/**
 * Tests for {@link StatsAccumulator}. This tests the stats methods for instances built with {@link
 * StatsAccumulator#add} and {@link StatsAccumulator#addAll}, and various error cases of the {@link
 * StatsAccumulator#add} and {@link StatsAccumulator#addAll} methods. For tests of the {@link
 * StatsAccumulator#snapshot} method which returns {@link Stats} instances, see {@link StatsTest}.
 *
 * @author Pete Gillin
 */

    CacheStats stats = counter.snapshot();
    assertEquals(0, stats.requestCount());
    assertEquals(0, stats.hitCount());
    assertEquals(1.0, stats.hitRate());
    assertEquals(0, stats.missCount());
    assertEquals(0.0, stats.missRate());
    assertEquals(0, stats.loadSuccessCount());
    assertEquals(0, stats.loadExceptionCount());
    assertEquals(0, stats.loadCount());

/**
 * Tests for {@link StatsAccumulator}. This tests the stats methods for instances built with {@link
 * StatsAccumulator#add} and {@link StatsAccumulator#addAll}, and various error cases of the {@link
 * StatsAccumulator#add} and {@link StatsAccumulator#addAll} methods. For tests of the {@link
 * StatsAccumulator#snapshot} method which returns {@link Stats} instances, see {@link StatsTest}.
 *
 * @author Pete Gillin
 */

    assertStatsApproxEqual(EMPTY_STATS_ITERABLE, emptyAccumulator.xStats());
    assertStatsApproxEqual(EMPTY_STATS_ITERABLE, emptyAccumulatorByAddAllEmptyPairedStats.xStats());
    assertStatsApproxEqual(ONE_VALUE_STATS, oneValueAccumulator.xStats());
    assertStatsApproxEqual(ONE_VALUE_STATS, oneValueAccumulatorByAddAllEmptyPairedStats.xStats());
    assertStatsApproxEqual(TWO_VALUES_STATS, twoValuesAccumulator.xStats());

    assertStatsApproxEqual(EMPTY_STATS_ITERABLE, emptyAccumulator.xStats());
    assertStatsApproxEqual(EMPTY_STATS_ITERABLE, emptyAccumulatorByAddAllEmptyPairedStats.xStats());
    assertStatsApproxEqual(ONE_VALUE_STATS, oneValueAccumulator.xStats());
    assertStatsApproxEqual(ONE_VALUE_STATS, oneValueAccumulatorByAddAllEmptyPairedStats.xStats());
    assertStatsApproxEqual(TWO_VALUES_STATS, twoValuesAccumulator.xStats());

  }

  public void testSize() {
    when(mock.size()).thenReturn(0L);
    assertEquals(0, forward.size());
  }

  public void testStats() {
    when(mock.stats()).thenReturn(null);
    assertNull(forward.stats());
  }

  public void testAsMap() {
    when(mock.asMap()).thenReturn(null);
    assertNull(forward.asMap());
  }

  public void testCleanUp() {
    forward.cleanUp();

        "Expected PairedStats.BYTES = %s, got %s",
        BYTES,
        byteArray.length);
    ByteBuffer buffer = ByteBuffer.wrap(byteArray).order(ByteOrder.LITTLE_ENDIAN);
    Stats xStats = Stats.readFrom(buffer);
    Stats yStats = Stats.readFrom(buffer);
    double sumOfProductsOfDeltas = buffer.getDouble();
    return new PairedStats(xStats, yStats, sumOfProductsOfDeltas);
  }

 *             missCount}.
 *       </ul>
 *   <li>When an entry is evicted from the cache, {@code evictionCount} is incremented.
 *   <li>No stats are modified when a cache entry is invalidated or manually removed.
 *   <li>No stats are modified by operations invoked on the {@linkplain Cache#asMap asMap} view of
 *       the cache.
 * </ul>
 *

 *             missCount}.
 *       </ul>
 *   <li>When an entry is evicted from the cache, {@code evictionCount} is incremented.
 *   <li>No stats are modified when a cache entry is invalidated or manually removed.
 *   <li>No stats are modified by operations invoked on the {@linkplain Cache#asMap asMap} view of
 *       the cache.
 * </ul>
 *

    CacheStats stats = cache.stats();
    assertEquals(0, stats.missCount());
    assertEquals(0, stats.loadSuccessCount());
    assertEquals(0, stats.loadExceptionCount());
    assertEquals(0, stats.hitCount());

    Object one = new Object();
    Object two = new Object();

    assertNull(cache.getIfPresent(one));
    stats = cache.stats();
    assertEquals(1, stats.missCount());