zulip/zerver/tests/test_messages.py

from django.db import IntegrityError
from django.db.models import Q
from django.conf import settings
from django.http import HttpResponse
from django.test import TestCase, override_settings
from django.utils.timezone import now as timezone_now

from zerver.lib import bugdown
from zerver.decorator import JsonableError
from zerver.lib.test_runner import slow
from zerver.lib.addressee import Addressee

from zerver.lib.actions import (
    check_message,
    check_send_stream_message,
    create_mirror_user_if_needed,
    do_add_alert_words,
    do_change_is_api_super_user,
    do_change_stream_invite_only,
    do_change_stream_post_policy,
    do_claim_attachments,
    do_create_user,
    do_deactivate_user,
    do_send_messages,
    do_update_message,
    do_set_realm_property,
    extract_private_recipients,
    extract_stream_indicator,
    gather_subscriptions_helper,
    get_active_presence_idle_user_ids,
    get_client,
    get_last_message_id,
    get_topic_messages,
    get_user_info_for_message_updates,
    internal_prep_private_message,
    internal_prep_stream_message_by_name,
    internal_send_huddle_message,
    internal_send_private_message,
    internal_send_stream_message,
    internal_send_stream_message_by_name,
    send_rate_limited_pm_notification_to_bot_owner,
)

from zerver.lib.cache import (
    cache_delete,
    get_stream_cache_key,
    to_dict_cache_key_id,
)


from zerver.lib.create_user import (
    create_user_profile,
)

from zerver.lib.message import (
    MessageDict,
    bulk_access_messages,
    get_first_visible_message_id,
    get_raw_unread_data,
    get_recent_private_conversations,
    maybe_update_first_visible_message_id,
    messages_for_ids,
    render_markdown,
    sew_messages_and_reactions,
    update_first_visible_message_id,
)

from zerver.lib.test_helpers import (
    get_subscription,
    get_user_messages,
    make_client,
    message_stream_count,
    most_recent_message,
    most_recent_usermessage,
    queries_captured,
    reset_emails_in_zulip_realm,
)

from zerver.lib.test_classes import (
    ZulipTestCase,
)

from zerver.lib.topic import (
    LEGACY_PREV_TOPIC,
    DB_TOPIC_NAME,
    TOPIC_LINKS,
    TOPIC_NAME,
)

from zerver.lib.types import DisplayRecipientT, UserDisplayRecipient
from zerver.lib.soft_deactivation import (
    add_missing_messages,
    do_soft_activate_users,
    do_soft_deactivate_users,
    reactivate_user_if_soft_deactivated,
)

from zerver.models import (
    MAX_MESSAGE_LENGTH, MAX_TOPIC_NAME_LENGTH,
    Message, Realm, Recipient, Stream, UserMessage, UserProfile, Attachment,
    RealmAuditLog, RealmDomain, get_realm, UserPresence, Subscription,
    get_stream, get_system_bot, get_user, Reaction,
    flush_per_request_caches, ScheduledMessage, get_huddle_recipient,
    bulk_get_huddle_user_ids, get_huddle_user_ids,
    get_display_recipient, RealmFilter
)


from zerver.lib.timestamp import convert_to_UTC, datetime_to_timestamp
from zerver.lib.timezone import get_timezone
from zerver.lib.upload import create_attachment
from zerver.lib.url_encoding import near_message_url

from zerver.views.messages import create_mirrored_message_users, InvalidMirrorInput

from analytics.lib.counts import COUNT_STATS
from analytics.models import RealmCount

import datetime
from unittest import mock
from operator import itemgetter
import time
import ujson
from typing import Any, Dict, List, Set, Union, Tuple

from collections import namedtuple

class MiscMessageTest(ZulipTestCase):
    def test_get_last_message_id(self) -> None:
        self.assertEqual(
            get_last_message_id(),
            Message.objects.latest('id').id
        )

        Message.objects.all().delete()

        self.assertEqual(get_last_message_id(), -1)

class TopicHistoryTest(ZulipTestCase):
    def test_topics_history_zephyr_mirror(self) -> None:
        user_profile = self.mit_user('sipbtest')
        stream_name = 'new_stream'

        # Send a message to this new stream from another user
        self.subscribe(self.mit_user("starnine"), stream_name)
        stream = get_stream(stream_name, user_profile.realm)
        self.send_stream_message(self.mit_user("starnine"), stream_name,
                                 topic_name="secret topic")

        # Now subscribe this MIT user to the new stream and verify
        # that the new topic is not accessible
        self.login_user(user_profile)
        self.subscribe(user_profile, stream_name)
        endpoint = '/json/users/me/%d/topics' % (stream.id,)
        result = self.client_get(endpoint, dict(), subdomain="zephyr")
        self.assert_json_success(result)
        history = result.json()['topics']
        self.assertEqual(history, [])

    def test_topics_history(self) -> None:
        # verified: int(UserMessage.flags.read) == 1
        user_profile = self.example_user('iago')
        self.login_user(user_profile)
        stream_name = 'Verona'

        stream = get_stream(stream_name, user_profile.realm)
        recipient = stream.recipient

        def create_test_message(topic: str) -> int:
            # TODO: Clean this up to send messages the normal way.

            hamlet = self.example_user('hamlet')
            message = Message(
                sender=hamlet,
                recipient=recipient,
                content='whatever',
                date_sent=timezone_now(),
                sending_client=get_client('whatever'),
            )
            message.set_topic_name(topic)
            message.save()

            UserMessage.objects.create(
                user_profile=user_profile,
                message=message,
                flags=0,
            )

            return message.id

        # our most recent topics are topic0, topic1, topic2

        # Create old messages with strange spellings.
        create_test_message('topic2')
        create_test_message('toPIc1')
        create_test_message('toPIc0')
        create_test_message('topic2')
        create_test_message('topic2')
        create_test_message('Topic2')

        # Create new messages
        topic2_msg_id = create_test_message('topic2')
        create_test_message('topic1')
        create_test_message('topic1')
        topic1_msg_id = create_test_message('topic1')
        topic0_msg_id = create_test_message('topic0')

        endpoint = '/json/users/me/%d/topics' % (stream.id,)
        result = self.client_get(endpoint, dict())
        self.assert_json_success(result)
        history = result.json()['topics']

        # We only look at the most recent three topics, because
        # the prior fixture data may be unreliable.
        history = history[:3]

        self.assertEqual([topic['name'] for topic in history], [
            'topic0',
            'topic1',
            'topic2',
        ])

        self.assertEqual([topic['max_id'] for topic in history], [
            topic0_msg_id,
            topic1_msg_id,
            topic2_msg_id,
        ])

        # Now try as cordelia, who we imagine as a totally new user in
        # that she doesn't have UserMessage rows.  We should see the
        # same results for a public stream.
        self.login('cordelia')
        result = self.client_get(endpoint, dict())
        self.assert_json_success(result)
        history = result.json()['topics']

        # We only look at the most recent three topics, because
        # the prior fixture data may be unreliable.
        history = history[:3]

        self.assertEqual([topic['name'] for topic in history], [
            'topic0',
            'topic1',
            'topic2',
        ])
        self.assertIn('topic0', [topic['name'] for topic in history])

        self.assertEqual([topic['max_id'] for topic in history], [
            topic0_msg_id,
            topic1_msg_id,
            topic2_msg_id,
        ])

        # Now make stream private, but subscribe cordelia
        do_change_stream_invite_only(stream, True)
        self.subscribe(self.example_user("cordelia"), stream.name)

        result = self.client_get(endpoint, dict())
        self.assert_json_success(result)
        history = result.json()['topics']
        history = history[:3]

        # Cordelia doesn't have these recent history items when we
        # wasn't subscribed in her results.
        self.assertNotIn('topic0', [topic['name'] for topic in history])
        self.assertNotIn('topic1', [topic['name'] for topic in history])
        self.assertNotIn('topic2', [topic['name'] for topic in history])

    def test_bad_stream_id(self) -> None:
        self.login('iago')

        # non-sensible stream id
        endpoint = '/json/users/me/9999999999/topics'
        result = self.client_get(endpoint, dict())
        self.assert_json_error(result, 'Invalid stream id')

        # out of realm
        bad_stream = self.make_stream(
            'mit_stream',
            realm=get_realm('zephyr')
        )
        endpoint = '/json/users/me/%s/topics' % (bad_stream.id,)
        result = self.client_get(endpoint, dict())
        self.assert_json_error(result, 'Invalid stream id')

        # private stream to which I am not subscribed
        private_stream = self.make_stream(
            'private_stream',
            invite_only=True
        )
        endpoint = '/json/users/me/%s/topics' % (private_stream.id,)
        result = self.client_get(endpoint, dict())
        self.assert_json_error(result, 'Invalid stream id')

class TopicDeleteTest(ZulipTestCase):
    def test_topic_delete(self) -> None:
        initial_last_msg_id = self.get_last_message().id
        stream_name = 'new_stream'
        topic_name = 'new topic 2'

        # NON-ADMIN USER
        user_profile = self.example_user('hamlet')
        self.subscribe(user_profile, stream_name)

        # Send message
        stream = get_stream(stream_name, user_profile.realm)
        self.send_stream_message(user_profile, stream_name, topic_name=topic_name)
        last_msg_id = self.send_stream_message(user_profile, stream_name, topic_name=topic_name)

        # Deleting the topic
        self.login_user(user_profile)
        endpoint = '/json/streams/' + str(stream.id) + '/delete_topic'
        result = self.client_post(endpoint, {
            "topic_name": topic_name
        })
        self.assert_json_error(result, "Must be an organization administrator")
        self.assertEqual(self.get_last_message().id, last_msg_id)

        # Make stream private with limited history
        do_change_stream_invite_only(stream, invite_only=True,
                                     history_public_to_subscribers=False)

        # ADMIN USER subscribed now
        user_profile = self.example_user('iago')
        self.subscribe(user_profile, stream_name)
        self.login_user(user_profile)
        new_last_msg_id = self.send_stream_message(user_profile, stream_name, topic_name=topic_name)

        # Now admin deletes all messages in topic -- which should only
        # delete new_last_msg_id, i.e. the one sent since they joined.
        self.assertEqual(self.get_last_message().id, new_last_msg_id)
        result = self.client_post(endpoint, {
            "topic_name": topic_name
        })
        self.assert_json_success(result)
        self.assertEqual(self.get_last_message().id, last_msg_id)

        # Try to delete all messages in the topic again. There are no messages accessible
        # to the administrator, so this should do nothing.
        result = self.client_post(endpoint, {
            "topic_name": topic_name
        })
        self.assert_json_success(result)
        self.assertEqual(self.get_last_message().id, last_msg_id)

        # Make the stream's history public to subscribers
        do_change_stream_invite_only(stream, invite_only=True,
                                     history_public_to_subscribers=True)
        # Delete the topic should now remove all messages
        result = self.client_post(endpoint, {
            "topic_name": topic_name
        })
        self.assert_json_success(result)
        self.assertEqual(self.get_last_message().id, initial_last_msg_id)

        # Delete again, to test the edge case of deleting an empty topic.
        result = self.client_post(endpoint, {
            "topic_name": topic_name
        })
        self.assert_json_success(result)
        self.assertEqual(self.get_last_message().id, initial_last_msg_id)

class TestCrossRealmPMs(ZulipTestCase):
    def make_realm(self, domain: str) -> Realm:
        realm = Realm.objects.create(string_id=domain, invite_required=False)
        RealmDomain.objects.create(realm=realm, domain=domain)
        return realm

    def create_user(self, email: str) -> UserProfile:
        subdomain = email.split("@")[1]
        self.register(email, 'test', subdomain=subdomain)
        return get_user(email, get_realm(subdomain))

    @slow("Sends a large number of messages")
    @override_settings(CROSS_REALM_BOT_EMAILS=['notification-bot@zulip.com',
                                               'welcome-bot@zulip.com',
                                               'support@3.example.com'])
    def test_realm_scenarios(self) -> None:
        self.make_realm('1.example.com')
        r2 = self.make_realm('2.example.com')
        self.make_realm('3.example.com')

        def assert_message_received(to_user: UserProfile, from_user: UserProfile) -> None:
            messages = get_user_messages(to_user)
            self.assertEqual(messages[-1].sender.id, from_user.id)

        def assert_invalid_user() -> Any:
            return self.assertRaisesRegex(
                JsonableError,
                'Invalid user ID ')

        user1_email = 'user1@1.example.com'
        user1a_email = 'user1a@1.example.com'
        user2_email = 'user2@2.example.com'
        user3_email = 'user3@3.example.com'
        notification_bot_email = 'notification-bot@zulip.com'
        support_email = 'support@3.example.com'  # note: not zulip.com

        user1 = self.create_user(user1_email)
        user1a = self.create_user(user1a_email)
        user2 = self.create_user(user2_email)
        user3 = self.create_user(user3_email)
        notification_bot = get_system_bot(notification_bot_email)
        with self.settings(CROSS_REALM_BOT_EMAILS=['notification-bot@zulip.com', 'welcome-bot@zulip.com']):
            # HACK: We should probably be creating this "bot" user another
            # way, but since you can't register a user with a
            # cross-realm email, we need to hide this for now.
            support_bot = self.create_user(support_email)

        # Users can PM themselves
        self.send_personal_message(user1, user1)
        assert_message_received(user1, user1)

        # Users on the same realm can PM each other
        self.send_personal_message(user1, user1a)
        assert_message_received(user1a, user1)

        # Cross-realm bots in the zulip.com realm can PM any realm
        # (They need lower level APIs to do this.)
        internal_send_private_message(
            realm=r2,
            sender=get_system_bot(notification_bot_email),
            recipient_user=get_user(user2_email, r2),
            content='bla',
        )
        assert_message_received(user2, notification_bot)

        # All users can PM cross-realm bots in the zulip.com realm
        self.send_personal_message(user1, notification_bot)
        assert_message_received(notification_bot, user1)

        # Users can PM cross-realm bots on non-zulip realms.
        # (The support bot represents some theoretical bot that we may
        # create in the future that does not have zulip.com as its realm.)
        self.send_personal_message(user1,  support_bot)
        assert_message_received(support_bot, user1)

        # Allow sending PMs to two different cross-realm bots simultaneously.
        # (We don't particularly need this feature, but since users can
        # already individually send PMs to cross-realm bots, we shouldn't
        # prevent them from sending multiple bots at once.  We may revisit
        # this if it's a nuisance for huddles.)
        self.send_huddle_message(user1, [notification_bot, support_bot])
        assert_message_received(notification_bot, user1)
        assert_message_received(support_bot, user1)

        # Prevent old loophole where I could send PMs to other users as long
        # as I copied a cross-realm bot from the same realm.
        with assert_invalid_user():
            self.send_huddle_message(user1, [user3, support_bot])

        # Users on three different realms can't PM each other,
        # even if one of the users is a cross-realm bot.
        with assert_invalid_user():
            self.send_huddle_message(user1, [user2, notification_bot])

        with assert_invalid_user():
            self.send_huddle_message(notification_bot, [user1, user2])

        # Users on the different realms cannot PM each other
        with assert_invalid_user():
            self.send_personal_message(user1, user2)

        # Users on non-zulip realms can't PM "ordinary" Zulip users
        with assert_invalid_user():
            self.send_personal_message(user1, self.example_user('hamlet'))

        # Users on three different realms cannot PM each other
        with assert_invalid_user():
            self.send_huddle_message(user1, [user2, user3])

class TestAddressee(ZulipTestCase):
    def test_addressee_for_user_ids(self) -> None:
        realm = get_realm('zulip')
        user_ids = [self.example_user('cordelia').id,
                    self.example_user('hamlet').id,
                    self.example_user('othello').id]

        result = Addressee.for_user_ids(user_ids=user_ids, realm=realm)
        user_profiles = result.user_profiles()
        result_user_ids = [user_profiles[0].id, user_profiles[1].id,
                           user_profiles[2].id]

        self.assertEqual(set(result_user_ids), set(user_ids))

    def test_addressee_for_user_ids_nonexistent_id(self) -> None:
        def assert_invalid_user_id() -> Any:
            return self.assertRaisesRegex(
                JsonableError,
                'Invalid user ID ')

        with assert_invalid_user_id():
            Addressee.for_user_ids(user_ids=[779], realm=get_realm('zulip'))

    def test_addressee_legacy_build_for_user_ids(self) -> None:
        realm = get_realm('zulip')
        self.login('hamlet')
        user_ids = [self.example_user('cordelia').id,
                    self.example_user('othello').id]

        result = Addressee.legacy_build(
            sender=self.example_user('hamlet'), message_type_name='private',
            message_to=user_ids, topic_name='random_topic',
            realm=realm
        )
        user_profiles = result.user_profiles()
        result_user_ids = [user_profiles[0].id, user_profiles[1].id]

        self.assertEqual(set(result_user_ids), set(user_ids))

    def test_addressee_legacy_build_for_stream_id(self) -> None:
        realm = get_realm('zulip')
        self.login('iago')
        sender = self.example_user('iago')
        self.subscribe(sender, "Denmark")
        stream = get_stream('Denmark', realm)

        result = Addressee.legacy_build(
            sender=sender, message_type_name='stream',
            message_to=[stream.id], topic_name='random_topic',
            realm=realm
        )

        stream_id = result.stream_id()
        self.assertEqual(stream.id, stream_id)

class InternalPrepTest(ZulipTestCase):

    def test_returns_for_internal_sends(self) -> None:
        # For our internal_send_* functions we return
        # if the prep stages fail.  This is mostly defensive
        # code, since we are generally creating the messages
        # ourselves, but we want to make sure that the functions
        # won't actually explode if we give them bad content.
        bad_content = ''
        realm = get_realm('zulip')
        cordelia = self.example_user('cordelia')
        hamlet = self.example_user('hamlet')
        othello = self.example_user('othello')
        stream = get_stream('Verona', realm)

        with mock.patch('logging.exception') as m:
            internal_send_private_message(
                realm=realm,
                sender=cordelia,
                recipient_user=hamlet,
                content=bad_content,
            )

        arg = m.call_args_list[0][0][0]
        self.assertIn('Message must not be empty', arg)

        with mock.patch('logging.exception') as m:
            internal_send_huddle_message(
                realm=realm,
                sender=cordelia,
                emails=[hamlet.email, othello.email],
                content=bad_content,
            )

        arg = m.call_args_list[0][0][0]
        self.assertIn('Message must not be empty', arg)

        with mock.patch('logging.exception') as m:
            internal_send_stream_message(
                realm=realm,
                sender=cordelia,
                topic='whatever',
                content=bad_content,
                stream=stream
            )

        arg = m.call_args_list[0][0][0]
        self.assertIn('Message must not be empty', arg)

        with mock.patch('logging.exception') as m:
            internal_send_stream_message_by_name(
                realm=realm,
                sender=cordelia,
                stream_name=stream.name,
                topic='whatever',
                content=bad_content
            )

        arg = m.call_args_list[0][0][0]
        self.assertIn('Message must not be empty', arg)

    def test_error_handling(self) -> None:
        realm = get_realm('zulip')
        sender = self.example_user('cordelia')
        recipient_user = self.example_user('hamlet')
        content = 'x' * 15000

        result = internal_prep_private_message(
            realm=realm,
            sender=sender,
            recipient_user=recipient_user,
            content=content)
        message = result['message']
        self.assertIn('message was too long', message.content)

        with self.assertRaises(RuntimeError):
            internal_prep_private_message(
                realm=None,  # should cause error
                sender=sender,
                recipient_user=recipient_user,
                content=content)

        # Simulate sending a message to somebody not in the
        # realm of the sender.
        recipient_user = self.mit_user('starnine')
        with mock.patch('logging.exception') as logging_mock:
            result = internal_prep_private_message(
                realm=realm,
                sender=sender,
                recipient_user=recipient_user,
                content=content)
        arg = logging_mock.call_args_list[0][0][0]
        prefix = "Error queueing internal message by cordelia@zulip.com: You can't send private messages outside of your organization."
        self.assertTrue(arg.startswith(prefix))

    def test_ensure_stream_gets_called(self) -> None:
        realm = get_realm('zulip')
        sender = self.example_user('cordelia')
        stream_name = 'test_stream'
        topic = 'whatever'
        content = 'hello'

        internal_prep_stream_message_by_name(
            realm=realm,
            sender=sender,
            stream_name=stream_name,
            topic=topic,
            content=content)

        # This would throw an error if the stream
        # wasn't automatically created.
        Stream.objects.get(name=stream_name, realm_id=realm.id)

class ExtractTest(TestCase):
    def test_extract_stream_indicator(self) -> None:
        self.assertEqual(
            extract_stream_indicator('development'),
            "development",
        )
        self.assertEqual(
            extract_stream_indicator('commas,are,fine'),
            "commas,are,fine",
        )
        self.assertEqual(
            extract_stream_indicator('"Who hasn\'t done this?"'),
            "Who hasn't done this?",
        )
        self.assertEqual(
            extract_stream_indicator("999"),
            999,
        )

        # For legacy reasons it's plausible that users will
        # put a single stream into an array and then encode it
        # as JSON.  We can probably eliminate this support
        # by mid 2020 at the latest.
        self.assertEqual(
            extract_stream_indicator('["social"]'),
            'social',
        )

        self.assertEqual(
            extract_stream_indicator("[123]"),
            123,
        )

        with self.assertRaisesRegex(JsonableError, 'Invalid data type for stream'):
            extract_stream_indicator('{}')

        with self.assertRaisesRegex(JsonableError, 'Invalid data type for stream'):
            extract_stream_indicator('[{}]')

        with self.assertRaisesRegex(JsonableError, 'Expected exactly one stream'):
            extract_stream_indicator('[1,2,"general"]')

    def test_extract_private_recipients_emails(self) -> None:

        # JSON list w/dups, empties, and trailing whitespace
        s = ujson.dumps([' alice@zulip.com ', ' bob@zulip.com ', '   ', 'bob@zulip.com'])
        # sorted() gets confused by extract_private_recipients' return type
        # For testing, ignorance here is better than manual casting
        result = sorted(extract_private_recipients(s))
        self.assertEqual(result, ['alice@zulip.com', 'bob@zulip.com'])

        # simple string with one name
        s = 'alice@zulip.com    '
        self.assertEqual(extract_private_recipients(s), ['alice@zulip.com'])

        # JSON-encoded string
        s = '"alice@zulip.com"'
        self.assertEqual(extract_private_recipients(s), ['alice@zulip.com'])

        # bare comma-delimited string
        s = 'bob@zulip.com, alice@zulip.com'
        result = sorted(extract_private_recipients(s))
        self.assertEqual(result, ['alice@zulip.com', 'bob@zulip.com'])

        # JSON-encoded, comma-delimited string
        s = '"bob@zulip.com,alice@zulip.com"'
        result = sorted(extract_private_recipients(s))
        self.assertEqual(result, ['alice@zulip.com', 'bob@zulip.com'])

        # Invalid data
        s = ujson.dumps(dict(color='red'))
        with self.assertRaisesRegex(JsonableError, 'Invalid data type for recipients'):
            extract_private_recipients(s)

        s = ujson.dumps([{}])
        with self.assertRaisesRegex(JsonableError, 'Invalid data type for recipients'):
            extract_private_recipients(s)

        # Empty list
        self.assertEqual(extract_private_recipients('[]'), [])

        # Heterogeneous lists are not supported
        mixed = ujson.dumps(['eeshan@example.com', 3, 4])
        with self.assertRaisesRegex(JsonableError, 'Recipient lists may contain emails or user IDs, but not both.'):
            extract_private_recipients(mixed)

    def test_extract_recipient_ids(self) -> None:
        # JSON list w/dups
        s = ujson.dumps([3, 3, 12])
        result = sorted(extract_private_recipients(s))
        self.assertEqual(result, [3, 12])

        # Invalid data
        ids = ujson.dumps(dict(recipient=12))
        with self.assertRaisesRegex(JsonableError, 'Invalid data type for recipients'):
            extract_private_recipients(ids)

