Issue 4231 - Fix unstable FilterEngineTest.testSetRemoveFilterChangeCallback

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

 /*
  * 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
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License
  * along with Adblock Plus.  If not, see <http://www.gnu.org/licenses/>.
  */
 
 package org.adblockplus.libadblockplus;
 
+import android.util.Log;
+
+import org.adblockplus.libadblockplus.android.Utils;
+
 public class MockFilterChangeCallback extends FilterChangeCallback
 {
-  private int timesCalled;
+  private static final String TAG = Utils.getTag(MockFilterChangeCallback.class);
+
+  private volatile int timesCalled;
 
   public MockFilterChangeCallback(int timesCalled)
   {
     this.timesCalled = timesCalled;
   }
 
   public int getTimesCalled()
   {
     return timesCalled;
   }
 
   @Override
   public void filterChangeCallback(String action, JsValue jsValue)
   {
+    Log.d(TAG, "callback: action=" + action + ", jsValue=" + jsValue);
     timesCalled++;
   }
 }