synapse/tests/handlers/test_sliding_sync.py

#
# This file is licensed under the Affero General Public License (AGPL) version 3.
#
# Copyright (C) 2024 New Vector, Ltd
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as
# published by the Free Software Foundation, either version 3 of the
# License, or (at your option) any later version.
#
# See the GNU Affero General Public License for more details:
# <https://www.gnu.org/licenses/agpl-3.0.html>.
#
# Originally licensed under the Apache License, Version 2.0:
# <http://www.apache.org/licenses/LICENSE-2.0>.
#
# [This file includes modifications made by New Vector Limited]
#
#
import logging
from copy import deepcopy
from typing import Optional
from unittest.mock import patch

from parameterized import parameterized

from twisted.test.proto_helpers import MemoryReactor

from synapse.api.constants import (
    AccountDataTypes,
    EventContentFields,
    EventTypes,
    JoinRules,
    Membership,
    RoomTypes,
)
from synapse.api.room_versions import RoomVersions
from synapse.handlers.sliding_sync import RoomSyncConfig, StateValues
from synapse.rest import admin
from synapse.rest.client import knock, login, room
from synapse.server import HomeServer
from synapse.storage.util.id_generators import MultiWriterIdGenerator
from synapse.types import JsonDict, UserID
from synapse.types.handlers import SlidingSyncConfig
from synapse.util import Clock

from tests.replication._base import BaseMultiWorkerStreamTestCase
from tests.unittest import HomeserverTestCase, TestCase

logger = logging.getLogger(__name__)


class RoomSyncConfigTestCase(TestCase):
    def _assert_room_config_equal(
        self,
        actual: RoomSyncConfig,
        expected: RoomSyncConfig,
        message_prefix: Optional[str] = None,
    ) -> None:
        self.assertEqual(actual.timeline_limit, expected.timeline_limit, message_prefix)

        # `self.assertEqual(...)` works fine to catch differences but the output is
        # almost impossible to read because of the way it truncates the output and the
        # order doesn't actually matter.
        self.assertCountEqual(
            actual.required_state_map, expected.required_state_map, message_prefix
        )
        for event_type, expected_state_keys in expected.required_state_map.items():
            self.assertCountEqual(
                actual.required_state_map[event_type],
                expected_state_keys,
                f"{message_prefix}: Mismatch for {event_type}",
            )

    @parameterized.expand(
        [
            (
                "from_list_config",
                """
                Test that we can convert a `SlidingSyncConfig.SlidingSyncList` to a
                `RoomSyncConfig`.
                """,
                # Input
                SlidingSyncConfig.SlidingSyncList(
                    timeline_limit=10,
                    required_state=[
                        (EventTypes.Name, ""),
                        (EventTypes.Member, "@foo"),
                        (EventTypes.Member, "@bar"),
                        (EventTypes.Member, "@baz"),
                        (EventTypes.CanonicalAlias, ""),
                    ],
                ),
                # Expected
                RoomSyncConfig(
                    timeline_limit=10,
                    required_state_map={
                        EventTypes.Name: {""},
                        EventTypes.Member: {
                            "@foo",
                            "@bar",
                            "@baz",
                        },
                        EventTypes.CanonicalAlias: {""},
                    },
                ),
            ),
            (
                "from_room_subscription",
                """
                Test that we can convert a `SlidingSyncConfig.RoomSubscription` to a
                `RoomSyncConfig`.
                """,
                # Input
                SlidingSyncConfig.RoomSubscription(
                    timeline_limit=10,
                    required_state=[
                        (EventTypes.Name, ""),
                        (EventTypes.Member, "@foo"),
                        (EventTypes.Member, "@bar"),
                        (EventTypes.Member, "@baz"),
                        (EventTypes.CanonicalAlias, ""),
                    ],
                ),
                # Expected
                RoomSyncConfig(
                    timeline_limit=10,
                    required_state_map={
                        EventTypes.Name: {""},
                        EventTypes.Member: {
                            "@foo",
                            "@bar",
                            "@baz",
                        },
                        EventTypes.CanonicalAlias: {""},
                    },
                ),
            ),
            (
                "wildcard",
                """
                Test that a wildcard (*) for both the `event_type` and `state_key` will override
                all other values.

                Note: MSC3575 describes different behavior to how we're handling things here but
                since it's not wrong to return more state than requested (`required_state` is
                just the minimum requested), it doesn't matter if we include things that the
                client wanted excluded. This complexity is also under scrutiny, see
                https://github.com/matrix-org/matrix-spec-proposals/pull/3575#discussion_r1185109050

                > One unique exception is when you request all state events via ["*", "*"]. When used,
                > all state events are returned by default, and additional entries FILTER OUT the returned set
                > of state events. These additional entries cannot use '*' themselves.
                > For example, ["*", "*"], ["m.room.member", "@alice:example.com"] will _exclude_ every m.room.member
                > event _except_ for @alice:example.com, and include every other state event.
                > In addition, ["*", "*"], ["m.space.child", "*"] is an error, the m.space.child filter is not
                > required as it would have been returned anyway.
                >
                > -- MSC3575 (https://github.com/matrix-org/matrix-spec-proposals/pull/3575)
                """,
                # Input
                SlidingSyncConfig.SlidingSyncList(
                    timeline_limit=10,
                    required_state=[
                        (EventTypes.Name, ""),
                        (StateValues.WILDCARD, StateValues.WILDCARD),
                        (EventTypes.Member, "@foo"),
                        (EventTypes.CanonicalAlias, ""),
                    ],
                ),
                # Expected
                RoomSyncConfig(
                    timeline_limit=10,
                    required_state_map={
                        StateValues.WILDCARD: {StateValues.WILDCARD},
                    },
                ),
            ),
            (
                "wildcard_type",
                """
                Test that a wildcard (*) as a `event_type` will override all other values for the
                same `state_key`.
                """,
                # Input
                SlidingSyncConfig.SlidingSyncList(
                    timeline_limit=10,
                    required_state=[
                        (EventTypes.Name, ""),
                        (StateValues.WILDCARD, ""),
                        (EventTypes.Member, "@foo"),
                        (EventTypes.CanonicalAlias, ""),
                    ],
                ),
                # Expected
                RoomSyncConfig(
                    timeline_limit=10,
                    required_state_map={
                        StateValues.WILDCARD: {""},
                        EventTypes.Member: {"@foo"},
                    },
                ),
            ),
            (
                "multiple_wildcard_type",
                """
                Test that multiple wildcard (*) as a `event_type` will override all other values
                for the same `state_key`.
                """,
                # Input
                SlidingSyncConfig.SlidingSyncList(
                    timeline_limit=10,
                    required_state=[
                        (EventTypes.Name, ""),
                        (StateValues.WILDCARD, ""),
                        (EventTypes.Member, "@foo"),
                        (StateValues.WILDCARD, "@foo"),
                        ("org.matrix.personal_count", "@foo"),
                        (EventTypes.Member, "@bar"),
                        (EventTypes.CanonicalAlias, ""),
                    ],
                ),
                # Expected
                RoomSyncConfig(
                    timeline_limit=10,
                    required_state_map={
                        StateValues.WILDCARD: {
                            "",
                            "@foo",
                        },
                        EventTypes.Member: {"@bar"},
                    },
                ),
            ),
            (
                "wildcard_state_key",
                """
                Test that a wildcard (*) as a `state_key` will override all other values for the
                same `event_type`.
                """,
                # Input
                SlidingSyncConfig.SlidingSyncList(
                    timeline_limit=10,
                    required_state=[
                        (EventTypes.Name, ""),
                        (EventTypes.Member, "@foo"),
                        (EventTypes.Member, StateValues.WILDCARD),
                        (EventTypes.Member, "@bar"),
                        (EventTypes.Member, StateValues.LAZY),
                        (EventTypes.Member, "@baz"),
                        (EventTypes.CanonicalAlias, ""),
                    ],
                ),
                # Expected
                RoomSyncConfig(
                    timeline_limit=10,
                    required_state_map={
                        EventTypes.Name: {""},
                        EventTypes.Member: {
                            StateValues.WILDCARD,
                        },
                        EventTypes.CanonicalAlias: {""},
                    },
                ),
            ),
            (
                "wildcard_merge",
                """
                Test that a wildcard (*) entries for the `event_type` and another one for
                `state_key` will play together.
                """,
                # Input
                SlidingSyncConfig.SlidingSyncList(
                    timeline_limit=10,
                    required_state=[
                        (EventTypes.Name, ""),
                        (StateValues.WILDCARD, ""),
                        (EventTypes.Member, "@foo"),
                        (EventTypes.Member, StateValues.WILDCARD),
                        (EventTypes.Member, "@bar"),
                        (EventTypes.CanonicalAlias, ""),
                    ],
                ),
                # Expected
                RoomSyncConfig(
                    timeline_limit=10,
                    required_state_map={
                        StateValues.WILDCARD: {""},
                        EventTypes.Member: {StateValues.WILDCARD},
                    },
                ),
            ),
            (
                "wildcard_merge2",
                """
                Test that an all wildcard ("*", "*") entry will override any other
                values (including other wildcards).
                """,
                # Input
                SlidingSyncConfig.SlidingSyncList(
                    timeline_limit=10,
                    required_state=[
                        (EventTypes.Name, ""),
                        (StateValues.WILDCARD, ""),
                        (EventTypes.Member, StateValues.WILDCARD),
                        (EventTypes.Member, "@foo"),
                        # One of these should take precedence over everything else
                        (StateValues.WILDCARD, StateValues.WILDCARD),
                        (StateValues.WILDCARD, StateValues.WILDCARD),
                        (EventTypes.CanonicalAlias, ""),
                    ],
                ),
                # Expected
                RoomSyncConfig(
                    timeline_limit=10,
                    required_state_map={
                        StateValues.WILDCARD: {StateValues.WILDCARD},
                    },
                ),
            ),
            (
                "lazy_members",
                """
                `$LAZY` room members should just be another additional key next to other
                explicit keys. We will unroll the special `$LAZY` meaning later.
                """,
                # Input
                SlidingSyncConfig.SlidingSyncList(
                    timeline_limit=10,
                    required_state=[
                        (EventTypes.Name, ""),
                        (EventTypes.Member, "@foo"),
                        (EventTypes.Member, "@bar"),
                        (EventTypes.Member, StateValues.LAZY),
                        (EventTypes.Member, "@baz"),
                        (EventTypes.CanonicalAlias, ""),
                    ],
                ),
                # Expected
                RoomSyncConfig(
                    timeline_limit=10,
                    required_state_map={
                        EventTypes.Name: {""},
                        EventTypes.Member: {
                            "@foo",
                            "@bar",
                            StateValues.LAZY,
                            "@baz",
                        },
                        EventTypes.CanonicalAlias: {""},
                    },
                ),
            ),
        ]
    )
    def test_from_room_config(
        self,
        _test_label: str,
        _test_description: str,
        room_params: SlidingSyncConfig.CommonRoomParameters,
        expected_room_sync_config: RoomSyncConfig,
    ) -> None:
        """
        Test `RoomSyncConfig.from_room_config(room_params)` will result in the `expected_room_sync_config`.
        """
        room_sync_config = RoomSyncConfig.from_room_config(room_params)

        self._assert_room_config_equal(
            room_sync_config,
            expected_room_sync_config,
        )