        # Heterogeneous lists are not supported
        mixed = ujson.dumps([3, 4, 'eeshan@example.com'])
        with self.assertRaisesRegex(JsonableError, 'Recipient lists may contain emails or user IDs, but not both.'):
            extract_private_recipients(mixed)

class PersonalMessagesTest(ZulipTestCase):

    def test_near_pm_message_url(self) -> None:
        realm = get_realm('zulip')
        message = dict(
            type='personal',
            id=555,
            display_recipient=[
                dict(id=77),
                dict(id=80),
            ],
        )
        url = near_message_url(
            realm=realm,
            message=message,
        )
        self.assertEqual(url, 'http://zulip.testserver/#narrow/pm-with/77,80-pm/near/555')

    def test_is_private_flag_not_leaked(self) -> None:
        """
        Make sure `is_private` flag is not leaked to the API.
        """
        self.login('hamlet')
        self.send_personal_message(self.example_user("hamlet"),
                                   self.example_user("cordelia"),
                                   "test")

        for msg in self.get_messages():
            self.assertNotIn('is_private', msg['flags'])

    def test_auto_subbed_to_personals(self) -> None:
        """
        Newly created users are auto-subbed to the ability to receive
        personals.
        """
        test_email = self.nonreg_email('test')
        self.register(test_email, "test")
        user_profile = self.nonreg_user('test')
        old_messages_count = message_stream_count(user_profile)
        self.send_personal_message(user_profile, user_profile)
        new_messages_count = message_stream_count(user_profile)
        self.assertEqual(new_messages_count, old_messages_count + 1)

        recipient = Recipient.objects.get(type_id=user_profile.id,
                                          type=Recipient.PERSONAL)
        message = most_recent_message(user_profile)
        self.assertEqual(message.recipient, recipient)

        with mock.patch('zerver.models.get_display_recipient', return_value='recip'):
            self.assertEqual(
                str(message),
                '<Message: recip /  / '
                '<UserProfile: {} {}>>'.format(user_profile.email, user_profile.realm))

            user_message = most_recent_usermessage(user_profile)
            self.assertEqual(
                str(user_message),
                f'<UserMessage: recip / {user_profile.email} ([])>'
            )

    @slow("checks several profiles")
    def test_personal_to_self(self) -> None:
        """
        If you send a personal to yourself, only you see it.
        """
        old_user_profiles = list(UserProfile.objects.all())
        test_email = self.nonreg_email('test1')
        self.register(test_email, "test1")

        old_messages = []
        for user_profile in old_user_profiles:
            old_messages.append(message_stream_count(user_profile))

        user_profile = self.nonreg_user('test1')
        self.send_personal_message(user_profile, user_profile)

        new_messages = []
        for user_profile in old_user_profiles:
            new_messages.append(message_stream_count(user_profile))

        self.assertEqual(old_messages, new_messages)

        user_profile = self.nonreg_user('test1')
        recipient = Recipient.objects.get(type_id=user_profile.id, type=Recipient.PERSONAL)
        self.assertEqual(most_recent_message(user_profile).recipient, recipient)

    def assert_personal(self, sender: UserProfile, receiver: UserProfile, content: str="testcontent") -> None:
        """
        Send a private message from `sender_email` to `receiver_email` and check
        that only those two parties actually received the message.
        """
        sender_messages = message_stream_count(sender)
        receiver_messages = message_stream_count(receiver)

        other_user_profiles = UserProfile.objects.filter(~Q(id=sender.id) &
                                                         ~Q(id=receiver.id))
        old_other_messages = []
        for user_profile in other_user_profiles:
            old_other_messages.append(message_stream_count(user_profile))

        self.send_personal_message(sender, receiver, content)

        # Users outside the conversation don't get the message.
        new_other_messages = []
        for user_profile in other_user_profiles:
            new_other_messages.append(message_stream_count(user_profile))

        self.assertEqual(old_other_messages, new_other_messages)

        # The personal message is in the streams of both the sender and receiver.
        self.assertEqual(message_stream_count(sender),
                         sender_messages + 1)
        self.assertEqual(message_stream_count(receiver),
                         receiver_messages + 1)

        recipient = Recipient.objects.get(type_id=receiver.id, type=Recipient.PERSONAL)
        self.assertEqual(most_recent_message(sender).recipient, recipient)
        self.assertEqual(most_recent_message(receiver).recipient, recipient)

    def test_personal(self) -> None:
        """
        If you send a personal, only you and the recipient see it.
        """
        self.login('hamlet')
        self.assert_personal(
            sender=self.example_user("hamlet"),
            receiver=self.example_user("othello")
        )

    def test_private_message_policy(self) -> None:
        """
        Tests that PRIVATE_MESSAGE_POLICY_DISABLED works correctly.
        """
        user_profile = self.example_user("hamlet")
        self.login_user(user_profile)
        do_set_realm_property(user_profile.realm, "private_message_policy",
                              Realm.PRIVATE_MESSAGE_POLICY_DISABLED)
        with self.assertRaises(JsonableError):
            self.send_personal_message(user_profile, self.example_user("cordelia"))

        bot_profile = self.create_test_bot("testbot", user_profile)
        self.send_personal_message(user_profile, get_system_bot(settings.NOTIFICATION_BOT))
        self.send_personal_message(user_profile, bot_profile)
        self.send_personal_message(bot_profile, user_profile)

    def test_non_ascii_personal(self) -> None:
        """
        Sending a PM containing non-ASCII characters succeeds.
        """
        self.login('hamlet')
        self.assert_personal(
            sender=self.example_user("hamlet"),
            receiver=self.example_user("othello"),
            content="hümbüǵ"
        )

class StreamMessagesTest(ZulipTestCase):

    def assert_stream_message(self, stream_name: str, topic_name: str="test topic",
                              content: str="test content") -> None:
        """
        Check that messages sent to a stream reach all subscribers to that stream.
        """
        realm = get_realm('zulip')
        subscribers = self.users_subscribed_to_stream(stream_name, realm)

        # Outgoing webhook bots don't store UserMessage rows; they will be processed later.
        subscribers = [subscriber for subscriber in subscribers
                       if subscriber.bot_type != UserProfile.OUTGOING_WEBHOOK_BOT]

        old_subscriber_messages = []
        for subscriber in subscribers:
            old_subscriber_messages.append(message_stream_count(subscriber))

        non_subscribers = [user_profile for user_profile in UserProfile.objects.all()
                           if user_profile not in subscribers]
        old_non_subscriber_messages = []
        for non_subscriber in non_subscribers:
            old_non_subscriber_messages.append(message_stream_count(non_subscriber))

        non_bot_subscribers = [user_profile for user_profile in subscribers
                               if not user_profile.is_bot]
        a_subscriber = non_bot_subscribers[0]
        self.login_user(a_subscriber)
        self.send_stream_message(a_subscriber, stream_name,
                                 content=content, topic_name=topic_name)

        # Did all of the subscribers get the message?
        new_subscriber_messages = []
        for subscriber in subscribers:
            new_subscriber_messages.append(message_stream_count(subscriber))

        # Did non-subscribers not get the message?
        new_non_subscriber_messages = []
        for non_subscriber in non_subscribers:
            new_non_subscriber_messages.append(message_stream_count(non_subscriber))

        self.assertEqual(old_non_subscriber_messages, new_non_subscriber_messages)
        self.assertEqual(new_subscriber_messages, [elt + 1 for elt in old_subscriber_messages])

    def test_performance(self) -> None:
        '''
        This test is part of the automated test suite, but
        it is more intended as an aid to measuring the
        performance of do_send_messages() with consistent
        data setup across different commits.  You can modify
        the values below and run just this test, and then
        comment out the print statement toward the bottom.
        '''
        num_messages = 2
        num_extra_users = 10

        sender = self.example_user('cordelia')
        realm = sender.realm
        message_content = 'whatever'
        stream = get_stream('Denmark', realm)
        topic_name = 'lunch'
        recipient = stream.recipient
        sending_client = make_client(name="test suite")

        for i in range(num_extra_users):
            # Make every other user be idle.
            long_term_idle = i % 2 > 0

            email = 'foo%d@example.com' % (i,)
            user = UserProfile.objects.create(
                realm=realm,
                email=email,
                pointer=0,
                long_term_idle=long_term_idle,
            )
            Subscription.objects.create(
                user_profile=user,
                recipient=recipient
            )

        def send_test_message() -> None:
            message = Message(
                sender=sender,
                recipient=recipient,
                content=message_content,
                date_sent=timezone_now(),
                sending_client=sending_client,
            )
            message.set_topic_name(topic_name)
            do_send_messages([dict(message=message)])

        before_um_count = UserMessage.objects.count()

        t = time.time()
        for i in range(num_messages):
            send_test_message()

        delay = time.time() - t
        assert(delay)  # quiet down lint
        # print(delay)

        after_um_count = UserMessage.objects.count()
        ums_created = after_um_count - before_um_count

        num_active_users = num_extra_users / 2
        self.assertTrue(ums_created > (num_active_users * num_messages))

    def test_not_too_many_queries(self) -> None:
        recipient_list  = [self.example_user("hamlet"), self.example_user("iago"),
                           self.example_user("cordelia"), self.example_user("othello")]
        for user_profile in recipient_list:
            self.subscribe(user_profile, "Denmark")

        sender = self.example_user('hamlet')
        sending_client = make_client(name="test suite")
        stream_name = 'Denmark'
        topic_name = 'foo'
        content = 'whatever'
        realm = sender.realm

        # To get accurate count of the queries, we should make sure that
        # caches don't come into play. If we count queries while caches are
        # filled, we will get a lower count. Caches are not supposed to be
        # persistent, so our test can also fail if cache is invalidated
        # during the course of the unit test.
        flush_per_request_caches()
        cache_delete(get_stream_cache_key(stream_name, realm.id))
        with queries_captured() as queries:
            check_send_stream_message(
                sender=sender,
                client=sending_client,
                stream_name=stream_name,
                topic=topic_name,
                body=content,
            )

        self.assert_length(queries, 14)

    def test_stream_message_dict(self) -> None:
        user_profile = self.example_user('iago')
        self.subscribe(user_profile, "Denmark")
        self.send_stream_message(self.example_user("hamlet"), "Denmark",
                                 content="whatever", topic_name="my topic")
        message = most_recent_message(user_profile)
        row = MessageDict.get_raw_db_rows([message.id])[0]
        dct = MessageDict.build_dict_from_raw_db_row(row)
        MessageDict.post_process_dicts([dct], apply_markdown=True, client_gravatar=False)
        self.assertEqual(dct['display_recipient'], 'Denmark')

        stream = get_stream('Denmark', user_profile.realm)
        self.assertEqual(dct['stream_id'], stream.id)

    def test_stream_message_unicode(self) -> None:
        receiving_user_profile = self.example_user('iago')
        sender = self.example_user('hamlet')
        self.subscribe(receiving_user_profile, "Denmark")
        self.send_stream_message(sender, "Denmark",
                                 content="whatever", topic_name="my topic")
        message = most_recent_message(receiving_user_profile)
        self.assertEqual(str(message),
                         '<Message: Denmark / my topic / '
                         '<UserProfile: {} {}>>'.format(sender.email, sender.realm))

    def test_message_mentions(self) -> None:
        user_profile = self.example_user('iago')
        self.subscribe(user_profile, "Denmark")
        self.send_stream_message(self.example_user("hamlet"), "Denmark",
                                 content="test @**Iago** rules")
        message = most_recent_message(user_profile)
        assert(UserMessage.objects.get(user_profile=user_profile, message=message).flags.mentioned.is_set)

    def test_is_private_flag(self) -> None:
        user_profile = self.example_user('iago')
        self.subscribe(user_profile, "Denmark")

        self.send_stream_message(self.example_user("hamlet"), "Denmark",
                                 content="test")
        message = most_recent_message(user_profile)
        self.assertFalse(UserMessage.objects.get(user_profile=user_profile, message=message).flags.is_private.is_set)

        self.send_personal_message(self.example_user("hamlet"), user_profile,
                                   content="test")
        message = most_recent_message(user_profile)
        self.assertTrue(UserMessage.objects.get(user_profile=user_profile, message=message).flags.is_private.is_set)

    def _send_stream_message(self, user: UserProfile, stream_name: str, content: str) -> Set[int]:
        with mock.patch('zerver.lib.actions.send_event') as m:
            self.send_stream_message(
                user,
                stream_name,
                content=content
            )
        self.assertEqual(m.call_count, 1)
        users = m.call_args[0][2]
        user_ids = {u['id'] for u in users}
        return user_ids

    def test_unsub_mention(self) -> None:
        cordelia = self.example_user('cordelia')
        hamlet = self.example_user('hamlet')

        stream_name = 'Test Stream'

        self.subscribe(hamlet, stream_name)

        UserMessage.objects.filter(
            user_profile=cordelia
        ).delete()

        def mention_cordelia() -> Set[int]:
            content = 'test @**Cordelia Lear** rules'

            user_ids = self._send_stream_message(
                user=hamlet,
                stream_name=stream_name,
                content=content
            )
            return user_ids

        def num_cordelia_messages() -> int:
            return UserMessage.objects.filter(
                user_profile=cordelia
            ).count()

        user_ids = mention_cordelia()
        self.assertEqual(0, num_cordelia_messages())
        self.assertNotIn(cordelia.id, user_ids)

        # Make sure test isn't too brittle-subscribing
        # Cordelia and mentioning her should give her a
        # message.
        self.subscribe(cordelia, stream_name)
        user_ids = mention_cordelia()
        self.assertIn(cordelia.id, user_ids)
        self.assertEqual(1, num_cordelia_messages())

    def test_message_bot_mentions(self) -> None:
        cordelia = self.example_user('cordelia')
        hamlet = self.example_user('hamlet')
        realm = hamlet.realm

        stream_name = 'Test Stream'

        self.subscribe(hamlet, stream_name)

        normal_bot = do_create_user(
            email='normal-bot@zulip.com',
            password='',
            realm=realm,
            full_name='Normal Bot',
            short_name='',
            bot_type=UserProfile.DEFAULT_BOT,
            bot_owner=cordelia,
        )

        content = 'test @**Normal Bot** rules'

        user_ids = self._send_stream_message(
            user=hamlet,
            stream_name=stream_name,
            content=content
        )

        self.assertIn(normal_bot.id, user_ids)
        user_message = most_recent_usermessage(normal_bot)
        self.assertEqual(user_message.message.content, content)
        self.assertTrue(user_message.flags.mentioned)

    def test_stream_message_mirroring(self) -> None:
        user = self.mit_user('starnine')
        self.subscribe(user, 'Verona')

        do_change_is_api_super_user(user, True)
        result = self.api_post(user, "/api/v1/messages", {"type": "stream",
                                                          "to": "Verona",
                                                          "sender": self.mit_email("sipbtest"),
                                                          "client": "zephyr_mirror",
                                                          "topic": "announcement",
                                                          "content": "Everyone knows Iago rules",
                                                          "forged": "true"},
                               subdomain="zephyr")
        self.assert_json_success(result)

        do_change_is_api_super_user(user, False)
        result = self.api_post(user, "/api/v1/messages", {"type": "stream",
                                                          "to": "Verona",
                                                          "sender": self.mit_email("sipbtest"),
                                                          "client": "zephyr_mirror",
                                                          "topic": "announcement",
                                                          "content": "Everyone knows Iago rules",
                                                          "forged": "true"},
                               subdomain="zephyr")
        self.assert_json_error(result, "User not authorized for this query")

    def test_message_to_stream(self) -> None:
        """
        If you send a message to a stream, everyone subscribed to the stream
        receives the messages.
        """
        self.assert_stream_message("Scotland")

    def test_non_ascii_stream_message(self) -> None:
        """
        Sending a stream message containing non-ASCII characters in the stream
        name, topic, or message body succeeds.
        """
        self.login('hamlet')

        # Subscribe everyone to a stream with non-ASCII characters.
        non_ascii_stream_name = "hümbüǵ"
        realm = get_realm("zulip")
        stream = self.make_stream(non_ascii_stream_name)
        for user_profile in UserProfile.objects.filter(is_active=True, is_bot=False,
                                                       realm=realm)[0:3]:
            self.subscribe(user_profile, stream.name)

        self.assert_stream_message(non_ascii_stream_name, topic_name="hümbüǵ",
                                   content="hümbüǵ")

    def test_get_raw_unread_data_for_huddle_messages(self) -> None:
        users = [
            self.example_user('hamlet'),
            self.example_user('cordelia'),
            self.example_user('iago'),
            self.example_user('prospero'),
            self.example_user('othello'),
        ]

        message1_id = self.send_huddle_message(users[0], users, "test content 1")
        message2_id = self.send_huddle_message(users[0], users, "test content 2")

        msg_data = get_raw_unread_data(users[1])

        # both the messages are present in msg_data
        self.assertIn(message1_id, msg_data["huddle_dict"].keys())
        self.assertIn(message2_id, msg_data["huddle_dict"].keys())

        # only these two messages are present in msg_data
        self.assertEqual(len(msg_data["huddle_dict"].keys()), 2)

        recent_conversations = get_recent_private_conversations(users[1])
        self.assertEqual(len(recent_conversations), 1)
        recent_conversation = list(recent_conversations.values())[0]
        self.assertEqual(set(recent_conversation['user_ids']), {user.id for user in users if
                                                                user != users[1]})
        self.assertEqual(recent_conversation['max_message_id'], message2_id)

class MessageDictTest(ZulipTestCase):
    def test_both_codepaths(self) -> None:
        '''
        We have two different codepaths that
        extract a particular shape of dictionary
        for messages to send to clients:

            events:

                These are the events we send to MANY
                clients when a message is originally
                sent.

            fetch:

                These are the messages we send to ONE
                client when they fetch messages via
                some narrow/search in the UI.

        Different clients have different needs
        when it comes to things like generating avatar
        hashes or including both rendered and unrendered
        markdown, so that explains the different shapes.

        And then the two codepaths have different
        performance needs.  In the events codepath, we
        have the Django view generate a single "wide"
        dictionary that gets put on the event queue,
        and then we send events to multiple clients,
        finalizing the payload for each of them depending
        on the "shape" they want.  (We also avoid
        doing extra work for any two clients who want
        the same shape dictionary, but that's out of the
        scope of this particular test).

        In the fetch scenario, the single client only needs
        a dictionary of one shape, but we need to re-hydrate
        the sender information, since the sender details
        may have changed since the message was originally
        sent.

        This test simply verifies that the two codepaths
        ultimately provide the same result.
        '''

        def reload_message(msg_id: int) -> Message:
            # Get a clean copy of the message, and
            # clear the cache.
            cache_delete(to_dict_cache_key_id(msg_id))
            msg = Message.objects.get(id=msg_id)
            return msg

        def get_send_message_payload(
                msg_id: int,
                apply_markdown: bool,
                client_gravatar: bool) -> Dict[str, Any]:
            msg = reload_message(msg_id)
            wide_dict = MessageDict.wide_dict(msg)

            narrow_dict = MessageDict.finalize_payload(
                wide_dict,
                apply_markdown=apply_markdown,
                client_gravatar=client_gravatar,
            )
            return narrow_dict

        def get_fetch_payload(
                msg_id: int,
                apply_markdown: bool,
                client_gravatar: bool) -> Dict[str, Any]:
            msg = reload_message(msg_id)
            unhydrated_dict = MessageDict.to_dict_uncached_helper([msg])[0]
            # The next step mutates the dict in place
            # for performance reasons.
            MessageDict.post_process_dicts(
                [unhydrated_dict],
                apply_markdown=apply_markdown,
                client_gravatar=client_gravatar,
            )
            final_dict = unhydrated_dict
            return final_dict

        def test_message_id() -> int:
            hamlet = self.example_user('hamlet')
            self.login_user(hamlet)
            msg_id = self.send_stream_message(
                hamlet,
                "Scotland",
                topic_name="editing",
                content="before edit"
            )
            return msg_id

        flag_setups = [
            [False, False],
            [False, True],
            [True, False],
            [True, True],
        ]

        msg_id = test_message_id()

        for (apply_markdown, client_gravatar) in flag_setups:
            send_message_payload = get_send_message_payload(
                msg_id,
                apply_markdown=apply_markdown,
                client_gravatar=client_gravatar,
            )

            fetch_payload = get_fetch_payload(
                msg_id,
                apply_markdown=apply_markdown,
                client_gravatar=client_gravatar,
            )

            self.assertEqual(send_message_payload, fetch_payload)

    @slow('builds lots of messages')
    def test_bulk_message_fetching(self) -> None:
        sender = self.example_user('othello')
        receiver = self.example_user('hamlet')
        pm_recipient = Recipient.objects.get(type_id=receiver.id, type=Recipient.PERSONAL)
        stream_name = 'Çiğdem'
        stream = self.make_stream(stream_name)
        stream_recipient = Recipient.objects.get(type_id=stream.id, type=Recipient.STREAM)
        sending_client = make_client(name="test suite")

        ids = []
        for i in range(300):
            for recipient in [pm_recipient, stream_recipient]:
                message = Message(
                    sender=sender,
                    recipient=recipient,
                    content='whatever %d' % (i,),
                    rendered_content='DOES NOT MATTER',
                    rendered_content_version=bugdown.version,
                    date_sent=timezone_now(),
                    sending_client=sending_client,
                    last_edit_time=timezone_now(),
                    edit_history='[]'
                )
                message.set_topic_name('whatever')
                message.save()
                ids.append(message.id)

                Reaction.objects.create(user_profile=sender, message=message,
                                        emoji_name='simple_smile')

        num_ids = len(ids)
        self.assertTrue(num_ids >= 600)

        flush_per_request_caches()
        t = time.time()
        with queries_captured() as queries:
            rows = list(MessageDict.get_raw_db_rows(ids))

            objs = [
                MessageDict.build_dict_from_raw_db_row(row)
                for row in rows
            ]
            MessageDict.post_process_dicts(objs, apply_markdown=False, client_gravatar=False)

        delay = time.time() - t
        # Make sure we don't take longer than 1.5ms per message to
        # extract messages.  Note that we increased this from 1ms to
        # 1.5ms to handle tests running in parallel being a bit
        # slower.
        error_msg = f"Number of ids: {num_ids}. Time delay: {delay}"
        self.assertTrue(delay < 0.0015 * num_ids, error_msg)
        self.assert_length(queries, 7)
        self.assertEqual(len(rows), num_ids)

    def test_applying_markdown(self) -> None:
        sender = self.example_user('othello')
        receiver = self.example_user('hamlet')
        recipient = Recipient.objects.get(type_id=receiver.id, type=Recipient.PERSONAL)
        sending_client = make_client(name="test suite")
        message = Message(
            sender=sender,
            recipient=recipient,
            content='hello **world**',
            date_sent=timezone_now(),
            sending_client=sending_client,
            last_edit_time=timezone_now(),
            edit_history='[]'
        )
        message.set_topic_name('whatever')
        message.save()

        # An important part of this test is to get the message through this exact code path,
        # because there is an ugly hack we need to cover.  So don't just say "row = message".
        row = MessageDict.get_raw_db_rows([message.id])[0]
        dct = MessageDict.build_dict_from_raw_db_row(row)
        expected_content = '<p>hello <strong>world</strong></p>'
        self.assertEqual(dct['rendered_content'], expected_content)
        message = Message.objects.get(id=message.id)
        self.assertEqual(message.rendered_content, expected_content)
        self.assertEqual(message.rendered_content_version, bugdown.version)

    @mock.patch("zerver.lib.message.bugdown.convert")
    def test_applying_markdown_invalid_format(self, convert_mock: Any) -> None:
        # pretend the converter returned an invalid message without raising an exception
        convert_mock.return_value = None
        sender = self.example_user('othello')
        receiver = self.example_user('hamlet')
        recipient = Recipient.objects.get(type_id=receiver.id, type=Recipient.PERSONAL)
        sending_client = make_client(name="test suite")
        message = Message(
            sender=sender,
            recipient=recipient,
            content='hello **world**',
            date_sent=timezone_now(),
            sending_client=sending_client,
            last_edit_time=timezone_now(),
            edit_history='[]'
        )
        message.set_topic_name('whatever')
        message.save()

        # An important part of this test is to get the message through this exact code path,
        # because there is an ugly hack we need to cover.  So don't just say "row = message".
        row = MessageDict.get_raw_db_rows([message.id])[0]
        dct = MessageDict.build_dict_from_raw_db_row(row)
        error_content = '<p>[Zulip note: Sorry, we could not understand the formatting of your message]</p>'
        self.assertEqual(dct['rendered_content'], error_content)

    def test_topic_links_use_stream_realm(self) -> None:
        # Set up a realm filter on 'zulip' and assert that messages
        # sent to a stream on 'zulip' have the topic linkified from
        # senders in both the 'zulip' and 'lear' realms as well as
        # the notification bot.
        zulip_realm = get_realm('zulip')
        url_format_string = r"https://trac.example.com/ticket/%(id)s"
        url = 'https://trac.example.com/ticket/123'
        topic_name = 'test #123'

        realm_filter = RealmFilter(realm=zulip_realm,
                                   pattern=r"#(?P<id>[0-9]{2,8})",
                                   url_format_string=url_format_string)
        self.assertEqual(
            realm_filter.__str__(),
            '<RealmFilter(zulip): #(?P<id>[0-9]{2,8})'
            ' https://trac.example.com/ticket/%(id)s>')

        def get_message(sender: UserProfile) -> Message:
            msg_id = self.send_stream_message(sender, 'Denmark', 'hello world', topic_name,
                                              zulip_realm)
            return Message.objects.get(id=msg_id)

        def assert_topic_links(links: List[str], msg: Message) -> None:
            dct = MessageDict.to_dict_uncached_helper([msg])[0]
            self.assertEqual(dct[TOPIC_LINKS], links)

