--- a/accessible/tests/mochitest/.eslintrc.js
+++ b/accessible/tests/mochitest/.eslintrc.js
@@ -8,12 +8,11 @@ module.exports = {
     "mozilla/no-cpows-in-tests": "error",
     "mozilla/reject-importGlobalProperties": "error",
 
     // XXX These are rules that are enabled in the recommended configuration, but
     // disabled here due to failures when initially implemented. They should be
     // removed (and hence enabled) at some stage.
     "no-nested-ternary": "off",
     "no-redeclare": "off",
-    "no-shadow": "off",
     "no-undef": "off",
   }
 };

--- a/accessible/tests/mochitest/attributes.js
+++ b/accessible/tests/mochitest/attributes.js
@@ -194,17 +194,17 @@ function testDefaultTextAttrs(aID, aDefA
  * Test text attributes for wrong offset.
  */
 function testTextAttrsWrongOffset(aID, aOffset) {
   var res = false;
   try {
   var s = {}, e = {};
   var acc = getAccessible(ID, [nsIAccessibleText]);
     acc.getTextAttributes(false, 157, s, e);
-  } catch (e) {
+  } catch (ex) {
     res = true;
   }
 
   ok(res,
      "text attributes are calculated successfully at wrong offset " + aOffset + " for " + prettyName(aID));
 }
 
 const kNormalFontWeight =

--- a/accessible/tests/mochitest/editabletext/editabletext.js
+++ b/accessible/tests/mochitest/editabletext/editabletext.js
@@ -57,74 +57,74 @@ function editableTextTest(aID) {
       dump(`\nsetTextContents '${aValue}'\n`);
       var acc = getAccessible(aID, nsIAccessibleEditableText);
       acc.setTextContents(aValue);
     }
 
     aSkipStartOffset = aSkipStartOffset || 0;
     var insertTripple = aValue ?
       [ aSkipStartOffset, aSkipStartOffset + aValue.length, aValue ] : null;
-    var oldValue = getValue(aID);
+    var oldValue = getValue();
     var removeTripple = oldValue ?
       [ aSkipStartOffset, aSkipStartOffset + oldValue.length, oldValue ] : null;
 
-    this.generateTest(aID, removeTripple, insertTripple, setTextContentsInvoke,
-                      getValueChecker(aID, aValue), testID);
+    this.generateTest(removeTripple, insertTripple, setTextContentsInvoke,
+                      getValueChecker(aValue), testID);
   };
 
   /**
    * insertText test.
    */
   this.insertText = function insertText(aStr, aPos, aResStr, aResPos) {
     var testID = "insertText '" + aStr + "' at " + aPos + " for " +
       prettyName(aID);
 
     function insertTextInvoke() {
       dump(`\ninsertText '${aStr}' at ${aPos} pos\n`);
       var acc = getAccessible(aID, nsIAccessibleEditableText);
       acc.insertText(aStr, aPos);
     }
 
     var resPos = (aResPos != undefined) ? aResPos : aPos;
-    this.generateTest(aID, null, [resPos, resPos + aStr.length, aStr],
-                      insertTextInvoke, getValueChecker(aID, aResStr), testID);
+    this.generateTest(null, [resPos, resPos + aStr.length, aStr],
+                      insertTextInvoke, getValueChecker(aResStr), testID);
   };
 
   /**
    * copyText test.
    */
   this.copyText = function copyText(aStartPos, aEndPos, aClipboardStr) {
     var testID = "copyText from " + aStartPos + " to " + aEndPos + " for " +
       prettyName(aID);
 
     function copyTextInvoke() {
       var acc = getAccessible(aID, nsIAccessibleEditableText);
       acc.copyText(aStartPos, aEndPos);
     }
 
-    this.generateTest(aID, null, null, copyTextInvoke,
-                      getClipboardChecker(aID, aClipboardStr), testID);
+    this.generateTest(null, null, copyTextInvoke,
+                      getClipboardChecker(aClipboardStr), testID);
   };
 
   /**
    * copyText and pasteText test.
    */
   this.copyNPasteText = function copyNPasteText(aStartPos, aEndPos,
                                                 aPos, aResStr) {
     var testID = "copyText from " + aStartPos + " to " + aEndPos +
       "and pasteText at " + aPos + " for " + prettyName(aID);
 
     function copyNPasteTextInvoke() {
       var acc = getAccessible(aID, nsIAccessibleEditableText);
       acc.copyText(aStartPos, aEndPos);
       acc.pasteText(aPos);
     }
 
