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 18 matching lines @@
 
 exports.testGetSelectorsForDomain = function(test)
 {
   function fromText(f)
   {
     return (filterText) => f(Filter.fromText(filterText));
   }
   let addFilter = fromText(ElemHide.add);
   let removeFilter = fromText(ElemHide.remove);
 
-  function selectorsEqual(domain, selectors, specificOnly)
+  function normalizeSelectors(selectors)
   {
-    test.deepEqual(ElemHide.getSelectorsForDomain(domain, specificOnly).sort(),
-                   selectors.sort());
+    // 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) =>
+    {
+      return index == 0 || selector != selectors[index -  1];
+    });
+  }
+  function selectorsEqual(domain, expectedSelectors, specificOnly)
+  {
+    test.deepEqual(
+      normalizeSelectors(ElemHide.getSelectorsForDomain(domain, specificOnly)),
+      normalizeSelectors(expectedSelectors)
+    );
   }
 
   selectorsEqual("", []);
 
   addFilter("~foo.example.com,example.com##foo");
   selectorsEqual("barfoo.example.com", ["foo"]);
   selectorsEqual("bar.foo.example.com", []);
   selectorsEqual("foo.example.com", []);
   selectorsEqual("example.com", ["foo"]);
   selectorsEqual("com", []);
@@ skipping 75 matching lines @@
   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");
 
   addFilter("##foo");
   selectorsEqual("foo.example.com", ["foo"]);
-  selectorsEqual("example.com", ["foo", "foo"]);

[Wladimir Palant, 2016/05/23 15:06:47]

Here you are cementing what is considerably a bug in the current implementation.
Instead, you should make sure that selectorsEqual will remove duplicates in
addition to sorting the list - and note in a comment that getSelectorsByDomain
is currently allowed to return duplicates for performance reasons.

[kzar, 2016/05/23 15:49:19]

Done.

+  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();
 };