*
* // We know 0 isn't in map.
* assert(!jmap_test(map, 0));
* for (i = 0; (val = jmap_nthval(map, i, &index)) != NULL; i++) {
* assert(jmap_popcount(map, 0, index) == i);
*
* // We know 0 isn't in map.
* assert(!jmap_test(map, 0));
* for (i = 0; (val = jmap_nthval(map, i, &index)) != NULL; i++) {
* assert(jmap_popcount(map, 0, index) == i);