Merging upstream version 125.0.1.

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

22 files changed, 527 insertions, 197 deletions

diff --git a/testing/mochitest/BrowserTestUtils/BrowserTestUtils.sys.mjs b/testing/mochitest/BrowserTestUtils/BrowserTestUtils.sys.mjs
index 741882d9be..1793a6646f 100644
--- a/testing/mochitest/BrowserTestUtils/BrowserTestUtils.sys.mjs
+++ b/testing/mochitest/BrowserTestUtils/BrowserTestUtils.sys.mjs
@@ -704,7 +704,7 @@ export var BrowserTestUtils = {
    * @resolves When STATE_START reaches the tab's progress listener
    */
   browserStarted(browser, expectedURI) {
-    let testFn = function (aStateFlags, aStatus) {
+    let testFn = function (aStateFlags) {
       return (
         aStateFlags & Ci.nsIWebProgressListener.STATE_IS_NETWORK &&
         aStateFlags & Ci.nsIWebProgressListener.STATE_START
@@ -763,7 +763,7 @@ export var BrowserTestUtils = {
     } else {
       urlMatches = urlToMatch => urlToMatch != "about:blank";
     }
-    return new Promise((resolve, reject) => {
+    return new Promise(resolve => {
       tabbrowser.tabContainer.addEventListener(
         "TabOpen",
         function tabOpenListener(openEvent) {
@@ -829,15 +829,9 @@ export var BrowserTestUtils = {
    * @resolves When onLocationChange fires.
    */
   waitForLocationChange(tabbrowser, url) {
-    return new Promise((resolve, reject) => {
+    return new Promise(resolve => {
       let progressListener = {
-        onLocationChange(
-          aBrowser,
-          aWebProgress,
-          aRequest,
-          aLocationURI,
-          aFlags
-        ) {
+        onLocationChange(aBrowser, aWebProgress, aRequest, aLocationURI) {
           if (
             (url && aLocationURI.spec != url) ||
             (!url && aLocationURI.spec == "about:blank")
@@ -885,7 +879,7 @@ export var BrowserTestUtils = {
     }
 
     return new Promise((resolve, reject) => {
-      let observe = async (win, topic, data) => {
+      let observe = async (win, topic) => {
         if (topic != "domwindowopened") {
           return;
         }
@@ -1002,7 +996,7 @@ export var BrowserTestUtils = {
    */
   domWindowOpened(win, checkFn) {
     return new Promise(resolve => {
-      async function observer(subject, topic, data) {
+      async function observer(subject, topic) {
         if (topic == "domwindowopened" && (!win || subject === win)) {
           let observedWindow = subject;
           if (checkFn && !(await checkFn(observedWindow))) {
@@ -1055,7 +1049,7 @@ export var BrowserTestUtils = {
    */
   domWindowClosed(win) {
     return new Promise(resolve => {
-      function observer(subject, topic, data) {
+      function observer(subject, topic) {
         if (topic == "domwindowclosed" && (!win || subject === win)) {
           Services.ww.unregisterNotification(observer);
           resolve(subject);
@@ -1167,7 +1161,7 @@ export var BrowserTestUtils = {
           win.gBrowser._insertBrowser(win.gBrowser.getTabForBrowser(browser));
         });
 
-        let observer = (subject, topic, data) => {
+        let observer = subject => {
           if (browserSet.has(subject)) {
             browserSet.delete(subject);
           }
@@ -1202,7 +1196,7 @@ export var BrowserTestUtils = {
     return new Promise(resolve => {
       let browser = tab.linkedBrowser;
       let flushTopic = "sessionstore-browser-shutdown-flush";
-      let observer = (subject, topic, data) => {
+      let observer = subject => {
         if (subject === browser) {
           Services.obs.removeObserver(observer, flushTopic);
           // Wait for the next event tick to make sure other listeners are
@@ -1615,7 +1609,7 @@ export var BrowserTestUtils = {
     }
   },
 
-  observe(subject, topic, data) {
+  observe(subject, topic) {
     switch (topic) {
       case "test-complete":
         this._cleanupContentEventListeners();
@@ -2054,7 +2048,7 @@ export var BrowserTestUtils = {
     let expectedPromises = [];
 
     let crashCleanupPromise = new Promise((resolve, reject) => {
-      let observer = (subject, topic, data) => {
+      let observer = (subject, topic) => {
         if (topic != "ipc:content-shutdown") {
           reject("Received incorrect observer topic: " + topic);
           return;
@@ -2129,7 +2123,7 @@ export var BrowserTestUtils = {
 
     if (shouldShowTabCrashPage) {
       expectedPromises.push(
-        new Promise((resolve, reject) => {
+        new Promise(resolve => {
           browser.addEventListener(
             "AboutTabCrashedReady",
             function onCrash() {
@@ -2187,7 +2181,7 @@ export var BrowserTestUtils = {
     });
 
     let sawNormalCrash = false;
-    let observer = (subject, topic, data) => {
+    let observer = () => {
       sawNormalCrash = true;
     };
 
@@ -2232,7 +2226,7 @@ export var BrowserTestUtils = {
   waitForAttribute(attr, element, value) {
     let MutationObserver = element.ownerGlobal.MutationObserver;
     return new Promise(resolve => {
-      let mut = new MutationObserver(mutations => {
+      let mut = new MutationObserver(() => {
         if (
           (!value && element.hasAttribute(attr)) ||
           (value && element.getAttribute(attr) === value)
@@ -2263,7 +2257,7 @@ export var BrowserTestUtils = {
     let MutationObserver = element.ownerGlobal.MutationObserver;
     return new Promise(resolve => {
       dump("Waiting for removal\n");
-      let mut = new MutationObserver(mutations => {
+      let mut = new MutationObserver(() => {
         if (!element.hasAttribute(attr)) {
           resolve();
           mut.disconnect();
diff --git a/testing/mochitest/BrowserTestUtils/content/content-about-page-utils.js b/testing/mochitest/BrowserTestUtils/content/content-about-page-utils.js
index e20100db4b..759e283bcb 100644
--- a/testing/mochitest/BrowserTestUtils/content/content-about-page-utils.js
+++ b/testing/mochitest/BrowserTestUtils/content/content-about-page-utils.js
@@ -14,7 +14,7 @@ function AboutPage(aboutHost, chromeURL, uriFlags) {
 
 AboutPage.prototype = {
   QueryInterface: ChromeUtils.generateQI(["nsIAboutModule"]),
-  getURIFlags(aURI) {
+  getURIFlags() {
     // eslint-disable-line no-unused-vars
     return this.uriFlags;
   },
diff --git a/testing/mochitest/api.js b/testing/mochitest/api.js
index bd578f03b8..fa4422f290 100644
--- a/testing/mochitest/api.js
+++ b/testing/mochitest/api.js
@@ -26,7 +26,7 @@ const windowTracker = {
     Services.obs.addObserver(this, "chrome-document-global-created");
   },
 
