Issue 4055 - Test ElemHide.getSelectorsFordomain

test/elemHide.js

 /*
  * This file is part of Adblock Plus <https://adblockplus.org/>,
  * Copyright (C) 2006-2016 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 20 matching lines @@
 {
   function fromText(f)
   {
     return (filterText) => f(Filter.fromText(filterText));
   }
   let addFilter = fromText(ElemHide.add);
   let removeFilter = fromText(ElemHide.remove);
 
   function normalizeSelectors(selectors)
   {
-    let lastSelector;
-    return selectors.sort().filter(selector =>
+    // getSelectorsForDomain is currently allowed to return duplicate selectors
+    // for performance reasons, so we need to remove duplicates here.
+    return selectors.sort().filter((selector, index, selectors) =>
     {
-      let unique = lastSelector != selector;
-      lastSelector = selector;
-      return unique;
+      return index == 0 || selector != selectors[index -  1];
     });

[Wladimir Palant, 2016/05/23 17:34:48]

How about a simpler filter function?

  (selector, index, array) =>
  {
    return index == 0 || selector != array[index - 1];
  }

[kzar, 2016/05/23 18:56:26]

Cool, didn't realise filter provided the index and array. Done.

   }
   function selectorsEqual(domain, expectedSelectors, specificOnly)
   {
     test.deepEqual(
       normalizeSelectors(ElemHide.getSelectorsForDomain(domain, specificOnly)),
       normalizeSelectors(expectedSelectors)
     );
   }
 
   selectorsEqual("", []);
@@ skipping 80 matching lines @@
 
   addFilter("example.com##dupe");
   addFilter("example.com##dupe");
   selectorsEqual("example.com", ["dupe"]);
   removeFilter("example.com##dupe");
   selectorsEqual("example.com", []);
   removeFilter("example.com##dupe");
 
   addFilter("~foo.example.com,example.com##foo");
 
-  // getSelectorsForDomain is currently allowed to return duplicate selectors
-  // for performance reasons. In reality example.com gives ["foo", "foo"] here
-  // but we normalize the selectors, removing duplicates, before performing the
-  // comparison.

[Wladimir Palant, 2016/05/23 17:34:48]

I think that this explanation belongs into normalizeSelectors() function -
that's where we remove duplicates and we should explain why we do it.

[kzar, 2016/05/23 18:56:26]

Done.

   addFilter("##foo");
   selectorsEqual("foo.example.com", ["foo"]);
   selectorsEqual("example.com", ["foo"]);
   selectorsEqual("com", ["foo"]);
   selectorsEqual("", ["foo"]);
   removeFilter("##foo");
 
   addFilter("example.org##foo");
   selectorsEqual("foo.example.com", []);
   selectorsEqual("example.com", ["foo"]);
   selectorsEqual("com", []);
   selectorsEqual("", []);
   removeFilter("example.org##foo");
 
   addFilter("~example.com##foo");
   selectorsEqual("foo.example.com", []);
   selectorsEqual("example.com", ["foo"]);
   selectorsEqual("com", ["foo"]);
   selectorsEqual("", ["foo"]);
   removeFilter("example.org##foo");
 
   test.done();
 };