Start thread with member function

I am trying to construct a std::thread with a member function that takes no arguments and returns void. I can’t figure out any syntax that works – the compiler complains no matter what. What is the correct way to implement spawn() so that it returns a std::thread that executes test()?

#include <thread>
class blub {
  void test() {
  }
public:
  std::thread spawn() {
    return { test };
  }
};