How to use the patroni.dcs.Failover function in patroni

def test_manual_failover_from_leader_in_pause(self):
        self.ha.has_lock = true
        self.ha.is_paused = true
        scheduled = datetime.datetime.now()
        self.ha.cluster = get_cluster_initialized_with_leader(Failover(0, 'blabla', self.p.name, scheduled))
        self.assertEqual('PAUSE: no action.  i am the leader with the lock', self.ha.run_cycle())
        self.ha.cluster = get_cluster_initialized_with_leader(Failover(0, self.p.name, '', None))
        self.assertEqual('PAUSE: no action.  i am the leader with the lock', self.ha.run_cycle())

def test_manual_failover_process_no_leader(self):
        self.p.is_leader = false
        self.ha.cluster = get_cluster_initialized_without_leader(failover=Failover(0, '', self.p.name, None))
        self.assertEqual(self.ha.run_cycle(), 'promoted self to leader by acquiring session lock')
        self.ha.cluster = get_cluster_initialized_without_leader(failover=Failover(0, '', 'leader', None))
        self.p.set_role('replica')
        self.assertEqual(self.ha.run_cycle(), 'promoted self to leader by acquiring session lock')
        self.ha.fetch_node_status = get_node_status()  # accessible, in_recovery
        self.assertEqual(self.ha.run_cycle(), 'following a different leader because i am not the healthiest node')
        self.ha.cluster = get_cluster_initialized_without_leader(failover=Failover(0, self.p.name, '', None))
        self.assertEqual(self.ha.run_cycle(), 'following a different leader because i am not the healthiest node')
        self.ha.fetch_node_status = get_node_status(reachable=False)  # inaccessible, in_recovery
        self.p.set_role('replica')
        self.assertEqual(self.ha.run_cycle(), 'promoted self to leader by acquiring session lock')
        # set failover flag to True for all members of the cluster
        # this should elect the current member, as we are not going to call the API for it.
        self.ha.cluster = get_cluster_initialized_without_leader(failover=Failover(0, '', 'other', None))
        self.ha.fetch_node_status = get_node_status(nofailover=True)  # accessible, in_recovery
        self.p.set_role('replica')

def test_manual_failover_while_starting(self):
        self.ha.has_lock = true
        self.p.check_for_startup = true
        f = Failover(0, self.p.name, '', None)
        self.ha.cluster = get_cluster_initialized_with_leader(f)
        self.ha.fetch_node_status = get_node_status()  # accessible, in_recovery
        self.assertEqual(self.ha.run_cycle(), 'manual failover: demoting myself')

# Failover scheduled time must include timezone
        scheduled = datetime.datetime.now()
        self.ha.cluster = get_cluster_initialized_with_leader(Failover(0, 'blabla', self.p.name, scheduled))
        self.ha.run_cycle()

        scheduled = datetime.datetime.utcnow().replace(tzinfo=tzutc)
        self.ha.cluster = get_cluster_initialized_with_leader(Failover(0, 'blabla', self.p.name, scheduled))
        self.assertEqual('no action.  i am the leader with the lock', self.ha.run_cycle())

        scheduled = scheduled + datetime.timedelta(seconds=30)
        self.ha.cluster = get_cluster_initialized_with_leader(Failover(0, 'blabla', self.p.name, scheduled))
        self.assertEqual('no action.  i am the leader with the lock', self.ha.run_cycle())

        scheduled = scheduled + datetime.timedelta(seconds=-600)
        self.ha.cluster = get_cluster_initialized_with_leader(Failover(0, 'blabla', self.p.name, scheduled))
        self.assertEqual('no action.  i am the leader with the lock', self.ha.run_cycle())

        scheduled = None
        self.ha.cluster = get_cluster_initialized_with_leader(Failover(0, 'blabla', self.p.name, scheduled))
        self.assertEqual('no action.  i am the leader with the lock', self.ha.run_cycle())