-  async observe(window, topic, data) {
+  async observe(window, topic) {
     if (topic === "chrome-document-global-created") {
       await new Promise(resolve =>
         window.addEventListener("DOMContentLoaded", resolve, { once: true })
diff --git a/testing/mochitest/baselinecoverage/browser_chrome/browser_baselinecoverage_browser-chrome.js b/testing/mochitest/baselinecoverage/browser_chrome/browser_baselinecoverage_browser-chrome.js
index 4015bd6edf..3095934ffd 100644
--- a/testing/mochitest/baselinecoverage/browser_chrome/browser_baselinecoverage_browser-chrome.js
+++ b/testing/mochitest/baselinecoverage/browser_chrome/browser_baselinecoverage_browser-chrome.js
@@ -13,7 +13,7 @@ add_task(async function () {
       gBrowser,
       url: "about:blank",
     },
-    async function (browser) {
+    async function () {
       ok(true, "Collecting baseline coverage for browser-chrome tests.");
       await new Promise(c => setTimeout(c, 30 * 1000));
     }
diff --git a/testing/mochitest/browser-test.js b/testing/mochitest/browser-test.js
index 98b9055605..1f9798bb36 100644
--- a/testing/mochitest/browser-test.js
+++ b/testing/mochitest/browser-test.js
@@ -45,7 +45,7 @@ var TabDestroyObserver = {
     Services.obs.removeObserver(this, "message-manager-disconnect");
   },
 
-  observe(subject, topic, data) {
+  observe(subject, topic) {
     if (topic == "message-manager-close") {
       this.outstanding.add(subject);
     } else if (topic == "message-manager-disconnect") {
@@ -516,7 +516,7 @@ Tester.prototype = {
     this.SimpleTest.waitForFocus(aCallback);
   },
 
-  finish: function Tester_finish(aSkipSummary) {
+  finish: function Tester_finish() {
     var passCount = this.tests.reduce((a, f) => a + f.passCount, 0);
     var failCount = this.tests.reduce((a, f) => a + f.failCount, 0);
     var todoCount = this.tests.reduce((a, f) => a + f.todoCount, 0);
@@ -564,7 +564,7 @@ Tester.prototype = {
     this.repeat = 0;
   },
 
-  observe: function Tester_observe(aSubject, aTopic, aData) {
+  observe: function Tester_observe(aSubject, aTopic) {
     if (!aTopic) {
       this.onConsoleMessage(aSubject);
     }
diff --git a/testing/mochitest/leaks.py b/testing/mochitest/leaks.py
index 76b6610963..08ed649a0c 100644
--- a/testing/mochitest/leaks.py
+++ b/testing/mochitest/leaks.py
@@ -8,8 +8,8 @@
 import re
 from operator import itemgetter
 
-RE_DOCSHELL = re.compile("I\/DocShellAndDOMWindowLeak ([+\-]{2})DOCSHELL")
-RE_DOMWINDOW = re.compile("I\/DocShellAndDOMWindowLeak ([+\-]{2})DOMWINDOW")
+RE_DOCSHELL = re.compile(r"I\/DocShellAndDOMWindowLeak ([+\-]{2})DOCSHELL")
+RE_DOMWINDOW = re.compile(r"I\/DocShellAndDOMWindowLeak ([+\-]{2})DOMWINDOW")
 
 
 class ShutdownLeaks(object):
@@ -233,7 +233,7 @@ class ShutdownLeaks(object):
                 self.hiddenDocShellsCount += 1
 
     def _parseValue(self, line, name):
-        match = re.search("\[%s = (.+?)\]" % name, line)
+        match = re.search(r"\[%s = (.+?)\]" % name, line)
         if match:
             return match.group(1)
         return None
@@ -329,17 +329,17 @@ class LSANLeaks(object):
         )
 
         self.startRegExp = re.compile(
-            "==\d+==ERROR: LeakSanitizer: detected memory leaks"
+            r"==\d+==ERROR: LeakSanitizer: detected memory leaks"
         )
         self.fatalErrorRegExp = re.compile(
-            "==\d+==LeakSanitizer has encountered a fatal error."
+            r"==\d+==LeakSanitizer has encountered a fatal error."
         )
         self.symbolizerOomRegExp = re.compile(
             "LLVMSymbolizer: error reading file: Cannot allocate memory"
         )
-        self.stackFrameRegExp = re.compile("    #\d+ 0x[0-9a-f]+ in ([^(</]+)")
+        self.stackFrameRegExp = re.compile(r"    #\d+ 0x[0-9a-f]+ in ([^(</]+)")
         self.sysLibStackFrameRegExp = re.compile(
-            "    #\d+ 0x[0-9a-f]+ \(([^+]+)\+0x[0-9a-f]+\)"
+            r"    #\d+ 0x[0-9a-f]+ \(([^+]+)\+0x[0-9a-f]+\)"
         )
 
     def log(self, line, path=""):
diff --git a/testing/mochitest/server.js b/testing/mochitest/server.js
index 740404d94e..934f0b281c 100644
--- a/testing/mochitest/server.js
+++ b/testing/mochitest/server.js
@@ -215,7 +215,7 @@ function createMochitestServer(serverBasePath) {
       });
       return file;
     },
-    QueryInterface(aIID) {
+    QueryInterface() {
       return this;
     },
   };
diff --git a/testing/mochitest/static/browser.template.txt b/testing/mochitest/static/browser.template.txt
index fe4f2080b2..2f889d19d7 100644
--- a/testing/mochitest/static/browser.template.txt
+++ b/testing/mochitest/static/browser.template.txt
@@ -1,5 +1,5 @@
 /* Any copyright is dedicated to the Public Domain.
-   http://creativecommons.org/publicdomain/zero/1.0/ */
+   https://creativecommons.org/publicdomain/zero/1.0/ */
 
 "use strict";
 
diff --git a/testing/mochitest/tests/Harness_sanity/SpecialPowersLoadChromeScript.js b/testing/mochitest/tests/Harness_sanity/SpecialPowersLoadChromeScript.js
index 9591f3bca4..92a84e1ffa 100644
--- a/testing/mochitest/tests/Harness_sanity/SpecialPowersLoadChromeScript.js
+++ b/testing/mochitest/tests/Harness_sanity/SpecialPowersLoadChromeScript.js
@@ -6,7 +6,7 @@ addMessageListener("foo", function (message) {
   sendAsyncMessage("bar", message);
 });
 
-addMessageListener("valid-assert", function (message) {
+addMessageListener("valid-assert", function () {
   assert.ok(true, "valid assertion");
   assert.equal(1, 1, "another valid assertion");
   sendAsyncMessage("valid-assert-done");
diff --git a/testing/mochitest/tests/Harness_sanity/test_SpecialPowersExtension.html b/testing/mochitest/tests/Harness_sanity/test_SpecialPowersExtension.html
index 34b75933a0..3d374735a6 100644
--- a/testing/mochitest/tests/Harness_sanity/test_SpecialPowersExtension.html
+++ b/testing/mochitest/tests/Harness_sanity/test_SpecialPowersExtension.html
@@ -14,11 +14,11 @@
 <script class="testbody" type="text/javascript">
 
 var eventCount = 0;
-function testEventListener(e) {
+function testEventListener() {
   ++eventCount;
 }
 
