._proc = winEventProc
+
+    def wait(self):
+        """Wait for and return the desired WinEvent."""
+        # Pump Windows messages until we get the desired event, which will be
+        # signalled using a kernel event.
+        handles = (ctypes.c_void_p * 1)(self._signal)
+        index = ctypes.wintypes.DWORD()
+        TIMEOUT = 10000
+        try:
+            ctypes.oledll.ole32.CoWaitForMultipleHandles(
+                COWAIT_DEFAULT, TIMEOUT, 1, handles, ctypes.byref(index)
+            )
+        except WindowsError as e:
+            if e.winerror == RPC_S_CALLPENDING:
+                raise TimeoutError("Timeout before desired event received")
+            raise
+        finally:
+            user32.UnhookWinEvent(self._hook)
+            self._proc = None
+        if isinstance(self._matched, Exception):
+            raise self._matched from self._matched
+        return self._matched
+
+
 def getDocUia():
     """Get the IUIAutomationElement for the document being tested."""
     # We start with IAccessible2 because there's no efficient way to
diff --git a/accessible/tests/browser/windows/ia2/browser.toml b/accessible/tests/browser/windows/ia2/browser.toml
index d72b5f8a2d..d6226b73cc 100644
--- a/accessible/tests/browser/windows/ia2/browser.toml
+++ b/accessible/tests/browser/windows/ia2/browser.toml
@@ -6,4 +6,6 @@ skip-if = [
 ]
 support-files = ["head.js"]
 
+["browser_osPicker.js"]
+
 ["browser_role.js"]
diff --git a/accessible/tests/browser/windows/ia2/browser_osPicker.js b/accessible/tests/browser/windows/ia2/browser_osPicker.js
new file mode 100644
index 0000000000..b14f2d0a5f
--- /dev/null
+++ b/accessible/tests/browser/windows/ia2/browser_osPicker.js
@@ -0,0 +1,51 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+"use strict";
+
+addAccessibleTask(
+  `<input id="file" type="file">`,
+  async function (browser, docAcc) {
+    info("Focusing file input");
+    await runPython(`
+      global focused
+      focused = WaitForWinEvent(EVENT_OBJECT_FOCUS, "file")
+    `);
+    const file = findAccessibleChildByID(docAcc, "file");
+    file.takeFocus();
+    await runPython(`
+      focused.wait()
+    `);
+    ok(true, "file input got focus");
+    info("Opening file picker");
+    await runPython(`
+      global focused
+      focused = WaitForWinEvent(
+        EVENT_OBJECT_FOCUS,
+        lambda evt: getWindowClass(evt.hwnd) == "Edit"
+      )
+    `);
+    file.doAction(0);
+    await runPython(`
+      global event
+      event = focused.wait()
+    `);
+    ok(true, "Picker got focus");
+    info("Dismissing picker");
+    await runPython(`
+      # If the picker is dismissed too quickly, it seems to re-enable the root
+      # window before we do. This sleep isn't ideal, but it's more likely to
+      # reproduce the case that our root window gets focus before it is enabled.
+      # See bug 1883568 for further details.
+      import time
+      time.sleep(1)
+      focused = WaitForWinEvent(EVENT_OBJECT_FOCUS, "file")
+      # Sending key presses to the picker is unreliable, so use WM_CLOSE.
+      pickerRoot = user32.GetAncestor(event.hwnd, GA_ROOT)
+      user32.SendMessageW(pickerRoot, WM_CLOSE, 0, 0)
+      focused.wait()
+    `);
+    ok(true, "file input got focus");
+  }
+);
diff --git a/accessible/tests/browser/windows/ia2/browser_role.js b/accessible/tests/browser/windows/ia2/browser_role.js
index 08e44c280f..89b560ab49 100644
--- a/accessible/tests/browser/windows/ia2/browser_role.js
+++ b/accessible/tests/browser/windows/ia2/browser_role.js
@@ -12,7 +12,7 @@ addAccessibleTask(
   `
 <p id="p">p</p>
   `,
-  async function (browser, docAcc) {
+  async function () {
     let role = await runPython(`
       global doc
       doc = getDocIa2()
diff --git a/accessible/tests/browser/windows/uia/browser.toml b/accessible/tests/browser/windows/uia/browser.toml
index f7974d69c7..d1513c1822 100644
--- a/accessible/tests/browser/windows/uia/browser.toml
+++ b/accessible/tests/browser/windows/uia/browser.toml
@@ -9,3 +9,5 @@ support-files = ["head.js"]
 ["browser_controlType.js"]
 
 ["browser_elementFromPoint.js"]
+
+["browser_tree.js"]
diff --git a/accessible/tests/browser/windows/uia/browser_controlType.js b/accessible/tests/browser/windows/uia/browser_controlType.js
index 16db892581..3bb994f437 100644
--- a/accessible/tests/browser/windows/uia/browser_controlType.js
+++ b/accessible/tests/browser/windows/uia/browser_controlType.js
@@ -9,11 +9,11 @@ const UIA_ButtonControlTypeId = 50000;
 const UIA_DocumentControlTypeId = 50030;
 /* eslint-enable camelcase */
 
-addAccessibleTask(
+addUiaTask(
   `
 <button id="button">button</button>
   `,
-  async function (browser, docAcc) {
+  async function () {
     let controlType = await runPython(`
       global doc
       doc = getDocUia()
diff --git a/accessible/tests/browser/windows/uia/browser_elementFromPoint.js b/accessible/tests/browser/windows/uia/browser_elementFromPoint.js
index e2fda4ab30..acf6fe91c7 100644
--- a/accessible/tests/browser/windows/uia/browser_elementFromPoint.js
+++ b/accessible/tests/browser/windows/uia/browser_elementFromPoint.js
@@ -4,12 +4,12 @@
 
 "use strict";
 
