// setCount with nulls:

  @CollectionSize.Require(absent = ZERO)
  @CollectionFeature.Require({SUPPORTS_REMOVE, ALLOWS_NULL_VALUES})
  public void testSetCount_removeNull_nullSupported() {
    initCollectionWithNullElement();
    assertSetCount(null, 0);
  }

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

    initCollectionWithNullElement();
    expectReturnsFalse(nullSingleton);
    expectContents(createArrayWithNullElement());
  }

  @CollectionFeature.Require({SUPPORTS_REMOVE, ALLOWS_NULL_VALUES})
  @CollectionSize.Require(absent = {ZERO, ONE})
  public void testRetainAll_nullSingletonPreviouslySeveralWithNull() {
    initCollectionWithNullElement();
    expectReturnsTrue(nullSingleton);

    initCollectionWithNullElement();
    expectReturnsFalse(nullSingleton);
    expectContents(createArrayWithNullElement());
  }

  @CollectionFeature.Require({SUPPORTS_REMOVE, ALLOWS_NULL_VALUES})
  @CollectionSize.Require(absent = {ZERO, ONE})
  public void testRetainAll_nullSingletonPreviouslySeveralWithNull() {
    initCollectionWithNullElement();
    expectReturnsTrue(nullSingleton);

    expectUnchanged();
  }

  @CollectionFeature.Require({SUPPORTS_REMOVE, ALLOWS_NULL_VALUES})
  @CollectionSize.Require(absent = ZERO)
  public void testRemoveAll_containsNullYes() {
    initCollectionWithNullElement();
    assertTrue("removeAll(containsNull) should return true", collection.removeAll(singleton(null)));
    // TODO: make this work with MinimalCollection
  }

  @CollectionFeature.Require(SUPPORTS_REMOVE)

  }

  @CollectionSize.Require(absent = ZERO)
  @CollectionFeature.Require({SUPPORTS_REMOVE, ALLOWS_NULL_VALUES})
  public void testRemove_nullPresent() {
    initCollectionWithNullElement();
    assertEquals(1, getMultiset().remove(null, 2));
    assertFalse(
        "multiset contains present after multiset.remove(present, 2)",
        getMultiset().contains(null));

  // setCount with nulls:

  @CollectionSize.Require(absent = ZERO)
  @CollectionFeature.Require({SUPPORTS_REMOVE, ALLOWS_NULL_VALUES})
  public void testSetCount_removeNull_nullSupported() {
    initCollectionWithNullElement();
    assertSetCount(null, 0);
  }

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

  }

  @CollectionSize.Require(absent = ZERO)
  @CollectionFeature.Require(ALLOWS_NULL_VALUES)
  public void testToString_null() {
    initCollectionWithNullElement();
    testToString_minimal();
  }

  }

  @CollectionSize.Require(absent = ZERO)
  @CollectionFeature.Require(ALLOWS_NULL_VALUES)
  public void testToString_null() {
    initCollectionWithNullElement();
    testToString_minimal();
  }

  }

  @CollectionSize.Require(absent = ZERO)
  @CollectionFeature.Require(ALLOWS_NULL_VALUES)
  public void testCount_nullPresent() {
    initCollectionWithNullElement();
    assertEquals(1, getMultiset().count(null));
  }

  public void testCount_wrongType() {
    assertEquals(
        "multiset.count(wrongType) didn't return 0", 0, getMultiset().count(WrongType.VALUE));

  }

  @CollectionFeature.Require(ALLOWS_NULL_VALUES)
  @CollectionSize.Require(absent = ZERO)
  public void testSpliteratorNullable() {
    initCollectionWithNullElement();
    assertFalse(collection.spliterator().hasCharacteristics(Spliterator.NONNULL));
  }

  @CollectionFeature.Require(SUPPORTS_ADD)
  public void testSpliteratorNotImmutable_collectionAllowsAdd() {