assertFalse(
        "Two Sets should not be equal if exactly one of them contains null.",
        getSet().equals(other));
  }

  @CollectionSize.Require(absent = CollectionSize.ZERO)
  public void testEquals_smallerSet() {
    Collection<E> fewerElements = getSampleElements(getNumElements() - 1);
    assertFalse(
        "Sets of different sizes should not be equal.",
        getSet().equals(MinimalSet.from(fewerElements)));
  }

    assertFalse(
        "Two Sets should not be equal if exactly one of them contains null.",
        getSet().equals(other));
  }

  @CollectionSize.Require(absent = CollectionSize.ZERO)
  public void testEquals_smallerSet() {
    Collection<E> fewerElements = getSampleElements(getNumElements() - 1);
    assertFalse(
        "Sets of different sizes should not be equal.",
        getSet().equals(MinimalSet.from(fewerElements)));
  }