-addAccessibleTask(
+addUiaTask(
   `
 <button id="button">button</p>
 <a id="a" href="#">a</a>
   `,
-  async function (browser, docAcc) {
+  async function () {
     ok(
       await runPython(`
         global doc
diff --git a/accessible/tests/browser/windows/uia/browser_tree.js b/accessible/tests/browser/windows/uia/browser_tree.js
new file mode 100644
index 0000000000..778609bedb
--- /dev/null
+++ b/accessible/tests/browser/windows/uia/browser_tree.js
@@ -0,0 +1,104 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+"use strict";
+
+async function testIsControl(pyVar, isControl) {
+  const result = await runPython(`bool(${pyVar}.CurrentIsControlElement)`);
+  if (isControl) {
+    ok(result, `${pyVar} is a control element`);
+  } else {
+    ok(!result, `${pyVar} isn't a control element`);
+  }
+}
+
+/**
+ * Define a global Python variable and assign it to a given Python expression.
+ */
+function definePyVar(varName, expression) {
+  return runPython(`
+    global ${varName}
+    ${varName} = ${expression}
+  `);
+}
+
+/**
+ * Get the UIA element with the given id and assign it to a global Python
+ * variable using the id as the variable name.
+ */
+function assignPyVarToUiaWithId(id) {
+  return definePyVar(id, `findUiaByDomId(doc, "${id}")`);
+}
+
+addUiaTask(
+  `
+<p id="p">paragraph</p>
+<div id="div">div</div>
+<!-- The spans are because the UIA -> IA2 proxy seems to remove a single text
+   leaf child from even the raw tree.
+  -->
+<a id="link" href="#">link<span> </span>></a>
+<h1 id="h1">h1<span> </span></h1>
+<h1 id="h1WithDiv"><div>h1 with div<span> </span></div></h1>
+<input id="range" type="range">
+<div onclick=";" id="clickable">clickable</div>
+<div id="editable" contenteditable>editable</div>
+<table id="table"><tr><th>th</th></tr></table>
+  `,
+  async function (browser, docAcc) {
+    await definePyVar("doc", `getDocUia()`);
+    await assignPyVarToUiaWithId("p");
+    await testIsControl("p", false);
+    await definePyVar(
+      "pTextLeaf",
+      `uiaClient.RawViewWalker.GetFirstChildElement(p)`
+    );
+    await testIsControl("pTextLeaf", true);
+    await assignPyVarToUiaWithId("div");
+    await testIsControl("div", false);
+    await definePyVar(
+      "divTextLeaf",
+      `uiaClient.RawViewWalker.GetFirstChildElement(div)`
+    );
+    await testIsControl("divTextLeaf", true);
+    await assignPyVarToUiaWithId("link");
+    await testIsControl("link", true);
+    await assignPyVarToUiaWithId("range");
+    await testIsControl("range", true);
+    await assignPyVarToUiaWithId("editable");
+    await testIsControl("editable", true);
+    await assignPyVarToUiaWithId("table");
+    await testIsControl("table", true);
+    if (!gIsUiaEnabled) {
+      // The remaining tests are broken with the UIA -> IA2 proxy.
+      return;
+    }
+    await definePyVar(
+      "linkTextLeaf",
+      `uiaClient.RawViewWalker.GetFirstChildElement(link)`
+    );
+    await testIsControl("linkTextLeaf", false);
+    await assignPyVarToUiaWithId("h1");
+    await testIsControl("h1", true);
+    await definePyVar(
+      "h1TextLeaf",
+      `uiaClient.RawViewWalker.GetFirstChildElement(h1)`
+    );
+    await testIsControl("h1TextLeaf", false);
+    await assignPyVarToUiaWithId("h1WithDiv");
+    await testIsControl("h1WithDiv", true);
+    // h1WithDiv's text leaf is its grandchild.
+    await definePyVar(
+      "h1WithDivTextLeaf",
+      `uiaClient.RawViewWalker.GetFirstChildElement(
+        uiaClient.RawViewWalker.GetFirstChildElement(
+          h1WithDiv
+        )
+      )`
+    );
+    await testIsControl("h1WithDivTextLeaf", false);
+    await assignPyVarToUiaWithId("clickable");
+    await testIsControl("clickable", true);
+  }
+);
diff --git a/accessible/tests/browser/windows/uia/head.js b/accessible/tests/browser/windows/uia/head.js
index afc50984bd..e659354c7c 100644
--- a/accessible/tests/browser/windows/uia/head.js
+++ b/accessible/tests/browser/windows/uia/head.js
@@ -4,6 +4,8 @@
 
 "use strict";
 
+/* exported gIsUiaEnabled, addUiaTask */
+
 // Load the shared-head file first.
 Services.scriptloader.loadSubScript(
   "chrome://mochitests/content/browser/accessible/tests/browser/shared-head.js",
@@ -16,3 +18,38 @@ loadScripts(
   { name: "common.js", dir: MOCHITESTS_DIR },
   { name: "promisified-events.js", dir: MOCHITESTS_DIR }
 );
+
+let gIsUiaEnabled = false;
+
+/**
+ * This is like addAccessibleTask, but takes two additional boolean options:
+ * - uiaEnabled: Whether to run a variation of this test with Gecko UIA enabled.
+ * - uiaDisabled: Whether to run a variation of this test with UIA disabled. In
+ *   this case, UIA will rely entirely on the IA2 -> UIA proxy.
+ * If both are set, the test will be run twice with different configurations.
+ * You can determine which variant is currently running using the gIsUiaEnabled
+ * variable. This is useful for conditional tests; e.g. if Gecko UIA supports
+ * something that the IA2 -> UIA proxy doesn't support.
+ */
+function addUiaTask(doc, task, options = {}) {
+  const { uiaEnabled = true, uiaDisabled = true } = options;
+
+  function addTask(shouldEnable) {
+    async function uiaTask(browser, docAcc, topDocAcc) {
+      await SpecialPowers.pushPrefEnv({
+        set: [["accessibility.uia.enable", shouldEnable]],
+      });
+      gIsUiaEnabled = shouldEnable;
+      info(shouldEnable ? "Gecko UIA enabled" : "Gecko UIA disabled");
+      await task(browser, docAcc, topDocAcc);
+    }
+    addAccessibleTask(doc, uiaTask, options);
+  }
+
+  if (uiaEnabled) {
+    addTask(true);
+  }
+  if (uiaDisabled) {
+    addTask(false);
+  }
+}
diff --git a/accessible/tests/crashtests/crashtests.list b/accessible/tests/crashtests/crashtests.list
index 2f628ddfe2..4787e09163 100644
--- a/accessible/tests/crashtests/crashtests.list
+++ b/accessible/tests/crashtests/crashtests.list
@@ -1,5 +1,5 @@
 load 448064.xhtml # This test instantiates a11y, so be careful about adding tests before it
-asserts-if(!browserIsRemote,2) load 884202.html
+load 884202.html
 load 1572811.html
 load 1578282.html
 load 890760.html
diff --git a/accessible/tests/mochitest/actions/test_media.html b/accessible/tests/mochitest/actions/test_media.html
index 5327901e56..99393b984b 100644
--- a/accessible/tests/mochitest/actions/test_media.html
+++ b/accessible/tests/mochitest/actions/test_media.html
@@ -32,7 +32,7 @@ https://bugzilla.mozilla.org/show_bug.cgi?id=483573
       this.getID = function focusChecker_getID() {
         return "focus handling";
       };
-      this.check = function focusChecker_check(aEvent) {
+      this.check = function focusChecker_check() {
         testStates(this.target, STATE_FOCUSED);
       };
     }
diff --git a/accessible/tests/mochitest/actions/test_tree.xhtml b/accessible/tests/mochitest/actions/test_tree.xhtml
index 17710cbdce..3279ac74ee 100644
--- a/accessible/tests/mochitest/actions/test_tree.xhtml
+++ b/accessible/tests/mochitest/actions/test_tree.xhtml
@@ -31,7 +31,7 @@
     {
       this.__proto__ = new focusChecker(aAcc);
 
