}

  @CollectionFeature.Require(SUPPORTS_ADD)
  public void testAddSeveralTimes() {
    int originalCount = getMultiset().count(e0());
    assertEquals(originalCount, getMultiset().add(e0(), 2));
    assertTrue(getMultiset().add(e0()));
    assertEquals(originalCount + 3, getMultiset().add(e0(), 1));
    assertEquals(originalCount + 4, getMultiset().count(e0()));
  }

  @CollectionFeature.Require(absent = SUPPORTS_ADD)

    assertEquals(3, getMultiset().count(e0()));
    Multiset.Entry<E> entry = Iterables.getOnlyElement(getMultiset().entrySet());
    assertEquals(3, entry.getCount());
    assertTrue(getMultiset().remove(e0()));
    assertEquals(2, entry.getCount());
    assertTrue(getMultiset().elementSet().remove(e0()));
    assertEquals(0, entry.getCount());
    getMultiset().add(e0(), 2);
    assertEquals(2, entry.getCount());
  }

  }

  @CollectionFeature.Require(SUPPORTS_ADD)
  public void testAddAll_withDuplicates() {
    MinimalCollection<E> elementsToAdd = MinimalCollection.of(e0(), e1(), e0(), e1());
    assertTrue("addAll(hasDuplicates) should return true", getList().addAll(elementsToAdd));
    expectAdded(e0(), e1(), e0(), e1());
  }

  public void testContainsAllMultisetIgnoresFrequency() {
    assertTrue(getMultiset().containsAll(getSubjectGenerator().create(e0(), e0(), e0())));
  }

  @CollectionSize.Require(absent = ZERO)
  public void testContainsAllListIgnoresFrequency() {
    assertTrue(getMultiset().containsAll(Arrays.asList(e0(), e0(), e0())));
  }

  @CollectionSize.Require(SEVERAL)
  public void testRetainAll_countIgnored() {
    resetContainer(getSubjectGenerator().create(e0(), e2(), e1(), e0()));
    assertTrue(getList().retainAll(Arrays.asList(e0(), e1())));
    assertContentsInOrder(getList(), e0(), e1(), e0());
  }

        1,
        getMultiset().remove(e0(), 2));
    assertFalse(
        "multiset contains present after multiset.remove(present, 2)",
        getMultiset().contains(e0()));
    assertEquals(0, getMultiset().count(e0()));
  }

  @CollectionSize.Require(SEVERAL)
  @CollectionFeature.Require(SUPPORTS_REMOVE)
  public void testRemove_some_occurrences_present() {

    new IteratorTester<E>(
        4,
        MODIFIABLE,
        getSubjectGenerator().order(Arrays.asList(e0(), e1(), e1(), e2())),
        IteratorTester.KnownOrder.KNOWN_ORDER) {
      @Override
      protected Iterator<E> newTargetIterator() {
        return getSubjectGenerator().create(e0(), e1(), e1(), e2()).iterator();
      }
    }.test();
  }

  }

  @CollectionFeature.Require(SUPPORTS_ADD)
  public void testAddSeveralTimes() {
    int originalCount = getMultiset().count(e0());
    assertEquals(originalCount, getMultiset().add(e0(), 2));
    assertTrue(getMultiset().add(e0()));
    assertEquals(originalCount + 3, getMultiset().add(e0(), 1));
    assertEquals(originalCount + 4, getMultiset().count(e0()));
  }

  @CollectionFeature.Require(absent = SUPPORTS_ADD)

  @CollectionSize.Require(SEVERAL)
  public void testRetainAll_countIgnored() {
    resetContainer(getSubjectGenerator().create(e0(), e2(), e1(), e0()));
    assertTrue(getList().retainAll(Arrays.asList(e0(), e1())));
    assertContentsInOrder(getList(), e0(), e1(), e0());
  }

    int initialSize = collection.size();
    assertTrue("remove(present) should return true", collection.remove(e0()));
    assertEquals(
        "remove(present) should decrease a collection's size by one.",
        initialSize - 1,
        collection.size());
    expectMissing(e0());
  }

  @CollectionFeature.Require({SUPPORTS_REMOVE, FAILS_FAST_ON_CONCURRENT_MODIFICATION})
  @CollectionSize.Require(SEVERAL)