Noissue - workaround to reduce the probability of the race condition in tests

test/BaseJsTest.h

 /*
  * 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
@@ skipping 156 matching lines @@
 public:
   void GET(const std::string& url, const AdblockPlus::HeaderList& requestHeaders, const GetCallback&) override
   {
     throw std::runtime_error("Unexpected GET: " + url);
   }
 };
 
 class LazyFileSystem : public AdblockPlus::IFileSystem, public AdblockPlus::FileSystem
 {
 public:
+  ~LazyFileSystem() {
+    std::this_thread::sleep_for(std::chrono::milliseconds(200));
+  }
   IOBuffer Read(const std::string& path) const
   {
     std::string dummyData("");
     if (path == "patterns.ini")
       dummyData = "# Adblock Plus preferences\n[Subscription]\nurl=~fl~";
     else if (path == "prefs.json")
       dummyData = "{}";
     return IOBuffer(dummyData.cbegin(), dummyData.cend());
   }
 
@@ skipping 124 matching lines @@
 protected:
   AdblockPlus::JsEnginePtr jsEngine;
 
   virtual void SetUp()
   {
     jsEngine = CreateJsEngine();
   }
 };
 
 #endif