Fixed unit tests

lib/stats.js

 /*
  * This file is part of Adblock Plus <http://adblockplus.org/>,
  * Copyright (C) 2006-2013 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 24 matching lines @@
 {
   if (!tab)
     return (key in Prefs.stats_total ? Prefs.stats_total[key] : 0);
 
   let frameData = getFrameData(tab, 0);
   return (frameData && key in frameData ? frameData[key] : 0);
 };
 
 FilterNotifier.addListener(function(action, item, newValue, oldValue, tab)
 {
-  if (action != "filter.hitCount")
+  if (action != "filter.hitCount" || !tab)
     return;
-  
+
   let blocked = item instanceof BlockingFilter;
-  
+
   // Increment counts
   if (blocked)
   {
     if ("blocked" in Prefs.stats_total)
       Prefs.stats_total.blocked++;
     else
       Prefs.stats_total.blocked = 1;
     Prefs.stats_total = Prefs.stats_total;
-    
+
     let frameData = getFrameData(tab, 0);
     if (frameData)
     {
       if ("blocked" in frameData)
         frameData.blocked++;
       else
         frameData.blocked = 1;
     }
-    
+
     // Update number in icon
     if (Prefs.show_statsinicon)
     {
       tab.browserAction.setBadge({
         color: badgeColor,
         number: frameData.blocked
       });
     }
   }
 });
@@ skipping 14 matching lines @@
           func(tabs[i]);
       });
     }
   });
 }
 
 Prefs.addListener(function(name)
 {
   if (name != "show_statsinicon")
     return;
-  
+
   forEachTab(function(tab)
   {
     let badge = null;
     if (Prefs.show_statsinicon)
     {
       let frameData = getFrameData(tab, 0);
       if (frameData && "blocked" in frameData)
       {
         badge = {
           color: badgeColor,
           number: frameData.blocked
         };
       }
     }
     tab.browserAction.setBadge(badge);
   });
 });