        # Send messages before and after saving the realm filter from each user.
        assert_topic_links([], get_message(self.example_user('othello')))
        assert_topic_links([], get_message(self.lear_user('cordelia')))
        assert_topic_links([], get_message(self.notification_bot()))
        realm_filter.save()
        assert_topic_links([url], get_message(self.example_user('othello')))
        assert_topic_links([url], get_message(self.lear_user('cordelia')))
        assert_topic_links([url], get_message(self.notification_bot()))

    def test_reaction(self) -> None:
        sender = self.example_user('othello')
        receiver = self.example_user('hamlet')
        recipient = Recipient.objects.get(type_id=receiver.id, type=Recipient.PERSONAL)
        sending_client = make_client(name="test suite")
        message = Message(
            sender=sender,
            recipient=recipient,
            content='hello **world**',
            date_sent=timezone_now(),
            sending_client=sending_client,
            last_edit_time=timezone_now(),
            edit_history='[]'
        )
        message.set_topic_name('whatever')
        message.save()

        reaction = Reaction.objects.create(
            message=message, user_profile=sender,
            emoji_name='simple_smile')
        row = MessageDict.get_raw_db_rows([message.id])[0]
        msg_dict = MessageDict.build_dict_from_raw_db_row(row)
        self.assertEqual(msg_dict['reactions'][0]['emoji_name'],
                         reaction.emoji_name)
        self.assertEqual(msg_dict['reactions'][0]['user_id'], sender.id)
        self.assertEqual(msg_dict['reactions'][0]['user']['id'],
                         sender.id)
        self.assertEqual(msg_dict['reactions'][0]['user']['email'],
                         sender.email)
        self.assertEqual(msg_dict['reactions'][0]['user']['full_name'],
                         sender.full_name)

    def test_missing_anchor(self) -> None:
        self.login('hamlet')
        result = self.client_get(
            '/json/messages?use_first_unread_anchor=false&num_before=1&num_after=1')

        self.assert_json_error(
            result, "Missing 'anchor' argument.")

    def test_invalid_anchor(self) -> None:
        self.login('hamlet')
        result = self.client_get(
            '/json/messages?use_first_unread_anchor=false&num_before=1&num_after=1&anchor=chocolate')

        self.assert_json_error(
            result, "Invalid anchor")

class SewMessageAndReactionTest(ZulipTestCase):
    def test_sew_messages_and_reaction(self) -> None:
        sender = self.example_user('othello')
        receiver = self.example_user('hamlet')
        pm_recipient = Recipient.objects.get(type_id=receiver.id, type=Recipient.PERSONAL)
        stream_name = 'Çiğdem'
        stream = self.make_stream(stream_name)
        stream_recipient = Recipient.objects.get(type_id=stream.id, type=Recipient.STREAM)
        sending_client = make_client(name="test suite")

        needed_ids = []
        for i in range(5):
            for recipient in [pm_recipient, stream_recipient]:
                message = Message(
                    sender=sender,
                    recipient=recipient,
                    content='whatever %d' % (i,),
                    date_sent=timezone_now(),
                    sending_client=sending_client,
                    last_edit_time=timezone_now(),
                    edit_history='[]'
                )
                message.set_topic_name('whatever')
                message.save()
                needed_ids.append(message.id)
                reaction = Reaction(user_profile=sender, message=message,
                                    emoji_name='simple_smile')
                reaction.save()

        messages = Message.objects.filter(id__in=needed_ids).values(
            *['id', 'content'])
        reactions = Reaction.get_raw_db_rows(needed_ids)
        tied_data = sew_messages_and_reactions(messages, reactions)
        for data in tied_data:
            self.assertEqual(len(data['reactions']), 1)
            self.assertEqual(data['reactions'][0]['emoji_name'],
                             'simple_smile')
            self.assertTrue(data['id'])
            self.assertTrue(data['content'])


class MessagePOSTTest(ZulipTestCase):

    def _send_and_verify_message(self, user: UserProfile, stream_name: str, error_msg: str=None) -> None:
        if error_msg is None:
            msg_id = self.send_stream_message(user, stream_name)
            result = self.api_get(user, '/json/messages/' + str(msg_id))
            self.assert_json_success(result)
        else:
            with self.assertRaisesRegex(JsonableError, error_msg):
                self.send_stream_message(user, stream_name)

    def test_message_to_self(self) -> None:
        """
        Sending a message to a stream to which you are subscribed is
        successful.
        """
        self.login('hamlet')
        result = self.client_post("/json/messages", {"type": "stream",
                                                     "to": "Verona",
                                                     "client": "test suite",
                                                     "content": "Test message",
                                                     "topic": "Test topic"})
        self.assert_json_success(result)

    def test_api_message_to_self(self) -> None:
        """
        Same as above, but for the API view
        """
        user = self.example_user('hamlet')
        result = self.api_post(user, "/api/v1/messages", {"type": "stream",
                                                          "to": "Verona",
                                                          "client": "test suite",
                                                          "content": "Test message",
                                                          "topic": "Test topic"})
        self.assert_json_success(result)

    def test_message_to_stream_with_nonexistent_id(self) -> None:
        cordelia = self.example_user('cordelia')
        bot = self.create_test_bot(
            short_name='whatever',
            user_profile=cordelia,
        )
        result = self.api_post(
            bot, "/api/v1/messages",
            {
                "type": "stream",
                "to": ujson.dumps([99999]),
                "client": "test suite",
                "content": "Stream message by ID.",
                "topic": "Test topic for stream ID message"
            }
        )
        self.assert_json_error(result, "Stream with ID '99999' does not exist")

        msg = self.get_last_message()
        expected = ("Your bot `whatever-bot@zulip.testserver` tried to send a message to "
                    "stream ID 99999, but there is no stream with that ID.")
        self.assertEqual(msg.content, expected)

    def test_message_to_stream_by_id(self) -> None:
        """
        Sending a message to a stream (by stream ID) to which you are
        subscribed is successful.
        """
        self.login('hamlet')
        realm = get_realm('zulip')
        stream = get_stream('Verona', realm)
        result = self.client_post("/json/messages", {"type": "stream",
                                                     "to": ujson.dumps([stream.id]),
                                                     "client": "test suite",
                                                     "content": "Stream message by ID.",
                                                     "topic": "Test topic for stream ID message"})
        self.assert_json_success(result)
        sent_message = self.get_last_message()
        self.assertEqual(sent_message.content, "Stream message by ID.")

    def test_sending_message_as_stream_post_policy_admins(self) -> None:
        """
        Sending messages to streams which only the admins can create and post to.
        """
        admin_profile = self.example_user("iago")
        self.login_user(admin_profile)

        stream_name = "Verona"
        stream = get_stream(stream_name, admin_profile.realm)
        do_change_stream_post_policy(stream, Stream.STREAM_POST_POLICY_ADMINS)

        # Admins and their owned bots can send to STREAM_POST_POLICY_ADMINS streams
        self._send_and_verify_message(admin_profile, stream_name)
        admin_owned_bot = self.create_test_bot(
            short_name='whatever1',
            full_name='whatever1',
            user_profile=admin_profile,
        )
        self._send_and_verify_message(admin_owned_bot, stream_name)

        non_admin_profile = self.example_user("hamlet")
        self.login_user(non_admin_profile)

        # Non admins and their owned bots cannot send to STREAM_POST_POLICY_ADMINS streams
        self._send_and_verify_message(non_admin_profile, stream_name,
                                      "Only organization administrators can send to this stream.")
        non_admin_owned_bot = self.create_test_bot(
            short_name='whatever2',
            full_name='whatever2',
            user_profile=non_admin_profile,
        )
        self._send_and_verify_message(non_admin_owned_bot, stream_name,
                                      "Only organization administrators can send to this stream.")

        # Bots without owner (except cross realm bot) cannot send to announcement only streams
        bot_without_owner = do_create_user(
            email='free-bot@zulip.testserver',
            password='',
            realm=non_admin_profile.realm,
            full_name='freebot',
            short_name='freebot',
            bot_type=UserProfile.DEFAULT_BOT,
        )
        self._send_and_verify_message(bot_without_owner, stream_name,
                                      "Only organization administrators can send to this stream.")

        # Cross realm bots should be allowed
        notification_bot = get_system_bot("notification-bot@zulip.com")
        internal_send_stream_message(stream.realm, notification_bot, stream,
                                     'Test topic', 'Test message by notification bot')
        self.assertEqual(self.get_last_message().content, 'Test message by notification bot')

    def test_sending_message_as_stream_post_policy_restrict_new_members(self) -> None:
        """
        Sending messages to streams which new members cannot create and post to.
        """
        admin_profile = self.example_user("iago")
        self.login_user(admin_profile)

        do_set_realm_property(admin_profile.realm, 'waiting_period_threshold', 10)
        admin_profile.date_joined = timezone_now() - datetime.timedelta(days=9)
        admin_profile.save()
        self.assertTrue(admin_profile.is_new_member)
        self.assertTrue(admin_profile.is_realm_admin)

        stream_name = "Verona"
        stream = get_stream(stream_name, admin_profile.realm)
        do_change_stream_post_policy(stream, Stream.STREAM_POST_POLICY_RESTRICT_NEW_MEMBERS)

        # Admins and their owned bots can send to STREAM_POST_POLICY_RESTRICT_NEW_MEMBERS streams,
        # even if the admin is a new user
        self._send_and_verify_message(admin_profile, stream_name)
        admin_owned_bot = self.create_test_bot(
            short_name='whatever1',
            full_name='whatever1',
            user_profile=admin_profile,
        )
        self._send_and_verify_message(admin_owned_bot, stream_name)

        non_admin_profile = self.example_user("hamlet")
        self.login_user(non_admin_profile)

        non_admin_profile.date_joined = timezone_now() - datetime.timedelta(days=9)
        non_admin_profile.save()
        self.assertTrue(non_admin_profile.is_new_member)
        self.assertFalse(non_admin_profile.is_realm_admin)

        # Non admins and their owned bots can send to STREAM_POST_POLICY_RESTRICT_NEW_MEMBERS streams,
        # if the user is not a new member
        self._send_and_verify_message(non_admin_profile, stream_name,
                                      "New members cannot send to this stream.")
        non_admin_owned_bot = self.create_test_bot(
            short_name='whatever2',
            full_name='whatever2',
            user_profile=non_admin_profile,
        )
        self._send_and_verify_message(non_admin_owned_bot, stream_name,
                                      "New members cannot send to this stream.")

        # Bots without owner (except cross realm bot) cannot send to announcement only stream
        bot_without_owner = do_create_user(
            email='free-bot@zulip.testserver',
            password='',
            realm=non_admin_profile.realm,
            full_name='freebot',
            short_name='freebot',
            bot_type=UserProfile.DEFAULT_BOT,
        )
        self._send_and_verify_message(bot_without_owner, stream_name,
                                      "New members cannot send to this stream.")

        # Cross realm bots should be allowed
        notification_bot = get_system_bot("notification-bot@zulip.com")
        internal_send_stream_message(stream.realm, notification_bot, stream,
                                     'Test topic', 'Test message by notification bot')
        self.assertEqual(self.get_last_message().content, 'Test message by notification bot')

    def test_api_message_with_default_to(self) -> None:
        """
        Sending messages without a to field should be sent to the default
        stream for the user_profile.
        """
        user = self.example_user('hamlet')
        user.default_sending_stream_id = get_stream('Verona', user.realm).id
        user.save()
        result = self.api_post(user, "/api/v1/messages", {"type": "stream",
                                                          "client": "test suite",
                                                          "content": "Test message no to",
                                                          "topic": "Test topic"})
        self.assert_json_success(result)

        sent_message = self.get_last_message()
        self.assertEqual(sent_message.content, "Test message no to")

    def test_message_to_nonexistent_stream(self) -> None:
        """
        Sending a message to a nonexistent stream fails.
        """
        self.login('hamlet')
        self.assertFalse(Stream.objects.filter(name="nonexistent_stream"))
        result = self.client_post("/json/messages", {"type": "stream",
                                                     "to": "nonexistent_stream",
                                                     "client": "test suite",
                                                     "content": "Test message",
                                                     "topic": "Test topic"})
        self.assert_json_error(result, "Stream 'nonexistent_stream' does not exist")

    def test_message_to_nonexistent_stream_with_bad_characters(self) -> None:
        """
        Nonexistent stream name with bad characters should be escaped properly.
        """
        self.login('hamlet')
        self.assertFalse(Stream.objects.filter(name="""&<"'><non-existent>"""))
        result = self.client_post("/json/messages", {"type": "stream",
                                                     "to": """&<"'><non-existent>""",
                                                     "client": "test suite",
                                                     "content": "Test message",
                                                     "topic": "Test topic"})
        self.assert_json_error(result, "Stream '&amp;&lt;&quot;&#39;&gt;&lt;non-existent&gt;' does not exist")

    def test_personal_message(self) -> None:
        """
        Sending a personal message to a valid username is successful.
        """
        user_profile = self.example_user("hamlet")
        self.login_user(user_profile)
        othello = self.example_user('othello')
        result = self.client_post("/json/messages", {"type": "private",
                                                     "content": "Test message",
                                                     "client": "test suite",
                                                     "to": othello.email})
        self.assert_json_success(result)
        message_id = ujson.loads(result.content.decode())['id']

        recent_conversations = get_recent_private_conversations(user_profile)
        self.assertEqual(len(recent_conversations), 1)
        recent_conversation = list(recent_conversations.values())[0]
        recipient_id = list(recent_conversations.keys())[0]
        self.assertEqual(set(recent_conversation['user_ids']), {othello.id})
        self.assertEqual(recent_conversation['max_message_id'], message_id)

        # Now send a message to yourself and see how that interacts with the data structure
        result = self.client_post("/json/messages", {"type": "private",
                                                     "content": "Test message",
                                                     "client": "test suite",
                                                     "to": user_profile.email})
        self.assert_json_success(result)
        self_message_id = ujson.loads(result.content.decode())['id']

        recent_conversations = get_recent_private_conversations(user_profile)
        self.assertEqual(len(recent_conversations), 2)
        recent_conversation = recent_conversations[recipient_id]
        self.assertEqual(set(recent_conversation['user_ids']), {othello.id})
        self.assertEqual(recent_conversation['max_message_id'], message_id)

        # Now verify we have the appropriate self-pm data structure
        del recent_conversations[recipient_id]
        recent_conversation = list(recent_conversations.values())[0]
        recipient_id = list(recent_conversations.keys())[0]
        self.assertEqual(set(recent_conversation['user_ids']), set())
        self.assertEqual(recent_conversation['max_message_id'], self_message_id)

    def test_personal_message_by_id(self) -> None:
        """
        Sending a personal message to a valid user ID is successful.
        """
        self.login('hamlet')
        result = self.client_post(
            "/json/messages",
            {
                "type": "private",
                "content": "Test message",
                "client": "test suite",
                "to": ujson.dumps([self.example_user("othello").id])
            }
        )
        self.assert_json_success(result)

        msg = self.get_last_message()
        self.assertEqual("Test message", msg.content)
        self.assertEqual(msg.recipient_id, self.example_user("othello").id)

    def test_group_personal_message_by_id(self) -> None:
        """
        Sending a personal message to a valid user ID is successful.
        """
        self.login('hamlet')
        result = self.client_post(
            "/json/messages",
            {
                "type": "private",
                "content": "Test message",
                "client": "test suite",
                "to": ujson.dumps([self.example_user("othello").id,
                                   self.example_user("cordelia").id])
            }
        )
        self.assert_json_success(result)

        msg = self.get_last_message()
        self.assertEqual("Test message", msg.content)
        self.assertEqual(msg.recipient_id, get_huddle_recipient(
            {self.example_user("hamlet").id,
             self.example_user("othello").id,
             self.example_user("cordelia").id}).id
        )

    def test_personal_message_copying_self(self) -> None:
        """
        Sending a personal message to yourself plus another user is successful,
        and counts as a message just to that user.
        """
        hamlet = self.example_user('hamlet')
        othello = self.example_user('othello')
        self.login_user(hamlet)
        result = self.client_post("/json/messages", {
            "type": "private",
            "content": "Test message",
            "client": "test suite",
            "to": ujson.dumps([hamlet.id, othello.id])})
        self.assert_json_success(result)
        msg = self.get_last_message()
        # Verify that we're not actually on the "recipient list"
        self.assertNotIn("Hamlet", str(msg.recipient))

    def test_personal_message_to_nonexistent_user(self) -> None:
        """
        Sending a personal message to an invalid email returns error JSON.
        """
        self.login('hamlet')
        result = self.client_post("/json/messages", {"type": "private",
                                                     "content": "Test message",
                                                     "client": "test suite",
                                                     "to": "nonexistent"})
        self.assert_json_error(result, "Invalid email 'nonexistent'")

    def test_personal_message_to_deactivated_user(self) -> None:
        """
        Sending a personal message to a deactivated user returns error JSON.
        """
        othello = self.example_user('othello')
        cordelia = self.example_user('cordelia')
        do_deactivate_user(othello)
        self.login('hamlet')

        result = self.client_post("/json/messages", {
            "type": "private",
            "content": "Test message",
            "client": "test suite",
            "to": ujson.dumps([othello.id])})
        self.assert_json_error(result, f"'{othello.email}' is no longer using Zulip.")

        result = self.client_post("/json/messages", {
            "type": "private",
            "content": "Test message",
            "client": "test suite",
            "to": ujson.dumps([othello.id, cordelia.id])})
        self.assert_json_error(result, f"'{othello.email}' is no longer using Zulip.")

    def test_invalid_type(self) -> None:
        """
        Sending a message of unknown type returns error JSON.
        """
        self.login('hamlet')
        othello = self.example_user('othello')
        result = self.client_post("/json/messages", {"type": "invalid type",
                                                     "content": "Test message",
                                                     "client": "test suite",
                                                     "to": othello.email})
        self.assert_json_error(result, "Invalid message type")

    def test_empty_message(self) -> None:
        """
        Sending a message that is empty or only whitespace should fail
        """
        self.login('hamlet')
        othello = self.example_user('othello')
        result = self.client_post("/json/messages", {"type": "private",
                                                     "content": " ",
                                                     "client": "test suite",
                                                     "to": othello.email})
        self.assert_json_error(result, "Message must not be empty")

    def test_empty_string_topic(self) -> None:
        """
        Sending a message that has empty string topic should fail
        """
        self.login('hamlet')
        result = self.client_post("/json/messages", {"type": "stream",
                                                     "to": "Verona",
                                                     "client": "test suite",
                                                     "content": "Test message",
                                                     "topic": ""})
        self.assert_json_error(result, "Topic can't be empty")

    def test_missing_topic(self) -> None:
        """
        Sending a message without topic should fail
        """
        self.login('hamlet')
        result = self.client_post("/json/messages", {"type": "stream",
                                                     "to": "Verona",
                                                     "client": "test suite",
                                                     "content": "Test message"})
        self.assert_json_error(result, "Missing topic")

    def test_invalid_message_type(self) -> None:
        """
        Messages other than the type of "private" or "stream" are considered as invalid
        """
        self.login('hamlet')
        result = self.client_post("/json/messages", {"type": "invalid",
                                                     "to": "Verona",
                                                     "client": "test suite",
                                                     "content": "Test message",
                                                     "topic": "Test topic"})
        self.assert_json_error(result, "Invalid message type")

    def test_private_message_without_recipients(self) -> None:
        """
        Sending private message without recipients should fail
        """
        self.login('hamlet')
        result = self.client_post("/json/messages", {"type": "private",
                                                     "content": "Test content",
                                                     "client": "test suite",
                                                     "to": ""})
        self.assert_json_error(result, "Message must have recipients")

    def test_mirrored_huddle(self) -> None:
        """
        Sending a mirrored huddle message works
        """
        result = self.api_post(self.mit_user("starnine"),
                               "/json/messages", {"type": "private",
                                                  "sender": self.mit_email("sipbtest"),
                                                  "content": "Test message",
                                                  "client": "zephyr_mirror",
                                                  "to": ujson.dumps([self.mit_email("starnine"),
                                                                     self.mit_email("espuser")])},
                               subdomain="zephyr")
        self.assert_json_success(result)

    def test_mirrored_personal(self) -> None:
        """
        Sending a mirrored personal message works
        """
        result = self.api_post(self.mit_user("starnine"),
                               "/json/messages", {"type": "private",
                                                  "sender": self.mit_email("sipbtest"),
                                                  "content": "Test message",
                                                  "client": "zephyr_mirror",
                                                  "to": self.mit_email("starnine")},
                               subdomain="zephyr")
        self.assert_json_success(result)

    def test_mirrored_personal_browser(self) -> None:
        """
        Sending a mirrored personal message via the browser should not work.
        """
        user = self.mit_user('starnine')
        self.login_user(user)
        result = self.client_post("/json/messages",
                                  {"type": "private",
                                   "sender": self.mit_email("sipbtest"),
                                   "content": "Test message",
                                   "client": "zephyr_mirror",
                                   "to": self.mit_email("starnine")},
                                  subdomain="zephyr")
        self.assert_json_error(result, "Invalid mirrored message")

    def test_mirrored_personal_to_someone_else(self) -> None:
        """
        Sending a mirrored personal message to someone else is not allowed.
        """
        result = self.api_post(self.mit_user("starnine"), "/api/v1/messages",
                               {"type": "private",
                                "sender": self.mit_email("sipbtest"),
                                "content": "Test message",
                                "client": "zephyr_mirror",
                                "to": self.mit_email("espuser")},
                               subdomain="zephyr")
        self.assert_json_error(result, "User not authorized for this query")

    def test_duplicated_mirrored_huddle(self) -> None:
        """
        Sending two mirrored huddles in the row return the same ID
        """
        msg = {"type": "private",
               "sender": self.mit_email("sipbtest"),
               "content": "Test message",
               "client": "zephyr_mirror",
               "to": ujson.dumps([self.mit_email("espuser"),
                                  self.mit_email("starnine")])}

        with mock.patch('DNS.dnslookup', return_value=[['starnine:*:84233:101:Athena Consulting Exchange User,,,:/mit/starnine:/bin/bash']]):
            result1 = self.api_post(self.mit_user("starnine"), "/api/v1/messages", msg,
                                    subdomain="zephyr")
            self.assert_json_success(result1)

        with mock.patch('DNS.dnslookup', return_value=[['espuser:*:95494:101:Esp Classroom,,,:/mit/espuser:/bin/athena/bash']]):
            result2 = self.api_post(self.mit_user("espuser"), "/api/v1/messages", msg,
                                    subdomain="zephyr")
            self.assert_json_success(result2)

        self.assertEqual(ujson.loads(result1.content)['id'],
                         ujson.loads(result2.content)['id'])

    def test_message_with_null_bytes(self) -> None:
        """
        A message with null bytes in it is handled.
        """
        self.login('hamlet')
        post_data = {"type": "stream", "to": "Verona", "client": "test suite",
                     "content": "  I like null bytes \x00 in my content", "topic": "Test topic"}
        result = self.client_post("/json/messages", post_data)
        self.assert_json_error(result, "Message must not contain null bytes")

    def test_strip_message(self) -> None:
        """
        A message with mixed whitespace at the end is cleaned up.
        """
        self.login('hamlet')
        post_data = {"type": "stream", "to": "Verona", "client": "test suite",
                     "content": "  I like whitespace at the end! \n\n \n", "topic": "Test topic"}
        result = self.client_post("/json/messages", post_data)
        self.assert_json_success(result)
        sent_message = self.get_last_message()
        self.assertEqual(sent_message.content, "  I like whitespace at the end!")

    def test_long_message(self) -> None:
        """
        Sending a message longer than the maximum message length succeeds but is
        truncated.
        """
        self.login('hamlet')
        long_message = "A" * (MAX_MESSAGE_LENGTH + 1)
        post_data = {"type": "stream", "to": "Verona", "client": "test suite",
                     "content": long_message, "topic": "Test topic"}
        result = self.client_post("/json/messages", post_data)
        self.assert_json_success(result)

        sent_message = self.get_last_message()
        self.assertEqual(sent_message.content,
                         "A" * (MAX_MESSAGE_LENGTH - 20) + "\n[message truncated]")

    def test_long_topic(self) -> None:
        """
        Sending a message with a topic longer than the maximum topic length
        succeeds, but the topic is truncated.
        """
        self.login('hamlet')
        long_topic = "A" * (MAX_TOPIC_NAME_LENGTH + 1)
        post_data = {"type": "stream", "to": "Verona", "client": "test suite",
                     "content": "test content", "topic": long_topic}
        result = self.client_post("/json/messages", post_data)
        self.assert_json_success(result)

        sent_message = self.get_last_message()
        self.assertEqual(sent_message.topic_name(),
                         "A" * (MAX_TOPIC_NAME_LENGTH - 3) + "...")