    @parameterized.expand(
        [
            (
                "no_direct_overlap",
                # A
                RoomSyncConfig(
                    timeline_limit=9,
                    required_state_map={
                        EventTypes.Name: {""},
                        EventTypes.Member: {
                            "@foo",
                            "@bar",
                        },
                    },
                ),
                # B
                RoomSyncConfig(
                    timeline_limit=10,
                    required_state_map={
                        EventTypes.Member: {
                            StateValues.LAZY,
                            "@baz",
                        },
                        EventTypes.CanonicalAlias: {""},
                    },
                ),
                # Expected
                RoomSyncConfig(
                    timeline_limit=10,
                    required_state_map={
                        EventTypes.Name: {""},
                        EventTypes.Member: {
                            "@foo",
                            "@bar",
                            StateValues.LAZY,
                            "@baz",
                        },
                        EventTypes.CanonicalAlias: {""},
                    },
                ),
            ),
            (
                "wildcard_overlap",
                # A
                RoomSyncConfig(
                    timeline_limit=10,
                    required_state_map={
                        StateValues.WILDCARD: {StateValues.WILDCARD},
                    },
                ),
                # B
                RoomSyncConfig(
                    timeline_limit=9,
                    required_state_map={
                        EventTypes.Dummy: {StateValues.WILDCARD},
                        StateValues.WILDCARD: {"@bar"},
                        EventTypes.Member: {"@foo"},
                    },
                ),
                # Expected
                RoomSyncConfig(
                    timeline_limit=10,
                    required_state_map={
                        StateValues.WILDCARD: {StateValues.WILDCARD},
                    },
                ),
            ),
            (
                "state_type_wildcard_overlap",
                # A
                RoomSyncConfig(
                    timeline_limit=10,
                    required_state_map={
                        EventTypes.Dummy: {"dummy"},
                        StateValues.WILDCARD: {
                            "",
                            "@foo",
                        },
                        EventTypes.Member: {"@bar"},
                    },
                ),
                # B
                RoomSyncConfig(
                    timeline_limit=9,
                    required_state_map={
                        EventTypes.Dummy: {"dummy2"},
                        StateValues.WILDCARD: {
                            "",
                            "@bar",
                        },
                        EventTypes.Member: {"@foo"},
                    },
                ),
                # Expected
                RoomSyncConfig(
                    timeline_limit=10,
                    required_state_map={
                        EventTypes.Dummy: {
                            "dummy",
                            "dummy2",
                        },
                        StateValues.WILDCARD: {
                            "",
                            "@foo",
                            "@bar",
                        },
                    },
                ),
            ),
            (
                "state_key_wildcard_overlap",
                # A
                RoomSyncConfig(
                    timeline_limit=10,
                    required_state_map={
                        EventTypes.Dummy: {"dummy"},
                        EventTypes.Member: {StateValues.WILDCARD},
                        "org.matrix.flowers": {StateValues.WILDCARD},
                    },
                ),
                # B
                RoomSyncConfig(
                    timeline_limit=9,
                    required_state_map={
                        EventTypes.Dummy: {StateValues.WILDCARD},
                        EventTypes.Member: {StateValues.WILDCARD},
                        "org.matrix.flowers": {"tulips"},
                    },
                ),
                # Expected
                RoomSyncConfig(
                    timeline_limit=10,
                    required_state_map={
                        EventTypes.Dummy: {StateValues.WILDCARD},
                        EventTypes.Member: {StateValues.WILDCARD},
                        "org.matrix.flowers": {StateValues.WILDCARD},
                    },
                ),
            ),
            (
                "state_type_and_state_key_wildcard_merge",
                # A
                RoomSyncConfig(
                    timeline_limit=10,
                    required_state_map={
                        EventTypes.Dummy: {"dummy"},
                        StateValues.WILDCARD: {
                            "",
                            "@foo",
                        },
                        EventTypes.Member: {"@bar"},
                    },
                ),
                # B
                RoomSyncConfig(
                    timeline_limit=9,
                    required_state_map={
                        EventTypes.Dummy: {"dummy2"},
                        StateValues.WILDCARD: {""},
                        EventTypes.Member: {StateValues.WILDCARD},
                    },
                ),
                # Expected
                RoomSyncConfig(
                    timeline_limit=10,
                    required_state_map={
                        EventTypes.Dummy: {
                            "dummy",
                            "dummy2",
                        },
                        StateValues.WILDCARD: {
                            "",
                            "@foo",
                        },
                        EventTypes.Member: {StateValues.WILDCARD},
                    },
                ),
            ),
        ]
    )
    def test_combine_room_sync_config(
        self,
        _test_label: str,
        a: RoomSyncConfig,
        b: RoomSyncConfig,
        expected: RoomSyncConfig,
    ) -> None:
        """
        Combine A into B and B into A to make sure we get the same result.
        """
        # Since we're mutating these in place, make a copy for each of our trials
        room_sync_config_a = deepcopy(a)
        room_sync_config_b = deepcopy(b)

        # Combine B into A
        room_sync_config_a.combine_room_sync_config(room_sync_config_b)

        self._assert_room_config_equal(room_sync_config_a, expected, "B into A")

        # Since we're mutating these in place, make a copy for each of our trials
        room_sync_config_a = deepcopy(a)
        room_sync_config_b = deepcopy(b)

        # Combine A into B
        room_sync_config_b.combine_room_sync_config(room_sync_config_a)

        self._assert_room_config_equal(room_sync_config_b, expected, "A into B")


class GetSyncRoomIdsForUserTestCase(HomeserverTestCase):
    """
    Tests Sliding Sync handler `get_sync_room_ids_for_user()` to make sure it returns
    the correct list of rooms IDs.
    """

    servlets = [
        admin.register_servlets,
        knock.register_servlets,
        login.register_servlets,
        room.register_servlets,
    ]

    def default_config(self) -> JsonDict:
        config = super().default_config()
        # Enable sliding sync
        config["experimental_features"] = {"msc3575_enabled": True}
        return config

    def prepare(self, reactor: MemoryReactor, clock: Clock, hs: HomeServer) -> None:
        self.sliding_sync_handler = self.hs.get_sliding_sync_handler()
        self.store = self.hs.get_datastores().main
        self.event_sources = hs.get_event_sources()
        self.storage_controllers = hs.get_storage_controllers()

    def test_no_rooms(self) -> None:
        """
        Test when the user has never joined any rooms before
        """
        user1_id = self.register_user("user1", "pass")
        # user1_tok = self.login(user1_id, "pass")

        now_token = self.event_sources.get_current_token()

        room_id_results = self.get_success(
            self.sliding_sync_handler.get_sync_room_ids_for_user(
                UserID.from_string(user1_id),
                from_token=now_token,
                to_token=now_token,
            )
        )

        self.assertEqual(room_id_results.keys(), set())

    def test_get_newly_joined_room(self) -> None:
        """
        Test that rooms that the user has newly_joined show up. newly_joined is when you
        join after the `from_token` and <= `to_token`.
        """
        user1_id = self.register_user("user1", "pass")
        user1_tok = self.login(user1_id, "pass")
        user2_id = self.register_user("user2", "pass")
        user2_tok = self.login(user2_id, "pass")

        before_room_token = self.event_sources.get_current_token()

        room_id = self.helper.create_room_as(user2_id, tok=user2_tok)
        join_response = self.helper.join(room_id, user1_id, tok=user1_tok)

        after_room_token = self.event_sources.get_current_token()

        room_id_results = self.get_success(
            self.sliding_sync_handler.get_sync_room_ids_for_user(
                UserID.from_string(user1_id),
                from_token=before_room_token,
                to_token=after_room_token,
            )
        )

        self.assertEqual(room_id_results.keys(), {room_id})
        # It should be pointing to the join event (latest membership event in the
        # from/to range)
        self.assertEqual(
            room_id_results[room_id].event_id,
            join_response["event_id"],
        )
        # We should be considered `newly_joined` because we joined during the token
        # range
        self.assertEqual(room_id_results[room_id].newly_joined, True)

    def test_get_already_joined_room(self) -> None:
        """
        Test that rooms that the user is already joined show up.
        """
        user1_id = self.register_user("user1", "pass")
        user1_tok = self.login(user1_id, "pass")
        user2_id = self.register_user("user2", "pass")
        user2_tok = self.login(user2_id, "pass")

        room_id = self.helper.create_room_as(user2_id, tok=user2_tok)
        join_response = self.helper.join(room_id, user1_id, tok=user1_tok)

        after_room_token = self.event_sources.get_current_token()

        room_id_results = self.get_success(
            self.sliding_sync_handler.get_sync_room_ids_for_user(
                UserID.from_string(user1_id),
                from_token=after_room_token,
                to_token=after_room_token,
            )
        )

        self.assertEqual(room_id_results.keys(), {room_id})
        # It should be pointing to the join event (latest membership event in the
        # from/to range)
        self.assertEqual(
            room_id_results[room_id].event_id,
            join_response["event_id"],
        )
        # We should *NOT* be `newly_joined` because we joined before the token range
        self.assertEqual(room_id_results[room_id].newly_joined, False)

    def test_get_invited_banned_knocked_room(self) -> None:
        """
        Test that rooms that the user is invited to, banned from, and knocked on show
        up.
        """
        user1_id = self.register_user("user1", "pass")
        user1_tok = self.login(user1_id, "pass")
        user2_id = self.register_user("user2", "pass")
        user2_tok = self.login(user2_id, "pass")

        before_room_token = self.event_sources.get_current_token()

        # Setup the invited room (user2 invites user1 to the room)
        invited_room_id = self.helper.create_room_as(user2_id, tok=user2_tok)
        invite_response = self.helper.invite(
            invited_room_id, targ=user1_id, tok=user2_tok
        )

        # Setup the ban room (user2 bans user1 from the room)
        ban_room_id = self.helper.create_room_as(
            user2_id, tok=user2_tok, is_public=True
        )
        self.helper.join(ban_room_id, user1_id, tok=user1_tok)
        ban_response = self.helper.ban(
            ban_room_id, src=user2_id, targ=user1_id, tok=user2_tok
        )

        # Setup the knock room (user1 knocks on the room)
        knock_room_id = self.helper.create_room_as(
            user2_id, tok=user2_tok, room_version=RoomVersions.V7.identifier
        )
        self.helper.send_state(
            knock_room_id,
            EventTypes.JoinRules,
            {"join_rule": JoinRules.KNOCK},
            tok=user2_tok,
        )
        # User1 knocks on the room
        knock_channel = self.make_request(
            "POST",
            "/_matrix/client/r0/knock/%s" % (knock_room_id,),
            b"{}",
            user1_tok,
        )
        self.assertEqual(knock_channel.code, 200, knock_channel.result)
        knock_room_membership_state_event = self.get_success(
            self.storage_controllers.state.get_current_state_event(
                knock_room_id, EventTypes.Member, user1_id
            )
        )
        assert knock_room_membership_state_event is not None

        after_room_token = self.event_sources.get_current_token()

        room_id_results = self.get_success(
            self.sliding_sync_handler.get_sync_room_ids_for_user(
                UserID.from_string(user1_id),
                from_token=before_room_token,
                to_token=after_room_token,
            )
        )

        # Ensure that the invited, ban, and knock rooms show up
        self.assertEqual(
            room_id_results.keys(),
            {
                invited_room_id,
                ban_room_id,
                knock_room_id,
            },
        )
        # It should be pointing to the the respective membership event (latest
        # membership event in the from/to range)
        self.assertEqual(
            room_id_results[invited_room_id].event_id,
            invite_response["event_id"],
        )
        self.assertEqual(
            room_id_results[ban_room_id].event_id,
            ban_response["event_id"],
        )
        self.assertEqual(
            room_id_results[knock_room_id].event_id,
            knock_room_membership_state_event.event_id,
        )
        # We should *NOT* be `newly_joined` because we were not joined at the the time
        # of the `to_token`.
        self.assertEqual(room_id_results[invited_room_id].newly_joined, False)
        self.assertEqual(room_id_results[ban_room_id].newly_joined, False)
        self.assertEqual(room_id_results[knock_room_id].newly_joined, False)

    def test_get_kicked_room(self) -> None:
        """
        Test that a room that the user was kicked from still shows up. When the user
        comes back to their client, they should see that they were kicked.
        """
        user1_id = self.register_user("user1", "pass")
        user1_tok = self.login(user1_id, "pass")
        user2_id = self.register_user("user2", "pass")
        user2_tok = self.login(user2_id, "pass")

        # Setup the kick room (user2 kicks user1 from the room)
        kick_room_id = self.helper.create_room_as(
            user2_id, tok=user2_tok, is_public=True
        )
        self.helper.join(kick_room_id, user1_id, tok=user1_tok)
        # Kick user1 from the room
        kick_response = self.helper.change_membership(
            room=kick_room_id,
            src=user2_id,
            targ=user1_id,
            tok=user2_tok,
            membership=Membership.LEAVE,
            extra_data={
                "reason": "Bad manners",
            },
        )

        after_kick_token = self.event_sources.get_current_token()

        room_id_results = self.get_success(
            self.sliding_sync_handler.get_sync_room_ids_for_user(
                UserID.from_string(user1_id),
                from_token=after_kick_token,
                to_token=after_kick_token,
            )
        )

        # The kicked room should show up
        self.assertEqual(room_id_results.keys(), {kick_room_id})
        # It should be pointing to the latest membership event in the from/to range
        self.assertEqual(
            room_id_results[kick_room_id].event_id,
            kick_response["event_id"],
        )
        # We should *NOT* be `newly_joined` because we were not joined at the the time
        # of the `to_token`.
        self.assertEqual(room_id_results[kick_room_id].newly_joined, False)

    def test_forgotten_rooms(self) -> None:
        """
        Forgotten rooms do not show up even if we forget after the from/to range.