-      this.check = function focusChecker_check(aEvent)
+      this.check = function focusChecker_check()
       {
         var states = aStates ? aStates : 0;
         testStates(this.target, STATE_FOCUSED | STATE_SELECTED | states);
@@ -71,7 +71,7 @@
           actionIndex: 1,
           events: CLICK_EVENTS,
           targetID: treeBodyNode,
-          checkOnClickEvent: function check(aEvent)
+          checkOnClickEvent: function check()
           {
             testStates(this.ID, STATE_EXPANDED);
           }
@@ -82,7 +82,7 @@
           actionIndex: 1,
           events: CLICK_EVENTS,
           targetID: treeBodyNode,
-          checkOnClickEvent: function check(aEvent)
+          checkOnClickEvent: function check()
           {
             testStates(this.ID, STATE_COLLAPSED);
           }
diff --git a/accessible/tests/mochitest/actions/test_treegrid.xhtml b/accessible/tests/mochitest/actions/test_treegrid.xhtml
index 1c6e1bb8aa..985018418b 100644
--- a/accessible/tests/mochitest/actions/test_treegrid.xhtml
+++ b/accessible/tests/mochitest/actions/test_treegrid.xhtml
@@ -37,7 +37,7 @@
       {
         return "focus handling";
       }
-      this.check = function focusChecker_check(aEvent)
+      this.check = function focusChecker_check()
       {
         var states = aStates ? aStates : 0;
         testStates(this.target, STATE_FOCUSED | STATE_SELECTED | states);
@@ -52,7 +52,7 @@
       {
         return "state change handling";
       }
-      this.check = function stateChangeChecker_check(aEvent)
+      this.check = function stateChangeChecker_check()
       {
         if (aIsEnabled)
           testStates(this.target, STATE_CHECKED);
@@ -95,7 +95,7 @@
           actionIndex: 1,
           events: CLICK_EVENTS,
           targetID: treeBodyNode,
-          check: function check(aEvent)
+          check: function check()
           {
             testStates(this.ID, STATE_EXPANDED);
           }
@@ -106,7 +106,7 @@
           actionIndex: 1,
           events: CLICK_EVENTS,
           targetID: treeBodyNode,
-          check: function check(aEvent)
+          check: function check()
           {
             testStates(this.ID, STATE_COLLAPSED);
           }
diff --git a/accessible/tests/mochitest/autocomplete.js b/accessible/tests/mochitest/autocomplete.js
index bd5458c51d..baf9529473 100644
--- a/accessible/tests/mochitest/autocomplete.js
+++ b/accessible/tests/mochitest/autocomplete.js
@@ -171,11 +171,11 @@ AutoCompleteResult.prototype = {
     return this.comments[aIndex];
   },
 
-  getStyleAt(aIndex) {
+  getStyleAt() {
     return null;
   },
 
-  getImageAt(aIndex) {
+  getImageAt() {
     return "";
   },
 
@@ -183,11 +183,11 @@ AutoCompleteResult.prototype = {
     return this.getValueAt(aIndex);
   },
 
-  isRemovableAt(aRowIndex) {
+  isRemovableAt() {
     return true;
   },
 
-  removeValueAt(aRowIndex) {},
+  removeValueAt() {},
 
   // nsISupports implementation
   QueryInterface: ChromeUtils.generateQI(["nsIAutoCompleteResult"]),
diff --git a/accessible/tests/mochitest/common.js b/accessible/tests/mochitest/common.js
index f0ee117452..7f40c33bff 100644
--- a/accessible/tests/mochitest/common.js
+++ b/accessible/tests/mochitest/common.js
@@ -976,7 +976,7 @@ function prettyName(aIdentifier) {
  * @param aString the string to shorten.
  * @returns the shortened string.
  */
-function shortenString(aString, aMaxLength) {
+function shortenString(aString) {
   if (aString.length <= MAX_TRIM_LENGTH) {
     return aString;
   }
diff --git a/accessible/tests/mochitest/events.js b/accessible/tests/mochitest/events.js
index a6c216e01d..d4e3221f95 100644
--- a/accessible/tests/mochitest/events.js
+++ b/accessible/tests/mochitest/events.js
@@ -928,10 +928,7 @@ function eventQueue(aEventType) {
     return invoker.getID();
   };
 
-  this.setInvokerStatus = function eventQueue_setInvokerStatus(
-    aStatus,
-    aLogMsg
-  ) {
+  this.setInvokerStatus = function eventQueue_setInvokerStatus(aStatus) {
     this.mNextInvokerStatus = aStatus;
 
     // Uncomment it to debug invoker processing logic.
@@ -2348,7 +2345,7 @@ var gA11yEventApplicantsCount = 0;
 
 var gA11yEventObserver = {
   // eslint-disable-next-line complexity
-  observe: function observe(aSubject, aTopic, aData) {
+  observe: function observe(aSubject, aTopic) {
     if (aTopic != "accessible-event") {
       return;
     }
diff --git a/accessible/tests/mochitest/events/a11y.toml b/accessible/tests/mochitest/events/a11y.toml
index 501b59f7b7..81f9fab3d9 100644
--- a/accessible/tests/mochitest/events/a11y.toml
+++ b/accessible/tests/mochitest/events/a11y.toml
@@ -40,8 +40,6 @@ support-files = [
 
 ["test_flush.html"]
 
-["test_focus_aria_activedescendant.html"]
-
 ["test_focus_autocomplete.html"]
 
 ["test_focus_autocomplete.xhtml"]
diff --git a/accessible/tests/mochitest/events/test_contextmenu.html b/accessible/tests/mochitest/events/test_contextmenu.html
index 6200efc00d..3047b4d46c 100644
--- a/accessible/tests/mochitest/events/test_contextmenu.html
+++ b/accessible/tests/mochitest/events/test_contextmenu.html
@@ -52,7 +52,7 @@
       };
     }
 