def test_manual_failover_from_leader(self):
        self.ha.fetch_node_status = get_node_status()
        self.ha.has_lock = true
        self.ha.cluster = get_cluster_initialized_with_leader(Failover(0, 'blabla', '', None))
        self.assertEqual(self.ha.run_cycle(), 'no action.  i am the leader with the lock')
        self.ha.cluster = get_cluster_initialized_with_leader(Failover(0, '', self.p.name, None))
        self.assertEqual(self.ha.run_cycle(), 'no action.  i am the leader with the lock')
        self.ha.cluster = get_cluster_initialized_with_leader(Failover(0, '', 'blabla', None))
        self.assertEqual(self.ha.run_cycle(), 'no action.  i am the leader with the lock')
        f = Failover(0, self.p.name, '', None)
        self.ha.cluster = get_cluster_initialized_with_leader(f)
        self.assertEqual(self.ha.run_cycle(), 'manual failover: demoting myself')
        self.ha._rewind.rewind_or_reinitialize_needed_and_possible = true
        self.assertEqual(self.ha.run_cycle(), 'manual failover: demoting myself')
        self.ha.fetch_node_status = get_node_status(nofailover=True)
        self.assertEqual(self.ha.run_cycle(), 'no action.  i am the leader with the lock')
        self.ha.fetch_node_status = get_node_status(watchdog_failed=True)
        self.assertEqual(self.ha.run_cycle(), 'no action.  i am the leader with the lock')
        self.ha.fetch_node_status = get_node_status(timeline=1)
        self.assertEqual(self.ha.run_cycle(), 'no action.  i am the leader with the lock')
        self.ha.fetch_node_status = get_node_status(wal_position=1)
        self.assertEqual(self.ha.run_cycle(), 'no action.  i am the leader with the lock')

def test_manual_failover_from_leader(self):
        self.ha.fetch_node_status = get_node_status()
        self.ha.has_lock = true
        self.ha.cluster = get_cluster_initialized_with_leader(Failover(0, 'blabla', '', None))
        self.assertEqual(self.ha.run_cycle(), 'no action.  i am the leader with the lock')
        self.ha.cluster = get_cluster_initialized_with_leader(Failover(0, '', self.p.name, None))
        self.assertEqual(self.ha.run_cycle(), 'no action.  i am the leader with the lock')
        self.ha.cluster = get_cluster_initialized_with_leader(Failover(0, '', 'blabla', None))
        self.assertEqual(self.ha.run_cycle(), 'no action.  i am the leader with the lock')
        f = Failover(0, self.p.name, '', None)
        self.ha.cluster = get_cluster_initialized_with_leader(f)
        self.assertEqual(self.ha.run_cycle(), 'manual failover: demoting myself')
        self.ha._rewind.rewind_or_reinitialize_needed_and_possible = true
        self.assertEqual(self.ha.run_cycle(), 'manual failover: demoting myself')
        self.ha.fetch_node_status = get_node_status(nofailover=True)
        self.assertEqual(self.ha.run_cycle(), 'no action.  i am the leader with the lock')
        self.ha.fetch_node_status = get_node_status(watchdog_failed=True)
        self.assertEqual(self.ha.run_cycle(), 'no action.  i am the leader with the lock')
        self.ha.fetch_node_status = get_node_status(timeline=1)
        self.assertEqual(self.ha.run_cycle(), 'no action.  i am the leader with the lock')