-    this.generateTest(aID, null, [aStartPos, aEndPos, getTextFromClipboard],
-                      copyNPasteTextInvoke, getValueChecker(aID, aResStr), testID);
+    this.generateTest(null, [aStartPos, aEndPos, getTextFromClipboard],
+                      copyNPasteTextInvoke, getValueChecker(aResStr), testID);
   };
 
   /**
    * cutText test.
    */
   this.cutText = function cutText(aStartPos, aEndPos, aResStr,
                                   aResStartPos, aResEndPos) {
     var testID = "cutText from " + aStartPos + " to " + aEndPos + " for " +
@@ -132,101 +132,101 @@ function editableTextTest(aID) {
 
     function cutTextInvoke() {
       var acc = getAccessible(aID, nsIAccessibleEditableText);
       acc.cutText(aStartPos, aEndPos);
     }
 
     var resStartPos = (aResStartPos != undefined) ? aResStartPos : aStartPos;
     var resEndPos = (aResEndPos != undefined) ? aResEndPos : aEndPos;
-    this.generateTest(aID, [resStartPos, resEndPos, getTextFromClipboard], null,
-                      cutTextInvoke, getValueChecker(aID, aResStr), testID);
+    this.generateTest([resStartPos, resEndPos, getTextFromClipboard], null,
+                      cutTextInvoke, getValueChecker(aResStr), testID);
   };
 
   /**
    * cutText and pasteText test.
    */
   this.cutNPasteText = function copyNPasteText(aStartPos, aEndPos,
                                                aPos, aResStr) {
     var testID = "cutText from " + aStartPos + " to " + aEndPos +
       " and pasteText at " + aPos + " for " + prettyName(aID);
 
     function cutNPasteTextInvoke() {
       var acc = getAccessible(aID, nsIAccessibleEditableText);
       acc.cutText(aStartPos, aEndPos);
       acc.pasteText(aPos);
     }
 
-    this.generateTest(aID, [aStartPos, aEndPos, getTextFromClipboard],
+    this.generateTest([aStartPos, aEndPos, getTextFromClipboard],
                       [aPos, -1, getTextFromClipboard],
-                      cutNPasteTextInvoke, getValueChecker(aID, aResStr),
+                      cutNPasteTextInvoke, getValueChecker(aResStr),
                       testID);
   };
 
   /**
    * pasteText test.
    */
   this.pasteText = function pasteText(aPos, aResStr) {
     var testID = "pasteText at " + aPos + " for " + prettyName(aID);
 
     function pasteTextInvoke() {
       var acc = getAccessible(aID, nsIAccessibleEditableText);
       acc.pasteText(aPos);
     }
 
-    this.generateTest(aID, null, [aPos, -1, getTextFromClipboard],
-                      pasteTextInvoke, getValueChecker(aID, aResStr), testID);
+    this.generateTest(null, [aPos, -1, getTextFromClipboard],
+                      pasteTextInvoke, getValueChecker(aResStr), testID);
   };
 
   /**
    * deleteText test.
    */
   this.deleteText = function deleteText(aStartPos, aEndPos, aResStr) {
     var testID = "deleteText from " + aStartPos + " to " + aEndPos +
       " for " + prettyName(aID);
 
-    var oldValue = getValue(aID).substring(aStartPos, aEndPos);
+    var oldValue = getValue().substring(aStartPos, aEndPos);
     var removeTripple = oldValue ? [aStartPos, aEndPos, oldValue] : null;
 
     function deleteTextInvoke() {
       var acc = getAccessible(aID, [nsIAccessibleEditableText]);
       acc.deleteText(aStartPos, aEndPos);
     }
 
-    this.generateTest(aID, removeTripple, null, deleteTextInvoke,
-                      getValueChecker(aID, aResStr), testID);
+    this.generateTest(removeTripple, null, deleteTextInvoke,
+                      getValueChecker(aResStr), testID);
   };
 
   // ////////////////////////////////////////////////////////////////////////////
   // Implementation details.
 