        Ideally, we would be able to track when the `/forget` happens and apply it
        accordingly in the token range but the forgotten flag is only an extra bool in
        the `room_memberships` table.
        """
        user1_id = self.register_user("user1", "pass")
        user1_tok = self.login(user1_id, "pass")
        user2_id = self.register_user("user2", "pass")
        user2_tok = self.login(user2_id, "pass")

        # Setup a normal room that we leave. This won't show up in the sync response
        # because we left it before our token but is good to check anyway.
        leave_room_id = self.helper.create_room_as(
            user2_id, tok=user2_tok, is_public=True
        )
        self.helper.join(leave_room_id, user1_id, tok=user1_tok)
        self.helper.leave(leave_room_id, user1_id, tok=user1_tok)

        # Setup the ban room (user2 bans user1 from the room)
        ban_room_id = self.helper.create_room_as(
            user2_id, tok=user2_tok, is_public=True
        )
        self.helper.join(ban_room_id, user1_id, tok=user1_tok)
        self.helper.ban(ban_room_id, src=user2_id, targ=user1_id, tok=user2_tok)

        # Setup the kick room (user2 kicks user1 from the room)
        kick_room_id = self.helper.create_room_as(
            user2_id, tok=user2_tok, is_public=True
        )
        self.helper.join(kick_room_id, user1_id, tok=user1_tok)
        # Kick user1 from the room
        self.helper.change_membership(
            room=kick_room_id,
            src=user2_id,
            targ=user1_id,
            tok=user2_tok,
            membership=Membership.LEAVE,
            extra_data={
                "reason": "Bad manners",
            },
        )

        before_room_forgets = self.event_sources.get_current_token()

        # Forget the room after we already have our tokens. This doesn't change
        # the membership event itself but will mark it internally in Synapse
        channel = self.make_request(
            "POST",
            f"/_matrix/client/r0/rooms/{leave_room_id}/forget",
            content={},
            access_token=user1_tok,
        )
        self.assertEqual(channel.code, 200, channel.result)
        channel = self.make_request(
            "POST",
            f"/_matrix/client/r0/rooms/{ban_room_id}/forget",
            content={},
            access_token=user1_tok,
        )
        self.assertEqual(channel.code, 200, channel.result)
        channel = self.make_request(
            "POST",
            f"/_matrix/client/r0/rooms/{kick_room_id}/forget",
            content={},
            access_token=user1_tok,
        )
        self.assertEqual(channel.code, 200, channel.result)

        room_id_results = self.get_success(
            self.sliding_sync_handler.get_sync_room_ids_for_user(
                UserID.from_string(user1_id),
                from_token=before_room_forgets,
                to_token=before_room_forgets,
            )
        )

        # We shouldn't see the room because it was forgotten
        self.assertEqual(room_id_results.keys(), set())

    def test_only_newly_left_rooms_show_up(self) -> None:
        """
        Test that newly_left rooms still show up in the sync response but rooms that
        were left before the `from_token` don't show up. See condition "2)" comments in
        the `get_sync_room_ids_for_user` method.
        """
        user1_id = self.register_user("user1", "pass")
        user1_tok = self.login(user1_id, "pass")

        # Leave before we calculate the `from_token`
        room_id1 = self.helper.create_room_as(user1_id, tok=user1_tok)
        self.helper.leave(room_id1, user1_id, tok=user1_tok)

        after_room1_token = self.event_sources.get_current_token()

        # Leave during the from_token/to_token range (newly_left)
        room_id2 = self.helper.create_room_as(user1_id, tok=user1_tok)
        _leave_response2 = self.helper.leave(room_id2, user1_id, tok=user1_tok)

        after_room2_token = self.event_sources.get_current_token()

        room_id_results = self.get_success(
            self.sliding_sync_handler.get_sync_room_ids_for_user(
                UserID.from_string(user1_id),
                from_token=after_room1_token,
                to_token=after_room2_token,
            )
        )

        # Only the newly_left room should show up
        self.assertEqual(room_id_results.keys(), {room_id2})
        # It should be pointing to the latest membership event in the from/to range but
        # the `event_id` is `None` because we left the room causing the server to leave
        # the room because no other local users are in it (quirk of the
        # `current_state_delta_stream` table that we source things from)
        self.assertEqual(
            room_id_results[room_id2].event_id,
            None,  # _leave_response2["event_id"],
        )
        # We should *NOT* be `newly_joined` because we are instead `newly_left`
        self.assertEqual(room_id_results[room_id2].newly_joined, False)

    def test_no_joins_after_to_token(self) -> None:
        """
        Rooms we join after the `to_token` should *not* show up. See condition "1b)"
        comments in the `get_sync_room_ids_for_user()` method.
        """
        user1_id = self.register_user("user1", "pass")
        user1_tok = self.login(user1_id, "pass")
        user2_id = self.register_user("user2", "pass")
        user2_tok = self.login(user2_id, "pass")

        before_room1_token = self.event_sources.get_current_token()

        room_id1 = self.helper.create_room_as(user2_id, tok=user2_tok)
        join_response1 = self.helper.join(room_id1, user1_id, tok=user1_tok)

        after_room1_token = self.event_sources.get_current_token()

        # Room join after our `to_token` shouldn't show up
        room_id2 = self.helper.create_room_as(user2_id, tok=user2_tok)
        self.helper.join(room_id2, user1_id, tok=user1_tok)

        room_id_results = self.get_success(
            self.sliding_sync_handler.get_sync_room_ids_for_user(
                UserID.from_string(user1_id),
                from_token=before_room1_token,
                to_token=after_room1_token,
            )
        )

        self.assertEqual(room_id_results.keys(), {room_id1})
        # It should be pointing to the latest membership event in the from/to range
        self.assertEqual(
            room_id_results[room_id1].event_id,
            join_response1["event_id"],
        )
        # We should be `newly_joined` because we joined during the token range
        self.assertEqual(room_id_results[room_id1].newly_joined, True)

    def test_join_during_range_and_left_room_after_to_token(self) -> None:
        """
        Room still shows up if we left the room but were joined during the
        from_token/to_token. See condition "1a)" comments in the
        `get_sync_room_ids_for_user()` method.
        """
        user1_id = self.register_user("user1", "pass")
        user1_tok = self.login(user1_id, "pass")
        user2_id = self.register_user("user2", "pass")
        user2_tok = self.login(user2_id, "pass")

        before_room1_token = self.event_sources.get_current_token()

        room_id1 = self.helper.create_room_as(user2_id, tok=user2_tok)
        join_response = self.helper.join(room_id1, user1_id, tok=user1_tok)

        after_room1_token = self.event_sources.get_current_token()

        # Leave the room after we already have our tokens
        leave_response = self.helper.leave(room_id1, user1_id, tok=user1_tok)

        room_id_results = self.get_success(
            self.sliding_sync_handler.get_sync_room_ids_for_user(
                UserID.from_string(user1_id),
                from_token=before_room1_token,
                to_token=after_room1_token,
            )
        )

        # We should still see the room because we were joined during the
        # from_token/to_token time period.
        self.assertEqual(room_id_results.keys(), {room_id1})
        # It should be pointing to the latest membership event in the from/to range
        self.assertEqual(
            room_id_results[room_id1].event_id,
            join_response["event_id"],
            "Corresponding map to disambiguate the opaque event IDs: "
            + str(
                {
                    "join_response": join_response["event_id"],
                    "leave_response": leave_response["event_id"],
                }
            ),
        )
        # We should be `newly_joined` because we joined during the token range
        self.assertEqual(room_id_results[room_id1].newly_joined, True)

    def test_join_before_range_and_left_room_after_to_token(self) -> None:
        """
        Room still shows up if we left the room but were joined before the `from_token`
        so it should show up. See condition "1a)" comments in the
        `get_sync_room_ids_for_user()` method.
        """
        user1_id = self.register_user("user1", "pass")
        user1_tok = self.login(user1_id, "pass")
        user2_id = self.register_user("user2", "pass")
        user2_tok = self.login(user2_id, "pass")

        room_id1 = self.helper.create_room_as(user2_id, tok=user2_tok)
        join_response = self.helper.join(room_id1, user1_id, tok=user1_tok)

        after_room1_token = self.event_sources.get_current_token()

        # Leave the room after we already have our tokens
        leave_response = self.helper.leave(room_id1, user1_id, tok=user1_tok)

        room_id_results = self.get_success(
            self.sliding_sync_handler.get_sync_room_ids_for_user(
                UserID.from_string(user1_id),
                from_token=after_room1_token,
                to_token=after_room1_token,
            )
        )

        # We should still see the room because we were joined before the `from_token`
        self.assertEqual(room_id_results.keys(), {room_id1})
        # It should be pointing to the latest membership event in the from/to range
        self.assertEqual(
            room_id_results[room_id1].event_id,
            join_response["event_id"],
            "Corresponding map to disambiguate the opaque event IDs: "
            + str(
                {
                    "join_response": join_response["event_id"],
                    "leave_response": leave_response["event_id"],
                }
            ),
        )
        # We should *NOT* be `newly_joined` because we joined before the token range
        self.assertEqual(room_id_results[room_id1].newly_joined, False)

    def test_kicked_before_range_and_left_after_to_token(self) -> None:
        """
        Room still shows up if we left the room but were kicked before the `from_token`
        so it should show up. See condition "1a)" comments in the
        `get_sync_room_ids_for_user()` method.
        """
        user1_id = self.register_user("user1", "pass")
        user1_tok = self.login(user1_id, "pass")
        user2_id = self.register_user("user2", "pass")
        user2_tok = self.login(user2_id, "pass")

        # Setup the kick room (user2 kicks user1 from the room)
        kick_room_id = self.helper.create_room_as(
            user2_id, tok=user2_tok, is_public=True
        )
        join_response1 = self.helper.join(kick_room_id, user1_id, tok=user1_tok)
        # Kick user1 from the room
        kick_response = self.helper.change_membership(
            room=kick_room_id,
            src=user2_id,
            targ=user1_id,
            tok=user2_tok,
            membership=Membership.LEAVE,
            extra_data={
                "reason": "Bad manners",
            },
        )

        after_kick_token = self.event_sources.get_current_token()

        # Leave the room after we already have our tokens
        #
        # We have to join before we can leave (leave -> leave isn't a valid transition
        # or at least it doesn't work in Synapse, 403 forbidden)
        join_response2 = self.helper.join(kick_room_id, user1_id, tok=user1_tok)
        leave_response = self.helper.leave(kick_room_id, user1_id, tok=user1_tok)

        room_id_results = self.get_success(
            self.sliding_sync_handler.get_sync_room_ids_for_user(
                UserID.from_string(user1_id),
                from_token=after_kick_token,
                to_token=after_kick_token,
            )
        )

        # We shouldn't see the room because it was forgotten
        self.assertEqual(room_id_results.keys(), {kick_room_id})
        # It should be pointing to the latest membership event in the from/to range
        self.assertEqual(
            room_id_results[kick_room_id].event_id,
            kick_response["event_id"],
            "Corresponding map to disambiguate the opaque event IDs: "
            + str(
                {
                    "join_response1": join_response1["event_id"],
                    "kick_response": kick_response["event_id"],
                    "join_response2": join_response2["event_id"],
                    "leave_response": leave_response["event_id"],
                }
            ),
        )
        # We should *NOT* be `newly_joined` because we were kicked
        self.assertEqual(room_id_results[kick_room_id].newly_joined, False)

    def test_newly_left_during_range_and_join_leave_after_to_token(self) -> None:
        """
        Newly left room should show up. But we're also testing that joining and leaving
        after the `to_token` doesn't mess with the results. See condition "2)" and "1a)"
        comments in the `get_sync_room_ids_for_user()` method.
        """
        user1_id = self.register_user("user1", "pass")
        user1_tok = self.login(user1_id, "pass")
        user2_id = self.register_user("user2", "pass")
        user2_tok = self.login(user2_id, "pass")

        before_room1_token = self.event_sources.get_current_token()

        # We create the room with user2 so the room isn't left with no members when we
        # leave and can still re-join.
        room_id1 = self.helper.create_room_as(user2_id, tok=user2_tok, is_public=True)
        # Join and leave the room during the from/to range
        join_response1 = self.helper.join(room_id1, user1_id, tok=user1_tok)
        leave_response1 = self.helper.leave(room_id1, user1_id, tok=user1_tok)

        after_room1_token = self.event_sources.get_current_token()

        # Join and leave the room after we already have our tokens
        join_response2 = self.helper.join(room_id1, user1_id, tok=user1_tok)
        leave_response2 = self.helper.leave(room_id1, user1_id, tok=user1_tok)

        room_id_results = self.get_success(
            self.sliding_sync_handler.get_sync_room_ids_for_user(
                UserID.from_string(user1_id),
                from_token=before_room1_token,
                to_token=after_room1_token,
            )
        )

