@Override
    public ReplicaInfo getReplicaInfoFor(DeviceId deviceId) {
        return buildFromRoleInfo(mastershipService.getMastershipFor(deviceId));
    }
@Test
    public void testGetReplicaInfoFor() {
        ReplicaInfo info1 = service.getReplicaInfoFor(DID1);
        assertEquals(Optional.of(NID1), info1.master());
        // backups are always empty for now
        assertEquals(Collections.emptyList(), info1.backups());

        ReplicaInfo info2 = service.getReplicaInfoFor(DID2);
        assertEquals("There's no master", Optional.empty(), info2.master());
        // backups are always empty for now
        assertEquals(Collections.emptyList(), info2.backups());
    }