-    function closeContextMenu(aID) {
+    function closeContextMenu() {
       this.eventSeq = [
         new invokerChecker(EVENT_MENUPOPUP_END,
                            getAccessible(getContextMenuNode())),
diff --git a/accessible/tests/mochitest/events/test_focus_aria_activedescendant.html b/accessible/tests/mochitest/events/test_focus_aria_activedescendant.html
deleted file mode 100644
index 661284619a..0000000000
--- a/accessible/tests/mochitest/events/test_focus_aria_activedescendant.html
+++ /dev/null
@@ -1,327 +0,0 @@
-<!DOCTYPE html>
-<html>
-<!--
-https://bugzilla.mozilla.org/show_bug.cgi?id=429547
--->
-<head>
-  <title>aria-activedescendant focus tests</title>
-  <link rel="stylesheet" type="text/css" href="chrome://mochikit/content/tests/SimpleTest/test.css" />
-
-  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"></script>
-
-  <script type="application/javascript"
-          src="../common.js"></script>
-  <script type="application/javascript"
-          src="../role.js"></script>
-  <script type="application/javascript"
-          src="../states.js"></script>
-  <script type="application/javascript"
-          src="../events.js"></script>
-
-  <script type="application/javascript">
-    let PromEvents = {};
-    Services.scriptloader.loadSubScript(
-      "chrome://mochitests/content/a11y/accessible/tests/mochitest/promisified-events.js",
-      PromEvents);
-    // gA11yEventDumpToConsole = true; // debugging
-
-    function changeARIAActiveDescendant(aContainer, aItem, aPrevItemId) {
-      let itemID = Node.isInstance(aItem) ? aItem.id : aItem;
-      this.eventSeq = [new focusChecker(aItem)];
-
-      if (aPrevItemId) {
-        this.eventSeq.push(
-          new stateChangeChecker(EXT_STATE_ACTIVE, true, false, aPrevItemId)
-        );
-      }
-
-      this.eventSeq.push(
-        new stateChangeChecker(EXT_STATE_ACTIVE, true, true, aItem)
-      );
-
-      this.invoke = function changeARIAActiveDescendant_invoke() {
-        getNode(aContainer).setAttribute("aria-activedescendant", itemID);
-      };
-
-      this.getID = function changeARIAActiveDescendant_getID() {
-        return "change aria-activedescendant on " + itemID;
-      };
-    }
-
-    function clearARIAActiveDescendant(aID, aPrevItemId) {
-      this.eventSeq = [
-        new focusChecker(aID),
-      ];
-
-      if (aPrevItemId) {
-        this.eventSeq.push(
-          new stateChangeChecker(EXT_STATE_ACTIVE, true, false, aPrevItemId)
-        );
-      }
-
-      this.invoke = function clearARIAActiveDescendant_invoke() {
-        getNode(aID).removeAttribute("aria-activedescendant");
-      };
-
-      this.getID = function clearARIAActiveDescendant_getID() {
-        return "clear aria-activedescendant on container " + aID;
-      };
-    }
-
-    /**
-     * Change aria-activedescendant to an invalid (non-existent) id.
-     * Ensure that focus is fired on the element itself.
-     */
-    function changeARIAActiveDescendantInvalid(aID, aInvalidID, aPrevItemId) {
-      if (!aInvalidID) {
-        aInvalidID = "invalid";
-      }
-
-      this.eventSeq = [
-        new focusChecker(aID),
-      ];
-
-      if (aPrevItemId) {
-        this.eventSeq.push(
-          new stateChangeChecker(EXT_STATE_ACTIVE, true, false, aPrevItemId)
-        );
-      }
-
-      this.invoke = function changeARIAActiveDescendant_invoke() {
-        getNode(aID).setAttribute("aria-activedescendant", aInvalidID);
-      };
-
-      this.getID = function changeARIAActiveDescendant_getID() {
-        return "change aria-activedescendant to invalid id";
-      };
-    }
-    
-    function insertItemNFocus(aID, aNewItemID, aPrevItemId) {
-      this.eventSeq = [
-        new invokerChecker(EVENT_SHOW, aNewItemID),
-        new focusChecker(aNewItemID),
-      ];
-
-      if (aPrevItemId) {
-        this.eventSeq.push(
-          new stateChangeChecker(EXT_STATE_ACTIVE, true, false, aPrevItemId)
-        );
-      }
-
-      this.eventSeq.push(
-        new stateChangeChecker(EXT_STATE_ACTIVE, true, true, aNewItemID)
-      );
-
-      this.invoke = function insertItemNFocus_invoke() {
-        var container  = getNode(aID);
-
-        var itemNode = document.createElement("div");
-        itemNode.setAttribute("id", aNewItemID);
-        itemNode.setAttribute("role", "listitem");
-        itemNode.textContent = aNewItemID;
-        container.appendChild(itemNode);
-
-        container.setAttribute("aria-activedescendant", aNewItemID);
-      };
-
-      this.getID = function insertItemNFocus_getID() {
-        return "insert new node and focus it with ID: " + aNewItemID;
-      };
-    }
-
-    /**
-     * Change the id of an element to another id which is the target of
-     * aria-activedescendant.
-     * If another element already has the desired id, remove it from that
-     * element first.
-     * Ensure that focus is fired on the target element which was given the
-     * desired id.
-     * @param aFromID The existing id of the target element.
-     * @param aToID The desired id to be given to the target element.
-    */
-    function moveARIAActiveDescendantID(aFromID, aToID) {
-      this.eventSeq = [
-        new focusChecker(aToID),
-        new stateChangeChecker(EXT_STATE_ACTIVE, true, true, aToID),
-      ];
-
-      this.invoke = function moveARIAActiveDescendantID_invoke() {
-        let orig = document.getElementById(aToID);
-        if (orig) {
-          orig.id = "";
-        }
-        document.getElementById(aFromID).id = aToID;
-      };
-
-      this.getID = function moveARIAActiveDescendantID_getID() {
-        return "move aria-activedescendant id " + aToID;
-      };
-    }
-
-    var gQueue = null;
-    async function doTest() {
-      gQueue = new eventQueue();
-      // Later tests use await.
-      let queueFinished = new Promise(resolve => {
-        gQueue.onFinish = function() {
-          resolve();
-          return DO_NOT_FINISH_TEST;
-        };
-      });
-
-      gQueue.push(new synthFocus("listbox", new focusChecker("item1")));
-      gQueue.push(new changeARIAActiveDescendant("listbox", "item2", "item1"));
-      gQueue.push(new changeARIAActiveDescendant("listbox", "item3", "item2"));
-
-      gQueue.push(new synthFocus("combobox_entry", new focusChecker("combobox_entry")));
-      gQueue.push(new changeARIAActiveDescendant("combobox", "combobox_option2"));
-
-      gQueue.push(new synthFocus("listbox", new focusChecker("item3")));
-      gQueue.push(new insertItemNFocus("listbox", "item4", "item3"));
-
-      gQueue.push(new clearARIAActiveDescendant("listbox", "item4"));
-      gQueue.push(new changeARIAActiveDescendant("listbox", "item1"));
-      gQueue.push(new changeARIAActiveDescendantInvalid("listbox", "invalid", "item1"));
-
-      gQueue.push(new changeARIAActiveDescendant("listbox", "roaming"));
-      gQueue.push(new moveARIAActiveDescendantID("roaming2", "roaming"));
-      gQueue.push(new changeARIAActiveDescendantInvalid("listbox", "roaming3", "roaming"));
-      gQueue.push(new moveARIAActiveDescendantID("roaming", "roaming3"));
-
-      gQueue.push(new synthFocus("activedesc_nondesc_input",
-        new focusChecker("activedesc_nondesc_option")));
-
-      let shadowRoot = document.getElementById("shadow").shadowRoot;
-      let shadowListbox = shadowRoot.getElementById("shadowListbox");
-      let shadowItem1 = shadowRoot.getElementById("shadowItem1");
-      let shadowItem2 = shadowRoot.getElementById("shadowItem2");
-      gQueue.push(new synthFocus(shadowListbox, new focusChecker(shadowItem1)));
-      gQueue.push(new changeARIAActiveDescendant(shadowListbox, shadowItem2));
-
-      gQueue.invoke();
-      await queueFinished;
-      // Tests beyond this point use await rather than eventQueue.
-
-      info("Testing simultaneous insertion, relocation and aria-activedescendant");
-      let comboboxWithHiddenList = getNode("comboboxWithHiddenList");
-      let evtProm = PromEvents.waitForEvent(EVENT_FOCUS, comboboxWithHiddenList);
-      comboboxWithHiddenList.focus();
-      await evtProm;
-      testStates(comboboxWithHiddenList, STATE_FOCUSED);
-      // hiddenList is owned, so unhiding causes insertion and relocation.
-      getNode("hiddenList").hidden = false;
-      evtProm = Promise.all([
-        PromEvents.waitForEvent(EVENT_FOCUS, "hiddenListOption"),
-        PromEvents.waitForStateChange("hiddenListOption", EXT_STATE_ACTIVE, true, true),
-      ]);
-      comboboxWithHiddenList.setAttribute("aria-activedescendant", "hiddenListOption");
-      await evtProm;
-      testStates("hiddenListOption", STATE_FOCUSED);
-
-      info("Testing active state changes when not focused");
-      testStates("listbox", 0, 0, STATE_FOCUSED);
-      evtProm = Promise.all([
-        PromEvents.waitForStateChange("roaming3", EXT_STATE_ACTIVE, false, true),
-        PromEvents.waitForStateChange("item1", EXT_STATE_ACTIVE, true, true),
-      ]);
-      getNode("listbox").setAttribute("aria-activedescendant", "item1");
-      await evtProm;
-
-      info("Testing that focus is always fired first");
-      const listbox = getNode("listbox");
-      evtProm = PromEvents.waitForEvent(EVENT_FOCUS, "item1");
-      listbox.focus();
-      await evtProm;
-      const item1 = getNode("item1");
-      evtProm = PromEvents.waitForOrderedEvents([
-        [EVENT_FOCUS, "item2"],
-        [EVENT_NAME_CHANGE, item1],
-      ], "Focus then name change");
-      item1.setAttribute("aria-label", "changed");
-      listbox.setAttribute("aria-activedescendant", "item2");
-      await evtProm;
-
-      info("Setting aria-activedescendant to invalid id on non-focused node");
-      const combobox_entry = getNode("combobox_entry");
-      evtProm = PromEvents.waitForEvents({
-        expected: [[EVENT_FOCUS, combobox_entry]],
-        unexpected: [[EVENT_FOCUS, listbox]],
-      });
-      combobox_entry.focus();
-      listbox.setAttribute("aria-activedescendant", "invalid");
-      await evtProm;
-
-      SimpleTest.finish();
-    }
-
-    SimpleTest.waitForExplicitFinish();
-    addA11yLoadEvent(doTest);
-  </script>
-</head>
-<body>
-
-  <a target="_blank"
-     href="https://bugzilla.mozilla.org/show_bug.cgi?id=429547"
-     title="Support aria-activedescendant usage in nsIAccesible::TakeFocus()">
-    Mozilla Bug 429547
-  </a>
-  <a target="_blank"
-     href="https://bugzilla.mozilla.org/show_bug.cgi?id=761102"
-     title="Focus may be missed when ARIA active-descendant is changed on active composite widget">
-    Mozilla Bug 761102
-  </a>
-  <p id="display"></p>
-  <div id="content" style="display: none"></div>
-  <pre id="test">
-  </pre>
-
-  <div role="listbox" aria-activedescendant="item1" id="listbox" tabindex="1"
-       aria-owns="item3">
-    <div role="listitem" id="item1">item1</div>
-    <div role="listitem" id="item2">item2</div>
-    <div role="listitem" id="roaming">roaming</div>
-    <div role="listitem" id="roaming2">roaming2</div>
-  </div>
-  <div role="listitem" id="item3">item3</div>
-
-  <div role="combobox" id="combobox">
-    <input id="combobox_entry">
-    <ul>
-      <li role="option" id="combobox_option1">option1</li>
-      <li role="option" id="combobox_option2">option2</li>
-    </ul>
-  </div>
-
-  <!-- aria-activedescendant targeting a non-descendant -->
-  <input id="activedesc_nondesc_input" aria-activedescendant="activedesc_nondesc_option">
-  <div role="listbox">
-    <div role="option" id="activedesc_nondesc_option">option</div>
-  </div>
-
-  <div id="shadow"></div>
-  <script>
-    let host = document.getElementById("shadow");
-    let shadow = host.attachShadow({mode: "open"});
-    let listbox = document.createElement("div");
-    listbox.id = "shadowListbox";
-    listbox.setAttribute("role", "listbox");
-    listbox.setAttribute("tabindex", "0");
-    shadow.appendChild(listbox);
-    let item = document.createElement("div");
-    item.id = "shadowItem1";
-    item.setAttribute("role", "option");
-    listbox.appendChild(item);
-    listbox.setAttribute("aria-activedescendant", "shadowItem1");
-    item = document.createElement("div");
-    item.id = "shadowItem2";
-    item.setAttribute("role", "option");
-    listbox.appendChild(item);
-  </script>
-
-  <div id="comboboxWithHiddenList" tabindex="0" role="combobox" aria-owns="hiddenList">
-  </div>
-  <div id="hiddenList" hidden role="listbox">
-    <div id="hiddenListOption" role="option"></div>
-  </div>
-</body>
-</html>
diff --git a/accessible/tests/mochitest/events/test_focus_doc.html b/accessible/tests/mochitest/events/test_focus_doc.html
index a35fc06ed0..bfb43895bd 100644
--- a/accessible/tests/mochitest/events/test_focus_doc.html
+++ b/accessible/tests/mochitest/events/test_focus_doc.html
@@ -47,7 +47,17 @@
 