-function testEventListener2(e) {
+function testEventListener2() {
   ++eventCount;
 }
 
diff --git a/testing/mochitest/tests/Harness_sanity/test_SpecialPowersLoadChromeScript.html b/testing/mochitest/tests/Harness_sanity/test_SpecialPowersLoadChromeScript.html
index 7242bd19f5..3c9bbf3913 100644
--- a/testing/mochitest/tests/Harness_sanity/test_SpecialPowersLoadChromeScript.html
+++ b/testing/mochitest/tests/Harness_sanity/test_SpecialPowersLoadChromeScript.html
@@ -37,7 +37,7 @@ function endOfFirstTest() {
   // that is used to run the chrome script.
   script2 = SpecialPowers.loadChromeScript(_ => {
     /* eslint-env mozilla/chrome-script */
-    addMessageListener("valid-assert", function (message) {
+    addMessageListener("valid-assert", function () {
       assert.equal(typeof XMLHttpRequest, "function", "XMLHttpRequest is defined");
       assert.equal(typeof CSS, "undefined", "CSS is not defined");
       sendAsyncMessage("valid-assert-done");
diff --git a/testing/mochitest/tests/Harness_sanity/test_SpecialPowersLoadChromeScript_function.html b/testing/mochitest/tests/Harness_sanity/test_SpecialPowersLoadChromeScript_function.html
index af31d7b25a..4de074800f 100644
--- a/testing/mochitest/tests/Harness_sanity/test_SpecialPowersLoadChromeScript_function.html
+++ b/testing/mochitest/tests/Harness_sanity/test_SpecialPowersLoadChromeScript_function.html
@@ -22,7 +22,7 @@ var script = SpecialPowers.loadChromeScript(function loadChromeScriptTest() {
     sendAsyncMessage("bar", message);
   });
 
-  addMessageListener("valid-assert", function (message) {
+  addMessageListener("valid-assert", function () {
     assert.ok(true, "valid assertion");
     assert.equal(1, 1, "another valid assertion");
     sendAsyncMessage("valid-assert-done");
diff --git a/testing/mochitest/tests/Harness_sanity/test_createFiles.html b/testing/mochitest/tests/Harness_sanity/test_createFiles.html
index 0e0637a230..7a06a2ad11 100644
--- a/testing/mochitest/tests/Harness_sanity/test_createFiles.html
+++ b/testing/mochitest/tests/Harness_sanity/test_createFiles.html
@@ -23,7 +23,7 @@
           is(f.type, fileType, "File should have the specified type");
           test2();
         },
-        function (msg) { ok(false, "Should be able to create a file without an error"); test2(); }
+        function () { ok(false, "Should be able to create a file without an error"); test2(); }
       );
     }
 
@@ -36,7 +36,7 @@
 
       SpecialPowers.createFiles([{name: "/\/\/\/\/\/\/\/\/\/\/\invalidname",}],
         function () { test3Check(false); },
-        function (msg) { test3Check(true); }
+        function () { test3Check(true); }
       );
     }
 
@@ -75,7 +75,7 @@
           ok(f.name, "test4 test file should have a name");
           SimpleTest.finish();
         },
-        function (msg) {
+        function () {
           ok(false, "Should be able to create a file without a name without an error");
           SimpleTest.finish();
         }
diff --git a/testing/mochitest/tests/Harness_sanity/test_sanityEventUtils.html b/testing/mochitest/tests/Harness_sanity/test_sanityEventUtils.html
index b24251b227..4a9abb2305 100644
--- a/testing/mochitest/tests/Harness_sanity/test_sanityEventUtils.html
+++ b/testing/mochitest/tests/Harness_sanity/test_sanityEventUtils.html
@@ -247,7 +247,7 @@ function starttest() {
 
       /* test synthesizeMouse* */
       //focus trick enables us to run this in iframes
-      $("radioTarget1").addEventListener('focus', function (aEvent) {
+      $("radioTarget1").addEventListener('focus', function () {
         synthesizeMouse($("radioTarget1"), 1, 1, {});
         is($("radioTarget1").checked, true, "synthesizeMouse should work")
         $("radioTarget1").checked = false;
@@ -260,7 +260,7 @@ function starttest() {
       $("radioTarget1").focus();
 
       //focus trick enables us to run this in iframes
-      $("textBoxA").addEventListener("focus", function (aEvent) {
+      $("textBoxA").addEventListener("focus", function () {
         check = false;
         $("textBoxA").addEventListener("click", function() { check = true; }, { once: true });
         synthesizeMouseAtCenter($("textBoxA"), {});
diff --git a/testing/mochitest/tests/SimpleTest/AccessibilityUtils.js b/testing/mochitest/tests/SimpleTest/AccessibilityUtils.js
index 0e95565019..cf4daaf416 100644
--- a/testing/mochitest/tests/SimpleTest/AccessibilityUtils.js
+++ b/testing/mochitest/tests/SimpleTest/AccessibilityUtils.js
@@ -388,19 +388,23 @@ this.AccessibilityUtils = (function () {
     if (accessible.role != Ci.nsIAccessibleRole.ROLE_PAGETAB) {
       return false; // Not a tab.
     }
-    // ToDo: We may eventually need to support intervening generics between
-    // a tab and its tablist here.
-    const tablist = accessible.parent;
+    const tablist = findNonGenericParentAccessible(accessible);
     if (!tablist || tablist.role != Ci.nsIAccessibleRole.ROLE_PAGETABLIST) {
       return false; // The tab isn't inside a tablist.
     }
     // ToDo: We may eventually need to support tablists which use
     // aria-activedescendant here.
     // Check that there is only one keyboard reachable tab.
-    const childCount = tablist.childCount;
     let foundFocusable = false;
-    for (let c = 0; c < childCount; c++) {
-      const tab = tablist.getChildAt(c);
+    for (const tab of findNonGenericChildrenAccessible(tablist)) {
+      // Allow whitespaces to be included in the tablist for styling purposes
+      const isWhitespace =
+        tab.role == Ci.nsIAccessibleRole.ROLE_TEXT_LEAF &&
+        tab.DOMNode.textContent.trim().length === 0;
+      if (tab.role != Ci.nsIAccessibleRole.ROLE_PAGETAB && !isWhitespace) {
+        // The tablist includes children other than tabs or whitespaces
+        a11yFail("Only tabs should be included in a tablist", accessible);
+      }
       // Use tabIndex rather than a11y focusable state because all tabs might
       // have tabindex="-1".
       if (tab.DOMNode.tabIndex == 0) {
@@ -461,6 +465,72 @@ this.AccessibilityUtils = (function () {
   }
 
