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

    assertEquals(0L, map.getAndAdd(key, value));
    assertEquals(value, map.get(key));

    assertEquals(value, map.getAndAdd(key, -1 * value));
    assertEquals(0L, map.get(key));
    assertTrue(map.containsKey(key));

    assertEquals(0L, map.getAndAdd(key, value));
    assertEquals(value, map.get(key));
  }

  public void testPut() {

    @Override
    public void increment() {
      getAndIncrement();
    }

    @Override
    public void add(long x) {
      getAndAdd(x);
    }

    @Override
    public long sum() {
      return get();
    }
  }

   */
  @CanIgnoreReturnValue
  public long getAndIncrement(K key) {
    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);
  }

  /**

  public FakeTicker setAutoIncrementStep(Duration autoIncrementStep) {
    return setAutoIncrementStep(autoIncrementStep.toNanos(), NANOSECONDS);
  }

  @Override
  public long read() {
    return nanos.getAndAdd(autoIncrementStepNanos);
  }

  public FakeTicker setAutoIncrementStep(Duration autoIncrementStep) {
    return setAutoIncrementStep(autoIncrementStep.toNanos(), NANOSECONDS);
  }

  @Override
  public long read() {
    return nanos.getAndAdd(autoIncrementStepNanos);
  }

   *
   * @param i the index
   * @param delta the value to add
   * @return the previous value
   */
  @CanIgnoreReturnValue
  public final double getAndAdd(int i, double delta) {
    return getAndAccumulate(i, delta, Double::sum);
  }

  /**
   * Atomically adds the given value to the element at index {@code i}.
   *
   * @param i the index