Noissue - Throw an error if the client code doesn't load

test/browser/elemHideEmulation.js

 /*
  * This file is part of Adblock Plus <https://adblockplus.org/>,
  * Copyright (C) 2006-2017 eyeo GmbH
  *
  * Adblock Plus is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 3 as
  * published by the Free Software Foundation.
  *
  * Adblock Plus is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ skipping 76 matching lines @@
   insertStyleRule("#" + element.id + " " + styleBlock);
   return element;
 }
 
 function createPseudoElementWithStyle(element, pseudo, styleBlock)
 {
   insertStyleRule(`#${element.id}${pseudo} ${styleBlock}`);
 }
 
 // Will ensure the class ElemHideEmulation is loaded.
-// NOTE: if it never loads, this will probably hang.
-function loadElemHideEmulation()
+// Pass true when it calls itself.
+function loadElemHideEmulation(inside)
 {
   if (typeof ElemHideEmulation == "undefined")
   {
+    if (inside)
+      return Promise.reject("Failed to load ElemHideEmulation.");
+
     return loadScript(myUrl + "/../../../lib/common.js").then(() =>
     {
       return loadScript(myUrl + "/../../../chrome/content/elemHideEmulation.js");
     }).then(() =>
     {
-      return loadElemHideEmulation();
+      return loadElemHideEmulation(true);
     });
   }
 
   return Promise.resolve();
 }
 
 // Create a new ElemHideEmulation instance with @selectors.
 function applyElemHideEmulation(selectors)
 {
   return loadElemHideEmulation().then(() =>
@@ skipping 358 matching lines @@
   createPseudoElementWithStyle(child, "::before", "{content: \"publicite\"}");
 
   applyElemHideEmulation(
     ["div:-abp-has(:-abp-properties-before(content: \"publicite\"))"]
   ).then(() =>
   {
     expectVisible(test, child);
     expectHidden(test, parent);
   }).catch(unexpectedError.bind(test)).then(() => test.done());
 };