   /**
+   * The gridcells are not expected to be interactive and focusable
+   * individually, but it is allowed to manually manage focus within the grid
+   * per ARIA Grid pattern (https://www.w3.org/WAI/ARIA/apg/patterns/grid/).
+   * Example of such grid would be a datepicker where one gridcell can be
+   * selected and the focus is moved with arrow keys once the user tabbed into
+   * the grid. In grids like a calendar, only one element would be included in
+   * the focus order and the rest of grid cells may not have an interactive
+   * accessible created. We need to special case the check for these gridcells.
+   */
+  function isAccessibleGridcell(node) {
+    if (!node || !node.ownerGlobal) {
+      return false;
+    }
+    const accessible = getAccessible(node);
+
+    if (!accessible || accessible.role != Ci.nsIAccessibleRole.ROLE_GRID_CELL) {
+      return false; // Not a grid cell.
+    }
+    // ToDo: We may eventually need to support intervening generics between
+    // a grid cell and its grid container here.
+    const gridRow = accessible.parent;
+    if (!gridRow || gridRow.role != Ci.nsIAccessibleRole.ROLE_ROW) {
+      return false; // The grid cell isn't inside a row.
+    }
+    let grid = gridRow.parent;
+    if (!grid) {
+      return false; // The grid cell isn't inside a grid.
+    }
+    if (grid.role == Ci.nsIAccessibleRole.ROLE_GROUPING) {
+      // Grid built on the HTML table may include <tbody> wrapper:
+      grid = grid.parent;
+      if (!grid || grid.role != Ci.nsIAccessibleRole.ROLE_GRID) {
+        return false; // The grid cell isn't inside a grid.
+      }
+    }
+    // Check that there is only one keyboard reachable grid cell.
+    let foundFocusable = false;
+    for (const gridCell of grid.DOMNode.querySelectorAll(
+      "td, [role=gridcell]"
+    )) {
+      // Grid cells are not expected to have a "tabindex" attribute and to be
+      // included in the focus order, with the exception of the only one cell
+      // that is included in the page tab sequence to provide access to the grid.
+      if (gridCell.tabIndex == 0) {
+        if (foundFocusable) {
+          // Only one grid cell within a grid should be focusable.
+          // ToDo: Fine-tune the a11y-check error message generated in this case.
+          // Strictly speaking, it's not ideal that we're performing an action
+          // from an is function, which normally only queries something without
+          // any externally observable behaviour. That said, fixing that would
+          // involve different return values for different cases (not a grid
+          // cell, too many focusable grid cells, etc) so we could move the
+          // a11yFail call to the caller.
+          a11yFail(
+            "Only one grid cell should be focusable in a grid",
+            accessible
+          );
+          return false;
+        }
+        foundFocusable = true;
+      }
+    }
+    return foundFocusable;
+  }
+
+  /**
    * XUL treecol elements currently aren't focusable, making them inaccessible.
    * For now, we don't flag these as a failure to avoid breaking multiple tests.
    * ToDo: We should remove this exception after this is fixed in bug 1848397.
@@ -477,7 +547,7 @@ this.AccessibilityUtils = (function () {
   }
 
   /**
-   * Determine if an accessible is a combobox container of the url bar. We
+   * Determine if a DOM node is a combobox container of the url bar. We
    * intentionally leave this element unlabeled, because its child is a search
    * input that is the target and main control of this component. In general, we
    * want to avoid duplication in the label announcement when a user focuses the
@@ -486,68 +556,125 @@ this.AccessibilityUtils = (function () {
    * difficult to keep the accessible name synchronized between the combobox and
    * the input. Thus, we need to special case the label check for this control.
    */
-  function isUnlabeledUrlBarCombobox(accessible) {
-    const node = accessible.DOMNode;
+  function isUnlabeledUrlBarCombobox(node) {
     if (!node || !node.ownerGlobal) {
       return false;
     }
-    const ariaRoles = getAriaRoles(accessible);
+    let ariaRole = node.getAttribute("role");
     // There are only two cases of this pattern: <moz-input-box> and <searchbar>
     const isMozInputBox =
       node.tagName == "moz-input-box" &&
       node.classList.contains("urlbar-input-box");
     const isSearchbar = node.tagName == "searchbar" && node.id == "searchbar";
-    return (isMozInputBox || isSearchbar) && ariaRoles.includes("combobox");
+    return (isMozInputBox || isSearchbar) && ariaRole == "combobox";
   }
 
   /**
-   * Determine if an accessible is an option within the url bar. We know each
+   * Determine if a DOM node is an option within the url bar. We know each
    * url bar option is accessible, but it disappears as soon as it is clicked
    * during tests and the a11y-checks do not have time to test the label,
    * because the Fluent localization is not yet completed by then. Thus, we
    * need to special case the label check for these controls.
    */
-  function isUnlabeledUrlBarOption(accessible) {
-    const node = accessible.DOMNode;
+  function isUnlabeledUrlBarOption(node) {
     if (!node || !node.ownerGlobal) {
       return false;
     }
-    const ariaRoles = getAriaRoles(accessible);
-    return (
+    const role = getAccessible(node)?.role;
+    const isOption =
       node.tagName == "span" &&
-      ariaRoles.includes("option") &&
-      node.classList.contains("urlbarView-row-inner") &&
-      node.hasAttribute("data-l10n-id")
-    );
+      node.getAttribute("role") == "option" &&
+      node.classList.contains("urlbarView-row-inner");
+    const isMenuItem =
+      node.tagName == "menuitem" &&
+      role == Ci.nsIAccessibleRole.ROLE_MENUITEM &&
+      node.classList.contains("urlbarView-result-menuitem");
+    // Not all options have "data-l10n-id" attributes in the URL Bar, because
+    // some of options are autocomplete options based on the user input and
+    // they are not expected to be localized.
+    return isOption || isMenuItem;
   }
 
