* assert(!jbit_test(set, 0));
* for (i = 0; (val = jbit_nth(set, i, 0)) != 0; i++) {
* assert(jbit_popcount(set, 0, val) == i);
* assert(!jbit_test(set, 0));
* for (i = 0; (val = jbit_nth(set, i, 0)) != 0; i++) {
* assert(jbit_popcount(set, 0, val) == i);