assertEquals(getNumElements(), getMap().size());
  }

  @MapFeature.Require({SUPPORTS_PUT, SUPPORTS_REMOVE, ALLOWS_NULL_VALUES})
  @CollectionSize.Require(absent = ZERO)
  public void testCompute_presentNullToNull() {
    // The spec is somewhat ambiguous about this case, but the actual default implementation
    // in Map will remove a present null.
    initMapWithNullValue();
    assertNull(