   /**
-   * Determine if an accessible is a menuitem within the XUL menu. We know each
+   * Determine if a DOM node is a menuitem within the XUL menu. We know each
    * menuitem is accessible, but it disappears as soon as it is clicked during
    * tests and the a11y-checks do not have time to test the label, because the
    * Fluent localization is not yet completed by then. Thus, we need to special
    * case the label check for these controls.
    */
-  function isUnlabeledMenuitem(accessible) {
-    const node = accessible.DOMNode;
+  function isUnlabeledMenuitem(node) {
     if (!node || !node.ownerGlobal) {
       return false;
     }
-    let hasLabel = false;
-    for (const child of node.childNodes) {
-      if (child.tagName == "label") {
-        hasLabel = true;
-      }
-    }
+    const hasLabel = node.querySelector("label, description");
+    const isMenuItem =
+      node.getAttribute("role") == "menuitem" ||
+      (node.tagName == "richlistitem" &&
+        node.classList.contains("autocomplete-richlistitem")) ||
+      (node.tagName == "menuitem" &&
+        node.classList.contains("urlbarView-result-menuitem"));
+
+    const isParentMenu =
+      node.parentNode.getAttribute("role") == "menu" ||
+      (node.parentNode.tagName == "richlistbox" &&
+        node.parentNode.classList.contains("autocomplete-richlistbox")) ||
+      (node.parentNode.tagName == "menupopup" &&
+        node.parentNode.classList.contains("urlbarView-result-menu"));
     return (
-      accessible.role == Ci.nsIAccessibleRole.ROLE_MENUITEM &&
-      accessible.parent.role == Ci.nsIAccessibleRole.ROLE_MENUPOPUP &&
+      isMenuItem &&
+      isParentMenu &&
       hasLabel &&
-      node.hasAttribute("data-l10n-id")
+      (node.hasAttribute("data-l10n-id") || node.tagName == "richlistitem")
+    );
+  }
+
+  /**
+   * Determine if the node is a "Show All" or one of image buttons on the
+   * about:config page, or a "X" close button on moz-message-bar. We know these
+   * buttons are accessible, but they disappear/are replaced as soon as they
+   * are clicked during tests and the a11y-checks do not have time to test the
+   * label, because the Fluent localization is not yet completed by then.
+   * Thus, we need to special case the label check for these controls.
+   */
+  function isUnlabeledImageButton(node) {
+    if (!node || !node.ownerGlobal) {
+      return false;
+    }
+    const isShowAllButton = node.id == "show-all";
+    const isReplacedImageButton =
+      node.classList.contains("button-add") ||
+      node.classList.contains("button-delete") ||
+      node.classList.contains("button-reset");
+    const isCloseMozMessageBarButton =
+      node.classList.contains("close") &&
+      node.getAttribute("data-l10n-id") == "moz-message-bar-close-button";
+    return (
+      node.tagName.toLowerCase() == "button" &&
+      node.hasAttribute("data-l10n-id") &&
+      (isShowAllButton || isReplacedImageButton || isCloseMozMessageBarButton)
     );
   }
 
   /**
+   * Determine if a node is a XUL:button on a prompt popup. We know this button
+   * is accessible, but it disappears as soon as it is clicked during tests and
+   * the a11y-checks do not have time to test the label, because the Fluent
+   * localization is not yet completed by then. Thus, we need to special case
+   * the label check for these controls.
+   */
+  function isUnlabeledXulButton(node) {
+    if (!node || !node.ownerGlobal) {
+      return false;
+    }
+    const hasLabel = node.querySelector("label, xul\\:label");
+    const isButton =
+      node.getAttribute("role") == "button" ||
+      node.tagName == "button" ||
+      node.tagName == "xul:button";
+    return isButton && hasLabel && node.hasAttribute("data-l10n-id");
+  }
+
+  /**
    * Determine if a node is a XUL element for which tabIndex should be ignored.
    * Some XUL elements report -1 for the .tabIndex property, even though they
    * are in fact keyboard focusable.
@@ -758,13 +885,6 @@ this.AccessibilityUtils = (function () {
     const { DOMNode } = accessible;
     let name = accessible.name;
     if (!name) {
-      if (
-        isUnlabeledUrlBarCombobox(accessible) ||
-        isUnlabeledUrlBarOption(accessible) ||
-        isUnlabeledMenuitem(accessible)
-      ) {
-        return;
-      }
       // If text has just been inserted into the tree, the a11y engine might not
       // have picked it up yet.
       forceRefreshDriverTick(DOMNode);
@@ -773,6 +893,21 @@ this.AccessibilityUtils = (function () {
       } catch (e) {
         // The Accessible died because the DOM node was removed or hidden.
         if (gEnv.labelRule) {
+          // Some elements disappear as soon as they are clicked during tests,
+          // their accessible dies before the Fluent localization is completed.
+          // We want to exclude these groups of nodes from the label check.
+          // Note: In other cases, this first block isn't necessarily hit
+          // because Fluent isn't finished yet. This might happen if a text
+          // node was inserted (whether by Fluent or something else) but a11y
+          // hasn't picked it up yet, but the node gets hidden before a11y
+          // can pick it up.
+          if (
+            isUnlabeledUrlBarOption(DOMNode) ||
+            isUnlabeledMenuitem(DOMNode) ||
+            isUnlabeledImageButton(DOMNode)
+          ) {
+            return;
+          }
           a11yWarn("Unlabeled element removed before l10n finished", {
             DOMNode,
           });
@@ -795,6 +930,13 @@ this.AccessibilityUtils = (function () {
               accessible.name;
             } catch (e) {
               // The Accessible died because the DOM node was removed or hidden.
+              if (
+                isUnlabeledUrlBarOption(DOMNode) ||
+                isUnlabeledImageButton(DOMNode) ||
+                isUnlabeledXulButton(DOMNode)
+              ) {
+                return;
+              }
               a11yWarn("Unlabeled element removed before l10n finished", {
                 DOMNode,
               });
@@ -811,6 +953,15 @@ this.AccessibilityUtils = (function () {
       name = name.trim();
     }
     if (gEnv.labelRule && !name) {
+      // The URL and Search Bar comboboxes are purposefully unlabeled,
+      // since they include labeled inputs that are receiving focus.
+      // Or the Accessible died because the DOM node was removed or hidden.
+      if (
+        isUnlabeledUrlBarCombobox(DOMNode) ||
+        isUnlabeledUrlBarOption(DOMNode)
+      ) {
+        return;
+      }
       a11yFail("Interactive elements must be labeled", accessible);
 
       return;
@@ -935,6 +1086,36 @@ this.AccessibilityUtils = (function () {
     return null;
   }
 
