public void testFind_nonNullWhenNullContained() {
    initCollectionWithNullElement();
    assertEquals(getMethodName() + "(notPresent) should return -1", -1, find(e3()));
  }

  @CollectionFeature.Require(ALLOWS_NULL_VALUES)
  @CollectionSize.Require(absent = ZERO)
  public void testFind_nullContained() {
    initCollectionWithNullElement();
    assertEquals(

  public void testContains_nonNullWhenNullContained() {
    initCollectionWithNullElement();
    assertFalse("contains(notPresent) should return false", collection.contains(e3()));
  }

  @CollectionFeature.Require(ALLOWS_NULL_VALUES)
  @CollectionSize.Require(absent = ZERO)
  public void testContains_nullContained() {
    initCollectionWithNullElement();
    assertTrue("contains(null) should return true", collection.contains(null));

  public void testFind_nonNullWhenNullContained() {
    initCollectionWithNullElement();
    assertEquals(getMethodName() + "(notPresent) should return -1", -1, find(e3()));
  }

  @CollectionFeature.Require(ALLOWS_NULL_VALUES)
  @CollectionSize.Require(absent = ZERO)
  public void testFind_nullContained() {
    initCollectionWithNullElement();
    assertEquals(

    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));

  protected E[] createArrayWithNullElement() {
    E[] array = createSamplesArray();
    array[getNullLocation()] = null;
    return array;
  }

  protected void initCollectionWithNullElement() {
    E[] array = createArrayWithNullElement();
    resetContainer(getSubjectGenerator().create(array));
  }

  /**

  }

  @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();
  }

  }

  @CollectionFeature.Require(ALLOWS_NULL_VALUES)
  @CollectionSize.Require(absent = ZERO)
  public void testContainsAll_nullPresent() {
    initCollectionWithNullElement();
    assertTrue(collection.containsAll(MinimalCollection.of((E) null)));
  }

  public void testContainsAll_wrongType() {
    Collection<WrongType> wrong = MinimalCollection.of(WrongType.VALUE);
    try {

  }

  @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));