### Question:
ConcurrentLongHashSet { public boolean remove(long item) { checkBiggerEqualZero(item); long h = hash(item); return getSection(h).remove(item, (int) h); } ConcurrentLongHashSet();  ConcurrentLongHashSet(int expectedItems);  ConcurrentLongHashSet(int expectedItems, int concurrencyLevel); long size(); long capacity(); boolean isEmpty(); boolean contains(long item); boolean add(long item); boolean remove(long item); void clear(); void forEach(ConsumerLong processor); Set<Long> items();  }### Answer:
@Test public void testRemove() { ConcurrentLongHashSet set = new ConcurrentLongHashSet(); assertTrue(set.isEmpty()); assertTrue(set.add(1)); assertFalse(set.isEmpty()); assertFalse(set.remove(0)); assertFalse(set.isEmpty()); assertTrue(set.remove(1)); assertTrue(set.isEmpty()); }