    def test_send_forged_message_as_not_superuser(self) -> None:
        self.login('hamlet')
        result = self.client_post("/json/messages", {"type": "stream",
                                                     "to": "Verona",
                                                     "client": "test suite",
                                                     "content": "Test message",
                                                     "topic": "Test topic",
                                                     "forged": "true"})
        self.assert_json_error(result, "User not authorized for this query")

    def test_send_message_as_not_superuser_to_different_domain(self) -> None:
        self.login('hamlet')
        result = self.client_post("/json/messages", {"type": "stream",
                                                     "to": "Verona",
                                                     "client": "test suite",
                                                     "content": "Test message",
                                                     "topic": "Test topic",
                                                     "realm_str": "mit"})
        self.assert_json_error(result, "User not authorized for this query")

    def test_send_message_as_superuser_to_domain_that_dont_exist(self) -> None:
        user = self.example_user("default_bot")
        password = "test_password"
        user.set_password(password)
        user.is_api_super_user = True
        user.save()
        result = self.api_post(user,
                               "/api/v1/messages", {"type": "stream",
                                                    "to": "Verona",
                                                    "client": "test suite",
                                                    "content": "Test message",
                                                    "topic": "Test topic",
                                                    "realm_str": "non-existing"})
        user.is_api_super_user = False
        user.save()
        self.assert_json_error(result, "Unknown organization 'non-existing'")

    def test_send_message_when_sender_is_not_set(self) -> None:
        result = self.api_post(self.mit_user("starnine"), "/api/v1/messages",
                               {"type": "private",
                                "content": "Test message",
                                "client": "zephyr_mirror",
                                "to": self.mit_email("starnine")},
                               subdomain="zephyr")
        self.assert_json_error(result, "Missing sender")

    def test_send_message_as_not_superuser_when_type_is_not_private(self) -> None:
        result = self.api_post(self.mit_user("starnine"), "/api/v1/messages",
                               {"type": "not-private",
                                "sender": self.mit_email("sipbtest"),
                                "content": "Test message",
                                "client": "zephyr_mirror",
                                "to": self.mit_email("starnine")},
                               subdomain="zephyr")
        self.assert_json_error(result, "User not authorized for this query")

    @mock.patch("zerver.views.messages.create_mirrored_message_users")
    def test_send_message_create_mirrored_message_user_returns_invalid_input(
            self, create_mirrored_message_users_mock: Any) -> None:
        create_mirrored_message_users_mock.side_effect = InvalidMirrorInput()
        result = self.api_post(self.mit_user("starnine"), "/api/v1/messages",
                               {"type": "private",
                                "sender": self.mit_email("sipbtest"),
                                "content": "Test message",
                                "client": "zephyr_mirror",
                                "to": self.mit_email("starnine")},
                               subdomain="zephyr")
        self.assert_json_error(result, "Invalid mirrored message")

    @mock.patch("zerver.views.messages.create_mirrored_message_users")
    def test_send_message_when_client_is_zephyr_mirror_but_string_id_is_not_zephyr(
            self, create_mirrored_message_users_mock: Any) -> None:
        create_mirrored_message_users_mock.return_value = mock.Mock()
        user = self.mit_user("starnine")
        user.realm.string_id = 'notzephyr'
        user.realm.save()
        result = self.api_post(user, "/api/v1/messages",
                               {"type": "private",
                                "sender": self.mit_email("sipbtest"),
                                "content": "Test message",
                                "client": "zephyr_mirror",
                                "to": user.email},
                               subdomain="notzephyr")
        self.assert_json_error(result, "Zephyr mirroring is not allowed in this organization")

    @mock.patch("zerver.views.messages.create_mirrored_message_users")
    def test_send_message_when_client_is_zephyr_mirror_but_recipient_is_user_id(
            self, create_mirrored_message_users_mock: Any) -> None:
        create_mirrored_message_users_mock.return_value = mock.Mock()
        user = self.mit_user("starnine")
        self.login_user(user)
        result = self.api_post(user, "/api/v1/messages",
                               {"type": "private",
                                "sender": self.mit_email("sipbtest"),
                                "content": "Test message",
                                "client": "zephyr_mirror",
                                "to": ujson.dumps([user.id])},
                               subdomain="zephyr")
        self.assert_json_error(result, "Mirroring not allowed with recipient user IDs")

    def test_send_message_irc_mirror(self) -> None:
        reset_emails_in_zulip_realm()
        self.login('hamlet')
        bot_info = {
            'full_name': 'IRC bot',
            'short_name': 'irc',
        }
        result = self.client_post("/json/bots", bot_info)
        self.assert_json_success(result)

        email = "irc-bot@zulip.testserver"
        user = get_user(email, get_realm('zulip'))
        user.is_api_super_user = True
        user.save()
        user = get_user(email, get_realm('zulip'))
        self.subscribe(user, "IRCland")

        # Simulate a mirrored message with a slightly old timestamp.
        fake_date_sent = timezone_now() - datetime.timedelta(minutes=37)
        fake_timestamp = datetime_to_timestamp(fake_date_sent)

        result = self.api_post(user, "/api/v1/messages", {"type": "stream",
                                                          "forged": "true",
                                                          "time": fake_timestamp,
                                                          "sender": "irc-user@irc.zulip.com",
                                                          "content": "Test message",
                                                          "client": "irc_mirror",
                                                          "topic": "from irc",
                                                          "to": "IRCLand"})
        self.assert_json_success(result)

        msg = self.get_last_message()
        self.assertEqual(int(datetime_to_timestamp(msg.date_sent)), int(fake_timestamp))

        # Now test again using forged=yes
        fake_date_sent = timezone_now() - datetime.timedelta(minutes=22)
        fake_timestamp = datetime_to_timestamp(fake_date_sent)

        result = self.api_post(user, "/api/v1/messages", {"type": "stream",
                                                          "forged": "yes",
                                                          "time": fake_timestamp,
                                                          "sender": "irc-user@irc.zulip.com",
                                                          "content": "Test message",
                                                          "client": "irc_mirror",
                                                          "topic": "from irc",
                                                          "to": "IRCLand"})
        self.assert_json_success(result)

        msg = self.get_last_message()
        self.assertEqual(int(datetime_to_timestamp(msg.date_sent)), int(fake_timestamp))

    def test_unsubscribed_api_super_user(self) -> None:
        reset_emails_in_zulip_realm()

        cordelia = self.example_user('cordelia')
        stream_name = 'private_stream'
        self.make_stream(stream_name, invite_only=True)

        self.unsubscribe(cordelia, stream_name)

        # As long as Cordelia is a super_user, she can send messages
        # to ANY stream, even one she is not unsubscribed to, and
        # she can do it for herself or on behalf of a mirrored user.

        def test_with(sender_email: str, client: str, forged: bool) -> None:
            payload = dict(
                type="stream",
                to=stream_name,
                client=client,
                topic='whatever',
                content='whatever',
                forged=ujson.dumps(forged),
            )

            # Only pass the 'sender' property when doing mirroring behavior.
            if forged:
                payload['sender'] = sender_email

            cordelia.is_api_super_user = False
            cordelia.save()

            result = self.api_post(cordelia, "/api/v1/messages", payload)
            self.assert_json_error_contains(result, 'authorized')

            cordelia.is_api_super_user = True
            cordelia.save()

            result = self.api_post(cordelia, "/api/v1/messages", payload)
            self.assert_json_success(result)

        test_with(
            sender_email=cordelia.email,
            client='test suite',
            forged=False,
        )

        test_with(
            sender_email='irc_person@zulip.com',
            client='irc_mirror',
            forged=True,
        )

    def test_bot_can_send_to_owner_stream(self) -> None:
        cordelia = self.example_user('cordelia')
        bot = self.create_test_bot(
            short_name='whatever',
            user_profile=cordelia,
        )

        stream_name = 'private_stream'
        self.make_stream(stream_name, invite_only=True)

        payload = dict(
            type="stream",
            to=stream_name,
            client='test suite',
            topic='whatever',
            content='whatever',
        )

        result = self.api_post(bot, "/api/v1/messages", payload)
        self.assert_json_error_contains(result, 'Not authorized to send')

        # We subscribe the bot owner! (aka cordelia)
        self.subscribe(bot.bot_owner, stream_name)

        result = self.api_post(bot, "/api/v1/messages", payload)
        self.assert_json_success(result)

    def test_cross_realm_bots_can_use_api_on_own_subdomain(self) -> None:
        # Cross realm bots should use internal_send_*_message, not the API:
        notification_bot = self.notification_bot()
        stream = self.make_stream("notify_channel", get_realm("zulipinternal"))

        result = self.api_post(notification_bot,
                               "/api/v1/messages",
                               {"type": "stream",
                                "to": "notify_channel",
                                "client": "test suite",
                                "content": "Test message",
                                "topic": "Test topic"},
                               subdomain='zulipinternal')

        self.assert_json_success(result)
        message = self.get_last_message()

        self.assertEqual(message.content, "Test message")
        self.assertEqual(message.sender, notification_bot)
        self.assertEqual(message.recipient.type_id, stream.id)

    def test_create_mirror_user_despite_race(self) -> None:
        realm = get_realm('zulip')

        email = 'fred@example.com'

        email_to_full_name = lambda email: 'fred'

        def create_user(**kwargs: Any) -> UserProfile:
            self.assertEqual(kwargs['full_name'], 'fred')
            self.assertEqual(kwargs['email'], email)
            self.assertEqual(kwargs['active'], False)
            self.assertEqual(kwargs['is_mirror_dummy'], True)
            # We create an actual user here to simulate a race.
            # We use the minimal, un-mocked function.
            kwargs['bot_type'] = None
            kwargs['bot_owner'] = None
            kwargs['tos_version'] = None
            kwargs['timezone'] = timezone_now()
            create_user_profile(**kwargs).save()
            raise IntegrityError()

        with mock.patch('zerver.lib.actions.create_user',
                        side_effect=create_user) as m:
            mirror_fred_user = create_mirror_user_if_needed(
                realm,
                email,
                email_to_full_name,
            )

        self.assertEqual(mirror_fred_user.delivery_email, email)
        m.assert_called()

    def test_guest_user(self) -> None:
        sender = self.example_user('polonius')

        stream_name = 'public stream'
        self.make_stream(stream_name, invite_only=False)
        payload = dict(
            type="stream",
            to=stream_name,
            client='test suite',
            topic='whatever',
            content='whatever',
        )

        # Guest user can't send message to unsubscribed public streams
        result = self.api_post(sender, "/api/v1/messages", payload)
        self.assert_json_error(result, "Not authorized to send to stream 'public stream'")

        self.subscribe(sender, stream_name)
        # Guest user can send message to subscribed public streams
        result = self.api_post(sender, "/api/v1/messages", payload)
        self.assert_json_success(result)

class ScheduledMessageTest(ZulipTestCase):

    def last_scheduled_message(self) -> ScheduledMessage:
        return ScheduledMessage.objects.all().order_by('-id')[0]

    def do_schedule_message(self, msg_type: str, to: str, msg: str,
                            defer_until: str='', tz_guess: str='',
                            delivery_type: str='send_later',
                            realm_str: str='zulip') -> HttpResponse:
        self.login('hamlet')

        topic_name = ''
        if msg_type == 'stream':
            topic_name = 'Test topic'

        payload = {"type": msg_type,
                   "to": to,
                   "client": "test suite",
                   "content": msg,
                   "topic": topic_name,
                   "realm_str": realm_str,
                   "delivery_type": delivery_type,
                   "tz_guess": tz_guess}
        if defer_until:
            payload["deliver_at"] = defer_until

        result = self.client_post("/json/messages", payload)
        return result

    def test_schedule_message(self) -> None:
        content = "Test message"
        defer_until = timezone_now().replace(tzinfo=None) + datetime.timedelta(days=1)
        defer_until_str = str(defer_until)

        # Scheduling a message to a stream you are subscribed is successful.
        result = self.do_schedule_message('stream', 'Verona',
                                          content + ' 1', defer_until_str)
        message = self.last_scheduled_message()
        self.assert_json_success(result)
        self.assertEqual(message.content, 'Test message 1')
        self.assertEqual(message.topic_name(), 'Test topic')
        self.assertEqual(message.scheduled_timestamp, convert_to_UTC(defer_until))
        self.assertEqual(message.delivery_type, ScheduledMessage.SEND_LATER)
        # Scheduling a message for reminders.
        result = self.do_schedule_message('stream', 'Verona',
                                          content + ' 2', defer_until_str,
                                          delivery_type='remind')
        message = self.last_scheduled_message()
        self.assert_json_success(result)
        self.assertEqual(message.delivery_type, ScheduledMessage.REMIND)

        # Scheduling a private message is successful.
        othello = self.example_user('othello')
        hamlet = self.example_user('hamlet')
        result = self.do_schedule_message('private', othello.email,
                                          content + ' 3', defer_until_str)
        message = self.last_scheduled_message()
        self.assert_json_success(result)
        self.assertEqual(message.content, 'Test message 3')
        self.assertEqual(message.scheduled_timestamp, convert_to_UTC(defer_until))
        self.assertEqual(message.delivery_type, ScheduledMessage.SEND_LATER)

        # Setting a reminder in PM's to other users causes a error.
        result = self.do_schedule_message('private', othello.email,
                                          content + ' 4', defer_until_str,
                                          delivery_type='remind')
        self.assert_json_error(result, 'Reminders can only be set for streams.')

        # Setting a reminder in PM's to ourself is successful.
        # Required by reminders from message actions popover caret feature.
        result = self.do_schedule_message('private', hamlet.email,
                                          content + ' 5', defer_until_str,
                                          delivery_type='remind')
        message = self.last_scheduled_message()
        self.assert_json_success(result)
        self.assertEqual(message.content, 'Test message 5')
        self.assertEqual(message.delivery_type, ScheduledMessage.REMIND)

        # Scheduling a message while guessing timezone.
        tz_guess = 'Asia/Kolkata'
        result = self.do_schedule_message('stream', 'Verona', content + ' 6',
                                          defer_until_str, tz_guess=tz_guess)
        message = self.last_scheduled_message()
        self.assert_json_success(result)
        self.assertEqual(message.content, 'Test message 6')
        local_tz = get_timezone(tz_guess)
        # Since mypy is not able to recognize localize and normalize as attributes of tzinfo we use ignore.
        utz_defer_until = local_tz.normalize(local_tz.localize(defer_until))  # type: ignore[attr-defined] # Reason in comment on previous line.
        self.assertEqual(message.scheduled_timestamp,
                         convert_to_UTC(utz_defer_until))
        self.assertEqual(message.delivery_type, ScheduledMessage.SEND_LATER)

        # Test with users timezone setting as set to some timezone rather than
        # empty. This will help interpret timestamp in users local timezone.
        user = self.example_user("hamlet")
        user.timezone = 'US/Pacific'
        user.save(update_fields=['timezone'])
        result = self.do_schedule_message('stream', 'Verona',
                                          content + ' 7', defer_until_str)
        message = self.last_scheduled_message()
        self.assert_json_success(result)
        self.assertEqual(message.content, 'Test message 7')
        local_tz = get_timezone(user.timezone)
        # Since mypy is not able to recognize localize and normalize as attributes of tzinfo we use ignore.
        utz_defer_until = local_tz.normalize(local_tz.localize(defer_until))  # type: ignore[attr-defined] # Reason in comment on previous line.
        self.assertEqual(message.scheduled_timestamp,
                         convert_to_UTC(utz_defer_until))
        self.assertEqual(message.delivery_type, ScheduledMessage.SEND_LATER)

    def test_scheduling_in_past(self) -> None:
        # Scheduling a message in past should fail.
        content = "Test message"
        defer_until = timezone_now()
        defer_until_str = str(defer_until)

        result = self.do_schedule_message('stream', 'Verona',
                                          content + ' 1', defer_until_str)
        self.assert_json_error(result, 'Time must be in the future.')

    def test_invalid_timestamp(self) -> None:
        # Scheduling a message from which timestamp couldn't be parsed
        # successfully should fail.
        content = "Test message"
        defer_until = 'Missed the timestamp'

        result = self.do_schedule_message('stream', 'Verona',
                                          content + ' 1', defer_until)
        self.assert_json_error(result, 'Invalid time format')

    def test_missing_deliver_at(self) -> None:
        content = "Test message"

        result = self.do_schedule_message('stream', 'Verona',
                                          content + ' 1')
        self.assert_json_error(result, 'Missing deliver_at in a request for delayed message delivery')

class EditMessageTest(ZulipTestCase):
    def check_topic(self,
                    msg_id: int,
                    topic_name: str) -> None:
        msg = Message.objects.get(id=msg_id)
        self.assertEqual(msg.topic_name(), topic_name)

    def check_message(self,
                      msg_id: int,
                      topic_name: str,
                      content: str) -> None:
        # Make sure we saved the message correctly to the DB.
        msg = Message.objects.get(id=msg_id)
        self.assertEqual(msg.topic_name(), topic_name)
        self.assertEqual(msg.content, content)

        '''
        Next, we will make sure we properly cached the
        messages.  We still have to do 2 queries to
        hydrate sender/recipient info, but we won't need
        to hit the zerver_message table.
        '''

        with queries_captured() as queries:
            (fetch_message_dict,) = messages_for_ids(
                message_ids = [msg.id],
                user_message_flags={msg_id: []},
                search_fields=dict(),
                apply_markdown=False,
                client_gravatar=False,
                allow_edit_history=True,
            )

        self.assertEqual(len(queries), 2)
        for query in queries:
            self.assertNotIn('message', query['sql'])

        self.assertEqual(
            fetch_message_dict[TOPIC_NAME],
            msg.topic_name()
        )
        self.assertEqual(
            fetch_message_dict['content'],
            msg.content
        )
        self.assertEqual(
            fetch_message_dict['sender_id'],
            msg.sender_id
        )

        if msg.edit_history:
            self.assertEqual(
                fetch_message_dict['edit_history'],
                ujson.loads(msg.edit_history)
            )

    def test_query_count_on_to_dict_uncached(self) -> None:
        # `to_dict_uncached` method is used by the mechanisms
        # tested in this class. Hence, its performance is tested here.
        # Generate 2 messages
        user = self.example_user("hamlet")
        self.login_user(user)
        stream_name = "public_stream"
        self.subscribe(user, stream_name)
        message_ids = []
        message_ids.append(self.send_stream_message(user,
                                                    stream_name, "Message one"))
        user_2 = self.example_user("cordelia")
        self.subscribe(user_2, stream_name)
        message_ids.append(self.send_stream_message(user_2,
                                                    stream_name, "Message two"))
        self.subscribe(self.notification_bot(), stream_name)
        message_ids.append(self.send_stream_message(self.notification_bot(),
                                                    stream_name, "Message three"))
        messages = [Message.objects.select_related().get(id=message_id)
                    for message_id in message_ids]

        # Check number of queries performed
        with queries_captured() as queries:
            MessageDict.to_dict_uncached(messages)
        # 1 query for realm_id per message = 3
        # 1 query each for reactions & submessage for all messages = 2
        self.assertEqual(len(queries), 5)

        realm_id = 2  # Fetched from stream object
        # Check number of queries performed with realm_id
        with queries_captured() as queries:
            MessageDict.to_dict_uncached(messages, realm_id)
        # 1 query each for reactions & submessage for all messages = 2
        self.assertEqual(len(queries), 2)

    def test_save_message(self) -> None:
        """This is also tested by a client test, but here we can verify
        the cache against the database"""
        self.login('hamlet')
        msg_id = self.send_stream_message(self.example_user("hamlet"), "Scotland",
                                          topic_name="editing", content="before edit")
        result = self.client_patch("/json/messages/" + str(msg_id), {
            'message_id': msg_id,
            'content': 'after edit'
        })
        self.assert_json_success(result)
        self.check_message(msg_id, topic_name="editing", content="after edit")

        result = self.client_patch("/json/messages/" + str(msg_id), {
            'message_id': msg_id,
            'topic': 'edited'
        })
        self.assert_json_success(result)
        self.check_topic(msg_id, topic_name="edited")

    def test_fetch_raw_message(self) -> None:
        self.login('hamlet')
        msg_id = self.send_personal_message(
            from_user=self.example_user("hamlet"),
            to_user=self.example_user("cordelia"),
            content="**before** edit",
        )
        result = self.client_get('/json/messages/' + str(msg_id))
        self.assert_json_success(result)
        self.assertEqual(result.json()['raw_content'], '**before** edit')

        # Test error cases
        result = self.client_get('/json/messages/999999')
        self.assert_json_error(result, 'Invalid message(s)')

        self.login('cordelia')
        result = self.client_get('/json/messages/' + str(msg_id))
        self.assert_json_success(result)

        self.login('othello')
        result = self.client_get('/json/messages/' + str(msg_id))
        self.assert_json_error(result, 'Invalid message(s)')

    def test_fetch_raw_message_stream_wrong_realm(self) -> None:
        user_profile = self.example_user("hamlet")
        self.login_user(user_profile)
        stream = self.make_stream('public_stream')
        self.subscribe(user_profile, stream.name)
        msg_id = self.send_stream_message(user_profile, stream.name,
                                          topic_name="test", content="test")
        result = self.client_get('/json/messages/' + str(msg_id))
        self.assert_json_success(result)

        mit_user = self.mit_user('sipbtest')
        self.login_user(mit_user)
        result = self.client_get('/json/messages/' + str(msg_id), subdomain="zephyr")
        self.assert_json_error(result, 'Invalid message(s)')

    def test_fetch_raw_message_private_stream(self) -> None:
        user_profile = self.example_user("hamlet")
        self.login_user(user_profile)
        stream = self.make_stream('private_stream', invite_only=True)
        self.subscribe(user_profile, stream.name)
        msg_id = self.send_stream_message(user_profile, stream.name,
                                          topic_name="test", content="test")
        result = self.client_get('/json/messages/' + str(msg_id))
        self.assert_json_success(result)
        self.login('othello')
        result = self.client_get('/json/messages/' + str(msg_id))
        self.assert_json_error(result, 'Invalid message(s)')

    def test_edit_message_no_permission(self) -> None:
        self.login('hamlet')
        msg_id = self.send_stream_message(self.example_user("iago"), "Scotland",
                                          topic_name="editing", content="before edit")
        result = self.client_patch("/json/messages/" + str(msg_id), {
            'message_id': msg_id,
            'content': 'content after edit',
        })
        self.assert_json_error(result, "You don't have permission to edit this message")

    def test_edit_message_no_changes(self) -> None:
        self.login('hamlet')
        msg_id = self.send_stream_message(self.example_user("hamlet"), "Scotland",
                                          topic_name="editing", content="before edit")
        result = self.client_patch("/json/messages/" + str(msg_id), {
            'message_id': msg_id,
        })
        self.assert_json_error(result, "Nothing to change")

    def test_edit_message_no_topic(self) -> None:
        self.login('hamlet')
        msg_id = self.send_stream_message(self.example_user("hamlet"), "Scotland",
                                          topic_name="editing", content="before edit")
        result = self.client_patch("/json/messages/" + str(msg_id), {
            'message_id': msg_id,
            'topic': ' '
        })
        self.assert_json_error(result, "Topic can't be empty")

    def test_edit_message_no_content(self) -> None:
        self.login('hamlet')
        msg_id = self.send_stream_message(self.example_user("hamlet"), "Scotland",
                                          topic_name="editing", content="before edit")
        result = self.client_patch("/json/messages/" + str(msg_id), {
            'message_id': msg_id,
            'content': ' '
        })
        self.assert_json_success(result)
        content = Message.objects.filter(id=msg_id).values_list('content', flat = True)[0]
        self.assertEqual(content, "(deleted)")

    def test_edit_message_history_disabled(self) -> None:
        user_profile = self.example_user("hamlet")
        do_set_realm_property(user_profile.realm, "allow_edit_history", False)
        self.login('hamlet')

        # Single-line edit
        msg_id_1 = self.send_stream_message(self.example_user("hamlet"),
                                            "Denmark",
                                            topic_name="editing",
                                            content="content before edit")

        new_content_1 = 'content after edit'
        result_1 = self.client_patch("/json/messages/" + str(msg_id_1), {
            'message_id': msg_id_1, 'content': new_content_1
        })
        self.assert_json_success(result_1)

        result = self.client_get(
            "/json/messages/" + str(msg_id_1) + "/history")
        self.assert_json_error(result, "Message edit history is disabled in this organization")

        # Now verify that if we fetch the message directly, there's no
        # edit history data attached.
        messages_result = self.client_get("/json/messages",
                                          {"anchor": msg_id_1, "num_before": 0, "num_after": 10})
        self.assert_json_success(messages_result)
        json_messages = ujson.loads(
            messages_result.content.decode('utf-8'))
        for msg in json_messages['messages']:
            self.assertNotIn("edit_history", msg)

    def test_edit_message_history(self) -> None:
        self.login('hamlet')

        # Single-line edit
        msg_id_1 = self.send_stream_message(
            self.example_user("hamlet"),
            "Scotland",
            topic_name="editing",
            content="content before edit")
        new_content_1 = 'content after edit'
        result_1 = self.client_patch("/json/messages/" + str(msg_id_1), {
            'message_id': msg_id_1, 'content': new_content_1
        })
        self.assert_json_success(result_1)

        message_edit_history_1 = self.client_get(
            "/json/messages/" + str(msg_id_1) + "/history")
        json_response_1 = ujson.loads(
            message_edit_history_1.content.decode('utf-8'))
        message_history_1 = json_response_1['message_history']

