svoid test_LongTreeSetWithComparator() {
  L<Long> list = repF(1000, () -> randomLong());
  TreeSet<Long> set = new((a, b) ->cmp(reverseBytesInLong(a), reverseBytesInLong(b)));
  set.addAll(list);
  LongTreeSet cset = new(set) {
    public int compare(long a, long b) {
      ret cmp(reverseBytesInLong(a), reverseBytesInLong(b));
    }
  };
  
  print(set);
  print(cset);
  assertEquals(asList(set), asList(cset));
  assertEqualsVerbose(l(set), cset.size());
  
  for (Long a : shuffledIterator(list)) {
    set.remove(a);
    cset.remove(a);
    assertEquals(asList(set), asList(cset));
    assertEqualsVerbose(l(set), cset.size());
  }
}

Began life as a copy of #1030400