static bool expectTimeJump(double secondsToWait) {
  long diff = now()-sysNow();
  long start = sysNow();
  while (elapsedSeconds(start) < secondsToWait) {
    sleep(500);
    long diff2 = now()-sysNow();
    if (diff2 > diff+100)
      ret true with print("Time jump occurred!");
  }
  ret false with print("No time jump occurred in " + secondsToWait + " seconds");
}