        # Check content of message after edit.
        self.assertEqual(message_history_1[0]['rendered_content'],
                         '<p>content before edit</p>')
        self.assertEqual(message_history_1[1]['rendered_content'],
                         '<p>content after edit</p>')
        self.assertEqual(message_history_1[1]['content_html_diff'],
                         ('<p>content '
                          '<span class="highlight_text_inserted">after</span> '
                          '<span class="highlight_text_deleted">before</span>'
                          ' edit</p>'))
        # Check content of message before edit.
        self.assertEqual(message_history_1[1]['prev_rendered_content'],
                         '<p>content before edit</p>')

        # Edits on new lines
        msg_id_2 = self.send_stream_message(
            self.example_user("hamlet"),
            "Scotland",
            topic_name="editing",
            content=('content before edit, line 1\n'
                     '\n'
                     'content before edit, line 3'))
        new_content_2 = ('content before edit, line 1\n'
                         'content after edit, line 2\n'
                         'content before edit, line 3')
        result_2 = self.client_patch("/json/messages/" + str(msg_id_2), {
            'message_id': msg_id_2, 'content': new_content_2
        })
        self.assert_json_success(result_2)

        message_edit_history_2 = self.client_get(
            "/json/messages/" + str(msg_id_2) + "/history")
        json_response_2 = ujson.loads(
            message_edit_history_2.content.decode('utf-8'))
        message_history_2 = json_response_2['message_history']

        self.assertEqual(message_history_2[0]['rendered_content'],
                         ('<p>content before edit, line 1</p>\n'
                          '<p>content before edit, line 3</p>'))
        self.assertEqual(message_history_2[1]['rendered_content'],
                         ('<p>content before edit, line 1<br>\n'
                          'content after edit, line 2<br>\n'
                          'content before edit, line 3</p>'))
        self.assertEqual(message_history_2[1]['content_html_diff'],
                         ('<p>content before edit, line 1<br> '
                          'content <span class="highlight_text_inserted">after edit, line 2<br> '
                          'content</span> before edit, line 3</p>'))
        self.assertEqual(message_history_2[1]['prev_rendered_content'],
                         ('<p>content before edit, line 1</p>\n'
                          '<p>content before edit, line 3</p>'))

    def test_edit_link(self) -> None:
        # Link editing
        self.login('hamlet')
        msg_id_1 = self.send_stream_message(
            self.example_user("hamlet"),
            "Scotland",
            topic_name="editing",
            content="Here is a link to [zulip](www.zulip.org).")
        new_content_1 = 'Here is a link to [zulip](www.zulipchat.com).'
        result_1 = self.client_patch("/json/messages/" + str(msg_id_1), {
            'message_id': msg_id_1, 'content': new_content_1
        })
        self.assert_json_success(result_1)

        message_edit_history_1 = self.client_get(
            "/json/messages/" + str(msg_id_1) + "/history")
        json_response_1 = ujson.loads(
            message_edit_history_1.content.decode('utf-8'))
        message_history_1 = json_response_1['message_history']

        # Check content of message after edit.
        self.assertEqual(message_history_1[0]['rendered_content'],
                         '<p>Here is a link to '
                         '<a href="http://www.zulip.org">zulip</a>.</p>')
        self.assertEqual(message_history_1[1]['rendered_content'],
                         '<p>Here is a link to '
                         '<a href="http://www.zulipchat.com">zulip</a>.</p>')
        self.assertEqual(message_history_1[1]['content_html_diff'],
                         ('<p>Here is a link to <a href="http://www.zulipchat.com"'
                          '>zulip '
                          '<span class="highlight_text_inserted"> Link: http://www.zulipchat.com .'
                          '</span> <span class="highlight_text_deleted"> Link: http://www.zulip.org .'
                          '</span> </a></p>'))

    def test_edit_history_unedited(self) -> None:
        self.login('hamlet')

        msg_id = self.send_stream_message(
            self.example_user('hamlet'),
            'Scotland',
            topic_name='editing',
            content='This message has not been edited.')

        result = self.client_get(f'/json/messages/{msg_id}/history')

        self.assert_json_success(result)

        message_history = result.json()['message_history']
        self.assert_length(message_history, 1)

    def test_user_info_for_updates(self) -> None:
        hamlet = self.example_user('hamlet')
        cordelia = self.example_user('cordelia')

        self.login_user(hamlet)
        self.subscribe(hamlet, 'Scotland')
        self.subscribe(cordelia, 'Scotland')

        msg_id = self.send_stream_message(hamlet, 'Scotland',
                                          content='@**Cordelia Lear**')

        user_info = get_user_info_for_message_updates(msg_id)
        message_user_ids = user_info['message_user_ids']
        self.assertIn(hamlet.id, message_user_ids)
        self.assertIn(cordelia.id, message_user_ids)

        mention_user_ids = user_info['mention_user_ids']
        self.assertEqual(mention_user_ids, {cordelia.id})

    def test_edit_cases(self) -> None:
        """This test verifies the accuracy of construction of Zulip's edit
        history data structures."""
        self.login('hamlet')
        hamlet = self.example_user('hamlet')
        msg_id = self.send_stream_message(self.example_user("hamlet"), "Scotland",
                                          topic_name="topic 1", content="content 1")
        result = self.client_patch("/json/messages/" + str(msg_id), {
            'message_id': msg_id,
            'content': 'content 2',
        })
        self.assert_json_success(result)
        history = ujson.loads(Message.objects.get(id=msg_id).edit_history)
        self.assertEqual(history[0]['prev_content'], 'content 1')
        self.assertEqual(history[0]['user_id'], hamlet.id)
        self.assertEqual(set(history[0].keys()),
                         {'timestamp', 'prev_content', 'user_id',
                          'prev_rendered_content', 'prev_rendered_content_version'})

        result = self.client_patch("/json/messages/" + str(msg_id), {
            'message_id': msg_id,
            'topic': 'topic 2',
        })
        self.assert_json_success(result)
        history = ujson.loads(Message.objects.get(id=msg_id).edit_history)
        self.assertEqual(history[0][LEGACY_PREV_TOPIC], 'topic 1')
        self.assertEqual(history[0]['user_id'], hamlet.id)
        self.assertEqual(set(history[0].keys()), {'timestamp', LEGACY_PREV_TOPIC, 'user_id'})

        result = self.client_patch("/json/messages/" + str(msg_id), {
            'message_id': msg_id,
            'content': 'content 3',
            'topic': 'topic 3',
        })
        self.assert_json_success(result)
        history = ujson.loads(Message.objects.get(id=msg_id).edit_history)
        self.assertEqual(history[0]['prev_content'], 'content 2')
        self.assertEqual(history[0][LEGACY_PREV_TOPIC], 'topic 2')
        self.assertEqual(history[0]['user_id'], hamlet.id)
        self.assertEqual(set(history[0].keys()),
                         {'timestamp', LEGACY_PREV_TOPIC, 'prev_content', 'user_id',
                          'prev_rendered_content', 'prev_rendered_content_version'})

        result = self.client_patch("/json/messages/" + str(msg_id), {
            'message_id': msg_id,
            'content': 'content 4',
        })
        self.assert_json_success(result)
        history = ujson.loads(Message.objects.get(id=msg_id).edit_history)
        self.assertEqual(history[0]['prev_content'], 'content 3')
        self.assertEqual(history[0]['user_id'], hamlet.id)

        self.login('iago')
        result = self.client_patch("/json/messages/" + str(msg_id), {
            'message_id': msg_id,
            'topic': 'topic 4',
        })
        self.assert_json_success(result)
        history = ujson.loads(Message.objects.get(id=msg_id).edit_history)
        self.assertEqual(history[0][LEGACY_PREV_TOPIC], 'topic 3')
        self.assertEqual(history[0]['user_id'], self.example_user('iago').id)

        history = ujson.loads(Message.objects.get(id=msg_id).edit_history)
        self.assertEqual(history[0][LEGACY_PREV_TOPIC], 'topic 3')
        self.assertEqual(history[2][LEGACY_PREV_TOPIC], 'topic 2')
        self.assertEqual(history[3][LEGACY_PREV_TOPIC], 'topic 1')
        self.assertEqual(history[1]['prev_content'], 'content 3')
        self.assertEqual(history[2]['prev_content'], 'content 2')
        self.assertEqual(history[4]['prev_content'], 'content 1')

        # Now, we verify that the edit history data sent back has the
        # correct filled-out fields
        message_edit_history = self.client_get("/json/messages/" + str(msg_id) + "/history")

        json_response = ujson.loads(message_edit_history.content.decode('utf-8'))

        # We reverse the message history view output so that the IDs line up with the above.
        message_history = list(reversed(json_response['message_history']))
        i = 0
        for entry in message_history:
            expected_entries = {'content', 'rendered_content', 'topic', 'timestamp', 'user_id'}
            if i in {0, 2, 3}:
                expected_entries.add('prev_topic')
            if i in {1, 2, 4}:
                expected_entries.add('prev_content')
                expected_entries.add('prev_rendered_content')
                expected_entries.add('content_html_diff')
            i += 1
            self.assertEqual(expected_entries, set(entry.keys()))
        self.assertEqual(len(message_history), 6)
        self.assertEqual(message_history[0]['prev_topic'], 'topic 3')
        self.assertEqual(message_history[0]['topic'], 'topic 4')
        self.assertEqual(message_history[1]['topic'], 'topic 3')
        self.assertEqual(message_history[2]['topic'], 'topic 3')
        self.assertEqual(message_history[2]['prev_topic'], 'topic 2')
        self.assertEqual(message_history[3]['topic'], 'topic 2')
        self.assertEqual(message_history[3]['prev_topic'], 'topic 1')
        self.assertEqual(message_history[4]['topic'], 'topic 1')

        self.assertEqual(message_history[0]['content'], 'content 4')
        self.assertEqual(message_history[1]['content'], 'content 4')
        self.assertEqual(message_history[1]['prev_content'], 'content 3')
        self.assertEqual(message_history[2]['content'], 'content 3')
        self.assertEqual(message_history[2]['prev_content'], 'content 2')
        self.assertEqual(message_history[3]['content'], 'content 2')
        self.assertEqual(message_history[4]['content'], 'content 2')
        self.assertEqual(message_history[4]['prev_content'], 'content 1')

        self.assertEqual(message_history[5]['content'], 'content 1')
        self.assertEqual(message_history[5]['topic'], 'topic 1')

    def test_edit_message_content_limit(self) -> None:
        def set_message_editing_params(allow_message_editing: bool,
                                       message_content_edit_limit_seconds: int,
                                       allow_community_topic_editing: bool) -> None:
            result = self.client_patch("/json/realm", {
                'allow_message_editing': ujson.dumps(allow_message_editing),
                'message_content_edit_limit_seconds': message_content_edit_limit_seconds,
                'allow_community_topic_editing': ujson.dumps(allow_community_topic_editing),
            })
            self.assert_json_success(result)

        def do_edit_message_assert_success(id_: int, unique_str: str, topic_only: bool=False) -> None:
            new_topic = 'topic' + unique_str
            new_content = 'content' + unique_str
            params_dict = {'message_id': id_, 'topic': new_topic}
            if not topic_only:
                params_dict['content'] = new_content
            result = self.client_patch("/json/messages/" + str(id_), params_dict)
            self.assert_json_success(result)
            if topic_only:
                self.check_topic(id_, topic_name=new_topic)
            else:
                self.check_message(id_, topic_name=new_topic, content=new_content)

        def do_edit_message_assert_error(id_: int, unique_str: str, error: str,
                                         topic_only: bool=False) -> None:
            message = Message.objects.get(id=id_)
            old_topic = message.topic_name()
            old_content = message.content
            new_topic = 'topic' + unique_str
            new_content = 'content' + unique_str
            params_dict = {'message_id': id_, 'topic': new_topic}
            if not topic_only:
                params_dict['content'] = new_content
            result = self.client_patch("/json/messages/" + str(id_), params_dict)
            message = Message.objects.get(id=id_)
            self.assert_json_error(result, error)

            msg = Message.objects.get(id=id_)
            self.assertEqual(msg.topic_name(), old_topic)
            self.assertEqual(msg.content, old_content)

        self.login('iago')
        # send a message in the past
        id_ = self.send_stream_message(self.example_user("iago"), "Scotland",
                                       content="content", topic_name="topic")
        message = Message.objects.get(id=id_)
        message.date_sent = message.date_sent - datetime.timedelta(seconds=180)
        message.save()

        # test the various possible message editing settings
        # high enough time limit, all edits allowed
        set_message_editing_params(True, 240, False)
        do_edit_message_assert_success(id_, 'A')

        # out of time, only topic editing allowed
        set_message_editing_params(True, 120, False)
        do_edit_message_assert_success(id_, 'B', True)
        do_edit_message_assert_error(id_, 'C', "The time limit for editing this message has passed")

        # infinite time, all edits allowed
        set_message_editing_params(True, 0, False)
        do_edit_message_assert_success(id_, 'D')

        # without allow_message_editing, nothing is allowed
        set_message_editing_params(False, 240, False)
        do_edit_message_assert_error(id_, 'E', "Your organization has turned off message editing", True)
        set_message_editing_params(False, 120, False)
        do_edit_message_assert_error(id_, 'F', "Your organization has turned off message editing", True)
        set_message_editing_params(False, 0, False)
        do_edit_message_assert_error(id_, 'G', "Your organization has turned off message editing", True)

    def test_allow_community_topic_editing(self) -> None:
        def set_message_editing_params(allow_message_editing: bool,
                                       message_content_edit_limit_seconds: int,
                                       allow_community_topic_editing: bool) -> None:
            result = self.client_patch("/json/realm", {
                'allow_message_editing': ujson.dumps(allow_message_editing),
                'message_content_edit_limit_seconds': message_content_edit_limit_seconds,
                'allow_community_topic_editing': ujson.dumps(allow_community_topic_editing),
            })
            self.assert_json_success(result)

        def do_edit_message_assert_success(id_: int, unique_str: str) -> None:
            new_topic = 'topic' + unique_str
            params_dict = {'message_id': id_, 'topic': new_topic}
            result = self.client_patch("/json/messages/" + str(id_), params_dict)
            self.assert_json_success(result)
            self.check_topic(id_, topic_name=new_topic)

        def do_edit_message_assert_error(id_: int, unique_str: str, error: str) -> None:
            message = Message.objects.get(id=id_)
            old_topic = message.topic_name()
            old_content = message.content
            new_topic = 'topic' + unique_str
            params_dict = {'message_id': id_, 'topic': new_topic}
            result = self.client_patch("/json/messages/" + str(id_), params_dict)
            message = Message.objects.get(id=id_)
            self.assert_json_error(result, error)
            msg = Message.objects.get(id=id_)
            self.assertEqual(msg.topic_name(), old_topic)
            self.assertEqual(msg.content, old_content)

        self.login('iago')
        # send a message in the past
        id_ = self.send_stream_message(self.example_user("hamlet"), "Scotland",
                                       content="content", topic_name="topic")
        message = Message.objects.get(id=id_)
        message.date_sent = message.date_sent - datetime.timedelta(seconds=180)
        message.save()

        # any user can edit the topic of a message
        set_message_editing_params(True, 0, True)
        # log in as a new user
        self.login('cordelia')
        do_edit_message_assert_success(id_, 'A')

        # only admins can edit the topics of messages
        self.login('iago')
        set_message_editing_params(True, 0, False)
        do_edit_message_assert_success(id_, 'B')
        self.login('cordelia')
        do_edit_message_assert_error(id_, 'C', "You don't have permission to edit this message")

        # users cannot edit topics if allow_message_editing is False
        self.login('iago')
        set_message_editing_params(False, 0, True)
        self.login('cordelia')
        do_edit_message_assert_error(id_, 'D', "Your organization has turned off message editing")

        # non-admin users cannot edit topics sent > 24 hrs ago
        message.date_sent = message.date_sent - datetime.timedelta(seconds=90000)
        message.save()
        self.login('iago')
        set_message_editing_params(True, 0, True)
        do_edit_message_assert_success(id_, 'E')
        self.login('cordelia')
        do_edit_message_assert_error(id_, 'F', "The time limit for editing this message has passed")

        # anyone should be able to edit "no topic" indefinitely
        message.set_topic_name("(no topic)")
        message.save()
        self.login('cordelia')
        do_edit_message_assert_success(id_, 'D')

    @mock.patch("zerver.lib.actions.send_event")
    def test_edit_topic_public_history_stream(self, mock_send_event: mock.MagicMock) -> None:
        stream_name = "Macbeth"
        hamlet = self.example_user("hamlet")
        cordelia = self.example_user("cordelia")
        self.make_stream(stream_name, history_public_to_subscribers=True)
        self.subscribe(hamlet, stream_name)
        self.login_user(hamlet)
        message_id = self.send_stream_message(hamlet, stream_name, "Where am I?")

        self.login_user(cordelia)
        self.subscribe(cordelia, stream_name)
        message = Message.objects.get(id=message_id)

        def do_update_message_topic_success(user_profile: UserProfile, message: Message,
                                            topic_name: str, users_to_be_notified: List[Dict[str, Any]]) -> None:
            do_update_message(
                user_profile=user_profile,
                message=message,
                new_stream=None,
                topic_name=topic_name,
                propagate_mode="change_later",
                send_notification_to_old_thread=False,
                send_notification_to_new_thread=False,
                content=None,
                rendered_content=None,
                prior_mention_user_ids=set(),
                mention_user_ids=set(),
                mention_data=None,
            )

            mock_send_event.assert_called_with(mock.ANY, mock.ANY, users_to_be_notified)

        # Returns the users that need to be notified when a message topic is changed
        def notify(user_id: int) -> Dict[str, Any]:
            um = UserMessage.objects.get(message=message_id)
            if um.user_profile_id == user_id:
                return {
                    "id": user_id,
                    "flags": um.flags_list()
                }

            else:
                return {
                    "id": user_id,
                    "flags": ["read"]
                }

        users_to_be_notified = list(map(notify, [hamlet.id, cordelia.id]))
        # Edit topic of a message sent before Cordelia subscribed the stream
        do_update_message_topic_success(cordelia, message, "Othello eats apple", users_to_be_notified)

        # If Cordelia is long-term idle, she doesn't get a notification.
        cordelia.long_term_idle = True
        cordelia.save()
        users_to_be_notified = list(map(notify, [hamlet.id]))
        do_update_message_topic_success(cordelia, message, "Another topic idle", users_to_be_notified)
        cordelia.long_term_idle = False
        cordelia.save()

        # Even if Hamlet unsubscribes the stream, he should be notified when the topic is changed
        # because he has a UserMessage row.
        self.unsubscribe(hamlet, stream_name)
        users_to_be_notified = list(map(notify, [hamlet.id, cordelia.id]))
        do_update_message_topic_success(cordelia, message, "Another topic", users_to_be_notified)

        # Hamlet subscribes to the stream again and Cordelia unsubscribes, then Hamlet changes
        # the message topic. Cordelia won't receive any updates when a message on that stream is
        # changed because she is not a subscriber and doesn't have a UserMessage row.
        self.subscribe(hamlet, stream_name)
        self.unsubscribe(cordelia, stream_name)
        self.login_user(hamlet)
        users_to_be_notified = list(map(notify, [hamlet.id]))
        do_update_message_topic_success(hamlet, message, "Change again", users_to_be_notified)

    @mock.patch("zerver.lib.actions.send_event")
    def test_wildcard_mention(self, mock_send_event: mock.MagicMock) -> None:
        stream_name = "Macbeth"
        hamlet = self.example_user("hamlet")
        cordelia = self.example_user("cordelia")
        self.make_stream(stream_name, history_public_to_subscribers=True)
        self.subscribe(hamlet, stream_name)
        self.subscribe(cordelia, stream_name)
        self.login_user(hamlet)
        message_id = self.send_stream_message(hamlet, stream_name, "Hello everyone")

        def notify(user_id: int) -> Dict[str, Any]:
            return {
                "id": user_id,
                "flags": ["wildcard_mentioned"]
            }

        users_to_be_notified = sorted(map(notify, [cordelia.id, hamlet.id]), key=itemgetter("id"))
        result = self.client_patch("/json/messages/" + str(message_id), {
            'message_id': message_id,
            'content': 'Hello @**everyone**',
        })
        self.assert_json_success(result)

        # Extract the send_event call where event type is 'update_message'.
        # Here we assert wildcard_mention_user_ids has been set properly.
        called = False
        for call_args in mock_send_event.call_args_list:
            (arg_realm, arg_event, arg_notified_users) = call_args[0]
            if arg_event['type'] == 'update_message':
                self.assertEqual(arg_event['type'], 'update_message')
                self.assertEqual(arg_event['wildcard_mention_user_ids'], [cordelia.id, hamlet.id])
                self.assertEqual(sorted(arg_notified_users, key=itemgetter("id")), users_to_be_notified)
                called = True
        self.assertTrue(called)

    def test_propagate_topic_forward(self) -> None:
        self.login('hamlet')
        id1 = self.send_stream_message(self.example_user("hamlet"), "Scotland",
                                       topic_name="topic1")
        id2 = self.send_stream_message(self.example_user("iago"), "Scotland",
                                       topic_name="topic1")
        id3 = self.send_stream_message(self.example_user("iago"), "Rome",
                                       topic_name="topic1")
        id4 = self.send_stream_message(self.example_user("hamlet"), "Scotland",
                                       topic_name="topic2")
        id5 = self.send_stream_message(self.example_user("iago"), "Scotland",
                                       topic_name="topic1")

        result = self.client_patch("/json/messages/" + str(id1), {
            'message_id': id1,
            'topic': 'edited',
            'propagate_mode': 'change_later'
        })
        self.assert_json_success(result)

        self.check_topic(id1, topic_name="edited")
        self.check_topic(id2, topic_name="edited")
        self.check_topic(id3, topic_name="topic1")
        self.check_topic(id4, topic_name="topic2")
        self.check_topic(id5, topic_name="edited")

    def test_propagate_all_topics(self) -> None:
        self.login('hamlet')
        id1 = self.send_stream_message(self.example_user("hamlet"), "Scotland",
                                       topic_name="topic1")
        id2 = self.send_stream_message(self.example_user("hamlet"), "Scotland",
                                       topic_name="topic1")
        id3 = self.send_stream_message(self.example_user("iago"), "Rome",
                                       topic_name="topic1")
        id4 = self.send_stream_message(self.example_user("hamlet"), "Scotland",
                                       topic_name="topic2")
        id5 = self.send_stream_message(self.example_user("iago"), "Scotland",
                                       topic_name="topic1")
        id6 = self.send_stream_message(self.example_user("iago"), "Scotland",
                                       topic_name="topic3")

        result = self.client_patch("/json/messages/" + str(id2), {
            'message_id': id2,
            'topic': 'edited',
            'propagate_mode': 'change_all'
        })
        self.assert_json_success(result)

        self.check_topic(id1, topic_name="edited")
        self.check_topic(id2, topic_name="edited")
        self.check_topic(id3, topic_name="topic1")
        self.check_topic(id4, topic_name="topic2")
        self.check_topic(id5, topic_name="edited")
        self.check_topic(id6, topic_name="topic3")

    def test_propagate_invalid(self) -> None:
        self.login('hamlet')
        id1 = self.send_stream_message(self.example_user("hamlet"), "Scotland",
                                       topic_name="topic1")

        result = self.client_patch("/json/messages/" + str(id1), {
            'topic': 'edited',
            'propagate_mode': 'invalid',
        })
        self.assert_json_error(result, 'Invalid propagate_mode')
        self.check_topic(id1, topic_name="topic1")

        result = self.client_patch("/json/messages/" + str(id1), {
            'content': 'edited',
            'propagate_mode': 'change_all',
        })
        self.assert_json_error(result, 'Invalid propagate_mode without topic edit')
        self.check_topic(id1, topic_name="topic1")

    def prepare_move_topics(self, user_email: str, old_stream: str, new_stream: str, topic: str) -> Tuple[UserProfile, Stream, Stream, int, int]:
        user_profile = self.example_user(user_email)
        self.login(user_email)
        stream = self.make_stream(old_stream)
        new_stream = self.make_stream(new_stream)
        self.subscribe(user_profile, stream.name)
        self.subscribe(user_profile, new_stream.name)
        msg_id = self.send_stream_message(user_profile, stream.name,
                                          topic_name=topic, content="First")
        msg_id_lt = self.send_stream_message(user_profile, stream.name,
                                             topic_name=topic, content="Second")

        self.send_stream_message(user_profile, stream.name,
                                 topic_name=topic, content="third")

        return (user_profile, stream, new_stream, msg_id, msg_id_lt)

    def test_move_message_to_stream(self) -> None:
        (user_profile, old_stream, new_stream, msg_id, msg_id_lt) = self.prepare_move_topics(
            "iago", "test move stream", "new stream", "test")

        result = self.client_patch("/json/messages/" + str(msg_id), {
            'message_id': msg_id,
            'stream_id': new_stream.id,
            'propagate_mode': 'change_all'
        })