+  /**
+   * Find the nearest non-generic ancestor for a node to account for generic
+   * containers to intervene between the ancestor and it child.
+   */
+  function findNonGenericParentAccessible(childAcc) {
+    for (let acc = childAcc.parent; acc; acc = acc.parent) {
+      if (acc.computedARIARole != "generic") {
+        return acc;
+      }
+    }
+    return null;
+  }
+
+  /**
+   * Find the nearest non-generic children for a node to account for generic
+   * containers to intervene between the ancestor and its children.
+   */
+  function* findNonGenericChildrenAccessible(parentAcc) {
+    const count = parentAcc.childCount;
+    for (let c = 0; c < count; ++c) {
+      const child = parentAcc.getChildAt(c);
+      // When Gecko will consider only one role as generic, we'd use child.role
+      if (child.computedARIARole == "generic") {
+        yield* findNonGenericChildrenAccessible(child);
+      } else {
+        yield child;
+      }
+    }
+  }
+
   function runIfA11YChecks(task) {
     return (...args) => (gA11YChecks ? task(...args) : null);
   }
@@ -956,7 +1137,7 @@ this.AccessibilityUtils = (function () {
       // node might be the image.
       const acc = findInteractiveAccessible(node);
       if (!acc) {
-        if (isInaccessibleXulTreecol(node)) {
+        if (isAccessibleGridcell(node) || isInaccessibleXulTreecol(node)) {
           return;
         }
         if (gEnv.mustHaveAccessibleRule) {
diff --git a/testing/mochitest/tests/SimpleTest/EventUtils.js b/testing/mochitest/tests/SimpleTest/EventUtils.js
index 739c7052ea..8833b8bc59 100644
--- a/testing/mochitest/tests/SimpleTest/EventUtils.js
+++ b/testing/mochitest/tests/SimpleTest/EventUtils.js
@@ -1,3 +1,4 @@
+/* eslint-disable no-nested-ternary */
 /**
  * EventUtils provides some utility methods for creating and sending DOM events.
  *
@@ -569,14 +570,86 @@ function synthesizeMouse(aTarget, aOffsetX, aOffsetY, aEvent, aWindow) {
     aWindow
   );
 }
-function synthesizeTouch(aTarget, aOffsetX, aOffsetY, aEvent, aWindow) {
-  var rect = aTarget.getBoundingClientRect();
-  return synthesizeTouchAtPoint(
-    rect.left + aOffsetX,
-    rect.top + aOffsetY,
-    aEvent,
-    aWindow
-  );
+
+/**
+ * Synthesize one or more touches on aTarget. aTarget can be either Element
+ * or Array of Elements.  aOffsetX, aOffsetY, aEvent.id, aEvent.rx, aEvent.ry,
+ * aEvent.angle, aEvent.force, aEvent.tiltX, aEvent.tiltY and aEvent.twist can
+ * be either Number or Array of Numbers (can be mixed).  If you specify array
+ * to synthesize a multi-touch, you need to specify same length arrays.  If
+ * you don't specify array to them, same values (or computed default values for
+ * aEvent.id) are used for all touches.
+ *
+ * @param {Element | Element[]} aTarget The target element which you specify
+ * relative offset from its top-left.
+ * @param {Number | Number[]} aOffsetX The relative offset from left of aTarget.
+ * @param {Number | Number[]} aOffsetY The relative offset from top of aTarget.
+ * @param {Object} aEvent
+ * type: The touch event type.  If undefined, "touchstart" and "touchend" will
+ * be synthesized at same point.
+ *
+ * id: The touch id.  If you don't specify this, default touch id will be used
+ * for first touch and further touch ids are the values incremented from the
+ * first id.
+ *
+ * rx, ry: The radii of the touch.
+ *
+ * angle: The angle in degree.
+ *
+ * force: The force of the touch.  If the type is "touchend", this should be 0.
+ * If unspecified, this is default to 0 for "touchend"  or 1 for the others.
+ *
+ * tiltX, tiltY: The tilt of the touch.
+ *
+ * twist: The twist of the touch.
+ * @param {Window} aWindow Default to `window`.
+ * @returns true if and only if aEvent.type is specified and default of the
+ * event is prevented.
+ */
+function synthesizeTouch(
+  aTarget,
+  aOffsetX,
+  aOffsetY,
+  aEvent = {},
+  aWindow = window
+) {
+  let rectX, rectY;
+  if (Array.isArray(aTarget)) {
+    let lastTarget, lastTargetRect;
+    aTarget.forEach(target => {
+      const rect =
+        target == lastTarget ? lastTargetRect : target.getBoundingClientRect();
+      rectX.push(rect.left);
+      rectY.push(rect.top);
+      lastTarget = target;
+      lastTargetRect = rect;
+    });
+  } else {
+    const rect = aTarget.getBoundingClientRect();
+    rectX = [rect.left];
+    rectY = [rect.top];
+  }
+  const offsetX = (() => {
+    if (Array.isArray(aOffsetX)) {
+      let ret = [];
+      aOffsetX.forEach((value, index) => {
+        ret.push(value + rectX[Math.min(index, rectX.length - 1)]);
+      });
+      return ret;
+    }
+    return aOffsetX + rectX[0];
+  })();
+  const offsetY = (() => {
+    if (Array.isArray(aOffsetY)) {
+      let ret = [];
+      aOffsetY.forEach((value, index) => {
+        ret.push(value + rectY[Math.min(index, rectY.length - 1)]);
+      });
+      return ret;
+    }
+    return aOffsetY + rectY[0];
+  })();
+  return synthesizeTouchAtPoint(offsetX, offsetY, aEvent, aWindow);
 }
 
 /**
@@ -776,68 +849,160 @@ function synthesizeMouseAtPoint(left, top, aEvent, aWindow = window) {
   return defaultPrevented;
 }
 
-function synthesizeTouchAtPoint(left, top, aEvent, aWindow = window) {
-  var utils = _getDOMWindowUtils(aWindow);
-  let defaultPrevented = false;
+/**
+ * Synthesize one or more touches at the points. aLeft, aTop, aEvent.id,
+ * aEvent.rx, aEvent.ry, aEvent.angle, aEvent.force, aEvent.tiltX, aEvent.tiltY
+ * and aEvent.twist can be either Number or Array of Numbers (can be mixed).
+ * If you specify array to synthesize a multi-touch, you need to specify same
+ * length arrays.  If you don't specify array to them, same values are used for
+ * all touches.
+ *
+ * @param {Element | Element[]} aTarget The target element which you specify
+ * relative offset from its top-left.
+ * @param {Number | Number[]} aOffsetX The relative offset from left of aTarget.
+ * @param {Number | Number[]} aOffsetY The relative offset from top of aTarget.
+ * @param {Object} aEvent
+ * type: The touch event type.  If undefined, "touchstart" and "touchend" will
+ * be synthesized at same point.
+ *
+ * id: The touch id.  If you don't specify this, default touch id will be used
+ * for first touch and further touch ids are the values incremented from the
+ * first id.
+ *
+ * rx, ry: The radii of the touch.
+ *
+ * angle: The angle in degree.
+ *
+ * force: The force of the touch.  If the type is "touchend", this should be 0.
+ * If unspecified, this is default to 0 for "touchend"  or 1 for the others.
+ *
+ * tiltX, tiltY: The tilt of the touch.
+ *
+ * twist: The twist of the touch.
+ * @param {Window} aWindow Default to `window`.
+ * @returns true if and only if aEvent.type is specified and default of the
+ * event is prevented.
+ */
+function synthesizeTouchAtPoint(aLeft, aTop, aEvent = {}, aWindow = window) {
+  let utils = _getDOMWindowUtils(aWindow);
+  if (!utils) {
+    return false;
+  }
 
-  if (utils) {
-    var id = aEvent.id || utils.DEFAULT_TOUCH_POINTER_ID;
-    var rx = aEvent.rx || 1;
-    var ry = aEvent.ry || 1;
-    var angle = aEvent.angle || 0;
-    var force = aEvent.force || (aEvent.type === "touchend" ? 0 : 1);
-    var tiltX = aEvent.tiltX || 0;
-    var tiltY = aEvent.tiltY || 0;
-    var twist = aEvent.twist || 0;
-    var modifiers = _parseModifiers(aEvent, aWindow);
+  if (
+    Array.isArray(aLeft) &&
+    Array.isArray(aTop) &&
+    aLeft.length != aTop.length
+  ) {
+    throw new Error(`aLeft and aTop should be same length array`);
+  }
 
