Method update

entityx/System_test.cc:45–55

  explicit MovementSystem(string label = "") : label(label) {}

  void update(EntityManager &es, EventManager &events, TimeDelta) override {
    EntityManager::View entities =
        es.entities_with_components<Position, Direction>();
    ComponentHandle<Position> position;
    ComponentHandle<Direction> direction;
    for (auto entity : entities) {
      entity.unpack<Position, Direction>(position, direction);
      position->x += direction->x;
      position->y += direction->y;
    }
  }

  string label;
};