public void testAddAll_nullSupported() {
    List<E> containsNull = singletonList(null);
    assertTrue("addAll(containsNull) should return true", collection.addAll(containsNull));
    /*
     * We need (E) to force interpretation of null as the single element of a
     * varargs array, not the array itself
     */
    expectAdded((E) null);
  }

  @CollectionFeature.Require(value = SUPPORTS_ADD, absent = ALLOWS_NULL_VALUES)

  public void testAddAll_nullSupported() {
    List<E> containsNull = singletonList(null);
    assertTrue("addAll(containsNull) should return true", collection.addAll(containsNull));
    /*
     * We need (E) to force interpretation of null as the single element of a
     * varargs array, not the array itself
     */
    expectAdded((E) null);
  }

  @CollectionFeature.Require(value = SUPPORTS_ADD, absent = ALLOWS_NULL_VALUES)