        # Room should still show up because it's newly_left during the from/to range
        self.assertEqual(room_id_results.keys(), {room_id1})
        # It should be pointing to the latest membership event in the from/to range
        self.assertEqual(
            room_id_results[room_id1].event_id,
            leave_response1["event_id"],
            "Corresponding map to disambiguate the opaque event IDs: "
            + str(
                {
                    "join_response1": join_response1["event_id"],
                    "leave_response1": leave_response1["event_id"],
                    "join_response2": join_response2["event_id"],
                    "leave_response2": leave_response2["event_id"],
                }
            ),
        )
        # We should *NOT* be `newly_joined` because we left during the token range
        self.assertEqual(room_id_results[room_id1].newly_joined, False)

    def test_newly_left_during_range_and_join_after_to_token(self) -> None:
        """
        Newly left room should show up. But we're also testing that joining after the
        `to_token` doesn't mess with the results. See condition "2)" and "1b)" comments
        in the `get_sync_room_ids_for_user()` method.
        """
        user1_id = self.register_user("user1", "pass")
        user1_tok = self.login(user1_id, "pass")
        user2_id = self.register_user("user2", "pass")
        user2_tok = self.login(user2_id, "pass")

        before_room1_token = self.event_sources.get_current_token()

        # We create the room with user2 so the room isn't left with no members when we
        # leave and can still re-join.
        room_id1 = self.helper.create_room_as(user2_id, tok=user2_tok, is_public=True)
        # Join and leave the room during the from/to range
        join_response1 = self.helper.join(room_id1, user1_id, tok=user1_tok)
        leave_response1 = self.helper.leave(room_id1, user1_id, tok=user1_tok)

        after_room1_token = self.event_sources.get_current_token()

        # Join the room after we already have our tokens
        join_response2 = self.helper.join(room_id1, user1_id, tok=user1_tok)

        room_id_results = self.get_success(
            self.sliding_sync_handler.get_sync_room_ids_for_user(
                UserID.from_string(user1_id),
                from_token=before_room1_token,
                to_token=after_room1_token,
            )
        )

        # Room should still show up because it's newly_left during the from/to range
        self.assertEqual(room_id_results.keys(), {room_id1})
        # It should be pointing to the latest membership event in the from/to range
        self.assertEqual(
            room_id_results[room_id1].event_id,
            leave_response1["event_id"],
            "Corresponding map to disambiguate the opaque event IDs: "
            + str(
                {
                    "join_response1": join_response1["event_id"],
                    "leave_response1": leave_response1["event_id"],
                    "join_response2": join_response2["event_id"],
                }
            ),
        )
        # We should *NOT* be `newly_joined` because we left during the token range
        self.assertEqual(room_id_results[room_id1].newly_joined, False)

    def test_no_from_token(self) -> None:
        """
        Test that if we don't provide a `from_token`, we get all the rooms that we we're
        joined up to the `to_token`.

        Providing `from_token` only really has the effect that it adds `newly_left`
        rooms to the response.
        """
        user1_id = self.register_user("user1", "pass")
        user1_tok = self.login(user1_id, "pass")
        user2_id = self.register_user("user2", "pass")
        user2_tok = self.login(user2_id, "pass")

        # We create the room with user2 so the room isn't left with no members when we
        # leave and can still re-join.
        room_id1 = self.helper.create_room_as(user2_id, tok=user2_tok, is_public=True)
        room_id2 = self.helper.create_room_as(user2_id, tok=user2_tok, is_public=True)

        # Join room1
        join_response1 = self.helper.join(room_id1, user1_id, tok=user1_tok)

        # Join and leave the room2 before the `to_token`
        self.helper.join(room_id2, user1_id, tok=user1_tok)
        self.helper.leave(room_id2, user1_id, tok=user1_tok)

        after_room1_token = self.event_sources.get_current_token()

        # Join the room2 after we already have our tokens
        self.helper.join(room_id2, user1_id, tok=user1_tok)

        room_id_results = self.get_success(
            self.sliding_sync_handler.get_sync_room_ids_for_user(
                UserID.from_string(user1_id),
                from_token=None,
                to_token=after_room1_token,
            )
        )

        # Only rooms we were joined to before the `to_token` should show up
        self.assertEqual(room_id_results.keys(), {room_id1})
        # It should be pointing to the latest membership event in the from/to range
        self.assertEqual(
            room_id_results[room_id1].event_id,
            join_response1["event_id"],
        )
        # We should *NOT* be `newly_joined` because there is no `from_token` to
        # define a "live" range to compare against
        self.assertEqual(room_id_results[room_id1].newly_joined, False)

    def test_from_token_ahead_of_to_token(self) -> None:
        """
        Test when the provided `from_token` comes after the `to_token`. We should
        basically expect the same result as having no `from_token`.
        """
        user1_id = self.register_user("user1", "pass")
        user1_tok = self.login(user1_id, "pass")
        user2_id = self.register_user("user2", "pass")
        user2_tok = self.login(user2_id, "pass")

        # We create the room with user2 so the room isn't left with no members when we
        # leave and can still re-join.
        room_id1 = self.helper.create_room_as(user2_id, tok=user2_tok, is_public=True)
        room_id2 = self.helper.create_room_as(user2_id, tok=user2_tok, is_public=True)
        room_id3 = self.helper.create_room_as(user2_id, tok=user2_tok, is_public=True)
        room_id4 = self.helper.create_room_as(user2_id, tok=user2_tok, is_public=True)

        # Join room1 before `before_room_token`
        join_response1 = self.helper.join(room_id1, user1_id, tok=user1_tok)

        # Join and leave the room2 before `before_room_token`
        self.helper.join(room_id2, user1_id, tok=user1_tok)
        self.helper.leave(room_id2, user1_id, tok=user1_tok)

        # Note: These are purposely swapped. The `from_token` should come after
        # the `to_token` in this test
        to_token = self.event_sources.get_current_token()

        # Join room2 after `before_room_token`
        self.helper.join(room_id2, user1_id, tok=user1_tok)

        # --------

        # Join room3 after `before_room_token`
        self.helper.join(room_id3, user1_id, tok=user1_tok)

        # Join and leave the room4 after `before_room_token`
        self.helper.join(room_id4, user1_id, tok=user1_tok)
        self.helper.leave(room_id4, user1_id, tok=user1_tok)

        # Note: These are purposely swapped. The `from_token` should come after the
        # `to_token` in this test
        from_token = self.event_sources.get_current_token()

        # Join the room4 after we already have our tokens
        self.helper.join(room_id4, user1_id, tok=user1_tok)

        room_id_results = self.get_success(
            self.sliding_sync_handler.get_sync_room_ids_for_user(
                UserID.from_string(user1_id),
                from_token=from_token,
                to_token=to_token,
            )
        )

        # Only rooms we were joined to before the `to_token` should show up
        #
        # There won't be any newly_left rooms because the `from_token` is ahead of the
        # `to_token` and that range will give no membership changes to check.
        self.assertEqual(room_id_results.keys(), {room_id1})
        # It should be pointing to the latest membership event in the from/to range
        self.assertEqual(
            room_id_results[room_id1].event_id,
            join_response1["event_id"],
        )
        # We should *NOT* be `newly_joined` because we joined `room1` before either of the tokens
        self.assertEqual(room_id_results[room_id1].newly_joined, False)

    def test_leave_before_range_and_join_leave_after_to_token(self) -> None:
        """
        Old left room shouldn't show up. But we're also testing that joining and leaving
        after the `to_token` doesn't mess with the results. See condition "1a)" comments
        in the `get_sync_room_ids_for_user()` method.
        """
        user1_id = self.register_user("user1", "pass")
        user1_tok = self.login(user1_id, "pass")
        user2_id = self.register_user("user2", "pass")
        user2_tok = self.login(user2_id, "pass")

        # We create the room with user2 so the room isn't left with no members when we
        # leave and can still re-join.
        room_id1 = self.helper.create_room_as(user2_id, tok=user2_tok, is_public=True)
        # Join and leave the room before the from/to range
        self.helper.join(room_id1, user1_id, tok=user1_tok)
        self.helper.leave(room_id1, user1_id, tok=user1_tok)

        after_room1_token = self.event_sources.get_current_token()

        # Join and leave the room after we already have our tokens
        self.helper.join(room_id1, user1_id, tok=user1_tok)
        self.helper.leave(room_id1, user1_id, tok=user1_tok)

        room_id_results = self.get_success(
            self.sliding_sync_handler.get_sync_room_ids_for_user(
                UserID.from_string(user1_id),
                from_token=after_room1_token,
                to_token=after_room1_token,
            )
        )

        # Room shouldn't show up because it was left before the `from_token`
        self.assertEqual(room_id_results.keys(), set())

    def test_leave_before_range_and_join_after_to_token(self) -> None:
        """
        Old left room shouldn't show up. But we're also testing that joining after the
        `to_token` doesn't mess with the results. See condition "1b)" comments in the
        `get_sync_room_ids_for_user()` method.
        """
        user1_id = self.register_user("user1", "pass")
        user1_tok = self.login(user1_id, "pass")
        user2_id = self.register_user("user2", "pass")
        user2_tok = self.login(user2_id, "pass")

        # We create the room with user2 so the room isn't left with no members when we
        # leave and can still re-join.
        room_id1 = self.helper.create_room_as(user2_id, tok=user2_tok, is_public=True)
        # Join and leave the room before the from/to range
        self.helper.join(room_id1, user1_id, tok=user1_tok)
        self.helper.leave(room_id1, user1_id, tok=user1_tok)

        after_room1_token = self.event_sources.get_current_token()

        # Join the room after we already have our tokens
        self.helper.join(room_id1, user1_id, tok=user1_tok)

        room_id_results = self.get_success(
            self.sliding_sync_handler.get_sync_room_ids_for_user(
                UserID.from_string(user1_id),
                from_token=after_room1_token,
                to_token=after_room1_token,
            )
        )

        # Room shouldn't show up because it was left before the `from_token`
        self.assertEqual(room_id_results.keys(), set())

    def test_join_leave_multiple_times_during_range_and_after_to_token(
        self,
    ) -> None:
        """
        Join and leave multiple times shouldn't affect rooms from showing up. It just
        matters that we were joined or newly_left in the from/to range. But we're also
        testing that joining and leaving after the `to_token` doesn't mess with the
        results.
        """
        user1_id = self.register_user("user1", "pass")
        user1_tok = self.login(user1_id, "pass")
        user2_id = self.register_user("user2", "pass")
        user2_tok = self.login(user2_id, "pass")

        before_room1_token = self.event_sources.get_current_token()

        # We create the room with user2 so the room isn't left with no members when we
        # leave and can still re-join.
        room_id1 = self.helper.create_room_as(user2_id, tok=user2_tok, is_public=True)
        # Join, leave, join back to the room before the from/to range
        join_response1 = self.helper.join(room_id1, user1_id, tok=user1_tok)
        leave_response1 = self.helper.leave(room_id1, user1_id, tok=user1_tok)
        join_response2 = self.helper.join(room_id1, user1_id, tok=user1_tok)

        after_room1_token = self.event_sources.get_current_token()

        # Leave and Join the room multiple times after we already have our tokens
        leave_response2 = self.helper.leave(room_id1, user1_id, tok=user1_tok)
        join_response3 = self.helper.join(room_id1, user1_id, tok=user1_tok)
        leave_response3 = self.helper.leave(room_id1, user1_id, tok=user1_tok)

        room_id_results = self.get_success(
            self.sliding_sync_handler.get_sync_room_ids_for_user(
                UserID.from_string(user1_id),
                from_token=before_room1_token,
                to_token=after_room1_token,
            )
        )

        # Room should show up because it was newly_left and joined during the from/to range
        self.assertEqual(room_id_results.keys(), {room_id1})
        # It should be pointing to the latest membership event in the from/to range
        self.assertEqual(
            room_id_results[room_id1].event_id,
            join_response2["event_id"],
            "Corresponding map to disambiguate the opaque event IDs: "
            + str(
                {
                    "join_response1": join_response1["event_id"],
                    "leave_response1": leave_response1["event_id"],
                    "join_response2": join_response2["event_id"],
                    "leave_response2": leave_response2["event_id"],
                    "join_response3": join_response3["event_id"],
                    "leave_response3": leave_response3["event_id"],
                }
            ),
        )
        # We should be `newly_joined` because we joined during the token range
        self.assertEqual(room_id_results[room_id1].newly_joined, True)

    def test_join_leave_multiple_times_before_range_and_after_to_token(
        self,
    ) -> None:
        """
        Join and leave multiple times before the from/to range shouldn't affect rooms
        from showing up. It just matters that we were joined or newly_left in the
        from/to range. But we're also testing that joining and leaving after the
        `to_token` doesn't mess with the results.
        """
        user1_id = self.register_user("user1", "pass")
        user1_tok = self.login(user1_id, "pass")
        user2_id = self.register_user("user2", "pass")
        user2_tok = self.login(user2_id, "pass")

