clock.waitUntil(clock.getTime() + ns1.getClusterInfo().getLeaseTime());
ns1.getClusterInfo().setLeaseTime(0);
ns2.getClusterInfo().setLeaseTime(0);
List<ClusterNodeInfoDocument> list = mem.query(
Collection.CLUSTER_NODES, "0", "a", Integer.MAX_VALUE);
assertEquals(2, list.size());
assertNull(mem.getReadPreference());
assertNull(mem.getWriteConcern());