       // focus on not editable document
       gQueue.push(new synthFocus(frame2InputAcc));
-      gQueue.push(new synthShiftTab(frame2DocAcc, new focusChecker(frame2DocAcc)));
+      var canTabMoveFocusToRootElement =
+          !SpecialPowers.getBoolPref("dom.disable_tab_focus_to_root_element");
+      if (canTabMoveFocusToRootElement) {
+        // Moves the focus to the root element
+        gQueue.push(new synthShiftTab(frame2DocAcc, new focusChecker(frame2DocAcc)));
+      } else {
+        // Skips the root element, so the focus got moved to buttonAcc2.
+        var buttonAcc2 = getAccessible("b2");
+        gQueue.push(new synthShiftTab(buttonAcc2, new focusChecker(buttonAcc2)));
+      }
+
 
       gQueue.invoke(); // Will call SimpleTest.finish();
     }
diff --git a/accessible/tests/mochitest/events/test_label.xhtml b/accessible/tests/mochitest/events/test_label.xhtml
index 5780629dc6..2f207eba65 100644
--- a/accessible/tests/mochitest/events/test_label.xhtml
+++ b/accessible/tests/mochitest/events/test_label.xhtml
@@ -93,7 +93,7 @@
     /**
      * Change @crop attribute.
      */
-    function setCrop(aID, aCropValue, aRemovedText, aInsertedText)
+    function setCrop(aID, aCropValue)
     {
       this.labelNode = getNode(aID);
       this.width = this.labelNode.getBoundingClientRect().width;
diff --git a/accessible/tests/mochitest/events/test_statechange.html b/accessible/tests/mochitest/events/test_statechange.html
index 0642851408..0ecf54b0d1 100644
--- a/accessible/tests/mochitest/events/test_statechange.html
+++ b/accessible/tests/mochitest/events/test_statechange.html
@@ -28,7 +28,7 @@
       await p;
     }
 
-    async function makeEditableDoc(aDocNode, aIsEnabled) {
+    async function makeEditableDoc(aDocNode) {
       let p = waitForStateChange(aDocNode, EXT_STATE_EDITABLE, true, true);
       aDocNode.designMode = "on";
       await p;
diff --git a/accessible/tests/mochitest/name/markup.js b/accessible/tests/mochitest/name/markup.js
index a267bd4f7b..4ad478482b 100644
--- a/accessible/tests/mochitest/name/markup.js
+++ b/accessible/tests/mochitest/name/markup.js
@@ -335,7 +335,7 @@ function testNameForElmRule(aElm, aRule) {
   parentNode.removeChild(labelElm);
 }
 
-function testNameForSubtreeRule(aElm, aRule) {
+function testNameForSubtreeRule(aElm) {
   var msg = "From subtree test (" + gTestIterator.testID + ").";
   testName(aElm, aElm.getAttribute("textequiv"), msg);
   testAbsentAttrs(aElm, { "explicit-name": "true" });
diff --git a/accessible/tests/mochitest/name/test_tree.xhtml b/accessible/tests/mochitest/name/test_tree.xhtml
index 3564481d00..282e4ea118 100644
--- a/accessible/tests/mochitest/name/test_tree.xhtml
+++ b/accessible/tests/mochitest/name/test_tree.xhtml
@@ -31,7 +31,7 @@
         this.DOMNode.view = new nsTreeTreeView();
       }
 
-      this.check = function treeTester_check(aEvent)
+      this.check = function treeTester_check()
       {
         var tree = {
           role: ROLE_OUTLINE,
@@ -89,7 +89,7 @@
         this.DOMNode.view = new nsTableTreeView(2);
       }
 
-      this.check = function tableTester_check(aEvent)
+      this.check = function tableTester_check()
       {
         var tree = {
           role: aIsTable ? ROLE_TABLE : ROLE_TREE_TABLE,
diff --git a/accessible/tests/mochitest/promisified-events.js b/accessible/tests/mochitest/promisified-events.js
index c58466dcf1..223be16147 100644
--- a/accessible/tests/mochitest/promisified-events.js
+++ b/accessible/tests/mochitest/promisified-events.js
@@ -141,7 +141,7 @@ function matchEvent(event, matchCriteria) {
 function waitForEvent(eventType, matchCriteria, message) {
   return new Promise(resolve => {
     let eventObserver = {
-      observe(subject, topic, data) {
+      observe(subject, topic) {
         if (topic !== "accessible-event") {
           return;
         }
@@ -185,7 +185,7 @@ class UnexpectedEvents {
     }
   }
 