        self.assert_json_success(result)

        messages = get_topic_messages(user_profile, old_stream, "test")
        self.assertEqual(len(messages), 1)
        self.assertEqual(messages[0].content, "This topic was moved by @_**Iago|%s** to #**new stream>test**" % (user_profile.id,))

        messages = get_topic_messages(user_profile, new_stream, "test")
        self.assertEqual(len(messages), 4)
        self.assertEqual(messages[3].content, "This topic was moved here from #**test move stream>test** by @_**Iago|%s**" % (user_profile.id,))

    def test_move_message_to_stream_change_later(self) -> None:
        (user_profile, old_stream, new_stream, msg_id, msg_id_later) = self.prepare_move_topics(
            "iago", "test move stream", "new stream", "test")

        result = self.client_patch("/json/messages/" + str(msg_id_later), {
            'message_id': msg_id_later,
            'stream_id': new_stream.id,
            'propagate_mode': 'change_later'
        })
        self.assert_json_success(result)

        messages = get_topic_messages(user_profile, old_stream, "test")
        self.assertEqual(len(messages), 2)
        self.assertEqual(messages[0].id, msg_id)
        self.assertEqual(messages[1].content, "This topic was moved by @_**Iago|%s** to #**new stream>test**" % (user_profile.id,))

        messages = get_topic_messages(user_profile, new_stream, "test")
        self.assertEqual(len(messages), 3)
        self.assertEqual(messages[0].id, msg_id_later)
        self.assertEqual(messages[2].content, "This topic was moved here from #**test move stream>test** by @_**Iago|%d**" % (user_profile.id,))

    def test_move_message_to_stream_no_allowed(self) -> None:
        (user_profile, old_stream, new_stream, msg_id, msg_id_later) = self.prepare_move_topics(
            "aaron", "test move stream", "new stream", "test")

        result = self.client_patch("/json/messages/" + str(msg_id), {
            'message_id': msg_id,
            'stream_id': new_stream.id,
            'propagate_mode': 'change_all'
        })
        self.assert_json_error(result, "You don't have permission to move this message")

        messages = get_topic_messages(user_profile, old_stream, "test")
        self.assertEqual(len(messages), 3)

        messages = get_topic_messages(user_profile, new_stream, "test")
        self.assertEqual(len(messages), 0)

    def test_move_message_to_stream_with_content(self) -> None:
        (user_profile, old_stream, new_stream, msg_id, msg_id_later) = self.prepare_move_topics(
            "iago", "test move stream", "new stream", "test")

        result = self.client_patch("/json/messages/" + str(msg_id), {
            'message_id': msg_id,
            'stream_id': new_stream.id,
            'propagate_mode': 'change_all',
            'content': 'Not allowed'
        })
        self.assert_json_error(result, "Cannot change message content while changing stream")

        messages = get_topic_messages(user_profile, old_stream, "test")
        self.assertEqual(len(messages), 3)

        messages = get_topic_messages(user_profile, new_stream, "test")
        self.assertEqual(len(messages), 0)

    def test_move_message_to_stream_and_topic(self) -> None:
        (user_profile, old_stream, new_stream, msg_id, msg_id_later) = self.prepare_move_topics(
            "iago", "test move stream", "new stream", "test")

        with queries_captured() as queries:
            result = self.client_patch("/json/messages/" + str(msg_id), {
                'message_id': msg_id,
                'stream_id': new_stream.id,
                'propagate_mode': 'change_all',
                'topic': 'new topic'
            })
        self.assertEqual(len(queries), 49)

        messages = get_topic_messages(user_profile, old_stream, "test")
        self.assertEqual(len(messages), 1)
        self.assertEqual(messages[0].content, "This topic was moved by @_**Iago|%s** to #**new stream>new topic**" % (user_profile.id,))

        messages = get_topic_messages(user_profile, new_stream, "new topic")
        self.assertEqual(len(messages), 4)
        self.assertEqual(messages[3].content, "This topic was moved here from #**test move stream>test** by @_**Iago|%s**" % (user_profile.id,))
        self.assert_json_success(result)

    def test_no_notify_move_message_to_stream(self) -> None:
        (user_profile, old_stream, new_stream, msg_id, msg_id_lt) = self.prepare_move_topics(
            "iago", "test move stream", "new stream", "test")

        result = self.client_patch("/json/messages/" + str(msg_id), {
            'message_id': msg_id,
            'stream_id': new_stream.id,
            'propagate_mode': 'change_all',
            'send_notification_to_old_thread': 'false',
            'send_notification_to_new_thread': 'false',
        })

        self.assert_json_success(result)

        messages = get_topic_messages(user_profile, old_stream, "test")
        self.assertEqual(len(messages), 0)

        messages = get_topic_messages(user_profile, new_stream, "test")
        self.assertEqual(len(messages), 3)

    def test_notify_new_thread_move_message_to_stream(self) -> None:
        (user_profile, old_stream, new_stream, msg_id, msg_id_lt) = self.prepare_move_topics(
            "iago", "test move stream", "new stream", "test")

        result = self.client_patch("/json/messages/" + str(msg_id), {
            'message_id': msg_id,
            'stream_id': new_stream.id,
            'propagate_mode': 'change_all',
            'send_notification_to_old_thread': 'false',
            'send_notification_to_new_thread': 'true',
        })

        self.assert_json_success(result)

        messages = get_topic_messages(user_profile, old_stream, "test")
        self.assertEqual(len(messages), 0)

        messages = get_topic_messages(user_profile, new_stream, "test")
        self.assertEqual(len(messages), 4)
        self.assertEqual(messages[3].content, "This topic was moved here from #**test move stream>test** by @_**Iago|%d**" % (user_profile.id,))

    def test_notify_old_thread_move_message_to_stream(self) -> None:
        (user_profile, old_stream, new_stream, msg_id, msg_id_lt) = self.prepare_move_topics(
            "iago", "test move stream", "new stream", "test")

        result = self.client_patch("/json/messages/" + str(msg_id), {
            'message_id': msg_id,
            'stream_id': new_stream.id,
            'propagate_mode': 'change_all',
            'send_notification_to_old_thread': 'true',
            'send_notification_to_new_thread': 'false',
        })

        self.assert_json_success(result)

        messages = get_topic_messages(user_profile, old_stream, "test")
        self.assertEqual(len(messages), 1)
        self.assertEqual(messages[0].content, "This topic was moved by @_**Iago|%s** to #**new stream>test**" % (user_profile.id,))

        messages = get_topic_messages(user_profile, new_stream, "test")
        self.assertEqual(len(messages), 3)

    def test_move_message_to_stream_to_private_stream(self) -> None:
        user_profile = self.example_user("iago")
        self.login("iago")
        stream = self.make_stream("test move stream")
        new_stream = self.make_stream("new stream", None, True)
        self.subscribe(user_profile, stream.name)
        self.subscribe(user_profile, new_stream.name)
        msg_id = self.send_stream_message(user_profile, stream.name,
                                          topic_name="test", content="First")
        self.send_stream_message(user_profile, stream.name,
                                 topic_name="test", content="Second")

        result = self.client_patch("/json/messages/" + str(msg_id), {
            'message_id': msg_id,
            'stream_id': new_stream.id,
            'propagate_mode': 'change_all',
        })

        self.assert_json_error(result, "Streams must be public")

        # We expect the messages to remain in the original stream/topic
        messages = get_topic_messages(user_profile, stream, "test")
        self.assertEqual(len(messages), 2)

        messages = get_topic_messages(user_profile, new_stream, "test")
        self.assertEqual(len(messages), 0)

class MirroredMessageUsersTest(ZulipTestCase):
    def test_invalid_sender(self) -> None:
        user = self.example_user('hamlet')
        recipients: List[str] = []

        Request = namedtuple('Request', ['POST'])
        request = Request(POST=dict())  # no sender

        with self.assertRaises(InvalidMirrorInput):
            create_mirrored_message_users(request, user, recipients)

    def test_invalid_client(self) -> None:
        client = get_client(name='banned_mirror')  # Invalid!!!

        user = self.example_user('hamlet')
        sender = user

        recipients: List[str] = []

        Request = namedtuple('Request', ['POST', 'client'])
        request = Request(POST = dict(sender=sender.email, type='private'),
                          client = client)

        with self.assertRaises(InvalidMirrorInput):
            create_mirrored_message_users(request, user, recipients)

    def test_invalid_email(self) -> None:
        invalid_email = 'alice AT example.com'
        recipients = [invalid_email]

        # We use an MIT user here to maximize code coverage
        user = self.mit_user('starnine')
        sender = user

        Request = namedtuple('Request', ['POST', 'client'])

        for client_name in ['zephyr_mirror', 'irc_mirror', 'jabber_mirror']:
            client = get_client(name=client_name)

            request = Request(POST = dict(sender=sender.email, type='private'),
                              client = client)

            with self.assertRaises(InvalidMirrorInput):
                create_mirrored_message_users(request, user, recipients)

    @mock.patch('DNS.dnslookup', return_value=[['sipbtest:*:20922:101:Fred Sipb,,,:/mit/sipbtest:/bin/athena/tcsh']])
    def test_zephyr_mirror_new_recipient(self, ignored: object) -> None:
        """Test mirror dummy user creation for PM recipients"""
        client = get_client(name='zephyr_mirror')

        user = self.mit_user('starnine')
        sender = self.mit_user('sipbtest')
        new_user_email = 'bob_the_new_user@mit.edu'
        new_user_realm = get_realm("zephyr")

        recipients = [user.email, new_user_email]

        # Now make the request.
        Request = namedtuple('Request', ['POST', 'client'])
        request = Request(POST = dict(sender=sender.email, type='private'),
                          client = client)

        mirror_sender = create_mirrored_message_users(request, user, recipients)

        self.assertEqual(mirror_sender, sender)

        realm_users = UserProfile.objects.filter(realm=sender.realm)
        realm_emails = {user.email for user in realm_users}
        self.assertIn(user.email, realm_emails)
        self.assertIn(new_user_email, realm_emails)

        bob = get_user(new_user_email, new_user_realm)
        self.assertTrue(bob.is_mirror_dummy)

    @mock.patch('DNS.dnslookup', return_value=[['sipbtest:*:20922:101:Fred Sipb,,,:/mit/sipbtest:/bin/athena/tcsh']])
    def test_zephyr_mirror_new_sender(self, ignored: object) -> None:
        """Test mirror dummy user creation for sender when sending to stream"""
        client = get_client(name='zephyr_mirror')

        user = self.mit_user('starnine')
        sender_email = 'new_sender@mit.edu'

        recipients = ['stream_name']

        # Now make the request.
        Request = namedtuple('Request', ['POST', 'client'])
        request = Request(POST = dict(sender=sender_email, type='stream'),
                          client = client)

        mirror_sender = create_mirrored_message_users(request, user, recipients)

        assert(mirror_sender is not None)
        self.assertEqual(mirror_sender.email, sender_email)
        self.assertTrue(mirror_sender.is_mirror_dummy)

    def test_irc_mirror(self) -> None:
        reset_emails_in_zulip_realm()
        client = get_client(name='irc_mirror')

        sender = self.example_user('hamlet')

        recipients = [self.nonreg_email('alice'), 'bob@irc.zulip.com', self.nonreg_email('cordelia')]

        # Now make the request.
        Request = namedtuple('Request', ['POST', 'client'])
        request = Request(POST = dict(sender=sender.email, type='private'),
                          client = client)

        mirror_sender = create_mirrored_message_users(request, sender, recipients)

        self.assertEqual(mirror_sender, sender)

        realm_users = UserProfile.objects.filter(realm=sender.realm)
        realm_emails = {user.email for user in realm_users}
        self.assertIn(self.nonreg_email('alice'), realm_emails)
        self.assertIn('bob@irc.zulip.com', realm_emails)

        bob = get_user('bob@irc.zulip.com', sender.realm)
        self.assertTrue(bob.is_mirror_dummy)

    def test_jabber_mirror(self) -> None:
        reset_emails_in_zulip_realm()
        client = get_client(name='jabber_mirror')

        sender = self.example_user('hamlet')
        user = sender

        recipients = [self.nonreg_email('alice'), self.nonreg_email('bob'), self.nonreg_email('cordelia')]

        # Now make the request.
        Request = namedtuple('Request', ['POST', 'client'])
        request = Request(POST = dict(sender=sender.email, type='private'),
                          client = client)

        mirror_sender = create_mirrored_message_users(request, user, recipients)

        self.assertEqual(mirror_sender, sender)

        realm_users = UserProfile.objects.filter(realm=sender.realm)
        realm_emails = {user.email for user in realm_users}
        self.assertIn(self.nonreg_email('alice'), realm_emails)
        self.assertIn(self.nonreg_email('bob'), realm_emails)

        bob = get_user(self.nonreg_email('bob'), sender.realm)
        self.assertTrue(bob.is_mirror_dummy)

class MessageAccessTests(ZulipTestCase):
    def test_update_invalid_flags(self) -> None:
        message = self.send_personal_message(
            self.example_user("cordelia"),
            self.example_user("hamlet"),
            "hello",
        )

        self.login('hamlet')
        result = self.client_post("/json/messages/flags",
                                  {"messages": ujson.dumps([message]),
                                   "op": "add",
                                   "flag": "invalid"})
        self.assert_json_error(result, "Invalid flag: 'invalid'")

        result = self.client_post("/json/messages/flags",
                                  {"messages": ujson.dumps([message]),
                                   "op": "add",
                                   "flag": "is_private"})
        self.assert_json_error(result, "Invalid flag: 'is_private'")

        result = self.client_post("/json/messages/flags",
                                  {"messages": ujson.dumps([message]),
                                   "op": "add",
                                   "flag": "active_mobile_push_notification"})
        self.assert_json_error(result, "Invalid flag: 'active_mobile_push_notification'")

        result = self.client_post("/json/messages/flags",
                                  {"messages": ujson.dumps([message]),
                                   "op": "add",
                                   "flag": "mentioned"})
        self.assert_json_error(result, "Flag not editable: 'mentioned'")

    def change_star(self, messages: List[int], add: bool=True, **kwargs: Any) -> HttpResponse:
        return self.client_post("/json/messages/flags",
                                {"messages": ujson.dumps(messages),
                                 "op": "add" if add else "remove",
                                 "flag": "starred"},
                                **kwargs)

    def test_change_star(self) -> None:
        """
        You can set a message as starred/un-starred through
        POST /json/messages/flags.
        """
        self.login('hamlet')
        message_ids = [self.send_personal_message(self.example_user("hamlet"),
                                                  self.example_user("hamlet"),
                                                  "test")]

        # Star a message.
        result = self.change_star(message_ids)
        self.assert_json_success(result)

        for msg in self.get_messages():
            if msg['id'] in message_ids:
                self.assertEqual(msg['flags'], ['starred'])
            else:
                self.assertEqual(msg['flags'], ['read'])

        result = self.change_star(message_ids, False)
        self.assert_json_success(result)

        # Remove the stars.
        for msg in self.get_messages():
            if msg['id'] in message_ids:
                self.assertEqual(msg['flags'], [])

    def test_change_star_public_stream_historical(self) -> None:
        """
        You can set a message as starred/un-starred through
        POST /json/messages/flags.
        """
        stream_name = "new_stream"
        self.subscribe(self.example_user("hamlet"), stream_name)
        self.login('hamlet')
        message_ids = [
            self.send_stream_message(self.example_user("hamlet"), stream_name, "test"),
        ]
        # Send a second message so we can verify it isn't modified
        other_message_ids = [
            self.send_stream_message(self.example_user("hamlet"), stream_name, "test_unused"),
        ]
        received_message_ids = [
            self.send_personal_message(
                self.example_user("hamlet"),
                self.example_user("cordelia"),
                "test_received"
            ),
        ]

        # Now login as another user who wasn't on that stream
        self.login('cordelia')
        # Send a message to yourself to make sure we have at least one with the read flag
        sent_message_ids = [
            self.send_personal_message(
                self.example_user("cordelia"),
                self.example_user("cordelia"),
                "test_read_message",
            ),
        ]
        result = self.client_post("/json/messages/flags",
                                  {"messages": ujson.dumps(sent_message_ids),
                                   "op": "add",
                                   "flag": "read"})

        # We can't change flags other than "starred" on historical messages:
        result = self.client_post("/json/messages/flags",
                                  {"messages": ujson.dumps(message_ids),
                                   "op": "add",
                                   "flag": "read"})
        self.assert_json_error(result, 'Invalid message(s)')

        # Trying to change a list of more than one historical message fails
        result = self.change_star(message_ids * 2)
        self.assert_json_error(result, 'Invalid message(s)')

        # Confirm that one can change the historical flag now
        result = self.change_star(message_ids)
        self.assert_json_success(result)

        for msg in self.get_messages():
            if msg['id'] in message_ids:
                self.assertEqual(set(msg['flags']), {'starred', 'historical', 'read'})
            elif msg['id'] in received_message_ids:
                self.assertEqual(msg['flags'], [])
            else:
                self.assertEqual(msg['flags'], ['read'])
            self.assertNotIn(msg['id'], other_message_ids)

        result = self.change_star(message_ids, False)
        self.assert_json_success(result)

        # But it still doesn't work if you're in another realm
        user = self.mit_user('sipbtest')
        self.login_user(user)
        result = self.change_star(message_ids, subdomain="zephyr")
        self.assert_json_error(result, 'Invalid message(s)')

    def test_change_star_private_message_security(self) -> None:
        """
        You can set a message as starred/un-starred through
        POST /json/messages/flags.
        """
        self.login('hamlet')
        message_ids = [
            self.send_personal_message(
                self.example_user("hamlet"),
                self.example_user("hamlet"),
                "test",
            ),
        ]

        # Starring private messages you didn't receive fails.
        self.login('cordelia')
        result = self.change_star(message_ids)
        self.assert_json_error(result, 'Invalid message(s)')

    def test_change_star_private_stream_security(self) -> None:
        stream_name = "private_stream"
        self.make_stream(stream_name, invite_only=True)
        self.subscribe(self.example_user("hamlet"), stream_name)
        self.login('hamlet')
        message_ids = [
            self.send_stream_message(self.example_user("hamlet"), stream_name, "test"),
        ]

        # Starring private stream messages you received works
        result = self.change_star(message_ids)
        self.assert_json_success(result)

        # Starring private stream messages you didn't receive fails.
        self.login('cordelia')
        result = self.change_star(message_ids)
        self.assert_json_error(result, 'Invalid message(s)')

        stream_name = "private_stream_2"
        self.make_stream(stream_name, invite_only=True,
                         history_public_to_subscribers=True)
        self.subscribe(self.example_user("hamlet"), stream_name)
        self.login('hamlet')
        message_ids = [
            self.send_stream_message(self.example_user("hamlet"), stream_name, "test"),
        ]

        # With stream.history_public_to_subscribers = True, you still
        # can't see it if you didn't receive the message and are
        # not subscribed.
        self.login('cordelia')
        result = self.change_star(message_ids)
        self.assert_json_error(result, 'Invalid message(s)')

        # But if you subscribe, then you can star the message
        self.subscribe(self.example_user("cordelia"), stream_name)
        result = self.change_star(message_ids)
        self.assert_json_success(result)

    def test_new_message(self) -> None:
        """
        New messages aren't starred.
        """
        sender = self.example_user('hamlet')
        self.login_user(sender)
        content = "Test message for star"
        self.send_stream_message(sender, "Verona",
                                 content=content)

        sent_message = UserMessage.objects.filter(
            user_profile=self.example_user('hamlet')
        ).order_by("id").reverse()[0]
        self.assertEqual(sent_message.message.content, content)
        self.assertFalse(sent_message.flags.starred)

    def test_change_star_public_stream_security_for_guest_user(self) -> None:
        # Guest user can't access(star) unsubscribed public stream messages
        normal_user = self.example_user("hamlet")
        stream_name = "public_stream"
        self.make_stream(stream_name)
        self.subscribe(normal_user, stream_name)
        self.login_user(normal_user)

        message_id = [
            self.send_stream_message(normal_user, stream_name, "test 1")
        ]

        guest_user = self.example_user('polonius')
        self.login_user(guest_user)
        result = self.change_star(message_id)
        self.assert_json_error(result, 'Invalid message(s)')

        # Subscribed guest users can access public stream messages sent before they join
        self.subscribe(guest_user, stream_name)
        result = self.change_star(message_id)
        self.assert_json_success(result)

        # And messages sent after they join
        self.login_user(normal_user)
        message_id = [
            self.send_stream_message(normal_user, stream_name, "test 2")
        ]
        self.login_user(guest_user)
        result = self.change_star(message_id)
        self.assert_json_success(result)

    def test_change_star_private_stream_security_for_guest_user(self) -> None:
        # Guest users can't access(star) unsubscribed private stream messages
        normal_user = self.example_user("hamlet")
        stream_name = "private_stream"
        stream = self.make_stream(stream_name, invite_only=True)
        self.subscribe(normal_user, stream_name)
        self.login_user(normal_user)

        message_id = [
            self.send_stream_message(normal_user, stream_name, "test 1")
        ]

        guest_user = self.example_user('polonius')
        self.login_user(guest_user)
        result = self.change_star(message_id)
        self.assert_json_error(result, 'Invalid message(s)')

        # Guest user can't access messages of subscribed private streams if
        # history is not public to subscribers
        self.subscribe(guest_user, stream_name)
        result = self.change_star(message_id)
        self.assert_json_error(result, 'Invalid message(s)')

        # Guest user can access messages of subscribed private streams if
        # history is public to subscribers
        do_change_stream_invite_only(stream, True, history_public_to_subscribers=True)
        result = self.change_star(message_id)
        self.assert_json_success(result)

        # With history not public to subscribers, they can still see new messages
        do_change_stream_invite_only(stream, True, history_public_to_subscribers=False)
        self.login_user(normal_user)
        message_id = [
            self.send_stream_message(normal_user, stream_name, "test 2")
        ]
        self.login_user(guest_user)
        result = self.change_star(message_id)
        self.assert_json_success(result)

    def test_bulk_access_messages_private_stream(self) -> None:
        user = self.example_user("hamlet")
        self.login_user(user)

        stream_name = "private_stream"
        stream = self.make_stream(stream_name, invite_only=True,
                                  history_public_to_subscribers=False)

        self.subscribe(user, stream_name)
        # Send a message before subscribing a new user to stream
        message_one_id = self.send_stream_message(user,
                                                  stream_name, "Message one")

        later_subscribed_user = self.example_user("cordelia")
        # Subscribe a user to private-protected history stream
        self.subscribe(later_subscribed_user, stream_name)

        # Send a message after subscribing a new user to stream
        message_two_id = self.send_stream_message(user,
                                                  stream_name, "Message two")

        message_ids = [message_one_id, message_two_id]
        messages = [Message.objects.select_related().get(id=message_id)
                    for message_id in message_ids]

        filtered_messages = bulk_access_messages(later_subscribed_user, messages)

        # Message sent before subscribing wouldn't be accessible by later
        # subscribed user as stream has protected history
        self.assertEqual(len(filtered_messages), 1)
        self.assertEqual(filtered_messages[0].id, message_two_id)

        do_change_stream_invite_only(stream, True, history_public_to_subscribers=True)

        filtered_messages = bulk_access_messages(later_subscribed_user, messages)

        # Message sent before subscribing are accessible by 8user as stream
        # don't have protected history
        self.assertEqual(len(filtered_messages), 2)

        # Testing messages accessiblity for an unsubscribed user
        unsubscribed_user = self.example_user("ZOE")

        filtered_messages = bulk_access_messages(unsubscribed_user, messages)

        self.assertEqual(len(filtered_messages), 0)

    def test_bulk_access_messages_public_stream(self) -> None:
        user = self.example_user("hamlet")
        self.login_user(user)

        # Testing messages accessiblity including a public stream message
        stream_name = "public_stream"
        self.subscribe(user, stream_name)
        message_one_id = self.send_stream_message(user,
                                                  stream_name, "Message one")

        later_subscribed_user = self.example_user("cordelia")
        self.subscribe(later_subscribed_user, stream_name)

        # Send a message after subscribing a new user to stream
        message_two_id = self.send_stream_message(user,
                                                  stream_name, "Message two")

        message_ids = [message_one_id, message_two_id]
        messages = [Message.objects.select_related().get(id=message_id)
                    for message_id in message_ids]

        # All public stream messages are always accessible
        filtered_messages = bulk_access_messages(later_subscribed_user, messages)
        self.assertEqual(len(filtered_messages), 2)

        unsubscribed_user = self.example_user("ZOE")
        filtered_messages = bulk_access_messages(unsubscribed_user, messages)

        self.assertEqual(len(filtered_messages), 2)

class MessageHasKeywordsTest(ZulipTestCase):
    '''Test for keywords like has_link, has_image, has_attachment.'''