        # We create the room with user2 so the room isn't left with no members when we
        # leave and can still re-join.
        room_id1 = self.helper.create_room_as(user2_id, tok=user2_tok, is_public=True)
        # Join, leave, join back to the room before the from/to range
        join_response1 = self.helper.join(room_id1, user1_id, tok=user1_tok)
        leave_response1 = self.helper.leave(room_id1, user1_id, tok=user1_tok)
        join_response2 = self.helper.join(room_id1, user1_id, tok=user1_tok)

        after_room1_token = self.event_sources.get_current_token()

        # Leave and Join the room multiple times after we already have our tokens
        leave_response2 = self.helper.leave(room_id1, user1_id, tok=user1_tok)
        join_response3 = self.helper.join(room_id1, user1_id, tok=user1_tok)
        leave_response3 = self.helper.leave(room_id1, user1_id, tok=user1_tok)

        room_id_results = self.get_success(
            self.sliding_sync_handler.get_sync_room_ids_for_user(
                UserID.from_string(user1_id),
                from_token=after_room1_token,
                to_token=after_room1_token,
            )
        )

        # Room should show up because we were joined before the from/to range
        self.assertEqual(room_id_results.keys(), {room_id1})
        # It should be pointing to the latest membership event in the from/to range
        self.assertEqual(
            room_id_results[room_id1].event_id,
            join_response2["event_id"],
            "Corresponding map to disambiguate the opaque event IDs: "
            + str(
                {
                    "join_response1": join_response1["event_id"],
                    "leave_response1": leave_response1["event_id"],
                    "join_response2": join_response2["event_id"],
                    "leave_response2": leave_response2["event_id"],
                    "join_response3": join_response3["event_id"],
                    "leave_response3": leave_response3["event_id"],
                }
            ),
        )
        # We should *NOT* be `newly_joined` because we joined before the token range
        self.assertEqual(room_id_results[room_id1].newly_joined, False)

    def test_invite_before_range_and_join_leave_after_to_token(
        self,
    ) -> None:
        """
        Make it look like we joined after the token range but we were invited before the
        from/to range so the room should still show up. See condition "1a)" comments in
        the `get_sync_room_ids_for_user()` method.
        """
        user1_id = self.register_user("user1", "pass")
        user1_tok = self.login(user1_id, "pass")
        user2_id = self.register_user("user2", "pass")
        user2_tok = self.login(user2_id, "pass")

        # We create the room with user2 so the room isn't left with no members when we
        # leave and can still re-join.
        room_id1 = self.helper.create_room_as(user2_id, tok=user2_tok, is_public=True)

        # Invited to the room before the token
        invite_response = self.helper.invite(
            room_id1, src=user2_id, targ=user1_id, tok=user2_tok
        )

        after_room1_token = self.event_sources.get_current_token()

        # Join and leave the room after we already have our tokens
        join_respsonse = self.helper.join(room_id1, user1_id, tok=user1_tok)
        leave_response = self.helper.leave(room_id1, user1_id, tok=user1_tok)

        room_id_results = self.get_success(
            self.sliding_sync_handler.get_sync_room_ids_for_user(
                UserID.from_string(user1_id),
                from_token=after_room1_token,
                to_token=after_room1_token,
            )
        )

        # Room should show up because we were invited before the from/to range
        self.assertEqual(room_id_results.keys(), {room_id1})
        # It should be pointing to the latest membership event in the from/to range
        self.assertEqual(
            room_id_results[room_id1].event_id,
            invite_response["event_id"],
            "Corresponding map to disambiguate the opaque event IDs: "
            + str(
                {
                    "invite_response": invite_response["event_id"],
                    "join_respsonse": join_respsonse["event_id"],
                    "leave_response": leave_response["event_id"],
                }
            ),
        )
        # We should *NOT* be `newly_joined` because we were only invited before the
        # token range
        self.assertEqual(room_id_results[room_id1].newly_joined, False)

    def test_join_and_display_name_changes_in_token_range(
        self,
    ) -> None:
        """
        Test that we point to the correct membership event within the from/to range even
        if there are multiple `join` membership events in a row indicating
        `displayname`/`avatar_url` updates.
        """
        user1_id = self.register_user("user1", "pass")
        user1_tok = self.login(user1_id, "pass")
        user2_id = self.register_user("user2", "pass")
        user2_tok = self.login(user2_id, "pass")

        before_room1_token = self.event_sources.get_current_token()

        # We create the room with user2 so the room isn't left with no members when we
        # leave and can still re-join.
        room_id1 = self.helper.create_room_as(user2_id, tok=user2_tok, is_public=True)
        join_response = self.helper.join(room_id1, user1_id, tok=user1_tok)
        # Update the displayname during the token range
        displayname_change_during_token_range_response = self.helper.send_state(
            room_id1,
            event_type=EventTypes.Member,
            state_key=user1_id,
            body={
                "membership": Membership.JOIN,
                "displayname": "displayname during token range",
            },
            tok=user1_tok,
        )

        after_room1_token = self.event_sources.get_current_token()

        # Update the displayname after the token range
        displayname_change_after_token_range_response = self.helper.send_state(
            room_id1,
            event_type=EventTypes.Member,
            state_key=user1_id,
            body={
                "membership": Membership.JOIN,
                "displayname": "displayname after token range",
            },
            tok=user1_tok,
        )

        room_id_results = self.get_success(
            self.sliding_sync_handler.get_sync_room_ids_for_user(
                UserID.from_string(user1_id),
                from_token=before_room1_token,
                to_token=after_room1_token,
            )
        )

        # Room should show up because we were joined during the from/to range
        self.assertEqual(room_id_results.keys(), {room_id1})
        # It should be pointing to the latest membership event in the from/to range
        self.assertEqual(
            room_id_results[room_id1].event_id,
            displayname_change_during_token_range_response["event_id"],
            "Corresponding map to disambiguate the opaque event IDs: "
            + str(
                {
                    "join_response": join_response["event_id"],
                    "displayname_change_during_token_range_response": displayname_change_during_token_range_response[
                        "event_id"
                    ],
                    "displayname_change_after_token_range_response": displayname_change_after_token_range_response[
                        "event_id"
                    ],
                }
            ),
        )
        # We should be `newly_joined` because we joined during the token range
        self.assertEqual(room_id_results[room_id1].newly_joined, True)

    def test_display_name_changes_in_token_range(
        self,
    ) -> None:
        """
        Test that we point to the correct membership event within the from/to range even
        if there is `displayname`/`avatar_url` updates.
        """
        user1_id = self.register_user("user1", "pass")
        user1_tok = self.login(user1_id, "pass")
        user2_id = self.register_user("user2", "pass")
        user2_tok = self.login(user2_id, "pass")

        # We create the room with user2 so the room isn't left with no members when we
        # leave and can still re-join.
        room_id1 = self.helper.create_room_as(user2_id, tok=user2_tok, is_public=True)
        join_response = self.helper.join(room_id1, user1_id, tok=user1_tok)

        after_room1_token = self.event_sources.get_current_token()

        # Update the displayname during the token range
        displayname_change_during_token_range_response = self.helper.send_state(
            room_id1,
            event_type=EventTypes.Member,
            state_key=user1_id,
            body={
                "membership": Membership.JOIN,
                "displayname": "displayname during token range",
            },
            tok=user1_tok,
        )

        after_change1_token = self.event_sources.get_current_token()

        room_id_results = self.get_success(
            self.sliding_sync_handler.get_sync_room_ids_for_user(
                UserID.from_string(user1_id),
                from_token=after_room1_token,
                to_token=after_change1_token,
            )
        )

        # Room should show up because we were joined during the from/to range
        self.assertEqual(room_id_results.keys(), {room_id1})
        # It should be pointing to the latest membership event in the from/to range
        self.assertEqual(
            room_id_results[room_id1].event_id,
            displayname_change_during_token_range_response["event_id"],
            "Corresponding map to disambiguate the opaque event IDs: "
            + str(
                {
                    "join_response": join_response["event_id"],
                    "displayname_change_during_token_range_response": displayname_change_during_token_range_response[
                        "event_id"
                    ],
                }
            ),
        )
        # We should *NOT* be `newly_joined` because we joined before the token range
        self.assertEqual(room_id_results[room_id1].newly_joined, False)

    def test_display_name_changes_before_and_after_token_range(
        self,
    ) -> None:
        """
        Test that we point to the correct membership event even though there are no
        membership events in the from/range but there are `displayname`/`avatar_url`
        changes before/after the token range.
        """
        user1_id = self.register_user("user1", "pass")
        user1_tok = self.login(user1_id, "pass")
        user2_id = self.register_user("user2", "pass")
        user2_tok = self.login(user2_id, "pass")

        # We create the room with user2 so the room isn't left with no members when we
        # leave and can still re-join.
        room_id1 = self.helper.create_room_as(user2_id, tok=user2_tok, is_public=True)
        join_response = self.helper.join(room_id1, user1_id, tok=user1_tok)
        # Update the displayname before the token range
        displayname_change_before_token_range_response = self.helper.send_state(
            room_id1,
            event_type=EventTypes.Member,
            state_key=user1_id,
            body={
                "membership": Membership.JOIN,
                "displayname": "displayname during token range",
            },
            tok=user1_tok,
        )

        after_room1_token = self.event_sources.get_current_token()

        # Update the displayname after the token range
        displayname_change_after_token_range_response = self.helper.send_state(
            room_id1,
            event_type=EventTypes.Member,
            state_key=user1_id,
            body={
                "membership": Membership.JOIN,
                "displayname": "displayname after token range",
            },
            tok=user1_tok,
        )

        room_id_results = self.get_success(
            self.sliding_sync_handler.get_sync_room_ids_for_user(
                UserID.from_string(user1_id),
                from_token=after_room1_token,
                to_token=after_room1_token,
            )
        )

        # Room should show up because we were joined before the from/to range
        self.assertEqual(room_id_results.keys(), {room_id1})
        # It should be pointing to the latest membership event in the from/to range
        self.assertEqual(
            room_id_results[room_id1].event_id,
            displayname_change_before_token_range_response["event_id"],
            "Corresponding map to disambiguate the opaque event IDs: "
            + str(
                {
                    "join_response": join_response["event_id"],
                    "displayname_change_before_token_range_response": displayname_change_before_token_range_response[
                        "event_id"
                    ],
                    "displayname_change_after_token_range_response": displayname_change_after_token_range_response[
                        "event_id"
                    ],
                }
            ),
        )
        # We should *NOT* be `newly_joined` because we joined before the token range
        self.assertEqual(room_id_results[room_id1].newly_joined, False)

    def test_display_name_changes_leave_after_token_range(
        self,
    ) -> None:
        """
        Test that we point to the correct membership event within the from/to range even
        if there are multiple `join` membership events in a row indicating
        `displayname`/`avatar_url` updates and we leave after the `to_token`.

