Object firstValue = sub.remove(first);
assertEquals(2, sub.size());
assertEquals(size - 1, sm.size());
assertEquals(size - 1, sm.inverseBidiMap().size());
assertEquals(false, sm.containsKey(first));
assertEquals(false, sm.containsValue(firstValue));
assertEquals(false, sm.inverseBidiMap().containsKey(firstValue));
assertEquals(false, sm.inverseBidiMap().containsValue(first));
assertEquals(false, sub.containsKey(first));
assertEquals(false, sub.containsValue(firstValue));