-  function getValue(aID) {
+  function getValue() {
     var elm = getNode(aID);
     if (elm instanceof Components.interfaces.nsIDOMNSEditableElement)
       return elm.value;
 
     if (elm instanceof Components.interfaces.nsIDOMHTMLDocument)
       return elm.body.textContent;
 
     return elm.textContent;
   }
 
   /**
    * Common checkers.
    */
-  function getValueChecker(aID, aValue) {
+  function getValueChecker(aValue) {
     var checker = {
       check: function valueChecker_check() {
-        is(getValue(aID), aValue, "Wrong value " + aValue);
+        is(getValue(), aValue, "Wrong value " + aValue);
       }
     };
     return checker;
   }
 
-  function getClipboardChecker(aID, aText) {
+  function getClipboardChecker(aText) {
     var checker = {
       check: function clipboardChecker_check() {
         is(getTextFromClipboard(), aText, "Wrong text in clipboard.");
       }
     };
     return checker;
   }
 
@@ -237,17 +237,17 @@ function editableTextTest(aID) {
     var data = this.mEventQueue.mInvokers[this.mEventQueue.mIndex + 1];
     if (data)
       data.func.apply(this, data.funcArgs);
   };
 
   /**
    * Used to generate an invoker object for the sheduled test.
    */
-  this.generateTest = function generateTest(aID, aRemoveTriple, aInsertTriple,
+  this.generateTest = function generateTest(aRemoveTriple, aInsertTriple,
                                             aInvokeFunc, aChecker, aInvokerID) {
     var et = this;
     var invoker = {
       eventSeq: [],
 
       invoke: aInvokeFunc,
       finalCheck: function finalCheck() {
         // dumpTree(aID, `'${aID}' tree:`);

--- a/accessible/tests/mochitest/events/test_aria_objattr.html
+++ b/accessible/tests/mochitest/events/test_aria_objattr.html
@@ -38,17 +38,17 @@
         return aAttr + " for " + aID + " " + aValue;
       };
     }
 
     function updateARIAHidden(aID, aIsDefined, aChildId) {
       this.__proto__ = new updateAttribute(aID, "aria-hidden",
                                            aIsDefined ? "true" : "false");
 
-      this.finalCheck = function updateARIAHidden() {
+      this.finalCheck = function updateARIAHidden_finalCheck() {
         if (aIsDefined) {
           testAttrs(aID, {"hidden": "true"}, true);
           testAttrs(aChildId, {"hidden": "true"}, true);
         } else {
           testAbsentAttrs(aID, { "hidden": "true"});
           testAbsentAttrs(aChildId, { "hidden": "true"});
         }
       };

--- a/accessible/tests/mochitest/treeview.js
+++ b/accessible/tests/mochitest/treeview.js
@@ -1,34 +1,34 @@
 /**
  * Helper method to start a single XUL tree test.
  */
 function loadXULTreeAndDoTest(aDoTestFunc, aTreeID, aTreeView) {
   var doTestFunc = aDoTestFunc ? aDoTestFunc : gXULTreeLoadContext.doTestFunc;
   var treeID = aTreeID ? aTreeID : gXULTreeLoadContext.treeID;
   var treeView = aTreeView ? aTreeView : gXULTreeLoadContext.treeView;
 
-  function loadXULTree(aTreeID, aTreeView) {
-    this.treeNode = getNode(aTreeID);
-
-    this.eventSeq = [
-      new invokerChecker(EVENT_REORDER, this.treeNode)
-    ];
-
-    this.invoke = function loadXULTree_invoke() {
-      this.treeNode.view = aTreeView;
-    };
-
-    this.getID = function loadXULTree_getID() {
-      return "Load XUL tree " + prettyName(aTreeID);
-    };
-  }
+  let treeNode = getNode(treeID);
 
   gXULTreeLoadContext.queue = new eventQueue();
-  gXULTreeLoadContext.queue.push(new loadXULTree(treeID, treeView));
+  gXULTreeLoadContext.queue.push({
+    treeNode,
+
+    eventSeq: [
+        new invokerChecker(EVENT_REORDER, treeNode)
+    ],
+
+    invoke() {
+      this.treeNode.view = treeView;
+    },
+
+    getID() {
+      return "Load XUL tree " + prettyName(treeID);
+    }
+  });
   gXULTreeLoadContext.queue.onFinish = function() {
     SimpleTest.executeSoon(doTestFunc);
     return DO_NOT_FINISH_TEST;
   };
   gXULTreeLoadContext.queue.invoke();
 }
 
 /**