Issue 4231 - Fix unstable FilterEngineTest.testSetRemoveFilterChangeCallback

libadblockplus-android-tests/src/org/adblockplus/libadblockplus/tests/FilterEngineGenericTest.java

 /*
  * 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 15 matching lines @@
 
     @Override
     protected void setUp() throws Exception
     {
         super.setUp();
 
         jsEngine.setWebRequest(new LazyWebRequest());
         jsEngine.setDefaultLogSystem();
 
         filterEngine = new FilterEngine(jsEngine);
+
+        // JsEngine has built-in default subscriptions
+        while (filterEngine.getListedSubscriptions().size() > 0)

[sergei, 2016/07/07 12:48:42]

It seems there is a race condition because the number of subscriptions can be
zero if they are not loaded yet. They can be loaded during the following
Thread.sleep for example.
So actually, firstly one needs to check the number of subscriptions, if it's
zero then wait for loading (using FilterNotifier.addListener, action == "load")
and only then one can remove them. If it's bigger than zero it means the loading
finished and they can be removed as it's done now.

Here is an example of waiting for the finishing of the loading of subscriptions
https://hg.adblockplus.org/abpcrawler/file/tip/lib/crawler.js#l214

[anton, 2016/07/07 13:33:54]

ok, since it's not good enough solution for the case #2 i'd prefer to prevent
default subscriptions to be loaded at all and switch to solution #3.

+            filterEngine.getListedSubscriptions().get(0).removeFromList();
+
+        Thread.sleep(100);
     }
 }