@Override
  public Map<CompoundKey, AlbumEntry> batchGet(Set<CompoundKey> ids)
  {
    Map<CompoundKey, AlbumEntry> result = new HashMap<>();
    for (CompoundKey key : ids)
      result.put(key, get(key));
    return result;
  }
@Test
  public void testBatchGet()
  {
    // get keys 1-3
    Set<CompoundKey> batchIds = new HashSet<>();
    for (int i = 1; i <= 3; i++)
    {
      batchIds.add(_keys[i]);
    }
    Map<CompoundKey, AlbumEntry> batchEntries = _entryRes.batchGet(batchIds);

    Assert.assertEquals(batchEntries.size(), 3);
    for (int i = 1; i <= 3; i++)
    {
      Assert.assertEquals(batchEntries.get(_keys[i]), _entries[i]);
    }
  }