        See condition "1a)" comments in the `get_sync_room_ids_for_user()` method.
        """
        user1_id = self.register_user("user1", "pass")
        user1_tok = self.login(user1_id, "pass")
        user2_id = self.register_user("user2", "pass")
        user2_tok = self.login(user2_id, "pass")

        before_room1_token = self.event_sources.get_current_token()

        # We create the room with user2 so the room isn't left with no members when we
        # leave and can still re-join.
        room_id1 = self.helper.create_room_as(user2_id, tok=user2_tok, is_public=True)
        join_response = self.helper.join(room_id1, user1_id, tok=user1_tok)
        # Update the displayname during the token range
        displayname_change_during_token_range_response = self.helper.send_state(
            room_id1,
            event_type=EventTypes.Member,
            state_key=user1_id,
            body={
                "membership": Membership.JOIN,
                "displayname": "displayname during token range",
            },
            tok=user1_tok,
        )

        after_room1_token = self.event_sources.get_current_token()

        # Update the displayname after the token range
        displayname_change_after_token_range_response = self.helper.send_state(
            room_id1,
            event_type=EventTypes.Member,
            state_key=user1_id,
            body={
                "membership": Membership.JOIN,
                "displayname": "displayname after token range",
            },
            tok=user1_tok,
        )

        # Leave after the token
        self.helper.leave(room_id1, user1_id, tok=user1_tok)

        room_id_results = self.get_success(
            self.sliding_sync_handler.get_sync_room_ids_for_user(
                UserID.from_string(user1_id),
                from_token=before_room1_token,
                to_token=after_room1_token,
            )
        )

        # Room should show up because we were joined during the from/to range
        self.assertEqual(room_id_results.keys(), {room_id1})
        # It should be pointing to the latest membership event in the from/to range
        self.assertEqual(
            room_id_results[room_id1].event_id,
            displayname_change_during_token_range_response["event_id"],
            "Corresponding map to disambiguate the opaque event IDs: "
            + str(
                {
                    "join_response": join_response["event_id"],
                    "displayname_change_during_token_range_response": displayname_change_during_token_range_response[
                        "event_id"
                    ],
                    "displayname_change_after_token_range_response": displayname_change_after_token_range_response[
                        "event_id"
                    ],
                }
            ),
        )
        # We should be `newly_joined` because we joined during the token range
        self.assertEqual(room_id_results[room_id1].newly_joined, True)

    def test_display_name_changes_join_after_token_range(
        self,
    ) -> None:
        """
        Test that multiple `join` membership events (after the `to_token`) in a row
        indicating `displayname`/`avatar_url` updates doesn't affect the results (we
        joined after the token range so it shouldn't show up)

        See condition "1b)" comments in the `get_sync_room_ids_for_user()` method.
        """
        user1_id = self.register_user("user1", "pass")
        user1_tok = self.login(user1_id, "pass")
        user2_id = self.register_user("user2", "pass")
        user2_tok = self.login(user2_id, "pass")

        before_room1_token = self.event_sources.get_current_token()

        # We create the room with user2 so the room isn't left with no members when we
        # leave and can still re-join.
        room_id1 = self.helper.create_room_as(user2_id, tok=user2_tok, is_public=True)

        after_room1_token = self.event_sources.get_current_token()

        self.helper.join(room_id1, user1_id, tok=user1_tok)
        # Update the displayname after the token range
        self.helper.send_state(
            room_id1,
            event_type=EventTypes.Member,
            state_key=user1_id,
            body={
                "membership": Membership.JOIN,
                "displayname": "displayname after token range",
            },
            tok=user1_tok,
        )

        room_id_results = self.get_success(
            self.sliding_sync_handler.get_sync_room_ids_for_user(
                UserID.from_string(user1_id),
                from_token=before_room1_token,
                to_token=after_room1_token,
            )
        )

        # Room shouldn't show up because we joined after the from/to range
        self.assertEqual(room_id_results.keys(), set())

    def test_newly_joined_with_leave_join_in_token_range(
        self,
    ) -> None:
        """
        Test that even though we're joined before the token range, if we leave and join
        within the token range, it's still counted as `newly_joined`.
        """
        user1_id = self.register_user("user1", "pass")
        user1_tok = self.login(user1_id, "pass")
        user2_id = self.register_user("user2", "pass")
        user2_tok = self.login(user2_id, "pass")

        # We create the room with user2 so the room isn't left with no members when we
        # leave and can still re-join.
        room_id1 = self.helper.create_room_as(user2_id, tok=user2_tok, is_public=True)
        self.helper.join(room_id1, user1_id, tok=user1_tok)

        after_room1_token = self.event_sources.get_current_token()

        # Leave and join back during the token range
        self.helper.leave(room_id1, user1_id, tok=user1_tok)
        join_response2 = self.helper.join(room_id1, user1_id, tok=user1_tok)

        after_more_changes_token = self.event_sources.get_current_token()

        room_id_results = self.get_success(
            self.sliding_sync_handler.get_sync_room_ids_for_user(
                UserID.from_string(user1_id),
                from_token=after_room1_token,
                to_token=after_more_changes_token,
            )
        )

        # Room should show up because we were joined during the from/to range
        self.assertEqual(room_id_results.keys(), {room_id1})
        # It should be pointing to the latest membership event in the from/to range
        self.assertEqual(
            room_id_results[room_id1].event_id,
            join_response2["event_id"],
        )
        # We should be considered `newly_joined` because there is some non-join event in
        # between our latest join event.
        self.assertEqual(room_id_results[room_id1].newly_joined, True)

    def test_newly_joined_only_joins_during_token_range(
        self,
    ) -> None:
        """
        Test that a join and more joins caused by display name changes, all during the
        token range, still count as `newly_joined`.
        """
        user1_id = self.register_user("user1", "pass")
        user1_tok = self.login(user1_id, "pass")
        user2_id = self.register_user("user2", "pass")
        user2_tok = self.login(user2_id, "pass")

        before_room1_token = self.event_sources.get_current_token()

        # We create the room with user2 so the room isn't left with no members when we
        # leave and can still re-join.
        room_id1 = self.helper.create_room_as(user2_id, tok=user2_tok, is_public=True)
        # Join, leave, join back to the room before the from/to range
        join_response1 = self.helper.join(room_id1, user1_id, tok=user1_tok)
        # Update the displayname during the token range (looks like another join)
        displayname_change_during_token_range_response1 = self.helper.send_state(
            room_id1,
            event_type=EventTypes.Member,
            state_key=user1_id,
            body={
                "membership": Membership.JOIN,
                "displayname": "displayname during token range",
            },
            tok=user1_tok,
        )
        # Update the displayname during the token range (looks like another join)
        displayname_change_during_token_range_response2 = self.helper.send_state(
            room_id1,
            event_type=EventTypes.Member,
            state_key=user1_id,
            body={
                "membership": Membership.JOIN,
                "displayname": "displayname during token range",
            },
            tok=user1_tok,
        )

        after_room1_token = self.event_sources.get_current_token()

        room_id_results = self.get_success(
            self.sliding_sync_handler.get_sync_room_ids_for_user(
                UserID.from_string(user1_id),
                from_token=before_room1_token,
                to_token=after_room1_token,
            )
        )

        # Room should show up because it was newly_left and joined during the from/to range
        self.assertEqual(room_id_results.keys(), {room_id1})
        # It should be pointing to the latest membership event in the from/to range
        self.assertEqual(
            room_id_results[room_id1].event_id,
            displayname_change_during_token_range_response2["event_id"],
            "Corresponding map to disambiguate the opaque event IDs: "
            + str(
                {
                    "join_response1": join_response1["event_id"],
                    "displayname_change_during_token_range_response1": displayname_change_during_token_range_response1[
                        "event_id"
                    ],
                    "displayname_change_during_token_range_response2": displayname_change_during_token_range_response2[
                        "event_id"
                    ],
                }
            ),
        )
        # We should be `newly_joined` because we first joined during the token range
        self.assertEqual(room_id_results[room_id1].newly_joined, True)

    def test_multiple_rooms_are_not_confused(
        self,
    ) -> None:
        """
        Test that multiple rooms are not confused as we fixup the list. This test is
        spawning from a real world bug in the code where I was accidentally using
        `event.room_id` in one of the fix-up loops but the `event` being referenced was
        actually from a different loop.
        """
        user1_id = self.register_user("user1", "pass")
        user1_tok = self.login(user1_id, "pass")
        user2_id = self.register_user("user2", "pass")
        user2_tok = self.login(user2_id, "pass")

        # We create the room with user2 so the room isn't left with no members when we
        # leave and can still re-join.
        room_id1 = self.helper.create_room_as(user2_id, tok=user2_tok, is_public=True)
        room_id2 = self.helper.create_room_as(user2_id, tok=user2_tok, is_public=True)

        # Invited and left the room before the token
        self.helper.invite(room_id1, src=user2_id, targ=user1_id, tok=user2_tok)
        self.helper.leave(room_id1, user1_id, tok=user1_tok)
        # Invited to room2
        self.helper.invite(room_id2, src=user2_id, targ=user1_id, tok=user2_tok)

        before_room3_token = self.event_sources.get_current_token()

        # Invited and left room3 during the from/to range
        room_id3 = self.helper.create_room_as(user2_id, tok=user2_tok, is_public=True)
        self.helper.invite(room_id3, src=user2_id, targ=user1_id, tok=user2_tok)
        self.helper.leave(room_id3, user1_id, tok=user1_tok)

        after_room3_token = self.event_sources.get_current_token()

        # Join and leave the room after we already have our tokens
        self.helper.join(room_id1, user1_id, tok=user1_tok)
        self.helper.leave(room_id1, user1_id, tok=user1_tok)
        # Leave room2
        self.helper.leave(room_id2, user1_id, tok=user1_tok)
        # Leave room3
        self.helper.leave(room_id3, user1_id, tok=user1_tok)

        room_id_results = self.get_success(
            self.sliding_sync_handler.get_sync_room_ids_for_user(
                UserID.from_string(user1_id),
                from_token=before_room3_token,
                to_token=after_room3_token,
            )
        )

        self.assertEqual(
            room_id_results.keys(),
            {
                # `room_id1` shouldn't show up because we left before the from/to range
                #
                # Room should show up because we were invited before the from/to range
                room_id2,
                # Room should show up because it was newly_left during the from/to range
                room_id3,
            },
        )


class GetSyncRoomIdsForUserEventShardTestCase(BaseMultiWorkerStreamTestCase):
    """
    Tests Sliding Sync handler `get_sync_room_ids_for_user()` to make sure it works with
    sharded event stream_writers enabled
    """

    servlets = [
        admin.register_servlets_for_client_rest_resource,
        room.register_servlets,
        login.register_servlets,
    ]

    def default_config(self) -> dict:
        config = super().default_config()
        # Enable sliding sync
        config["experimental_features"] = {"msc3575_enabled": True}

        # Enable shared event stream_writers
        config["stream_writers"] = {"events": ["worker1", "worker2", "worker3"]}
        config["instance_map"] = {
            "main": {"host": "testserv", "port": 8765},
            "worker1": {"host": "testserv", "port": 1001},
            "worker2": {"host": "testserv", "port": 1002},
            "worker3": {"host": "testserv", "port": 1003},
        }
        return config

    def prepare(self, reactor: MemoryReactor, clock: Clock, hs: HomeServer) -> None:
        self.sliding_sync_handler = self.hs.get_sliding_sync_handler()
        self.store = self.hs.get_datastores().main
        self.event_sources = hs.get_event_sources()

    def _create_room(self, room_id: str, user_id: str, tok: str) -> None:
        """
        Create a room with a specific room_id. We use this so that that we have a
        consistent room_id across test runs that hashes to the same value and will be
        sharded to a known worker in the tests.
        """

        # We control the room ID generation by patching out the
        # `_generate_room_id` method
        with patch(
            "synapse.handlers.room.RoomCreationHandler._generate_room_id"
        ) as mock:
            mock.side_effect = lambda: room_id
            self.helper.create_room_as(user_id, tok=tok)

    def test_sharded_event_persisters(self) -> None:
        """
        This test should catch bugs that would come from flawed stream position
        (`stream_ordering`) comparisons or making `RoomStreamToken`'s naively. To
        compare event positions properly, you need to consider both the `instance_name`
        and `stream_ordering` together.

        The test creates three event persister workers and a room that is sharded to
        each worker. On worker2, we make the event stream position stuck so that it lags
        behind the other workers and we start getting `RoomStreamToken` that have an
        `instance_map` component (i.e. q`m{min_pos}~{writer1}.{pos1}~{writer2}.{pos2}`).

