cache.invalidateAll(toInvalidate);
    assertEquals(toInvalidate, invalidated);
  }

  public void testEmptySimpleStats() {
    StatsCounter counter = new SimpleStatsCounter();
    CacheStats stats = counter.snapshot();
    assertEquals(0, stats.requestCount());
    assertEquals(0, stats.hitCount());
    assertEquals(1.0, stats.hitRate());
    assertEquals(0, stats.missCount());

    assertEquals(
        ImmutableMap.of("key", Boolean.TRUE), forward.getAllPresent(ImmutableList.of("key")));
  }

  public void testInvalidate() {
    forward.invalidate("key");
    verify(mock).invalidate("key");
  }

  public void testInvalidateAllIterable() {
    forward.invalidateAll(ImmutableList.of("key"));
    verify(mock).invalidateAll(ImmutableList.of("key"));
  }

 * {@code get}; {@link #getAllPresent} is implemented in terms of {@code getIfPresent}; {@link
 * #putAll} is implemented in terms of {@link #put}, {@link #invalidateAll(Iterable)} is implemented
 * in terms of {@link #invalidate}. The method {@link #cleanUp} is a no-op. All other methods throw
 * an {@link UnsupportedOperationException}.
 *
 * @author Charles Fry
 * @since 11.0
 */
@GwtIncompatible
@ElementTypesAreNonnullByDefault

 * {@code get}; {@link #getAllPresent} is implemented in terms of {@code getIfPresent}; {@link
 * #putAll} is implemented in terms of {@link #put}, {@link #invalidateAll(Iterable)} is implemented
 * in terms of {@link #invalidate}. The method {@link #cleanUp} is a no-op. All other methods throw
 * an {@link UnsupportedOperationException}.
 *
 * @author Charles Fry
 * @since 11.0
 */
@GwtIncompatible
@ElementTypesAreNonnullByDefault

  }

  @Override
  public void invalidate(Object key) {
    throw new UnsupportedOperationException();
  }

  /** @since 11.0 */
  @Override
  // For discussion of <? extends Object>, see getAllPresent.
  public void invalidateAll(Iterable<? extends Object> keys) {
    for (Object key : keys) {
      invalidate(key);
    }
  }

  @Override
  public void invalidateAll() {

    cache.put(0, 10);

    assertEquals(Integer.valueOf(10), cache.get(0, loader));
    assertEquals(Integer.valueOf(1), cache.get(20, loader));
    assertEquals(Integer.valueOf(2), cache.get(34, loader));

    cache.invalidate(0);
    assertEquals(Integer.valueOf(3), cache.get(0, loader));

    cache.put(0, 10);
    cache.invalidateAll();
    assertEquals(Integer.valueOf(4), cache.get(0, loader));
  }

  }

  public void testApply() {
    when(mock.apply("key")).thenReturn(Boolean.TRUE);
    assertSame(Boolean.TRUE, forward.apply("key"));
  }

  public void testInvalidate() {
    forward.invalidate("key");
    verify(mock).invalidate("key");
  }

  public void testRefresh() throws ExecutionException {
    forward.refresh("key");
    verify(mock).refresh("key");
  }

  public void testInvalidateAll() {

  }

  public void testApply() {
    when(mock.apply("key")).thenReturn(Boolean.TRUE);
    assertSame(Boolean.TRUE, forward.apply("key"));
  }

  public void testInvalidate() {
    forward.invalidate("key");
    verify(mock).invalidate("key");
  }

  public void testRefresh() throws ExecutionException {
    forward.refresh("key");
    verify(mock).refresh("key");
  }

  public void testInvalidateAll() {

  }

  @Override
  public void invalidate(Object key) {
    throw new UnsupportedOperationException();
  }

  /** @since 11.0 */
  @Override
  // For discussion of <? extends Object>, see getAllPresent.
  public void invalidateAll(Iterable<? extends Object> keys) {
    for (Object key : keys) {
      invalidate(key);
    }
  }

  @Override
  public void invalidateAll() {

    assertEquals(
        ImmutableMap.of("key", Boolean.TRUE), forward.getAllPresent(ImmutableList.of("key")));
  }

  public void testInvalidate() {
    forward.invalidate("key");
    verify(mock).invalidate("key");
  }

  public void testInvalidateAllIterable() {
    forward.invalidateAll(ImmutableList.of("key"));
    verify(mock).invalidateAll(ImmutableList.of("key"));
  }