assertEquals(0L, map.get(key));
    assertFalse(map.containsKey(key));

    assertEquals(0L, map.getAndDecrement(key));
    assertEquals(-1L, map.get(key));

    assertEquals(-1L, map.getAndIncrement(key));
    assertEquals(0L, map.get(key));
    assertTrue(map.containsKey(key));

    assertEquals(0L, map.getAndDecrement(key));
    assertEquals(-1L, map.get(key));
  }

  public void testAddAndGet() {

    return getAndAdd(key, 1);
  }

  /**
   * Decrements by one the value currently associated with {@code key}, and returns the old value.
   */
  @CanIgnoreReturnValue
  public long getAndDecrement(K key) {
    return getAndAdd(key, -1);
  }

  /**
   * Adds {@code delta} to the value currently associated with {@code key}, and returns the old
   * value.
   */
  @CanIgnoreReturnValue