-    if ("type" in aEvent && aEvent.type) {
-      defaultPrevented = utils.sendTouchEvent(
-        aEvent.type,
-        [id],
-        [left],
-        [top],
-        [rx],
-        [ry],
-        [angle],
-        [force],
-        [tiltX],
-        [tiltY],
-        [twist],
-        modifiers
-      );
-    } else {
-      utils.sendTouchEvent(
-        "touchstart",
-        [id],
-        [left],
-        [top],
-        [rx],
-        [ry],
-        [angle],
-        [force],
-        [tiltX],
-        [tiltY],
-        [twist],
-        modifiers
-      );
-      utils.sendTouchEvent(
-        "touchend",
-        [id],
-        [left],
-        [top],
-        [rx],
-        [ry],
-        [angle],
-        [force],
-        [tiltX],
-        [tiltY],
-        [twist],
-        modifiers
+  const arrayLength = Array.isArray(aLeft)
+    ? aLeft.length
+    : Array.isArray(aTop)
+    ? aTop.length
+    : 1;
+
+  function throwExceptionIfDifferentLengthArray(aArray, aName) {
+    if (Array.isArray(aArray) && arrayLength !== aArray.length) {
+      throw new Error(`${aName} is different length array`);
+    }
+  }
+  const leftArray = (() => {
+    if (Array.isArray(aLeft)) {
+      return aLeft;
+    }
+    return new Array(arrayLength).fill(aLeft);
+  })();
+  const topArray = (() => {
+    if (Array.isArray(aTop)) {
+      throwExceptionIfDifferentLengthArray(aTop, "aTop");
+      return aTop;
+    }
+    return new Array(arrayLength).fill(aTop);
+  })();
+  const idArray = (() => {
+    if ("id" in aEvent && Array.isArray(aEvent.id)) {
+      throwExceptionIfDifferentLengthArray(aEvent.id, "aEvent.id");
+      return aEvent.id;
+    }
+    let id = aEvent.id || utils.DEFAULT_TOUCH_POINTER_ID;
+    let ret = [];
+    for (let i = 0; i < arrayLength; i++) {
+      ret.push(id++);
+    }
+    return ret;
+  })();
+  function getSameLengthArrayOfEventProperty(aProperty, aDefaultValue) {
+    if (aProperty in aEvent && Array.isArray(aEvent[aProperty])) {
+      throwExceptionIfDifferentLengthArray(
+        aEvent.rx,
+        arrayLength,
+        `aEvent.${aProperty}`
       );
+      return aEvent[aProperty];
     }
+    return new Array(arrayLength).fill(aEvent[aProperty] || aDefaultValue);
   }
-  return defaultPrevented;
+  const rxArray = getSameLengthArrayOfEventProperty("rx", 1);
+  const ryArray = getSameLengthArrayOfEventProperty("ry", 1);
+  const angleArray = getSameLengthArrayOfEventProperty("angle", 0);
+  const forceArray = getSameLengthArrayOfEventProperty(
+    "force",
+    aEvent.type === "touchend" ? 0 : 1
+  );
+  const tiltXArray = getSameLengthArrayOfEventProperty("tiltX", 0);
+  const tiltYArray = getSameLengthArrayOfEventProperty("tiltY", 0);
+  const twistArray = getSameLengthArrayOfEventProperty("twist", 0);
+
+  const modifiers = _parseModifiers(aEvent, aWindow);
+
+  if ("type" in aEvent && aEvent.type) {
+    return utils.sendTouchEvent(
+      aEvent.type,
+      idArray,
+      leftArray,
+      topArray,
+      rxArray,
+      ryArray,
+      angleArray,
+      forceArray,
+      tiltXArray,
+      tiltYArray,
+      twistArray,
+      modifiers
+    );
+  }
+
+  utils.sendTouchEvent(
+    "touchstart",
+    idArray,
+    leftArray,
+    topArray,
+    rxArray,
+    ryArray,
+    angleArray,
+    forceArray,
+    tiltXArray,
+    tiltYArray,
+    twistArray,
+    modifiers
+  );
+  utils.sendTouchEvent(
+    "touchend",
+    idArray,
+    leftArray,
+    topArray,
+    rxArray,
+    ryArray,
+    angleArray,
+    forceArray,
+    tiltXArray,
+    tiltYArray,
+    twistArray,
+    modifiers
+  );
+  return false;
 }
 
 // Call synthesizeMouse with coordinates at the center of aTarget.
@@ -851,7 +1016,7 @@ function synthesizeMouseAtCenter(aTarget, aEvent, aWindow) {
     aWindow
   );
 }
-function synthesizeTouchAtCenter(aTarget, aEvent, aWindow) {
+function synthesizeTouchAtCenter(aTarget, aEvent = {}, aWindow = window) {
   var rect = aTarget.getBoundingClientRect();
   synthesizeTouchAtPoint(
     rect.left + rect.width / 2,
@@ -1020,7 +1185,9 @@ function _sendWheelAndPaint(
   }
 
   var onwheel = function () {
-    SpecialPowers.removeSystemEventListener(window, "wheel", onwheel);
+    SpecialPowers.wrap(window).removeEventListener("wheel", onwheel, {
+      mozSystemGroup: true,
+    });
 
     // Wait one frame since the wheel event has not caused a refresh observer
     // to be added yet.
@@ -1055,7 +1222,9 @@ function _sendWheelAndPaint(
 
   // Listen for the system wheel event, because it happens after all of
   // the other wheel events, including legacy events.
-  SpecialPowers.addSystemEventListener(aWindow, "wheel", onwheel);
+  SpecialPowers.wrap(aWindow).addEventListener("wheel", onwheel, {
+    mozSystemGroup: true,
+  });
   if (aFlushMode === _FlushModes.FLUSH) {
     synthesizeWheel(aTarget, aOffsetX, aOffsetY, aEvent, aWindow);
   } else {
@@ -1405,13 +1574,10 @@ function synthesizeAndWaitNativeMouseMove(
   );
 
   let eventRegisteredPromise = new Promise(resolve => {
-    mm.addMessageListener(
-      "Test:MouseMoveRegistered",
-      function processed(message) {
-        mm.removeMessageListener("Test:MouseMoveRegistered", processed);
-        resolve();
-      }
-    );
+    mm.addMessageListener("Test:MouseMoveRegistered", function processed() {
+      mm.removeMessageListener("Test:MouseMoveRegistered", processed);
+      resolve();
+    });
   });
   let eventReceivedPromise = ContentTask.spawn(
     browser,
@@ -1579,7 +1745,7 @@ function synthesizeAndWaitKey(
   );
 
