final byte[] metrics = { 'm', 'e', 't', 'r', 'i', 'c', 's' };
final byte[] tagk = { 't', 'a', 'g', 'k' };
final byte[] tagv = { 't', 'a', 'g', 'v' };
final TSDB tsdb = mock(TSDB.class);
when(tsdb.getClient()).thenReturn(client);
when(tsdb.uidTable()).thenReturn(new byte[] { 'u', 'i', 'd' });
when(client.get(anyGet()))
.thenReturn(Deferred.fromResult(kvs));
final byte[][] kinds = { metrics, tagk, tagv };
final Map<String, Long> uids = UniqueId.getUsedUIDs(tsdb, kinds)