Modern C++ Programming with Test-Driven Development

9.8 Exposing Concurrency Issues

We want to demonstrate that the worker thread can pull and execute multiple work items from the queue.

TEST(AThreadPool, ExecutesAllWork) {
   pool.start();
   unsigned int count{0};
   unsigned int NumberOfWorkItems{3};
   condition_variable wasExecuted;
   Work work{[&] {
      std::unique_lock<std::mutex> lock(m);
      ++count;
      wasExecuted.notify_all();
   }};
   for (unsigned int i{0}; i < NumberOfWorkItems; i++)
      pool.add(work);
   unique_lock<mutex> lock(m);
   CHECK_TRUE(wasExecuted.wait_for(lock, chrono::milliseconds(100),
         [&] { return count == NumberOfWorkItems; }));
}

Our implementation introduces a ​while​ loop and a boolean flag that tells the loop to stop when the ThreadPool ...