@Override
  @Nullable
  @GuardedBy("getLock()")
  public PageInfo evict(CacheScope scope, PageStoreDir pageStoreDir) {
    return evictInternal(pageStoreDir.getEvictor());
  }
@Test
  public void evict() throws Exception {
    mMetaStore.addPage(mPage, mPageInfo);
    assertEquals(mPageInfo, mMetaStore.evict(mPageStoreDir));
    mMetaStore.removePage(mPageInfo.getPageId());
    Assert.assertNull(mMetaStore.evict(mPageStoreDir));
    assertEquals(0, mCachedPageGauge.getValue());
  }