        We then send some events to advance the stream positions of worker1 and worker3
        but worker2 is lagging behind because it's stuck. We are specifically testing
        that `get_sync_room_ids_for_user(from_token=xxx, to_token=xxx)` should work
        correctly in these adverse conditions.
        """
        user1_id = self.register_user("user1", "pass")
        user1_tok = self.login(user1_id, "pass")
        user2_id = self.register_user("user2", "pass")
        user2_tok = self.login(user2_id, "pass")

        self.make_worker_hs(
            "synapse.app.generic_worker",
            {"worker_name": "worker1"},
        )

        worker_hs2 = self.make_worker_hs(
            "synapse.app.generic_worker",
            {"worker_name": "worker2"},
        )

        self.make_worker_hs(
            "synapse.app.generic_worker",
            {"worker_name": "worker3"},
        )

        # Specially crafted room IDs that get persisted on different workers.
        #
        # Sharded to worker1
        room_id1 = "!fooo:test"
        # Sharded to worker2
        room_id2 = "!bar:test"
        # Sharded to worker3
        room_id3 = "!quux:test"

        # Create rooms on the different workers.
        self._create_room(room_id1, user2_id, user2_tok)
        self._create_room(room_id2, user2_id, user2_tok)
        self._create_room(room_id3, user2_id, user2_tok)
        join_response1 = self.helper.join(room_id1, user1_id, tok=user1_tok)
        join_response2 = self.helper.join(room_id2, user1_id, tok=user1_tok)
        # Leave room2
        self.helper.leave(room_id2, user1_id, tok=user1_tok)
        join_response3 = self.helper.join(room_id3, user1_id, tok=user1_tok)
        # Leave room3
        self.helper.leave(room_id3, user1_id, tok=user1_tok)

        # Ensure that the events were sharded to different workers.
        pos1 = self.get_success(
            self.store.get_position_for_event(join_response1["event_id"])
        )
        self.assertEqual(pos1.instance_name, "worker1")
        pos2 = self.get_success(
            self.store.get_position_for_event(join_response2["event_id"])
        )
        self.assertEqual(pos2.instance_name, "worker2")
        pos3 = self.get_success(
            self.store.get_position_for_event(join_response3["event_id"])
        )
        self.assertEqual(pos3.instance_name, "worker3")

        before_stuck_activity_token = self.event_sources.get_current_token()

        # We now gut wrench into the events stream `MultiWriterIdGenerator` on worker2 to
        # mimic it getting stuck persisting an event. This ensures that when we send an
        # event on worker1/worker3 we end up in a state where worker2 events stream
        # position lags that on worker1/worker3, resulting in a RoomStreamToken with a
        # non-empty `instance_map` component.
        #
        # Worker2's event stream position will not advance until we call `__aexit__`
        # again.
        worker_store2 = worker_hs2.get_datastores().main
        assert isinstance(worker_store2._stream_id_gen, MultiWriterIdGenerator)
        actx = worker_store2._stream_id_gen.get_next()
        self.get_success(actx.__aenter__())

        # For room_id1/worker1: leave and join the room to advance the stream position
        # and generate membership changes.
        self.helper.leave(room_id1, user1_id, tok=user1_tok)
        self.helper.join(room_id1, user1_id, tok=user1_tok)
        # For room_id2/worker2: which is currently stuck, join the room.
        join_on_worker2_response = self.helper.join(room_id2, user1_id, tok=user1_tok)
        # For room_id3/worker3: leave and join the room to advance the stream position
        # and generate membership changes.
        self.helper.leave(room_id3, user1_id, tok=user1_tok)
        join_on_worker3_response = self.helper.join(room_id3, user1_id, tok=user1_tok)

        # Get a token while things are stuck after our activity
        stuck_activity_token = self.event_sources.get_current_token()
        # Let's make sure we're working with a token that has an `instance_map`
        self.assertNotEqual(len(stuck_activity_token.room_key.instance_map), 0)

        # Just double check that the join event on worker2 (that is stuck) happened
        # after the position recorded for worker2 in the token but before the max
        # position in the token. This is crucial for the behavior we're trying to test.
        join_on_worker2_pos = self.get_success(
            self.store.get_position_for_event(join_on_worker2_response["event_id"])
        )
        # Ensure the join technially came after our token
        self.assertGreater(
            join_on_worker2_pos.stream,
            stuck_activity_token.room_key.get_stream_pos_for_instance("worker2"),
        )
        # But less than the max stream position of some other worker
        self.assertLess(
            join_on_worker2_pos.stream,
            # max
            stuck_activity_token.room_key.get_max_stream_pos(),
        )

        # Just double check that the join event on worker3 happened after the min stream
        # value in the token but still within the position recorded for worker3. This is
        # crucial for the behavior we're trying to test.
        join_on_worker3_pos = self.get_success(
            self.store.get_position_for_event(join_on_worker3_response["event_id"])
        )
        # Ensure the join came after the min but still encapsulated by the token
        self.assertGreaterEqual(
            join_on_worker3_pos.stream,
            # min
            stuck_activity_token.room_key.stream,
        )
        self.assertLessEqual(
            join_on_worker3_pos.stream,
            stuck_activity_token.room_key.get_stream_pos_for_instance("worker3"),
        )

        # We finish the fake persisting an event we started above and advance worker2's
        # event stream position (unstuck worker2).
        self.get_success(actx.__aexit__(None, None, None))

        # The function under test
        room_id_results = self.get_success(
            self.sliding_sync_handler.get_sync_room_ids_for_user(
                UserID.from_string(user1_id),
                from_token=before_stuck_activity_token,
                to_token=stuck_activity_token,
            )
        )

        self.assertEqual(
            room_id_results.keys(),
            {
                room_id1,
                # room_id2 shouldn't show up because we left before the from/to range
                # and the join event during the range happened while worker2 was stuck.
                # This means that from the perspective of the master, where the
                # `stuck_activity_token` is generated, the stream position for worker2
                # wasn't advanced to the join yet. Looking at the `instance_map`, the
                # join technically comes after `stuck_activity_token``.
                #
                # room_id2,
                room_id3,
            },
        )


class FilterRoomsTestCase(HomeserverTestCase):
    """
    Tests Sliding Sync handler `filter_rooms()` to make sure it includes/excludes rooms
    correctly.
    """

    servlets = [
        admin.register_servlets,
        knock.register_servlets,
        login.register_servlets,
        room.register_servlets,
    ]

    def default_config(self) -> JsonDict:
        config = super().default_config()
        # Enable sliding sync
        config["experimental_features"] = {"msc3575_enabled": True}
        return config

    def prepare(self, reactor: MemoryReactor, clock: Clock, hs: HomeServer) -> None:
        self.sliding_sync_handler = self.hs.get_sliding_sync_handler()
        self.store = self.hs.get_datastores().main
        self.event_sources = hs.get_event_sources()

    def _create_dm_room(
        self,
        inviter_user_id: str,
        inviter_tok: str,
        invitee_user_id: str,
        invitee_tok: str,
    ) -> str:
        """
        Helper to create a DM room as the "inviter" and invite the "invitee" user to the room. The
        "invitee" user also will join the room. The `m.direct` account data will be set
        for both users.
        """

        # Create a room and send an invite the other user
        room_id = self.helper.create_room_as(
            inviter_user_id,
            is_public=False,
            tok=inviter_tok,
        )
        self.helper.invite(
            room_id,
            src=inviter_user_id,
            targ=invitee_user_id,
            tok=inviter_tok,
            extra_data={"is_direct": True},
        )
        # Person that was invited joins the room
        self.helper.join(room_id, invitee_user_id, tok=invitee_tok)

        # Mimic the client setting the room as a direct message in the global account
        # data
        self.get_success(
            self.store.add_account_data_for_user(
                invitee_user_id,
                AccountDataTypes.DIRECT,
                {inviter_user_id: [room_id]},
            )
        )
        self.get_success(
            self.store.add_account_data_for_user(
                inviter_user_id,
                AccountDataTypes.DIRECT,
                {invitee_user_id: [room_id]},
            )
        )

        return room_id

    def test_filter_dm_rooms(self) -> None:
        """
        Test `filter.is_dm` for DM rooms
        """
        user1_id = self.register_user("user1", "pass")
        user1_tok = self.login(user1_id, "pass")
        user2_id = self.register_user("user2", "pass")
        user2_tok = self.login(user2_id, "pass")

        # Create a normal room
        room_id = self.helper.create_room_as(user1_id, tok=user1_tok)

        # Create a DM room
        dm_room_id = self._create_dm_room(
            inviter_user_id=user1_id,
            inviter_tok=user1_tok,
            invitee_user_id=user2_id,
            invitee_tok=user2_tok,
        )

        after_rooms_token = self.event_sources.get_current_token()

        # Get the rooms the user should be syncing with
        sync_room_map = self.get_success(
            self.sliding_sync_handler.get_sync_room_ids_for_user(
                UserID.from_string(user1_id),
                from_token=None,
                to_token=after_rooms_token,
            )
        )

        # Try with `is_dm=True`
        truthy_filtered_room_map = self.get_success(
            self.sliding_sync_handler.filter_rooms(
                UserID.from_string(user1_id),
                sync_room_map,
                SlidingSyncConfig.SlidingSyncList.Filters(
                    is_dm=True,
                ),
                after_rooms_token,
            )
        )

        self.assertEqual(truthy_filtered_room_map.keys(), {dm_room_id})

        # Try with `is_dm=False`
        falsy_filtered_room_map = self.get_success(
            self.sliding_sync_handler.filter_rooms(
                UserID.from_string(user1_id),
                sync_room_map,
                SlidingSyncConfig.SlidingSyncList.Filters(
                    is_dm=False,
                ),
                after_rooms_token,
            )
        )

        self.assertEqual(falsy_filtered_room_map.keys(), {room_id})

    def test_filter_encrypted_rooms(self) -> None:
        """
        Test `filter.is_encrypted` for encrypted rooms
        """
        user1_id = self.register_user("user1", "pass")
        user1_tok = self.login(user1_id, "pass")

        # Create a normal room
        room_id = self.helper.create_room_as(user1_id, tok=user1_tok)

        # Create an encrypted room
        encrypted_room_id = self.helper.create_room_as(user1_id, tok=user1_tok)
        self.helper.send_state(
            encrypted_room_id,
            EventTypes.RoomEncryption,
            {"algorithm": "m.megolm.v1.aes-sha2"},
            tok=user1_tok,
        )

        after_rooms_token = self.event_sources.get_current_token()

        # Get the rooms the user should be syncing with
        sync_room_map = self.get_success(
            self.sliding_sync_handler.get_sync_room_ids_for_user(
                UserID.from_string(user1_id),
                from_token=None,
                to_token=after_rooms_token,
            )
        )

        # Try with `is_encrypted=True`
        truthy_filtered_room_map = self.get_success(
            self.sliding_sync_handler.filter_rooms(
                UserID.from_string(user1_id),
                sync_room_map,
                SlidingSyncConfig.SlidingSyncList.Filters(
                    is_encrypted=True,
                ),
                after_rooms_token,
            )
        )

        self.assertEqual(truthy_filtered_room_map.keys(), {encrypted_room_id})

        # Try with `is_encrypted=False`
        falsy_filtered_room_map = self.get_success(
            self.sliding_sync_handler.filter_rooms(
                UserID.from_string(user1_id),
                sync_room_map,
                SlidingSyncConfig.SlidingSyncList.Filters(
                    is_encrypted=False,
                ),
                after_rooms_token,
            )
        )

        self.assertEqual(falsy_filtered_room_map.keys(), {room_id})

    def test_filter_invite_rooms(self) -> None:
        """
        Test `filter.is_invite` for rooms that the user has been invited to
        """
        user1_id = self.register_user("user1", "pass")
        user1_tok = self.login(user1_id, "pass")
        user2_id = self.register_user("user2", "pass")
        user2_tok = self.login(user2_id, "pass")

        # Create a normal room
        room_id = self.helper.create_room_as(user2_id, tok=user2_tok)
        self.helper.join(room_id, user1_id, tok=user1_tok)

        # Create a room that user1 is invited to
        invite_room_id = self.helper.create_room_as(user2_id, tok=user2_tok)
        self.helper.invite(invite_room_id, src=user2_id, targ=user1_id, tok=user2_tok)

        after_rooms_token = self.event_sources.get_current_token()

        # Get the rooms the user should be syncing with
        sync_room_map = self.get_success(
            self.sliding_sync_handler.get_sync_room_ids_for_user(
                UserID.from_string(user1_id),
                from_token=None,
                to_token=after_rooms_token,
            )
        )

        # Try with `is_invite=True`
        truthy_filtered_room_map = self.get_success(
            self.sliding_sync_handler.filter_rooms(
                UserID.from_string(user1_id),
                sync_room_map,
                SlidingSyncConfig.SlidingSyncList.Filters(
                    is_invite=True,
                ),
                after_rooms_token,
            )
        )

        self.assertEqual(truthy_filtered_room_map.keys(), {invite_room_id})

        # Try with `is_invite=False`
        falsy_filtered_room_map = self.get_success(
            self.sliding_sync_handler.filter_rooms(
                UserID.from_string(user1_id),
                sync_room_map,
                SlidingSyncConfig.SlidingSyncList.Filters(
                    is_invite=False,
                ),
                after_rooms_token,
            )
        )

        self.assertEqual(falsy_filtered_room_map.keys(), {room_id})

    def test_filter_room_types(self) -> None:
        """
        Test `filter.room_types` for different room types
        """
        user1_id = self.register_user("user1", "pass")
        user1_tok = self.login(user1_id, "pass")

        # Create a normal room (no room type)
        room_id = self.helper.create_room_as(user1_id, tok=user1_tok)

        # Create a space room
        space_room_id = self.helper.create_room_as(
            user1_id,
            tok=user1_tok,
            extra_content={
                "creation_content": {EventContentFields.ROOM_TYPE: RoomTypes.SPACE}
            },
        )

        # Create an arbitrarily typed room
        foo_room_id = self.helper.create_room_as(
            user1_id,
            tok=user1_tok,
            extra_content={
                "creation_content": {
                    EventContentFields.ROOM_TYPE: "org.matrix.foobarbaz"
                }
            },
        )

        after_rooms_token = self.event_sources.get_current_token()