-  observe(subject, topic, data) {
+  observe(subject, topic) {
     if (topic !== "accessible-event") {
       return;
     }
diff --git a/accessible/tests/mochitest/relations/test_tabbrowser.xhtml b/accessible/tests/mochitest/relations/test_tabbrowser.xhtml
index 3356bc6140..4820419c1e 100644
--- a/accessible/tests/mochitest/relations/test_tabbrowser.xhtml
+++ b/accessible/tests/mochitest/relations/test_tabbrowser.xhtml
@@ -43,7 +43,7 @@
         browserDocument().documentElement.getBoundingClientRect();
       }
 
-      this.finalCheck = function testTabRelations_finalCheck(aEvent)
+      this.finalCheck = function testTabRelations_finalCheck()
       {
         ////////////////////////////////////////////////////////////////////////
         // 'labelled by'/'label for' relations for xul:tab and xul:tabpanel
diff --git a/accessible/tests/mochitest/role.js b/accessible/tests/mochitest/role.js
index 07b820c2ac..66cb6de4d2 100644
--- a/accessible/tests/mochitest/role.js
+++ b/accessible/tests/mochitest/role.js
@@ -40,6 +40,7 @@ const ROLE_FLAT_EQUATION = nsIAccessibleRole.ROLE_FLAT_EQUATION;
 const ROLE_FORM = nsIAccessibleRole.ROLE_FORM;
 const ROLE_FORM_LANDMARK = nsIAccessibleRole.ROLE_FORM_LANDMARK;
 const ROLE_GRAPHIC = nsIAccessibleRole.ROLE_GRAPHIC;
+const ROLE_GRID = nsIAccessibleRole.ROLE_GRID;
 const ROLE_GRID_CELL = nsIAccessibleRole.ROLE_GRID_CELL;
 const ROLE_GROUPING = nsIAccessibleRole.ROLE_GROUPING;
 const ROLE_HEADING = nsIAccessibleRole.ROLE_HEADING;
diff --git a/accessible/tests/mochitest/role/test_aria.html b/accessible/tests/mochitest/role/test_aria.html
index bd7ffd27fb..0e7873c485 100644
--- a/accessible/tests/mochitest/role/test_aria.html
+++ b/accessible/tests/mochitest/role/test_aria.html
@@ -56,16 +56,16 @@
       testRole("aria_directory_mixed", ROLE_LIST);
       testRole("aria_document", ROLE_NON_NATIVE_DOCUMENT);
       testRole("aria_document_mixed", ROLE_NON_NATIVE_DOCUMENT);
-      testRole("aria_form", ROLE_FORM);
-      testRole("aria_form_mixed", ROLE_FORM);
+      testRole("aria_form", ROLE_TEXT);
+      testRole("aria_form_mixed", ROLE_TEXT);
       testRole("aria_form_with_label", ROLE_FORM);
       testRole("aria_form_with_label_mixed", ROLE_FORM);
       testRole("aria_feed", ROLE_GROUPING);
       testRole("aria_feed_mixed", ROLE_GROUPING);
       testRole("aria_figure", ROLE_FIGURE);
       testRole("aria_figure_mixed", ROLE_FIGURE);
-      testRole("aria_grid", ROLE_TABLE);
-      testRole("aria_grid_mixed", ROLE_TABLE);
+      testRole("aria_grid", ROLE_GRID);
+      testRole("aria_grid_mixed", ROLE_GRID);
       testRole("aria_gridcell", ROLE_GRID_CELL);
       testRole("aria_gridcell_mixed", ROLE_GRID_CELL);
       testRole("aria_group", ROLE_GROUPING);
@@ -184,8 +184,10 @@
 
       testRole("articlemain", ROLE_LANDMARK);
       testRole("articlemain_mixed", ROLE_LANDMARK);
-      testRole("articleform", ROLE_FORM);
-      testRole("articleform_mixed", ROLE_FORM);
+      testRole("articleform", ROLE_ARTICLE);
+      testRole("articleform_mixed", ROLE_ARTICLE);
+      testRole("articleform_label", ROLE_FORM);
+      testRole("articleform_label_mixed", ROLE_FORM);
 
       // Test article exposed as article
       testRole("testArticle", ROLE_ARTICLE);
@@ -204,8 +206,10 @@
       // strong landmark
       testRole("application", ROLE_APPLICATION);
       testRole("application_mixed", ROLE_APPLICATION);
-      testRole("form", ROLE_FORM);
-      testRole("form_mixed", ROLE_FORM);
+      testRole("form", ROLE_SECTION);
+      testRole("form_mixed", ROLE_SECTION);
+      testRole("form_label", ROLE_FORM);
+      testRole("form_label_mixed", ROLE_FORM);
       testRole("application_table", ROLE_APPLICATION);
       testRole("application_table_mixed", ROLE_APPLICATION);
 
@@ -535,6 +539,8 @@
   <article id="articlemain_mixed" role="mAIn">a main area</article>
   <article id="articleform" role="form">a form area</article>
   <article id="articleform_mixed" role="fORm">a form area</article>
+  <article id="articleform_label" aria-label="form" role="form">a form area</article>
+  <article id="articleform_label_mixed" aria-label="form" role="fORm">a form area</article>
 
   <div id="testArticle" role="article" title="Test article">
     <p>This is a paragraph inside the article.</p>
@@ -561,6 +567,8 @@
   <div role="aPPLICATIOn" id="application_mixed">application</div>
   <div role="form" id="form">form</div>
   <div role="fORm" id="form_mixed">form</div>
+  <div role="form" id="form_label" aria-label="form">form</div>
+  <div role="fORm" id="form_label_mixed" aria-label="form">form</div>
 
   <!-- weak landmarks -->
   <div role="banner" id="banner">banner</div>
diff --git a/accessible/tests/mochitest/role/test_general.html b/accessible/tests/mochitest/role/test_general.html
index 38dde3325a..c0afd39360 100644
--- a/accessible/tests/mochitest/role/test_general.html
+++ b/accessible/tests/mochitest/role/test_general.html
@@ -161,7 +161,7 @@
          id="nav_overflow">overflow nav</nav>
     <header style="overflow: hidden;"
             id="header_overflow">overflow header</header>
-    <aside style="overflow: hidden;"
+    <aside style="overflow: hidden;" aria-label="aside"
            id="aside_overflow">overflow aside</aside>
     <footer style="overflow: hidden;"
             id="footer_overflow">overflow footer</footer>
diff --git a/accessible/tests/mochitest/states/test_aria_widgetitems.html b/accessible/tests/mochitest/states/test_aria_widgetitems.html
index c2d546ba01..d17f110c22 100644
--- a/accessible/tests/mochitest/states/test_aria_widgetitems.html
+++ b/accessible/tests/mochitest/states/test_aria_widgetitems.html
@@ -26,7 +26,7 @@
         this.DOMNode.focus();
       };
 
-      this.check = function focusARIAItem_check(aEvent) {
+      this.check = function focusARIAItem_check() {
         testStates(this.DOMNode, aIsSelected ? STATE_SELECTED : 0, 0,
                    aIsSelected ? 0 : STATE_SELECTED);
       };
@@ -47,7 +47,7 @@
         this.widgetDOMNode.focus();
       };
 