    def setup_dummy_attachments(self, user_profile: UserProfile) -> List[str]:
        sample_size = 10
        realm_id = user_profile.realm_id
        dummy_files = [
            ('zulip.txt', '%s/31/4CBjtTLYZhk66pZrF8hnYGwc/zulip.txt' % (realm_id,), sample_size),
            ('temp_file.py', '%s/31/4CBjtTLYZhk66pZrF8hnYGwc/temp_file.py' % (realm_id,), sample_size),
            ('abc.py', '%s/31/4CBjtTLYZhk66pZrF8hnYGwc/abc.py' % (realm_id,), sample_size)
        ]

        for file_name, path_id, size in dummy_files:
            create_attachment(file_name, path_id, user_profile, size)

        # return path ids
        return [x[1] for x in dummy_files]

    def test_claim_attachment(self) -> None:
        user_profile = self.example_user('hamlet')
        dummy_path_ids = self.setup_dummy_attachments(user_profile)
        dummy_urls = [f"http://zulip.testserver/user_uploads/{x}" for x in dummy_path_ids]

        # Send message referring the attachment
        self.subscribe(user_profile, "Denmark")

        def assert_attachment_claimed(path_id: str, claimed: bool) -> None:
            attachment = Attachment.objects.get(path_id=path_id)
            self.assertEqual(attachment.is_claimed(), claimed)

        # This message should claim attachments 1 only because attachment 2
        # is not being parsed as a link by Bugdown.
        body = ("Some files here ...[zulip.txt]({})" +
                "{}.... Some more...." +
                "{}").format(dummy_urls[0], dummy_urls[1], dummy_urls[1])
        self.send_stream_message(user_profile, "Denmark", body, "test")
        assert_attachment_claimed(dummy_path_ids[0], True)
        assert_attachment_claimed(dummy_path_ids[1], False)

        # This message tries to claim the third attachment but fails because
        # Bugdown would not set has_attachments = True here.
        body = f"Link in code: `{dummy_urls[2]}`"
        self.send_stream_message(user_profile, "Denmark", body, "test")
        assert_attachment_claimed(dummy_path_ids[2], False)

        # Another scenario where we wouldn't parse the link.
        body = f"Link to not parse: .{dummy_urls[2]}.`"
        self.send_stream_message(user_profile, "Denmark", body, "test")
        assert_attachment_claimed(dummy_path_ids[2], False)

        # Finally, claim attachment 3.
        body = f"Link: {dummy_urls[2]}"
        self.send_stream_message(user_profile, "Denmark", body, "test")
        assert_attachment_claimed(dummy_path_ids[2], True)
        assert_attachment_claimed(dummy_path_ids[1], False)

    def test_finds_all_links(self) -> None:
        msg_ids = []
        msg_contents = ["foo.org", "[bar](baz.gov)", "http://quux.ca"]
        for msg_content in msg_contents:
            msg_ids.append(self.send_stream_message(self.example_user('hamlet'),
                                                    'Denmark', content=msg_content))
        msgs = [Message.objects.get(id=id) for id in msg_ids]
        self.assertTrue(all([msg.has_link for msg in msgs]))

    def test_finds_only_links(self) -> None:
        msg_ids = []
        msg_contents = ["`example.org`", '``example.org```', '$$https://example.org$$', "foo"]
        for msg_content in msg_contents:
            msg_ids.append(self.send_stream_message(self.example_user('hamlet'),
                                                    'Denmark', content=msg_content))
        msgs = [Message.objects.get(id=id) for id in msg_ids]
        self.assertFalse(all([msg.has_link for msg in msgs]))

    def update_message(self, msg: Message, content: str) -> None:
        hamlet = self.example_user('hamlet')
        realm_id = hamlet.realm.id
        rendered_content = render_markdown(msg, content)
        mention_data = bugdown.MentionData(realm_id, content)
        do_update_message(hamlet, msg, None, None, "change_one", False, False, content,
                          rendered_content, set(), set(), mention_data=mention_data)

    def test_finds_link_after_edit(self) -> None:
        hamlet = self.example_user('hamlet')
        msg_id = self.send_stream_message(hamlet, 'Denmark', content='a')
        msg = Message.objects.get(id=msg_id)

        self.assertFalse(msg.has_link)
        self.update_message(msg, 'a http://foo.com')
        self.assertTrue(msg.has_link)
        self.update_message(msg, 'a')
        self.assertFalse(msg.has_link)
        # Check in blockquotes work
        self.update_message(msg, '> http://bar.com')
        self.assertTrue(msg.has_link)
        self.update_message(msg, 'a `http://foo.com`')
        self.assertFalse(msg.has_link)

    def test_has_image(self) -> None:
        msg_ids = []
        msg_contents = ["Link: foo.org",
                        "Image: https://www.google.com/images/srpr/logo4w.png",
                        "Image: https://www.google.com/images/srpr/logo4w.pdf",
                        "[Google Link](https://www.google.com/images/srpr/logo4w.png)"]
        for msg_content in msg_contents:
            msg_ids.append(self.send_stream_message(self.example_user('hamlet'),
                                                    'Denmark', content=msg_content))
        msgs = [Message.objects.get(id=id) for id in msg_ids]
        self.assertEqual([False, True, False, True], [msg.has_image for msg in msgs])

        self.update_message(msgs[0], 'https://www.google.com/images/srpr/logo4w.png')
        self.assertTrue(msgs[0].has_image)
        self.update_message(msgs[0], 'No Image Again')
        self.assertFalse(msgs[0].has_image)

    def test_has_attachment(self) -> None:
        hamlet = self.example_user('hamlet')
        dummy_path_ids = self.setup_dummy_attachments(hamlet)
        dummy_urls = [f"http://zulip.testserver/user_uploads/{x}" for x in dummy_path_ids]
        self.subscribe(hamlet, "Denmark")

        body = ("Files ...[zulip.txt]({}) {} {}").format(dummy_urls[0], dummy_urls[1], dummy_urls[2])

        msg_id = self.send_stream_message(hamlet, "Denmark", body, "test")
        msg = Message.objects.get(id=msg_id)
        self.assertTrue(msg.has_attachment)
        self.update_message(msg, 'No Attachments')
        self.assertFalse(msg.has_attachment)
        self.update_message(msg, body)
        self.assertTrue(msg.has_attachment)
        self.update_message(msg, f'Link in code: `{dummy_urls[1]}`')
        self.assertFalse(msg.has_attachment)
        # Test blockquotes
        self.update_message(msg, f'> {dummy_urls[1]}')
        self.assertTrue(msg.has_attachment)

        # Additional test to check has_attachment is being set is due to the correct attachment.
        self.update_message(msg, f'Outside: {dummy_urls[0]}. In code: `{dummy_urls[1]}`.')
        self.assertTrue(msg.has_attachment)
        self.assertTrue(msg.attachment_set.filter(path_id=dummy_path_ids[0]))
        self.assertEqual(msg.attachment_set.count(), 1)

        self.update_message(msg, f'Outside: {dummy_urls[1]}. In code: `{dummy_urls[0]}`.')
        self.assertTrue(msg.has_attachment)
        self.assertTrue(msg.attachment_set.filter(path_id=dummy_path_ids[1]))
        self.assertEqual(msg.attachment_set.count(), 1)

        self.update_message(msg, f'Both in code: `{dummy_urls[1]} {dummy_urls[0]}`.')
        self.assertFalse(msg.has_attachment)
        self.assertEqual(msg.attachment_set.count(), 0)

    def test_potential_attachment_path_ids(self) -> None:
        hamlet = self.example_user('hamlet')
        self.subscribe(hamlet, "Denmark")
        dummy_path_ids = self.setup_dummy_attachments(hamlet)

        body = "Hello"
        msg_id = self.send_stream_message(hamlet, "Denmark", body, "test")
        msg = Message.objects.get(id=msg_id)

        with mock.patch("zerver.lib.actions.do_claim_attachments",
                        wraps=do_claim_attachments) as m:
            self.update_message(msg, '[link](http://{}/user_uploads/{})'.format(
                hamlet.realm.host, dummy_path_ids[0]))
            self.assertTrue(m.called)
            m.reset_mock()

            self.update_message(msg, f'[link](/user_uploads/{dummy_path_ids[1]})')
            self.assertTrue(m.called)
            m.reset_mock()

            self.update_message(msg, f'[new text link](/user_uploads/{dummy_path_ids[1]})')
            self.assertFalse(m.called)
            m.reset_mock()

            # It's not clear this is correct behavior
            self.update_message(msg, f'[link](user_uploads/{dummy_path_ids[2]})')
            self.assertFalse(m.called)
            m.reset_mock()

            self.update_message(msg, '[link](https://github.com/user_uploads/{})'.format(
                dummy_path_ids[0]))
            self.assertFalse(m.called)
            m.reset_mock()

class MissedMessageTest(ZulipTestCase):
    def test_presence_idle_user_ids(self) -> None:
        UserPresence.objects.all().delete()

        sender = self.example_user('cordelia')
        realm = sender.realm
        hamlet = self.example_user('hamlet')
        othello = self.example_user('othello')
        recipient_ids = {hamlet.id, othello.id}
        message_type = 'stream'
        user_flags: Dict[int, List[str]] = {}

        def assert_missing(user_ids: List[int]) -> None:
            presence_idle_user_ids = get_active_presence_idle_user_ids(
                realm=realm,
                sender_id=sender.id,
                message_type=message_type,
                active_user_ids=recipient_ids,
                user_flags=user_flags,
            )
            self.assertEqual(sorted(user_ids), sorted(presence_idle_user_ids))

        def set_presence(user: UserProfile, client_name: str, ago: int) -> None:
            when = timezone_now() - datetime.timedelta(seconds=ago)
            UserPresence.objects.create(
                user_profile_id=user.id,
                realm_id=user.realm_id,
                client=get_client(client_name),
                timestamp=when,
            )

        message_type = 'private'
        assert_missing([hamlet.id, othello.id])

        message_type = 'stream'
        user_flags[hamlet.id] = ['mentioned']
        assert_missing([hamlet.id])

        set_presence(hamlet, 'iPhone', ago=5000)
        assert_missing([hamlet.id])

        set_presence(hamlet, 'webapp', ago=15)
        assert_missing([])

        message_type = 'private'
        assert_missing([othello.id])

class LogDictTest(ZulipTestCase):
    def test_to_log_dict(self) -> None:
        user = self.example_user('hamlet')
        stream_name = 'Denmark'
        topic_name = 'Copenhagen'
        content = 'find me some good coffee shops'
        message_id = self.send_stream_message(user, stream_name,
                                              topic_name=topic_name,
                                              content=content)
        message = Message.objects.get(id=message_id)
        dct = message.to_log_dict()

        self.assertTrue('timestamp' in dct)

        self.assertEqual(dct['content'], 'find me some good coffee shops')
        self.assertEqual(dct['id'], message.id)
        self.assertEqual(dct['recipient'], 'Denmark')
        self.assertEqual(dct['sender_realm_str'], 'zulip')
        self.assertEqual(dct['sender_email'], user.email)
        self.assertEqual(dct['sender_full_name'], 'King Hamlet')
        self.assertEqual(dct['sender_id'], user.id)
        self.assertEqual(dct['sender_short_name'], 'hamlet')
        self.assertEqual(dct['sending_client'], 'test suite')
        self.assertEqual(dct[DB_TOPIC_NAME], 'Copenhagen')
        self.assertEqual(dct['type'], 'stream')

class CheckMessageTest(ZulipTestCase):
    def test_basic_check_message_call(self) -> None:
        sender = self.example_user('othello')
        client = make_client(name="test suite")
        stream_name = 'España y Francia'
        self.make_stream(stream_name)
        topic_name = 'issue'
        message_content = 'whatever'
        addressee = Addressee.for_stream_name(stream_name, topic_name)
        ret = check_message(sender, client, addressee, message_content)
        self.assertEqual(ret['message'].sender.id, sender.id)

    def test_bot_pm_feature(self) -> None:
        """We send a PM to a bot's owner if their bot sends a message to
        an unsubscribed stream"""
        parent = self.example_user('othello')
        bot = do_create_user(
            email='othello-bot@zulip.com',
            password='',
            realm=parent.realm,
            full_name='',
            short_name='',
            bot_type=UserProfile.DEFAULT_BOT,
            bot_owner=parent
        )
        bot.last_reminder = None

        sender = bot
        client = make_client(name="test suite")
        stream_name = 'Россия'
        topic_name = 'issue'
        addressee = Addressee.for_stream_name(stream_name, topic_name)
        message_content = 'whatever'
        old_count = message_stream_count(parent)

        # Try sending to stream that doesn't exist sends a reminder to
        # the sender
        with self.assertRaises(JsonableError):
            check_message(sender, client, addressee, message_content)

        new_count = message_stream_count(parent)
        self.assertEqual(new_count, old_count + 1)
        self.assertIn("that stream does not exist.", most_recent_message(parent).content)

        # Try sending to stream that exists with no subscribers soon
        # after; due to rate-limiting, this should send nothing.
        self.make_stream(stream_name)
        ret = check_message(sender, client, addressee, message_content)
        new_count = message_stream_count(parent)
        self.assertEqual(new_count, old_count + 1)

        # Try sending to stream that exists with no subscribers longer
        # after; this should send an error to the bot owner that the
        # stream doesn't exist
        assert(sender.last_reminder is not None)
        sender.last_reminder = sender.last_reminder - datetime.timedelta(hours=1)
        sender.save(update_fields=["last_reminder"])
        ret = check_message(sender, client, addressee, message_content)

        new_count = message_stream_count(parent)
        self.assertEqual(new_count, old_count + 2)
        self.assertEqual(ret['message'].sender.email, 'othello-bot@zulip.com')
        self.assertIn("does not have any subscribers", most_recent_message(parent).content)

    def test_bot_pm_error_handling(self) -> None:
        # This just test some defensive code.
        cordelia = self.example_user('cordelia')
        test_bot = self.create_test_bot(
            short_name='test',
            user_profile=cordelia,
        )
        content = 'whatever'
        good_realm = test_bot.realm
        wrong_realm = get_realm("zephyr")
        wrong_sender = cordelia

        send_rate_limited_pm_notification_to_bot_owner(test_bot, wrong_realm, content)
        self.assertEqual(test_bot.last_reminder, None)

        send_rate_limited_pm_notification_to_bot_owner(wrong_sender, good_realm, content)
        self.assertEqual(test_bot.last_reminder, None)

        test_bot.realm.deactivated = True
        send_rate_limited_pm_notification_to_bot_owner(test_bot, good_realm, content)
        self.assertEqual(test_bot.last_reminder, None)

class DeleteMessageTest(ZulipTestCase):
    def test_delete_message_invalid_request_format(self) -> None:
        self.login('iago')
        hamlet = self.example_user('hamlet')
        msg_id = self.send_stream_message(hamlet, "Scotland")
        result = self.client_delete(f'/json/messages/{msg_id + 1}',
                                    {'message_id': msg_id})
        self.assert_json_error(result, "Invalid message(s)")
        result = self.client_delete(f'/json/messages/{msg_id}')
        self.assert_json_success(result)

    def test_delete_message_by_user(self) -> None:
        def set_message_deleting_params(allow_message_deleting: bool,
                                        message_content_delete_limit_seconds: int) -> None:
            self.login('iago')
            result = self.client_patch("/json/realm", {
                'allow_message_deleting': ujson.dumps(allow_message_deleting),
                'message_content_delete_limit_seconds': message_content_delete_limit_seconds
            })
            self.assert_json_success(result)

        def test_delete_message_by_admin(msg_id: int) -> HttpResponse:
            self.login('iago')
            result = self.client_delete(f'/json/messages/{msg_id}')
            return result

        def test_delete_message_by_owner(msg_id: int) -> HttpResponse:
            self.login('hamlet')
            result = self.client_delete(f'/json/messages/{msg_id}')
            return result

        def test_delete_message_by_other_user(msg_id: int) -> HttpResponse:
            self.login('cordelia')
            result = self.client_delete(f'/json/messages/{msg_id}')
            return result

        # Test if message deleting is not allowed(default).
        set_message_deleting_params(False, 0)
        hamlet = self.example_user('hamlet')
        self.login_user(hamlet)
        msg_id = self.send_stream_message(hamlet, "Scotland")

        result = test_delete_message_by_owner(msg_id=msg_id)
        self.assert_json_error(result, "You don't have permission to delete this message")

        result = test_delete_message_by_other_user(msg_id=msg_id)
        self.assert_json_error(result, "You don't have permission to delete this message")

        result = test_delete_message_by_admin(msg_id=msg_id)
        self.assert_json_success(result)

        # Test if message deleting is allowed.
        # Test if time limit is zero(no limit).
        set_message_deleting_params(True, 0)
        msg_id = self.send_stream_message(hamlet, "Scotland")
        message = Message.objects.get(id=msg_id)
        message.date_sent = message.date_sent - datetime.timedelta(seconds=600)
        message.save()

        result = test_delete_message_by_other_user(msg_id=msg_id)
        self.assert_json_error(result, "You don't have permission to delete this message")

        result = test_delete_message_by_owner(msg_id=msg_id)
        self.assert_json_success(result)

        # Test if time limit is non-zero.
        set_message_deleting_params(True, 240)
        msg_id_1 = self.send_stream_message(hamlet, "Scotland")
        message = Message.objects.get(id=msg_id_1)
        message.date_sent = message.date_sent - datetime.timedelta(seconds=120)
        message.save()

        msg_id_2 = self.send_stream_message(hamlet, "Scotland")
        message = Message.objects.get(id=msg_id_2)
        message.date_sent = message.date_sent - datetime.timedelta(seconds=360)
        message.save()

        result = test_delete_message_by_other_user(msg_id=msg_id_1)
        self.assert_json_error(result, "You don't have permission to delete this message")

        result = test_delete_message_by_owner(msg_id=msg_id_1)
        self.assert_json_success(result)
        result = test_delete_message_by_owner(msg_id=msg_id_2)
        self.assert_json_error(result, "The time limit for deleting this message has passed")

        # No limit for admin.
        result = test_delete_message_by_admin(msg_id=msg_id_2)
        self.assert_json_success(result)

        # Test multiple delete requests with no latency issues
        msg_id = self.send_stream_message(hamlet, "Scotland")
        result = test_delete_message_by_owner(msg_id=msg_id)
        self.assert_json_success(result)
        result = test_delete_message_by_owner(msg_id=msg_id)
        self.assert_json_error(result, "Invalid message(s)")

        # Test handling of 500 error caused by multiple delete requests due to latency.
        # see issue #11219.
        with mock.patch("zerver.views.messages.do_delete_messages") as m, \
                mock.patch("zerver.views.messages.validate_can_delete_message", return_value=None), \
                mock.patch("zerver.views.messages.access_message", return_value=(None, None)):
            m.side_effect = IntegrityError()
            result = test_delete_message_by_owner(msg_id=msg_id)
            self.assert_json_error(result, "Message already deleted")
            m.side_effect = Message.DoesNotExist()
            result = test_delete_message_by_owner(msg_id=msg_id)
            self.assert_json_error(result, "Message already deleted")

class SoftDeactivationMessageTest(ZulipTestCase):

    def test_reactivate_user_if_soft_deactivated(self) -> None:
        recipient_list  = [self.example_user("hamlet"), self.example_user("iago")]
        for user_profile in recipient_list:
            self.subscribe(user_profile, "Denmark")

        sender = self.example_user('iago')
        stream_name = 'Denmark'
        topic_name = 'foo'

        def last_realm_audit_log_entry(event_type: int) -> RealmAuditLog:
            return RealmAuditLog.objects.filter(
                event_type=event_type
            ).order_by('-event_time')[0]

        long_term_idle_user = self.example_user('hamlet')
        # We are sending this message to ensure that long_term_idle_user has
        # at least one UserMessage row.
        self.send_stream_message(long_term_idle_user, stream_name)
        do_soft_deactivate_users([long_term_idle_user])

        message = 'Test Message 1'
        message_id = self.send_stream_message(sender, stream_name,
                                              message, topic_name)
        idle_user_msg_list = get_user_messages(long_term_idle_user)
        idle_user_msg_count = len(idle_user_msg_list)
        self.assertNotEqual(idle_user_msg_list[-1].content, message)
        with queries_captured() as queries:
            reactivate_user_if_soft_deactivated(long_term_idle_user)
        self.assert_length(queries, 8)
        self.assertFalse(long_term_idle_user.long_term_idle)
        self.assertEqual(last_realm_audit_log_entry(
            RealmAuditLog.USER_SOFT_ACTIVATED).modified_user, long_term_idle_user)
        idle_user_msg_list = get_user_messages(long_term_idle_user)
        self.assertEqual(len(idle_user_msg_list), idle_user_msg_count + 1)
        self.assertEqual(idle_user_msg_list[-1].content, message)
        long_term_idle_user.refresh_from_db()
        self.assertEqual(long_term_idle_user.last_active_message_id, message_id)

    def test_add_missing_messages(self) -> None:
        recipient_list  = [self.example_user("hamlet"), self.example_user("iago")]
        for user_profile in recipient_list:
            self.subscribe(user_profile, "Denmark")

        sender = self.example_user('iago')
        realm = sender.realm
        sending_client = make_client(name="test suite")
        stream_name = 'Denmark'
        stream = get_stream(stream_name, realm)
        topic_name = 'foo'

        def send_fake_message(message_content: str, stream: Stream) -> Message:
            recipient = stream.recipient
            message = Message(sender = sender,
                              recipient = recipient,
                              content = message_content,
                              date_sent = timezone_now(),
                              sending_client = sending_client)
            message.set_topic_name(topic_name)
            message.save()
            return message

        long_term_idle_user = self.example_user('hamlet')
        self.send_stream_message(long_term_idle_user, stream_name)
        do_soft_deactivate_users([long_term_idle_user])

        # Test that add_missing_messages() in simplest case of adding a
        # message for which UserMessage row doesn't exist for this user.
        sent_message = send_fake_message('Test Message 1', stream)
        idle_user_msg_list = get_user_messages(long_term_idle_user)
        idle_user_msg_count = len(idle_user_msg_list)
        self.assertNotEqual(idle_user_msg_list[-1], sent_message)
        with queries_captured() as queries:
            add_missing_messages(long_term_idle_user)
        self.assert_length(queries, 6)
        idle_user_msg_list = get_user_messages(long_term_idle_user)
        self.assertEqual(len(idle_user_msg_list), idle_user_msg_count + 1)
        self.assertEqual(idle_user_msg_list[-1], sent_message)
        long_term_idle_user.refresh_from_db()
        self.assertEqual(long_term_idle_user.last_active_message_id, sent_message.id)

        # Test that add_missing_messages() only adds messages that aren't
        # already present in the UserMessage table. This test works on the
        # fact that previous test just above this added a message but didn't
        # updated the last_active_message_id field for the user.
        sent_message = send_fake_message('Test Message 2', stream)
        idle_user_msg_list = get_user_messages(long_term_idle_user)
        idle_user_msg_count = len(idle_user_msg_list)
        self.assertNotEqual(idle_user_msg_list[-1], sent_message)
        with queries_captured() as queries:
            add_missing_messages(long_term_idle_user)
        self.assert_length(queries, 7)
        idle_user_msg_list = get_user_messages(long_term_idle_user)
        self.assertEqual(len(idle_user_msg_list), idle_user_msg_count + 1)
        self.assertEqual(idle_user_msg_list[-1], sent_message)
        long_term_idle_user.refresh_from_db()
        self.assertEqual(long_term_idle_user.last_active_message_id, sent_message.id)

        # Test UserMessage rows are created correctly in case of stream
        # Subscription was altered by admin while user was away.

