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));
Object secondValue = sub.remove(second);
assertEquals(0, sub.size());
assertEquals(size - 2, sm.size());