private void testNextClearBit() {
BitSet set = new BitSet();
BitField field = new BitField();
set.set(0, 640);
field.set(0, 640, true);
assertEquals(set.nextClearBit(0), field.nextClearBit(0));
Random random = new Random(1);
field = new BitField();
field.set(0, 500, true);
for (int i = 0; i < 100000; i++) {