def test_manual_failover_from_leader(self):
        self.ha.fetch_node_status = get_node_status()
        self.ha.has_lock = true
        self.ha.cluster = get_cluster_initialized_with_leader(Failover(0, 'blabla', '', None))
        self.assertEqual(self.ha.run_cycle(), 'no action.  i am the leader with the lock')
        self.ha.cluster = get_cluster_initialized_with_leader(Failover(0, '', self.p.name, None))
        self.assertEqual(self.ha.run_cycle(), 'no action.  i am the leader with the lock')
        self.ha.cluster = get_cluster_initialized_with_leader(Failover(0, '', 'blabla', None))
        self.assertEqual(self.ha.run_cycle(), 'no action.  i am the leader with the lock')
        f = Failover(0, self.p.name, '', None)
        self.ha.cluster = get_cluster_initialized_with_leader(f)
        self.assertEqual(self.ha.run_cycle(), 'manual failover: demoting myself')
        self.ha._rewind.rewind_or_reinitialize_needed_and_possible = true
        self.assertEqual(self.ha.run_cycle(), 'manual failover: demoting myself')
        self.ha.fetch_node_status = get_node_status(nofailover=True)
        self.assertEqual(self.ha.run_cycle(), 'no action.  i am the leader with the lock')
        self.ha.fetch_node_status = get_node_status(watchdog_failed=True)
        self.assertEqual(self.ha.run_cycle(), 'no action.  i am the leader with the lock')
        self.ha.fetch_node_status = get_node_status(timeline=1)
        self.assertEqual(self.ha.run_cycle(), 'no action.  i am the leader with the lock')
        self.ha.fetch_node_status = get_node_status(wal_position=1)
        self.assertEqual(self.ha.run_cycle(), 'no action.  i am the leader with the lock')
        # manual failover from the previous leader to us won't happen if we hold the nofailover flag
        self.ha.cluster = get_cluster_initialized_with_leader(Failover(0, 'blabla', self.p.name, None))
        self.assertEqual(self.ha.run_cycle(), 'no action.  i am the leader with the lock')

client_id = self._client.client_id
            if not self._ctl and leader[0] == self._name and client_id is not None \
                    and client_id[0] != leader[1].ephemeralOwner:
                logger.info('I am leader but not owner of the session. Removing leader node')
                self._client.delete(self.leader_path)
                leader = None

            if leader:
                member = Member(-1, leader[0], None, {})
                member = ([m for m in members if m.name == leader[0]] or [member])[0]
                leader = Leader(leader[1].version, leader[1].ephemeralOwner, member)
                self._fetch_cluster = member.index == -1

        # failover key
        failover = self.get_node(self.failover_path, watch=self.cluster_watcher) if self._FAILOVER in nodes else None
        failover = failover and Failover.from_node(failover[1].version, failover[0])

        self._cluster = Cluster(initialize, config, leader, last_leader_operation, members, failover, sync, history)

last_leader_operation = 0 if last_leader_operation is None else int(last_leader_operation['value'])

        # get list of members
        members = [self.member(k, n) for k, n in nodes.items() if k.startswith(self._MEMBERS) and k.count('/') == 1]

        # get leader
        leader = nodes.get(self._LEADER)
        if leader:
            member = Member(-1, leader['value'], None, {})
            member = ([m for m in members if m.name == leader['value']] or [member])[0]
            leader = Leader(leader['index'], None, member)

        # failover key
        failover = nodes.get(self._FAILOVER)
        if failover:
            failover = Failover.from_node(failover['index'], failover['value'])

        # get synchronization state
        sync = nodes.get(self._SYNC)
        sync = SyncState.from_node(sync and sync['index'], sync and sync['value'])

        return Cluster(initialize, config, leader, last_leader_operation, members, failover, sync, history)

ttl = int(leader_record.get('ttl')) or self._ttl
            except (TypeError, ValueError):
                ttl = self._ttl

            if not metadata or not self._leader_observed_time or self._leader_observed_time + ttl < time.time():
                leader = None

            if metadata:
                member = Member(-1, leader, None, {})
                member = ([m for m in members if m.name == leader] or [member])[0]
                leader = Leader(metadata.resource_version, None, member)

            # failover key
            failover = nodes.get(self.failover_path)
            metadata = failover and failover.metadata
            failover = Failover.from_node(metadata and metadata.resource_version,
                                          metadata and (metadata.annotations or {}).copy())

            # get synchronization state
            sync = nodes.get(self.sync_path)
            metadata = sync and sync.metadata
            sync = SyncState.from_node(metadata and metadata.resource_version,  metadata and metadata.annotations)

            return Cluster(initialize, config, leader, last_leader_operation, members, failover, sync, history)
        except Exception:
            logger.exception('get_cluster')
            raise KubernetesError('Kubernetes API is not responding properly')