-      this.check = function focusActiveDescendantItem_check(aEvent) {
+      this.check = function focusActiveDescendantItem_check() {
         testStates(this.DOMNode, aIsSelected ? STATE_SELECTED : 0, 0,
                    aIsSelected ? 0 : STATE_SELECTED);
       };
diff --git a/accessible/tests/mochitest/test_bug420863.html b/accessible/tests/mochitest/test_bug420863.html
index 4f3a608fe1..9d515ab3c6 100644
--- a/accessible/tests/mochitest/test_bug420863.html
+++ b/accessible/tests/mochitest/test_bug420863.html
@@ -40,7 +40,7 @@ https://bugzilla.mozilla.org/show_bug.cgi?id=420863
 
       // register 'click' event handler
       gClickHandler = {
-        handleEvent: function handleEvent(aEvent) {
+        handleEvent: function handleEvent() {
         },
       };
       td3Node.addEventListener("click", gClickHandler);
@@ -58,7 +58,7 @@ https://bugzilla.mozilla.org/show_bug.cgi?id=420863
           actionName: "click",
           actionIndex: 0,
           events: CLICK_EVENTS,
-          checkOnClickEvent: function check(aEvent) {
+          checkOnClickEvent: function check() {
             // unregister click event handler
             this.ID.removeEventListener("click", gClickHandler);
 
diff --git a/accessible/tests/mochitest/text.js b/accessible/tests/mochitest/text.js
index 21392336a1..6fe2a00b83 100644
--- a/accessible/tests/mochitest/text.js
+++ b/accessible/tests/mochitest/text.js
@@ -197,9 +197,17 @@ function testTextAfterOffset(
   aBoundaryType,
   aText,
   aStartOffset,
-  aEndOffset
+  aEndOffset,
+  ...aArgs
 ) {
-  testTextSuperHelper("getTextAfterOffset", arguments);
+  testTextSuperHelper("getTextAfterOffset", [
+    aOffset,
+    aBoundaryType,
+    aText,
+    aStartOffset,
+    aEndOffset,
+    ...aArgs,
+  ]);
 }
 
 /**
@@ -261,9 +269,17 @@ function testTextBeforeOffset(
   aBoundaryType,
   aText,
   aStartOffset,
-  aEndOffset
+  aEndOffset,
+  ...aArgs
 ) {
-  testTextSuperHelper("getTextBeforeOffset", arguments);
+  testTextSuperHelper("getTextBeforeOffset", [
+    aOffset,
+    aBoundaryType,
+    aText,
+    aStartOffset,
+    aEndOffset,
+    ...aArgs,
+  ]);
 }
 
 /**
diff --git a/accessible/tests/mochitest/tree/test_aria_display_contents.html b/accessible/tests/mochitest/tree/test_aria_display_contents.html
index 5c6f7f20fb..454e4e46e1 100644
--- a/accessible/tests/mochitest/tree/test_aria_display_contents.html
+++ b/accessible/tests/mochitest/tree/test_aria_display_contents.html
@@ -17,7 +17,7 @@
       // Test ARIA grids that have display: contents; on different elements.
       // They should all have equivalent trees.
       var accTree =
-        { TABLE: [
+        { GRID: [
           { ROW: [
             { role: ROLE_COLUMNHEADER,
               children: [ { TEXT_LEAF: [ ] }, ]
diff --git a/accessible/tests/mochitest/tree/test_aria_grid.html b/accessible/tests/mochitest/tree/test_aria_grid.html
index 80ff97095b..4dd30e4183 100644
--- a/accessible/tests/mochitest/tree/test_aria_grid.html
+++ b/accessible/tests/mochitest/tree/test_aria_grid.html
@@ -18,7 +18,7 @@
       // grid having rowgroups
 
       var accTree =
-        { TABLE: [
+        { GRID: [
           { GROUPING: [
             { ROW: [
               { GRID_CELL: [
@@ -34,7 +34,7 @@
       // strange grids (mix of ARIA and HTML tables)
 
       accTree = {
-        role: ROLE_TABLE,
+        role: ROLE_GRID,
         children: [
           { // div@role="row"
             role: ROLE_ROW,
@@ -67,7 +67,7 @@
       testAccessibleTree("strange_grid1", accTree);
 
       accTree = {
-        role: ROLE_TABLE,
+        role: ROLE_GRID,
         children: [
           { // tr@role="row"
             role: ROLE_ROW,
@@ -95,7 +95,7 @@
       testAccessibleTree("strange_grid2", accTree);
 
       accTree = {
-        role: ROLE_TABLE,
+        role: ROLE_GRID,
         children: [
           { // div@role="row"
             role: ROLE_ROW,
@@ -122,7 +122,7 @@
       testAccessibleTree("strange_grid3", accTree);
 
       accTree = {
-        role: ROLE_TABLE,
+        role: ROLE_GRID,
         children: [
           { // div@role="row"
             role: ROLE_ROW,
@@ -192,7 +192,7 @@
       // grids that could contain text container accessibles but shouldn't.
 
       accTree =
-        { TABLE: [
+        { GRID: [
           { ROW: [
             { GRID_CELL: [
               { TEXT_LEAF: [ ] },
diff --git a/accessible/tests/mochitest/tree/test_aria_owns.html b/accessible/tests/mochitest/tree/test_aria_owns.html
index a01968521b..760cf7565b 100644
--- a/accessible/tests/mochitest/tree/test_aria_owns.html
+++ b/accessible/tests/mochitest/tree/test_aria_owns.html
@@ -96,7 +96,7 @@
       testAccessibleTree("ariaowns_container", tree);
 
       tree =
-        { TABLE: [
+        { GRID: [
           { ROW: [
             { GRID_CELL: [
               { TEXT_LEAF: [] },
@@ -160,7 +160,7 @@
   <!-- natural and aria-owns hierarchy -->
   <div id="t5_2" role="note"><div aria-owns="t5_3" role="heading"></div></div>
   <div id="t5_1"><div aria-owns="t5_2" role="group"></div></div>
-  <div id="t5_3" role="form"><div aria-owns="t5_1" role="tooltip"></div></div>
+  <div id="t5_3" aria-label="form" role="form"><div aria-owns="t5_1" role="tooltip"></div></div>
 
   <!-- rearrange children -->
   <div id="t6_1" aria-owns="t6_3 t6_2">
diff --git a/accessible/tests/mochitest/tree/test_tabbrowser.xhtml b/accessible/tests/mochitest/tree/test_tabbrowser.xhtml
index 401ea1a2b1..3ccf83e4dc 100644
--- a/accessible/tests/mochitest/tree/test_tabbrowser.xhtml
+++ b/accessible/tests/mochitest/tree/test_tabbrowser.xhtml
@@ -42,7 +42,7 @@
         browserDocument().documentElement.getBoundingClientRect();
       }
 
-      this.finalCheck = function testTabHierarchy_finalCheck(aEvent)
+      this.finalCheck = function testTabHierarchy_finalCheck()
       {
         ////////////////////
         // Tab bar
diff --git a/accessible/tests/mochitest/tree/test_tree.xhtml b/accessible/tests/mochitest/tree/test_tree.xhtml
index e22b3faa9d..e70ef134e9 100644
--- a/accessible/tests/mochitest/tree/test_tree.xhtml
+++ b/accessible/tests/mochitest/tree/test_tree.xhtml
@@ -97,7 +97,7 @@
       {
         this.DOMNode.view = aView;
       }
-      this.check = function check(aEvent)
+      this.check = function check()
       {
         testAccessibleTreeFor(this.DOMNode, aRole);
       }
diff --git a/accessible/tests/mochitest/treeupdate/test_contextmenu.xhtml b/accessible/tests/mochitest/treeupdate/test_contextmenu.xhtml
index f81d77332d..9edac19af6 100644
--- a/accessible/tests/mochitest/treeupdate/test_contextmenu.xhtml
+++ b/accessible/tests/mochitest/treeupdate/test_contextmenu.xhtml
@@ -31,7 +31,7 @@
         getNode(aID).openPopup(button, "after_start", 0, 0, true, false);
       }
 
