Count existingCounter;
    int oldCount;
    if (count == 0) {
      existingCounter = backingMap.remove(element);
      oldCount = getAndSet(existingCounter, count);
    } else {
      existingCounter = backingMap.get(element);
      oldCount = getAndSet(existingCounter, count);

      if (existingCounter == null) {
        backingMap.put(element, new Count(count));
      }
    }

          public void run() {
            assertFalse("previous tearDown should have run before setUp", setUpRan.getAndSet(true));
          }
        };
    Runnable tearDown =
        new Runnable() {
          @Override
          public void run() {
            assertTrue("setUp should have run", setUpRan.getAndSet(false));
          }
        };
    return MapTestSuiteBuilder.using(new CheckSetUpHashMapGenerator(setUpRan))

  public void testAddAndGet() {
    Count holder = new Count(20);
    assertEquals(21, holder.addAndGet(1));
  }

  public void testGetAndSet() {
    Count holder = new Count(10);
    assertEquals(10, holder.getAndSet(20));
    assertEquals(20, holder.get());
  }

  public void testSet() {
    Count holder = new Count(10);
    holder.set(20);
    assertEquals(20, holder.get());
  }

        requireNonNull(message, "message");
        entries.get().add(new Entry(level, message, error));
    }

    @Override
    public List<Entry> drain() {
        return entries.getAndSet(new CopyOnWriteArrayList<>());
    }

    @Nullable Listener gasListeners(AbstractFutureState<?> future, Listener update) {
      return (Listener) listenersUpdater.getAndSet(future, update);
    }

    @Override
    @Nullable Waiter gasWaiters(AbstractFutureState<?> future, Waiter update) {
      return (Waiter) waitersUpdater.getAndSet(future, update);
    }

    @Override

          public void run() {
            assertFalse("previous tearDown should have run before setUp", setUpRan.getAndSet(true));
          }
        };
    Runnable tearDown =
        new Runnable() {
          @Override
          public void run() {
            assertTrue("setUp should have run", setUpRan.getAndSet(false));
          }
        };
    return MapTestSuiteBuilder.using(new CheckSetUpHashMapGenerator(setUpRan))

  public void testAddAndGet() {
    Count holder = new Count(20);
    assertEquals(21, holder.addAndGet(1));
  }

  public void testGetAndSet() {
    Count holder = new Count(10);
    assertEquals(10, holder.getAndSet(20));
    assertEquals(20, holder.get());
  }

  public void testSet() {
    Count holder = new Count(10);
    holder.set(20);
    assertEquals(20, holder.get());
  }

   *
   * @param i the index
   * @param newValue the new value
   * @return the previous value
   */
  public final double getAndSet(int i, double newValue) {
    long next = doubleToRawLongBits(newValue);
    return longBitsToDouble(longs.getAndSet(i, next));
  }

  /**
   * Atomically sets the element at position {@code i} to the given updated value if the current

    @Override
    @Nullable Listener gasListeners(AbstractFutureState<?> future, Listener update) {
      return listenersUpdater.getAndSet(future, update);
    }

    @Override
    @Nullable Waiter gasWaiters(AbstractFutureState<?> future, Waiter update) {
      return waitersUpdater.getAndSet(future, update);
    }

    @Override
    boolean casValue(AbstractFutureState<?> future, @Nullable Object expect, Object update) {

        // not all.  See the test cases for examples on how this can happen.
        try {
          ((Thread) currentRunner).interrupt();
        } finally {
          Runnable prev = getAndSet(DONE);
          if (prev == PARKED) {
            LockSupport.unpark((Thread) currentRunner);
          }
        }
      }
    }
  }

  /**