        # Test for a public stream.
        sent_message_list = []
        sent_message_list.append(send_fake_message('Test Message 3', stream))
        # Alter subscription to stream.
        self.unsubscribe(long_term_idle_user, stream_name)
        send_fake_message('Test Message 4', stream)
        self.subscribe(long_term_idle_user, stream_name)
        sent_message_list.append(send_fake_message('Test Message 5', stream))
        sent_message_list.reverse()
        idle_user_msg_list = get_user_messages(long_term_idle_user)
        idle_user_msg_count = len(idle_user_msg_list)
        for sent_message in sent_message_list:
            self.assertNotEqual(idle_user_msg_list.pop(), sent_message)
        with queries_captured() as queries:
            add_missing_messages(long_term_idle_user)
        self.assert_length(queries, 6)
        idle_user_msg_list = get_user_messages(long_term_idle_user)
        self.assertEqual(len(idle_user_msg_list), idle_user_msg_count + 2)
        for sent_message in sent_message_list:
            self.assertEqual(idle_user_msg_list.pop(), sent_message)
        long_term_idle_user.refresh_from_db()
        self.assertEqual(long_term_idle_user.last_active_message_id, sent_message_list[0].id)

        # Test consecutive subscribe/unsubscribe in a public stream
        sent_message_list = []

        sent_message_list.append(send_fake_message('Test Message 6', stream))
        # Unsubscribe from stream and then immediately subscribe back again.
        self.unsubscribe(long_term_idle_user, stream_name)
        self.subscribe(long_term_idle_user, stream_name)
        sent_message_list.append(send_fake_message('Test Message 7', stream))
        # Again unsubscribe from stream and send a message.
        # This will make sure that if initially in a unsubscribed state
        # a consecutive subscribe/unsubscribe doesn't misbehave.
        self.unsubscribe(long_term_idle_user, stream_name)
        send_fake_message('Test Message 8', stream)
        # Do a subscribe and unsubscribe immediately.
        self.subscribe(long_term_idle_user, stream_name)
        self.unsubscribe(long_term_idle_user, stream_name)

        sent_message_list.reverse()
        idle_user_msg_list = get_user_messages(long_term_idle_user)
        idle_user_msg_count = len(idle_user_msg_list)
        for sent_message in sent_message_list:
            self.assertNotEqual(idle_user_msg_list.pop(), sent_message)
        with queries_captured() as queries:
            add_missing_messages(long_term_idle_user)
        self.assert_length(queries, 6)
        idle_user_msg_list = get_user_messages(long_term_idle_user)
        self.assertEqual(len(idle_user_msg_list), idle_user_msg_count + 2)
        for sent_message in sent_message_list:
            self.assertEqual(idle_user_msg_list.pop(), sent_message)
        long_term_idle_user.refresh_from_db()
        self.assertEqual(long_term_idle_user.last_active_message_id, sent_message_list[0].id)

        # Test for when user unsubscribes before soft deactivation
        # (must reactivate them in order to do this).

        do_soft_activate_users([long_term_idle_user])
        self.subscribe(long_term_idle_user, stream_name)
        # Send a real message to update last_active_message_id
        sent_message_id = self.send_stream_message(
            sender, stream_name, 'Test Message 9')
        self.unsubscribe(long_term_idle_user, stream_name)
        # Soft deactivate and send another message to the unsubscribed stream.
        do_soft_deactivate_users([long_term_idle_user])
        send_fake_message('Test Message 10', stream)

        idle_user_msg_list = get_user_messages(long_term_idle_user)
        idle_user_msg_count = len(idle_user_msg_list)
        self.assertEqual(idle_user_msg_list[-1].id, sent_message_id)
        with queries_captured() as queries:
            add_missing_messages(long_term_idle_user)
        # There are no streams to fetch missing messages from, so
        # the Message.objects query will be avoided.
        self.assert_length(queries, 4)
        idle_user_msg_list = get_user_messages(long_term_idle_user)
        # No new UserMessage rows should have been created.
        self.assertEqual(len(idle_user_msg_list), idle_user_msg_count)

        # Note: At this point in this test we have long_term_idle_user
        # unsubscribed from the 'Denmark' stream.

        # Test for a Private Stream.
        stream_name = "Core"
        private_stream = self.make_stream('Core', invite_only=True)
        self.subscribe(self.example_user("iago"), stream_name)
        sent_message_list = []
        send_fake_message('Test Message 11', private_stream)
        self.subscribe(self.example_user("hamlet"), stream_name)
        sent_message_list.append(send_fake_message('Test Message 12', private_stream))
        self.unsubscribe(long_term_idle_user, stream_name)
        send_fake_message('Test Message 13', private_stream)
        self.subscribe(long_term_idle_user, stream_name)
        sent_message_list.append(send_fake_message('Test Message 14', private_stream))
        sent_message_list.reverse()
        idle_user_msg_list = get_user_messages(long_term_idle_user)
        idle_user_msg_count = len(idle_user_msg_list)
        for sent_message in sent_message_list:
            self.assertNotEqual(idle_user_msg_list.pop(), sent_message)
        with queries_captured() as queries:
            add_missing_messages(long_term_idle_user)
        self.assert_length(queries, 6)
        idle_user_msg_list = get_user_messages(long_term_idle_user)
        self.assertEqual(len(idle_user_msg_list), idle_user_msg_count + 2)
        for sent_message in sent_message_list:
            self.assertEqual(idle_user_msg_list.pop(), sent_message)
        long_term_idle_user.refresh_from_db()
        self.assertEqual(long_term_idle_user.last_active_message_id, sent_message_list[0].id)

    @mock.patch('zerver.lib.soft_deactivation.BULK_CREATE_BATCH_SIZE', 2)
    def test_add_missing_messages_pagination(self) -> None:
        recipient_list  = [self.example_user("hamlet"), self.example_user("iago")]
        stream_name = 'Denmark'
        for user_profile in recipient_list:
            self.subscribe(user_profile, stream_name)

        sender = self.example_user('iago')
        long_term_idle_user = self.example_user('hamlet')
        self.send_stream_message(long_term_idle_user, stream_name)
        do_soft_deactivate_users([long_term_idle_user])

        num_new_messages = 5
        message_ids = []
        for _ in range(num_new_messages):
            message_id = self.send_stream_message(sender, stream_name)
            message_ids.append(message_id)

        idle_user_msg_list = get_user_messages(long_term_idle_user)
        idle_user_msg_count = len(idle_user_msg_list)
        with queries_captured() as queries:
            add_missing_messages(long_term_idle_user)
        self.assert_length(queries, 10)
        idle_user_msg_list = get_user_messages(long_term_idle_user)
        self.assertEqual(len(idle_user_msg_list), idle_user_msg_count + num_new_messages)
        long_term_idle_user.refresh_from_db()
        self.assertEqual(long_term_idle_user.last_active_message_id, message_ids[-1])

    def test_user_message_filter(self) -> None:
        # In this test we are basically testing out the logic used out in
        # do_send_messages() in action.py for filtering the messages for which
        # UserMessage rows should be created for a soft-deactivated user.
        recipient_list  = [
            self.example_user("hamlet"),
            self.example_user("iago"),
            self.example_user('cordelia')
        ]
        for user_profile in recipient_list:
            self.subscribe(user_profile, "Denmark")

        cordelia = self.example_user('cordelia')
        sender = self.example_user('iago')
        stream_name = 'Denmark'
        topic_name = 'foo'

        def send_stream_message(content: str) -> None:
            self.send_stream_message(sender, stream_name,
                                     content, topic_name)

        def send_personal_message(content: str) -> None:
            self.send_personal_message(sender, self.example_user("hamlet"), content)

        long_term_idle_user = self.example_user('hamlet')
        self.send_stream_message(long_term_idle_user, stream_name)
        do_soft_deactivate_users([long_term_idle_user])

        def assert_um_count(user: UserProfile, count: int) -> None:
            user_messages = get_user_messages(user)
            self.assertEqual(len(user_messages), count)

        def assert_last_um_content(user: UserProfile, content: str, negate: bool=False) -> None:
            user_messages = get_user_messages(user)
            if negate:
                self.assertNotEqual(user_messages[-1].content, content)
            else:
                self.assertEqual(user_messages[-1].content, content)

        # Test that sending a message to a stream with soft deactivated user
        # doesn't end up creating UserMessage row for deactivated user.
        general_user_msg_count = len(get_user_messages(cordelia))
        soft_deactivated_user_msg_count = len(get_user_messages(long_term_idle_user))
        message = 'Test Message 1'
        send_stream_message(message)
        assert_last_um_content(long_term_idle_user, message, negate=True)
        assert_um_count(long_term_idle_user, soft_deactivated_user_msg_count)
        assert_um_count(cordelia, general_user_msg_count + 1)
        assert_last_um_content(cordelia, message)

        # Test that sending a message to a stream with soft deactivated user
        # and push/email notifications on creates a UserMessage row for the
        # deactivated user.
        sub = get_subscription(stream_name, long_term_idle_user)
        sub.push_notifications = True
        sub.save()
        general_user_msg_count = len(get_user_messages(cordelia))
        soft_deactivated_user_msg_count = len(get_user_messages(long_term_idle_user))
        message = 'Test private stream message'
        send_stream_message(message)
        assert_um_count(long_term_idle_user, soft_deactivated_user_msg_count + 1)
        assert_last_um_content(long_term_idle_user, message)
        sub.push_notifications = False
        sub.save()

        # Test sending a private message to soft deactivated user creates
        # UserMessage row.
        soft_deactivated_user_msg_count = len(get_user_messages(long_term_idle_user))
        message = 'Test PM'
        send_personal_message(message)
        assert_um_count(long_term_idle_user, soft_deactivated_user_msg_count + 1)
        assert_last_um_content(long_term_idle_user, message)

        # Test UserMessage row is created while user is deactivated if
        # user itself is mentioned.
        general_user_msg_count = len(get_user_messages(cordelia))
        soft_deactivated_user_msg_count = len(get_user_messages(long_term_idle_user))
        message = 'Test @**King Hamlet** mention'
        send_stream_message(message)
        assert_last_um_content(long_term_idle_user, message)
        assert_um_count(long_term_idle_user, soft_deactivated_user_msg_count + 1)
        assert_um_count(cordelia, general_user_msg_count + 1)
        assert_last_um_content(cordelia, message)

        # Test UserMessage row is not created while user is deactivated if
        # anyone is mentioned but the user.
        general_user_msg_count = len(get_user_messages(cordelia))
        soft_deactivated_user_msg_count = len(get_user_messages(long_term_idle_user))
        message = 'Test @**Cordelia Lear**  mention'
        send_stream_message(message)
        assert_last_um_content(long_term_idle_user, message, negate=True)
        assert_um_count(long_term_idle_user, soft_deactivated_user_msg_count)
        assert_um_count(cordelia, general_user_msg_count + 1)
        assert_last_um_content(cordelia, message)

        # Test UserMessage row is created while user is deactivated if
        # there is a wildcard mention such as @all or @everyone
        general_user_msg_count = len(get_user_messages(cordelia))
        soft_deactivated_user_msg_count = len(get_user_messages(long_term_idle_user))
        message = 'Test @**all** mention'
        send_stream_message(message)
        assert_last_um_content(long_term_idle_user, message)
        assert_um_count(long_term_idle_user, soft_deactivated_user_msg_count + 1)
        assert_um_count(cordelia, general_user_msg_count + 1)
        assert_last_um_content(cordelia, message)

        general_user_msg_count = len(get_user_messages(cordelia))
        soft_deactivated_user_msg_count = len(get_user_messages(long_term_idle_user))
        message = 'Test @**everyone** mention'
        send_stream_message(message)
        assert_last_um_content(long_term_idle_user, message)
        assert_um_count(long_term_idle_user, soft_deactivated_user_msg_count + 1)
        assert_um_count(cordelia, general_user_msg_count + 1)
        assert_last_um_content(cordelia, message)

        general_user_msg_count = len(get_user_messages(cordelia))
        soft_deactivated_user_msg_count = len(get_user_messages(long_term_idle_user))
        message = 'Test @**stream** mention'
        send_stream_message(message)
        assert_last_um_content(long_term_idle_user, message)
        assert_um_count(long_term_idle_user, soft_deactivated_user_msg_count + 1)
        assert_um_count(cordelia, general_user_msg_count + 1)
        assert_last_um_content(cordelia, message)

        # Test UserMessage row is not created while user is deactivated if there
        # is a alert word in message.
        do_add_alert_words(long_term_idle_user, ['test_alert_word'])
        general_user_msg_count = len(get_user_messages(cordelia))
        soft_deactivated_user_msg_count = len(get_user_messages(long_term_idle_user))
        message = 'Testing test_alert_word'
        send_stream_message(message)
        assert_last_um_content(long_term_idle_user, message)
        assert_um_count(long_term_idle_user, soft_deactivated_user_msg_count + 1)
        assert_um_count(cordelia, general_user_msg_count + 1)
        assert_last_um_content(cordelia, message)

        # Test UserMessage row is created while user is deactivated if
        # message is a me message.
        general_user_msg_count = len(get_user_messages(cordelia))
        soft_deactivated_user_msg_count = len(get_user_messages(long_term_idle_user))
        message = '/me says test'
        send_stream_message(message)
        assert_last_um_content(long_term_idle_user, message, negate=True)
        assert_um_count(long_term_idle_user, soft_deactivated_user_msg_count)
        assert_um_count(cordelia, general_user_msg_count + 1)
        assert_last_um_content(cordelia, message)

class MessageHydrationTest(ZulipTestCase):
    def test_hydrate_stream_recipient_info(self) -> None:
        realm = get_realm('zulip')
        cordelia = self.example_user('cordelia')

        stream_id = get_stream('Verona', realm).id

        obj = dict(
            recipient_type=Recipient.STREAM,
            recipient_type_id=stream_id,
            sender_is_mirror_dummy=False,
            sender_email=cordelia.email,
            sender_full_name=cordelia.full_name,
            sender_short_name=cordelia.short_name,
            sender_id=cordelia.id,
        )

        MessageDict.hydrate_recipient_info(obj, 'Verona')

        self.assertEqual(obj['display_recipient'], 'Verona')
        self.assertEqual(obj['type'], 'stream')

    def test_hydrate_pm_recipient_info(self) -> None:
        cordelia = self.example_user('cordelia')
        display_recipient: List[UserDisplayRecipient] = [
            dict(
                email='aaron@example.com',
                full_name='Aaron Smith',
                short_name='Aaron',
                id=999,
                is_mirror_dummy=False
            ),
        ]

        obj = dict(
            recipient_type=Recipient.PERSONAL,
            recipient_type_id=None,
            sender_is_mirror_dummy=False,
            sender_email=cordelia.email,
            sender_full_name=cordelia.full_name,
            sender_short_name=cordelia.short_name,
            sender_id=cordelia.id,
        )

        MessageDict.hydrate_recipient_info(obj, display_recipient)

        self.assertEqual(
            obj['display_recipient'],
            [
                dict(
                    email='aaron@example.com',
                    full_name='Aaron Smith',
                    short_name='Aaron',
                    id=999,
                    is_mirror_dummy=False
                ),
                dict(
                    email=cordelia.email,
                    full_name=cordelia.full_name,
                    id=cordelia.id,
                    short_name=cordelia.short_name,
                    is_mirror_dummy=False,
                ),
            ],
        )
        self.assertEqual(obj['type'], 'private')

    def test_messages_for_ids(self) -> None:
        hamlet = self.example_user('hamlet')
        cordelia = self.example_user('cordelia')

        stream_name = 'test stream'
        self.subscribe(cordelia, stream_name)

        old_message_id = self.send_stream_message(cordelia, stream_name, content='foo')

        self.subscribe(hamlet, stream_name)

        content = 'hello @**King Hamlet**'
        new_message_id = self.send_stream_message(cordelia, stream_name, content=content)

        user_message_flags = {
            old_message_id: ['read', 'historical'],
            new_message_id: ['mentioned'],
        }

        messages = messages_for_ids(
            message_ids=[old_message_id, new_message_id],
            user_message_flags=user_message_flags,
            search_fields={},
            apply_markdown=True,
            client_gravatar=True,
            allow_edit_history=False,
        )

        self.assertEqual(len(messages), 2)

        for message in messages:
            if message['id'] == old_message_id:
                old_message = message
            elif message['id'] == new_message_id:
                new_message = message

        self.assertEqual(old_message['content'], '<p>foo</p>')
        self.assertEqual(old_message['flags'], ['read', 'historical'])

        self.assertIn('class="user-mention"', new_message['content'])
        self.assertEqual(new_message['flags'], ['mentioned'])

    def test_display_recipient_up_to_date(self) -> None:
        """
        This is a test for a bug where due to caching of message_dicts,
        after updating a user's information, fetching those cached messages
        via messages_for_ids would return message_dicts with display_recipient
        still having the old information. The returned message_dicts should have
        up-to-date display_recipients and we check for that here.
        """

        hamlet = self.example_user('hamlet')
        cordelia = self.example_user('cordelia')
        message_id = self.send_personal_message(hamlet, cordelia, 'test')

        cordelia_recipient = cordelia.recipient
        # Cause the display_recipient to get cached:
        get_display_recipient(cordelia_recipient)

        # Change cordelia's email:
        cordelia_new_email = 'new-cordelia@zulip.com'
        cordelia.email = cordelia_new_email
        cordelia.save()

        # Local display_recipient cache needs to be flushed.
        # flush_per_request_caches() is called after every request,
        # so it makes sense to run it here.
        flush_per_request_caches()

        messages = messages_for_ids(
            message_ids=[message_id],
            user_message_flags={message_id: ['read']},
            search_fields={},
            apply_markdown=True,
            client_gravatar=True,
            allow_edit_history=False,
        )
        message = messages[0]

        # Find which display_recipient in the list is cordelia:
        for display_recipient in message['display_recipient']:
            if display_recipient['short_name'] == 'cordelia':
                cordelia_display_recipient = display_recipient

        # Make sure the email is up-to-date.
        self.assertEqual(cordelia_display_recipient['email'], cordelia_new_email)

class TestMessageForIdsDisplayRecipientFetching(ZulipTestCase):
    def _verify_display_recipient(self, display_recipient: DisplayRecipientT,
                                  expected_recipient_objects: Union[Stream, List[UserProfile]]) -> None:
        if isinstance(expected_recipient_objects, Stream):
            self.assertEqual(display_recipient, expected_recipient_objects.name)

        else:
            for user_profile in expected_recipient_objects:
                recipient_dict: UserDisplayRecipient = {
                    'email': user_profile.email,
                    'full_name': user_profile.full_name,
                    'short_name': user_profile.short_name,
                    'id': user_profile.id,
                    'is_mirror_dummy': user_profile.is_mirror_dummy,
                }
                self.assertTrue(recipient_dict in display_recipient)

    def test_display_recipient_personal(self) -> None:
        hamlet = self.example_user('hamlet')
        cordelia = self.example_user('cordelia')
        othello = self.example_user('othello')
        message_ids = [
            self.send_personal_message(hamlet, cordelia, 'test'),
            self.send_personal_message(cordelia, othello, 'test')
        ]

        messages = messages_for_ids(
            message_ids=message_ids,
            user_message_flags={message_id: ['read'] for message_id in message_ids},
            search_fields={},
            apply_markdown=True,
            client_gravatar=True,
            allow_edit_history=False,
        )

        self._verify_display_recipient(messages[0]['display_recipient'], [hamlet, cordelia])
        self._verify_display_recipient(messages[1]['display_recipient'], [cordelia, othello])

    def test_display_recipient_stream(self) -> None:
        cordelia = self.example_user('cordelia')
        message_ids = [
            self.send_stream_message(cordelia, "Verona", content='test'),
            self.send_stream_message(cordelia, "Denmark", content='test')
        ]

        messages = messages_for_ids(
            message_ids=message_ids,
            user_message_flags={message_id: ['read'] for message_id in message_ids},
            search_fields={},
            apply_markdown=True,
            client_gravatar=True,
            allow_edit_history=False,
        )

        self._verify_display_recipient(messages[0]['display_recipient'], get_stream("Verona", cordelia.realm))
        self._verify_display_recipient(messages[1]['display_recipient'], get_stream("Denmark", cordelia.realm))

    def test_display_recipient_huddle(self) -> None:
        hamlet = self.example_user('hamlet')
        cordelia = self.example_user('cordelia')
        othello = self.example_user('othello')
        iago = self.example_user('iago')
        message_ids = [
            self.send_huddle_message(hamlet, [cordelia, othello], 'test'),
            self.send_huddle_message(cordelia, [hamlet, othello, iago], 'test')
        ]

        messages = messages_for_ids(
            message_ids=message_ids,
            user_message_flags={message_id: ['read'] for message_id in message_ids},
            search_fields={},
            apply_markdown=True,
            client_gravatar=True,
            allow_edit_history=False,
        )

        self._verify_display_recipient(messages[0]['display_recipient'], [hamlet, cordelia, othello])
        self._verify_display_recipient(messages[1]['display_recipient'], [hamlet, cordelia, othello, iago])

    def test_display_recipient_various_types(self) -> None:
        hamlet = self.example_user('hamlet')
        cordelia = self.example_user('cordelia')
        othello = self.example_user('othello')
        iago = self.example_user('iago')
        message_ids = [
            self.send_huddle_message(hamlet, [cordelia, othello], 'test'),
            self.send_stream_message(cordelia, "Verona", content='test'),
            self.send_personal_message(hamlet, cordelia, 'test'),
            self.send_stream_message(cordelia, "Denmark", content='test'),
            self.send_huddle_message(cordelia, [hamlet, othello, iago], 'test'),
            self.send_personal_message(cordelia, othello, 'test')
        ]

        messages = messages_for_ids(
            message_ids=message_ids,
            user_message_flags={message_id: ['read'] for message_id in message_ids},
            search_fields={},
            apply_markdown=True,
            client_gravatar=True,
            allow_edit_history=False,
        )

        self._verify_display_recipient(messages[0]['display_recipient'], [hamlet, cordelia, othello])
        self._verify_display_recipient(messages[1]['display_recipient'], get_stream("Verona", hamlet.realm))
        self._verify_display_recipient(messages[2]['display_recipient'], [hamlet, cordelia])
        self._verify_display_recipient(messages[3]['display_recipient'], get_stream("Denmark", hamlet.realm))
        self._verify_display_recipient(messages[4]['display_recipient'], [hamlet, cordelia, othello, iago])
        self._verify_display_recipient(messages[5]['display_recipient'], [cordelia, othello])

class MessageVisibilityTest(ZulipTestCase):
    def test_update_first_visible_message_id(self) -> None:
        Message.objects.all().delete()
        message_ids = [self.send_stream_message(self.example_user("othello"), "Scotland") for i in range(15)]

        # If message_visibility_limit is None update_first_visible_message_id
        # should set first_visible_message_id to 0
        realm = get_realm("zulip")
        realm.message_visibility_limit = None
        # Setting to a random value other than 0 as the default value of
        # first_visible_message_id is 0
        realm.first_visible_message_id = 5
        realm.save()
        update_first_visible_message_id(realm)
        self.assertEqual(get_first_visible_message_id(realm), 0)

        realm.message_visibility_limit = 10
        realm.save()
        expected_message_id = message_ids[5]
        update_first_visible_message_id(realm)
        self.assertEqual(get_first_visible_message_id(realm), expected_message_id)

        # If the message_visibility_limit is greater than number of messages
        # get_first_visible_message_id should return 0
        realm.message_visibility_limit = 50
        realm.save()
        update_first_visible_message_id(realm)
        self.assertEqual(get_first_visible_message_id(realm), 0)

    def test_maybe_update_first_visible_message_id(self) -> None:
        realm = get_realm("zulip")
        lookback_hours = 30

        realm.message_visibility_limit = None
        realm.save()

        end_time = timezone_now() - datetime.timedelta(hours=lookback_hours - 5)
        stat = COUNT_STATS['messages_sent:is_bot:hour']

        RealmCount.objects.create(realm=realm, property=stat.property,
                                  end_time=end_time, value=5)
        with mock.patch("zerver.lib.message.update_first_visible_message_id") as m:
            maybe_update_first_visible_message_id(realm, lookback_hours)
        m.assert_not_called()

        realm.message_visibility_limit = 10
        realm.save()
        RealmCount.objects.all().delete()
        with mock.patch("zerver.lib.message.update_first_visible_message_id") as m:
            maybe_update_first_visible_message_id(realm, lookback_hours)
        m.assert_not_called()

        RealmCount.objects.create(realm=realm, property=stat.property,
                                  end_time=end_time, value=5)
        with mock.patch("zerver.lib.message.update_first_visible_message_id") as m:
            maybe_update_first_visible_message_id(realm, lookback_hours)
        m.assert_called_once_with(realm)

class TestBulkGetHuddleUserIds(ZulipTestCase):
    def test_bulk_get_huddle_user_ids(self) -> None:
        hamlet = self.example_user('hamlet')
        cordelia = self.example_user('cordelia')
        othello = self.example_user('othello')
        iago = self.example_user('iago')
        message_ids = [
            self.send_huddle_message(hamlet, [cordelia, othello], 'test'),
            self.send_huddle_message(cordelia, [hamlet, othello, iago], 'test')
        ]

        messages = Message.objects.filter(id__in=message_ids).order_by("id")
        first_huddle_recipient = messages[0].recipient
        first_huddle_user_ids = list(get_huddle_user_ids(first_huddle_recipient))
        second_huddle_recipient = messages[1].recipient
        second_huddle_user_ids = list(get_huddle_user_ids(second_huddle_recipient))

        huddle_user_ids = bulk_get_huddle_user_ids([first_huddle_recipient, second_huddle_recipient])
        self.assertEqual(huddle_user_ids[first_huddle_recipient.id], first_huddle_user_ids)
        self.assertEqual(huddle_user_ids[second_huddle_recipient.id], second_huddle_user_ids)

    def test_bulk_get_huddle_user_ids_empty_list(self) -> None:
        self.assertEqual(bulk_get_huddle_user_ids([]), {})

class NoRecipientIDsTest(ZulipTestCase):
    def test_no_recipient_ids(self) -> None:
        user_profile = self.example_user('cordelia')

        Subscription.objects.filter(user_profile=user_profile, recipient__type=Recipient.STREAM).delete()
        subs = gather_subscriptions_helper(user_profile)

        # Checks that gather_subscriptions_helper will not return anything
        # since there will not be any recipients, without crashing.
        #
        # This covers a rare corner case.
        self.assertEqual(len(subs[0]), 0)