@Test
public void testPowerSet() {
final ImmutableBitSet empty = ImmutableBitSet.of();
assertThat(Iterables.size(empty.powerSet()), equalTo(1));
assertThat(empty.powerSet().toString(), equalTo("[{}]"));
final ImmutableBitSet single = ImmutableBitSet.of(2);
assertThat(Iterables.size(single.powerSet()), equalTo(2));
assertThat(single.powerSet().toString(), equalTo("[{}, {2}]"));
final ImmutableBitSet two = ImmutableBitSet.of(2, 10);
assertThat(Iterables.size(two.powerSet()), equalTo(4));
assertThat(two.powerSet().toString(), equalTo("[{}, {10}, {2}, {2, 10}]"));
final ImmutableBitSet seventeen = ImmutableBitSet.range(3, 20);
assertThat(Iterables.size(seventeen.powerSet()), equalTo(131072));
}