   let keyRegisteredPromise = new Promise(resolve => {
-    mm.addMessageListener("Test:KeyRegistered", function processed(message) {
+    mm.addMessageListener("Test:KeyRegistered", function processed() {
       mm.removeMessageListener("Test:KeyRegistered", processed);
       resolve();
     });
@@ -3853,21 +4019,19 @@ async function synthesizePlainDragAndCancel(
       aExpectedDataTransferItems
     );
   }
-  SpecialPowers.addSystemEventListener(
-    srcElement.ownerDocument,
+  SpecialPowers.wrap(srcElement.ownerDocument).addEventListener(
     "dragstart",
     onDragStart,
-    { capture: true }
+    { capture: true, mozSystemGroup: true }
   );
   try {
     aParams.expectCancelDragStart = true;
     await synthesizePlainDragAndDrop(aParams);
   } finally {
-    SpecialPowers.removeSystemEventListener(
-      srcElement.ownerDocument,
+    SpecialPowers.wrap(srcElement.ownerDocument).removeEventListener(
       "dragstart",
       onDragStart,
-      { capture: true }
+      { capture: true, mozSystemGroup: true }
     );
   }
   return result;
@@ -3884,33 +4048,23 @@ class EventCounter {
     // SpecialPowers is picky and needs to be passed an explicit reference to
     // the function to be called. To avoid having to bind "this", we therefore
     // define the method this way, via a property.
-    this.handleEvent = aEvent => {
+    this.handleEvent = () => {
       this.eventCount++;
     };
 
-    if (aOptions.mozSystemGroup) {
-      SpecialPowers.addSystemEventListener(
-        aTarget,
-        aType,
-        this.handleEvent,
-        aOptions.capture
-      );
-    } else {
-      aTarget.addEventListener(aType, this, aOptions);
-    }
+    SpecialPowers.wrap(aTarget).addEventListener(
+      aType,
+      this.handleEvent,
+      aOptions
+    );
   }
 
   unregister() {
-    if (this.options.mozSystemGroup) {
-      SpecialPowers.removeSystemEventListener(
-        this.target,
-        this.type,
-        this.handleEvent,
-        this.options.capture
-      );
-    } else {
-      this.target.removeEventListener(this.type, this, this.options);
-    }
+    SpecialPowers.wrap(this.target).removeEventListener(
+      this.type,
+      this.handleEvent,
+      this.options
+    );
   }
 
   get count() {
diff --git a/testing/mochitest/tests/SimpleTest/LogController.js b/testing/mochitest/tests/SimpleTest/LogController.js
index 29580022f8..d0888d6032 100644
--- a/testing/mochitest/tests/SimpleTest/LogController.js
+++ b/testing/mochitest/tests/SimpleTest/LogController.js
@@ -48,7 +48,7 @@ LogController.extend = function (args, skip) {
 };
 
 /* logs message with given level. Currently used locally by log() and error() */
-LogController.logWithLevel = function (level, message /*, ...*/) {
+LogController.logWithLevel = function (level /*, ...*/) {
   var msg = LogController.createLogMessage(
     level,
     LogController.extend(arguments, 1)
diff --git a/testing/mochitest/tests/SimpleTest/SimpleTest.js b/testing/mochitest/tests/SimpleTest/SimpleTest.js
index a237c25103..16f5c3ae8a 100644
--- a/testing/mochitest/tests/SimpleTest/SimpleTest.js
+++ b/testing/mochitest/tests/SimpleTest/SimpleTest.js
@@ -384,7 +384,7 @@ function usesFailurePatterns() {
  * @return {boolean} Whether a matched failure pattern is found.
  */
 function recordIfMatchesFailurePattern(name, diag) {
-  let index = SimpleTest.expected.findIndex(([pat, count]) => {
+  let index = SimpleTest.expected.findIndex(([pat]) => {
     return (
       pat == null ||
       (typeof name == "string" && name.includes(pat)) ||
diff --git a/testing/mochitest/tests/SimpleTest/TestRunner.js b/testing/mochitest/tests/SimpleTest/TestRunner.js
index 5f305a176b..2e48969d8d 100644
--- a/testing/mochitest/tests/SimpleTest/TestRunner.js
+++ b/testing/mochitest/tests/SimpleTest/TestRunner.js
@@ -63,7 +63,7 @@ function extend(obj, /* optional */ skip) {
   return ret;
 }
 
-function flattenArguments(lst /* ...*/) {
+function flattenArguments(/* ...*/) {
   var res = [];
   var args = extend(arguments);
   while (args.length) {
diff --git a/testing/mochitest/tests/SimpleTest/paint_listener.js b/testing/mochitest/tests/SimpleTest/paint_listener.js
index 2fc6ab425a..89740454f2 100644
--- a/testing/mochitest/tests/SimpleTest/paint_listener.js
+++ b/testing/mochitest/tests/SimpleTest/paint_listener.js
@@ -100,7 +100,7 @@
 
   window.promiseAllPaintsDone = function (subdoc = null, flush = false) {
     var flushmode = flush ? FlushModes.FLUSH : FlushModes.NOFLUSH;
-    return new Promise(function (resolve, reject) {
+    return new Promise(function (resolve) {
       // The callback is given the components of the rect, but resolve() can
       // only be given one arg, so we turn it back into an array.
       waitForPaints((l, r, t, b) => resolve([l, r, t, b]), subdoc, flushmode);
diff --git a/testing/mochitest/tests/SimpleTest/setup.js b/testing/mochitest/tests/SimpleTest/setup.js
index 05ba8066a1..2a8509bc0a 100644
--- a/testing/mochitest/tests/SimpleTest/setup.js
+++ b/testing/mochitest/tests/SimpleTest/setup.js
@@ -247,7 +247,7 @@ TestRunner.logger.addListener(
 var gTestList = [];
 var RunSet = {};
 
-RunSet.runall = function (e) {
+RunSet.runall = function () {
   // Filter tests to include|exclude tests based on data in params.filter.
   // This allows for including or excluding tests from the gTestList
   // TODO Only used by ipc tests, remove once those are implemented sanely
@@ -265,7 +265,7 @@ RunSet.runall = function (e) {
   }
 };
 
-RunSet.runtests = function (e) {
+RunSet.runtests = function () {
   // Which tests we're going to run
   var my_tests = gTestList;
 
diff --git a/testing/mochitest/tests/browser/browser_document_builder_sjs.js b/testing/mochitest/tests/browser/browser_document_builder_sjs.js
index 4b653a792d..fdf1691b7f 100644
--- a/testing/mochitest/tests/browser/browser_document_builder_sjs.js
+++ b/testing/mochitest/tests/browser/browser_document_builder_sjs.js
@@ -23,8 +23,9 @@ add_task(async function assertHtmlParam() {
   const duration = performance.now() - startTime;
 
   is(response.status, 200, "Response is a 200");
-  ok(
-    duration > delay,
+  Assert.greater(
+    duration,
+    delay,
     `The delay parameter works as expected (took ${duration}ms)`
   );