-      this.finalCheck = function openMenu_finalCheck(aEvent)
+      this.finalCheck = function openMenu_finalCheck()
       {
         testAccessibleTree(aID, aTree);
       }
@@ -70,7 +70,7 @@
         synthesizeKey("KEY_Enter");
       }
 
-      this.finalCheck = function openSubMenu_finalCheck(aEvent)
+      this.finalCheck = function openSubMenu_finalCheck()
       {
         testAccessibleTree(aMenuID, aTree);
       }
diff --git a/accessible/tests/mochitest/treeupdate/test_delayed_removal.html b/accessible/tests/mochitest/treeupdate/test_delayed_removal.html
index 3f421f0c5b..2ba1e31203 100644
--- a/accessible/tests/mochitest/treeupdate/test_delayed_removal.html
+++ b/accessible/tests/mochitest/treeupdate/test_delayed_removal.html
@@ -218,7 +218,7 @@
     }
 
     // Check to see that a reframed body gets its children pruned correctly.
-    async function bodyReframe(argument) {
+    async function bodyReframe() {
       // Load sub-document in iframe.
       let event = waitForEvent(EVENT_REORDER, "iframe", "bodyReframe");
       getNode("iframe").src =
diff --git a/accessible/tests/mochitest/treeupdate/test_shadow_slots.html b/accessible/tests/mochitest/treeupdate/test_shadow_slots.html
index 27baef0e4a..6680971401 100644
--- a/accessible/tests/mochitest/treeupdate/test_shadow_slots.html
+++ b/accessible/tests/mochitest/treeupdate/test_shadow_slots.html
@@ -55,7 +55,7 @@
 
     async function changeSlotFlat() {
       await _dynamicShadowTest("changeSlotFlat",
-        (container, host) => {
+        (container) => {
           container.querySelector('.red').removeAttribute('slot');
           container.querySelector('.green').setAttribute('slot', 'myslot');
         }, { SECTION: [{ SECTION: [{ name: "green"} ] }] });
@@ -63,7 +63,7 @@
 
     async function changeSlotOneDeep() {
       await _dynamicShadowTest("changeSlotOneDeep",
-        (container, host) => {
+        (container) => {
           container.querySelector('.red').removeAttribute('slot');
           container.querySelector('.green').setAttribute('slot', 'myslot');
         }, { SECTION: [{ SECTION: [{ SECTION: [{ name: "green"} ] }] }] }, ["shadowdiv"]);
@@ -72,7 +72,7 @@
     // Nested roots and slots
     async function changeSlotNested() {
       await _dynamicShadowTest("changeSlotNested",
-        (container, host) => {
+        (container) => {
           testAccessibleTree(getNode("changeSlotNested"),
             { SECTION: [{ SECTION: [{ SECTION: [{ name: "red"} ] }] }] });
           container.querySelector('.red').removeAttribute('slot');
@@ -82,14 +82,14 @@
 
     async function changeSlotSingleChild() {
       await _dynamicShadowTest("changeSlotSingleChild",
-        (container, host) => {
+        (container) => {
           container.querySelector('.red').setAttribute('slot', 'invalid');
         }, { SECTION: [{ SECTION: [] }] });
     }
 
     async function changeSlotNoShadow() {
       await _dynamicShadowTest("changeSlotNoShadow",
-        (container, host) => {
+        (container) => {
           // Make sure changing the slot attribute doesn't remove an element
           // even when it remains in the flat tree.
           container.querySelector('.red').setAttribute('slot', 'invalid');
diff --git a/accessible/tests/mochitest/treeupdate/test_shutdown.xhtml b/accessible/tests/mochitest/treeupdate/test_shutdown.xhtml
index ad8aebf812..9be24cb6f4 100644
--- a/accessible/tests/mochitest/treeupdate/test_shutdown.xhtml
+++ b/accessible/tests/mochitest/treeupdate/test_shutdown.xhtml
@@ -57,7 +57,7 @@
         getNode(aID).remove();
       };
 
-      this.check = function check(aEvent)
+      this.check = function check()
       {
         testIsDefunct(this.tree, aID);
         testIsDefunct(this.lastItem, "last item of " + aID);
diff --git a/accessible/tests/mochitest/treeview.js b/accessible/tests/mochitest/treeview.js
index 5dc3b595d8..6b50e5fecc 100644
--- a/accessible/tests/mochitest/treeview.js
+++ b/accessible/tests/mochitest/treeview.js
@@ -91,11 +91,11 @@ nsTreeView.prototype = {
 
     return data.text + aCol.id;
   },
-  getCellValue: function getCellValue(aRow, aCol) {
+  getCellValue: function getCellValue(aRow) {
     var data = this.getDataForIndex(aRow);
     return data.value;
   },
-  getRowProperties: function getRowProperties(aIndex) {
+  getRowProperties: function getRowProperties() {
     return "";
   },
   getCellProperties: function getCellProperties(aIndex, aCol) {
@@ -106,19 +106,19 @@ nsTreeView.prototype = {
     var data = this.getDataForIndex(aIndex);
     return this.mCyclerStates[data.cyclerState];
   },
-  getColumnProperties: function getColumnProperties(aCol) {
+  getColumnProperties: function getColumnProperties() {
     return "";
   },
   getParentIndex: function getParentIndex(aRowIndex) {
     var info = this.getInfoByIndex(aRowIndex);
     return info.parentIndex;
   },
-  hasNextSibling: function hasNextSibling(aRowIndex, aAfterIndex) {},
+  hasNextSibling: function hasNextSibling() {},
   getLevel: function getLevel(aIndex) {
     var info = this.getInfoByIndex(aIndex);
     return info.level;
   },
-  getImageSrc: function getImageSrc(aRow, aCol) {},
+  getImageSrc: function getImageSrc() {},
   isContainer: function isContainer(aIndex) {
     var data = this.getDataForIndex(aIndex);
     return data.open != undefined;
@@ -131,7 +131,7 @@ nsTreeView.prototype = {
     var data = this.getDataForIndex(aIndex);
     return data.open == undefined;
   },
-  isSeparator: function isSeparator(aIndex) {},
+  isSeparator: function isSeparator() {},
   isSorted: function isSorted() {},
   toggleOpenState: function toggleOpenState(aIndex) {
     var data = this.getDataForIndex(aIndex);
@@ -146,14 +146,14 @@ nsTreeView.prototype = {
     }
   },
   selectionChanged: function selectionChanged() {},
-  cycleHeader: function cycleHeader(aCol) {},
+  cycleHeader: function cycleHeader() {},
   cycleCell: function cycleCell(aRow, aCol) {
     var data = this.getDataForIndex(aRow);
     data.cyclerState = (data.cyclerState + 1) % 3;
 
     this.mTree.invalidateCell(aRow, aCol);
   },
-  isEditable: function isEditable(aRow, aCol) {
+  isEditable: function isEditable() {
     return true;
   },
   setCellText: function setCellText(aRow, aCol, aValue) {