Modern C++ Programming with Test-Driven Development

9.4 Performance Requirements

We have a performance challenge. Our product owner indicates that we expect a large volume of users. The initial release should support tracking 50,000 users simultaneously.

We write a test that emulates scaling up to large numbers of users.

TEST(AGeoServer_UsersInBox, HandlesLargeNumbersOfUsers) {
   Location anotherLocation{aUserLocation.go(10, West)};
   const unsigned int lots {500000};
   for (unsigned int i{0}; i < lots; i++) {
      string user{"user" + to_string(i)};
      server.track(user);
      server.updateLocation(user, anotherLocation);
   }

   auto users = server.usersInBox(aUser, Width, Height);
   CHECK_EQUAL(lots, users.size());
}

When we run our tests, we notice a pause ...