gaps documentation is ambiguous w/r/t empty ranges #38
Description
The documentation says:
/// Gets an iterator over all the maximally-sized ranges
/// contained in `outer_range` that are not covered by
/// any range stored in the map.
This indicates that gaps will find holes in the range-map that intersect outer_range... We had an engineer check if a range was completely covered by the RangeMap by if range_map.gaps(&check_range).next().is_none() {...}, which seems like it should work (based on the documentation), but broke in our case, because the gaps iterator can return empty ranges:
#[test]
fn adjacent_no_coalesce() {
let mut range_map: RangeMap<u32, bool> = RangeMap::new();
range_map.insert(2..5, false);
range_map.insert(5..8, true);
let outer_range = 2..8;
let mut gaps = range_map.gaps(&outer_range);
// Should yield an empty range.
let gap = gaps.next();
assert_eq!(gap, Some(5..5));
assert_eq!(gap.unwrap().is_empty(), true);
}I think the current behavior is good, but the documentation could be improved to better indicate that gaps can return empty ranges.