}

  public void testCount_elementAbsent() {
    when(backingMap.get(KEY)).thenReturn(null);

    assertEquals(0, multiset.count(KEY));
  }

  public void testAdd_zero() {
    final int INITIAL_COUNT = 32;

    when(backingMap.get(KEY)).thenReturn(new AtomicInteger(INITIAL_COUNT));
    assertEquals(INITIAL_COUNT, multiset.add(KEY, 0));
  }

  }

  public void testCount_elementAbsent() {
    when(backingMap.get(KEY)).thenReturn(null);

    assertEquals(0, multiset.count(KEY));
  }

  public void testAdd_zero() {
    final int INITIAL_COUNT = 32;

    when(backingMap.get(KEY)).thenReturn(new AtomicInteger(INITIAL_COUNT));
    assertEquals(INITIAL_COUNT, multiset.add(KEY, 0));
  }