        # Get the rooms the user should be syncing with
        sync_room_map = self.get_success(
            self.sliding_sync_handler.get_sync_room_ids_for_user(
                UserID.from_string(user1_id),
                from_token=None,
                to_token=after_rooms_token,
            )
        )

        # Try finding only normal rooms
        filtered_room_map = self.get_success(
            self.sliding_sync_handler.filter_rooms(
                UserID.from_string(user1_id),
                sync_room_map,
                SlidingSyncConfig.SlidingSyncList.Filters(room_types=[None]),
                after_rooms_token,
            )
        )

        self.assertEqual(filtered_room_map.keys(), {room_id})

        # Try finding only spaces
        filtered_room_map = self.get_success(
            self.sliding_sync_handler.filter_rooms(
                UserID.from_string(user1_id),
                sync_room_map,
                SlidingSyncConfig.SlidingSyncList.Filters(room_types=[RoomTypes.SPACE]),
                after_rooms_token,
            )
        )

        self.assertEqual(filtered_room_map.keys(), {space_room_id})

        # Try finding normal rooms and spaces
        filtered_room_map = self.get_success(
            self.sliding_sync_handler.filter_rooms(
                UserID.from_string(user1_id),
                sync_room_map,
                SlidingSyncConfig.SlidingSyncList.Filters(
                    room_types=[None, RoomTypes.SPACE]
                ),
                after_rooms_token,
            )
        )

        self.assertEqual(filtered_room_map.keys(), {room_id, space_room_id})

        # Try finding an arbitrary room type
        filtered_room_map = self.get_success(
            self.sliding_sync_handler.filter_rooms(
                UserID.from_string(user1_id),
                sync_room_map,
                SlidingSyncConfig.SlidingSyncList.Filters(
                    room_types=["org.matrix.foobarbaz"]
                ),
                after_rooms_token,
            )
        )

        self.assertEqual(filtered_room_map.keys(), {foo_room_id})

    def test_filter_not_room_types(self) -> None:
        """
        Test `filter.not_room_types` for different room types
        """
        user1_id = self.register_user("user1", "pass")
        user1_tok = self.login(user1_id, "pass")

        # Create a normal room (no room type)
        room_id = self.helper.create_room_as(user1_id, tok=user1_tok)

        # Create a space room
        space_room_id = self.helper.create_room_as(
            user1_id,
            tok=user1_tok,
            extra_content={
                "creation_content": {EventContentFields.ROOM_TYPE: RoomTypes.SPACE}
            },
        )

        # Create an arbitrarily typed room
        foo_room_id = self.helper.create_room_as(
            user1_id,
            tok=user1_tok,
            extra_content={
                "creation_content": {
                    EventContentFields.ROOM_TYPE: "org.matrix.foobarbaz"
                }
            },
        )

        after_rooms_token = self.event_sources.get_current_token()

        # Get the rooms the user should be syncing with
        sync_room_map = self.get_success(
            self.sliding_sync_handler.get_sync_room_ids_for_user(
                UserID.from_string(user1_id),
                from_token=None,
                to_token=after_rooms_token,
            )
        )

        # Try finding *NOT* normal rooms
        filtered_room_map = self.get_success(
            self.sliding_sync_handler.filter_rooms(
                UserID.from_string(user1_id),
                sync_room_map,
                SlidingSyncConfig.SlidingSyncList.Filters(not_room_types=[None]),
                after_rooms_token,
            )
        )

        self.assertEqual(filtered_room_map.keys(), {space_room_id, foo_room_id})

        # Try finding *NOT* spaces
        filtered_room_map = self.get_success(
            self.sliding_sync_handler.filter_rooms(
                UserID.from_string(user1_id),
                sync_room_map,
                SlidingSyncConfig.SlidingSyncList.Filters(
                    not_room_types=[RoomTypes.SPACE]
                ),
                after_rooms_token,
            )
        )

        self.assertEqual(filtered_room_map.keys(), {room_id, foo_room_id})

        # Try finding *NOT* normal rooms or spaces
        filtered_room_map = self.get_success(
            self.sliding_sync_handler.filter_rooms(
                UserID.from_string(user1_id),
                sync_room_map,
                SlidingSyncConfig.SlidingSyncList.Filters(
                    not_room_types=[None, RoomTypes.SPACE]
                ),
                after_rooms_token,
            )
        )

        self.assertEqual(filtered_room_map.keys(), {foo_room_id})

        # Test how it behaves when we have both `room_types` and `not_room_types`.
        # `not_room_types` should win.
        filtered_room_map = self.get_success(
            self.sliding_sync_handler.filter_rooms(
                UserID.from_string(user1_id),
                sync_room_map,
                SlidingSyncConfig.SlidingSyncList.Filters(
                    room_types=[None], not_room_types=[None]
                ),
                after_rooms_token,
            )
        )

        # Nothing matches because nothing is both a normal room and not a normal room
        self.assertEqual(filtered_room_map.keys(), set())

        # Test how it behaves when we have both `room_types` and `not_room_types`.
        # `not_room_types` should win.
        filtered_room_map = self.get_success(
            self.sliding_sync_handler.filter_rooms(
                UserID.from_string(user1_id),
                sync_room_map,
                SlidingSyncConfig.SlidingSyncList.Filters(
                    room_types=[None, RoomTypes.SPACE], not_room_types=[None]
                ),
                after_rooms_token,
            )
        )

        self.assertEqual(filtered_room_map.keys(), {space_room_id})


class SortRoomsTestCase(HomeserverTestCase):
    """
    Tests Sliding Sync handler `sort_rooms()` to make sure it sorts/orders rooms
    correctly.
    """

    servlets = [
        admin.register_servlets,
        knock.register_servlets,
        login.register_servlets,
        room.register_servlets,
    ]

    def default_config(self) -> JsonDict:
        config = super().default_config()
        # Enable sliding sync
        config["experimental_features"] = {"msc3575_enabled": True}
        return config

    def prepare(self, reactor: MemoryReactor, clock: Clock, hs: HomeServer) -> None:
        self.sliding_sync_handler = self.hs.get_sliding_sync_handler()
        self.store = self.hs.get_datastores().main
        self.event_sources = hs.get_event_sources()

    def test_sort_activity_basic(self) -> None:
        """
        Rooms with newer activity are sorted first.
        """
        user1_id = self.register_user("user1", "pass")
        user1_tok = self.login(user1_id, "pass")

        room_id1 = self.helper.create_room_as(
            user1_id,
            tok=user1_tok,
        )
        room_id2 = self.helper.create_room_as(
            user1_id,
            tok=user1_tok,
        )

        after_rooms_token = self.event_sources.get_current_token()

        # Get the rooms the user should be syncing with
        sync_room_map = self.get_success(
            self.sliding_sync_handler.get_sync_room_ids_for_user(
                UserID.from_string(user1_id),
                from_token=None,
                to_token=after_rooms_token,
            )
        )

        # Sort the rooms (what we're testing)
        sorted_sync_rooms = self.get_success(
            self.sliding_sync_handler.sort_rooms(
                sync_room_map=sync_room_map,
                to_token=after_rooms_token,
            )
        )

        self.assertEqual(
            [room_membership.room_id for room_membership in sorted_sync_rooms],
            [room_id2, room_id1],
        )

    @parameterized.expand(
        [
            (Membership.LEAVE,),
            (Membership.INVITE,),
            (Membership.KNOCK,),
            (Membership.BAN,),
        ]
    )
    def test_activity_after_xxx(self, room1_membership: str) -> None:
        """
        When someone has left/been invited/knocked/been banned from a room, they
        shouldn't take anything into account after that membership event.
        """
        user1_id = self.register_user("user1", "pass")
        user1_tok = self.login(user1_id, "pass")
        user2_id = self.register_user("user2", "pass")
        user2_tok = self.login(user2_id, "pass")

        before_rooms_token = self.event_sources.get_current_token()

        # Create the rooms as user2 so we can have user1 with a clean slate to work from
        # and join in whatever order we need for the tests.
        room_id1 = self.helper.create_room_as(user2_id, tok=user2_tok, is_public=True)
        # If we're testing knocks, set the room to knock
        if room1_membership == Membership.KNOCK:
            self.helper.send_state(
                room_id1,
                EventTypes.JoinRules,
                {"join_rule": JoinRules.KNOCK},
                tok=user2_tok,
            )
        room_id2 = self.helper.create_room_as(user2_id, tok=user2_tok, is_public=True)
        room_id3 = self.helper.create_room_as(user2_id, tok=user2_tok, is_public=True)

        # Here is the activity with user1 that will determine the sort of the rooms
        # (room2, room1, room3)
        self.helper.join(room_id3, user1_id, tok=user1_tok)
        if room1_membership == Membership.LEAVE:
            self.helper.join(room_id1, user1_id, tok=user1_tok)
            self.helper.leave(room_id1, user1_id, tok=user1_tok)
        elif room1_membership == Membership.INVITE:
            self.helper.invite(room_id1, src=user2_id, targ=user1_id, tok=user2_tok)
        elif room1_membership == Membership.KNOCK:
            self.helper.knock(room_id1, user1_id, tok=user1_tok)
        elif room1_membership == Membership.BAN:
            self.helper.ban(room_id1, src=user2_id, targ=user1_id, tok=user2_tok)
        self.helper.join(room_id2, user1_id, tok=user1_tok)

        # Activity before the token but the user is only been xxx to this room so it
        # shouldn't be taken into account
        self.helper.send(room_id1, "activity in room1", tok=user2_tok)

        after_rooms_token = self.event_sources.get_current_token()

        # Activity after the token. Just make it in a different order than what we
        # expect to make sure we're not taking the activity after the token into
        # account.
        self.helper.send(room_id1, "activity in room1", tok=user2_tok)
        self.helper.send(room_id2, "activity in room2", tok=user2_tok)
        self.helper.send(room_id3, "activity in room3", tok=user2_tok)

        # Get the rooms the user should be syncing with
        sync_room_map = self.get_success(
            self.sliding_sync_handler.get_sync_room_ids_for_user(
                UserID.from_string(user1_id),
                from_token=before_rooms_token,
                to_token=after_rooms_token,
            )
        )

        # Sort the rooms (what we're testing)
        sorted_sync_rooms = self.get_success(
            self.sliding_sync_handler.sort_rooms(
                sync_room_map=sync_room_map,
                to_token=after_rooms_token,
            )
        )

        self.assertEqual(
            [room_membership.room_id for room_membership in sorted_sync_rooms],
            [room_id2, room_id1, room_id3],
            "Corresponding map to disambiguate the opaque room IDs: "
            + str(
                {
                    "room_id1": room_id1,
                    "room_id2": room_id2,
                    "room_id3": room_id3,
                }
            ),
        )

    def test_default_bump_event_types(self) -> None:
        """
        Test that we only consider the *latest* event in the room when sorting (not
        `bump_event_types`).
        """
        user1_id = self.register_user("user1", "pass")
        user1_tok = self.login(user1_id, "pass")

        room_id1 = self.helper.create_room_as(
            user1_id,
            tok=user1_tok,
        )
        message_response = self.helper.send(room_id1, "message in room1", tok=user1_tok)
        room_id2 = self.helper.create_room_as(
            user1_id,
            tok=user1_tok,
        )
        self.helper.send(room_id2, "message in room2", tok=user1_tok)

        # Send a reaction in room1 which isn't in `DEFAULT_BUMP_EVENT_TYPES` but we only
        # care about sorting by the *latest* event in the room.
        self.helper.send_event(
            room_id1,
            type=EventTypes.Reaction,
            content={
                "m.relates_to": {
                    "event_id": message_response["event_id"],
                    "key": "👍",
                    "rel_type": "m.annotation",
                }
            },
            tok=user1_tok,
        )

        after_rooms_token = self.event_sources.get_current_token()

        # Get the rooms the user should be syncing with
        sync_room_map = self.get_success(
            self.sliding_sync_handler.get_sync_room_ids_for_user(
                UserID.from_string(user1_id),
                from_token=None,
                to_token=after_rooms_token,
            )
        )

        # Sort the rooms (what we're testing)
        sorted_sync_rooms = self.get_success(
            self.sliding_sync_handler.sort_rooms(
                sync_room_map=sync_room_map,
                to_token=after_rooms_token,
            )
        )

        self.assertEqual(
            [room_membership.room_id for room_membership in sorted_sync_rooms],
            # room1 sorts before room2 because it has the latest event (the reaction).
            # We only care about the *latest* event in the room.
            [room_id1, room_id2],
        )