*/
    abstract E castForTesting(InternalEntry<K, V, ?> entry);

    /** Unsafely extracts the key reference queue used by this segment. */
    ReferenceQueue<K> getKeyReferenceQueueForTesting() {
      throw new AssertionError();
    }

    /** Unsafely extracts the value reference queue used by this segment. */
    ReferenceQueue<V> getValueReferenceQueueForTesting() {

        assertFalse(map.containsKey(keyOne));
        assertFalse(map.containsValue(valueOne));
        assertNull(map.get(keyOne));
        assertEquals(1, map.size());
        assertNull(segment.getKeyReferenceQueueForTesting().poll());
      }
    }
  }

  public void testDrainValueReferenceQueueOnWrite() {
    for (MapMaker maker : allWeakValueStrengthMakers()) {

        assertFalse(map.containsKey(keyOne));
        assertFalse(map.containsValue(valueOne));
        assertNull(map.get(keyOne));
        assertEquals(1, map.size());
        assertNull(segment.getKeyReferenceQueueForTesting().poll());
      }
    }
  }

  public void testDrainValueReferenceQueueOnWrite() {
    for (MapMaker maker : allWeakValueStrengthMakers()) {