mjolnir/test/integration/banListTest.ts

import { strict as assert } from "assert";
import { newTestUser } from "./clientHelper";
import { LogService, MatrixClient, Permalinks, UserID } from "matrix-bot-sdk";
import PolicyList, { ChangeType, ListRuleChange } from "../../src/models/PolicyList";
import { ServerAcl } from "../../src/models/ServerAcl";
import { getFirstReaction } from "./commands/commandUtils";
import { getMessagesByUserIn } from "../../src/utils";
import { Mjolnir } from "../../src/Mjolnir";
import { ALL_RULE_TYPES, Recommendation, RULE_SERVER, RULE_USER, SERVER_RULE_TYPES } from "../../src/models/ListRule";
import AccessControlUnit, { Access, EntityAccess } from "../../src/models/AccessControlUnit";
import { randomUUID } from "crypto";

/**
 * Create a policy rule in a policy room.
 * @param client A matrix client that is logged in
 * @param policyRoomId The room id to add the policy to.
 * @param policyType The type of policy to add e.g. m.policy.rule.user. (Use RULE_USER though).
 * @param entity The entity to ban e.g. @foo:example.org
 * @param reason A reason for the rule e.g. 'Wouldn't stop posting spam links'
 * @param template The template to use for the policy rule event.
 * @returns The event id of the newly created policy rule.
 */
async function createPolicyRule(client: MatrixClient, policyRoomId: string, policyType: string, entity: string, reason: string, template = { recommendation: 'm.ban' }, stateKey = `rule:${entity}`) {
    return await client.sendStateEvent(policyRoomId, policyType, stateKey, {
        entity,
        reason,
        ...template,
    });
}

/**
 * Remove a policy rule from a list.
 * @param client A matrix client that is logged in
 * @param policyRoomId The room id to add the policy to.
 * @param policyType The type of policy to add e.g. m.policy.rule.user. (Use RULE_USER though).
 * @param entity The entity to ban e.g. @foo:example.org
 * @param stateKey The key for the rule.
 * @returns The event id of the void rule that was created to override the old one.
 */
async function removePolicyRule(client: MatrixClient, policyRoomId: string, policyType: string, entity: string, stateKey = `rule:${entity}`) {
    return await client.sendStateEvent(policyRoomId, policyType, stateKey, {});
}

describe("Test: Updating the PolicyList", function() {
    it("Calculates what has changed correctly.", async function() {
        this.timeout(10000);
        const mjolnir: Mjolnir = this.mjolnir!
        const moderator = await newTestUser(this.config.homeserverUrl, { name: { contains: "moderator" } });
        const banListId = await mjolnir.client.createRoom({ invite: [await moderator.getUserId()] });
        const banList = new PolicyList(banListId, banListId, mjolnir.client);
        await mjolnir.client.setUserPowerLevel(await moderator.getUserId(), banListId, 100);

        assert.equal(banList.allRules.length, 0);

        // Test adding a new rule
        await createPolicyRule(mjolnir.client, banListId, RULE_USER, '@added:localhost:9999', '');
        let changes: ListRuleChange[] = await banList.updateList();
        assert.equal(changes.length, 1, 'There should only be one change');
        assert.equal(changes[0].changeType, ChangeType.Added);
        assert.equal(changes[0].sender, await mjolnir.client.getUserId());
        assert.equal(banList.userRules.length, 1);
        assert.equal(banList.allRules.length, 1);

        // Test modifiying a rule
        let originalEventId = await createPolicyRule(mjolnir.client, banListId, RULE_USER, '@modified:localhost:9999', '');
        await banList.updateList();
        let modifyingEventId = await createPolicyRule(mjolnir.client, banListId, RULE_USER, '@modified:localhost:9999', 'modified reason');
        changes = await banList.updateList();
        assert.equal(changes.length, 1);
        assert.equal(changes[0].changeType, ChangeType.Modified);
        assert.equal(changes[0].previousState['event_id'], originalEventId, 'There should be a previous state event for a modified rule');
        assert.equal(changes[0].event['event_id'], modifyingEventId);
        let modifyingAgainEventId = await createPolicyRule(mjolnir.client, banListId, RULE_USER, '@modified:localhost:9999', 'modified again');
        changes = await banList.updateList();
        assert.equal(changes.length, 1);
        assert.equal(changes[0].changeType, ChangeType.Modified);
        assert.equal(changes[0].previousState['event_id'], modifyingEventId, 'There should be a previous state event for a modified rule');
        assert.equal(changes[0].event['event_id'], modifyingAgainEventId);
        assert.equal(banList.userRules.length, 2, 'There should be two rules, one for @modified:localhost:9999 and one for @added:localhost:9999');

        // Test redacting a rule
        const redactThis = await createPolicyRule(mjolnir.client, banListId, RULE_USER, '@redacted:localhost:9999', '');
        await banList.updateList();
        assert.equal(banList.userRules.filter(r => r.entity === '@redacted:localhost:9999').length, 1);
        await mjolnir.client.redactEvent(banListId, redactThis);
        changes = await banList.updateList();
        assert.equal(changes.length, 1);
        assert.equal(changes[0].changeType, ChangeType.Removed);
        assert.equal(changes[0].event['event_id'], redactThis, 'Should show the new version of the event with redacted content');
        assert.equal(Object.keys(changes[0].event['content']).length, 0, 'Should show the new version of the event with redacted content');
        assert.notEqual(Object.keys(changes[0].previousState['content']), 0, 'Should have a copy of the unredacted state');
        assert.notEqual(changes[0].rule, undefined, 'The previous rule should be present');
        assert.equal(banList.userRules.filter(r => r.entity === '@redacted:localhost:9999').length, 0, 'The rule should be removed.');

        // Test soft redaction of a rule
        const softRedactedEntity = '@softredacted:localhost:9999'
        await createPolicyRule(mjolnir.client, banListId, RULE_USER, softRedactedEntity, '');
        await banList.updateList();
        assert.equal(banList.userRules.filter(r => r.entity === softRedactedEntity).length, 1);
        await mjolnir.client.sendStateEvent(banListId, RULE_USER, `rule:${softRedactedEntity}`, {});
        changes = await banList.updateList();
        assert.equal(changes.length, 1);
        assert.equal(changes[0].changeType, ChangeType.Removed);
        assert.equal(Object.keys(changes[0].event['content']).length, 0, 'Should show the new version of the event with redacted content');
        assert.notEqual(Object.keys(changes[0].previousState['content']), 0, 'Should have a copy of the unredacted state');
        assert.notEqual(changes[0].rule, undefined, 'The previous rule should be present');
        assert.equal(banList.userRules.filter(r => r.entity === softRedactedEntity).length, 0, 'The rule should have been removed');

        // Now test a double soft redaction just to make sure stuff doesn't explode
        await mjolnir.client.sendStateEvent(banListId, RULE_USER, `rule:${softRedactedEntity}`, {});
        changes = await banList.updateList();
        assert.equal(changes.length, 0, "It shouldn't detect a double soft redaction as a change, it should be seen as adding an invalid rule.");
        assert.equal(banList.userRules.filter(r => r.entity === softRedactedEntity).length, 0, 'The rule should have been removed');

        // Test that different (old) rule types will be modelled as the latest event type.
        originalEventId = await createPolicyRule(mjolnir.client, banListId, 'org.matrix.mjolnir.rule.user', '@old:localhost:9999', '');
        changes = await banList.updateList();
        assert.equal(changes.length, 1);
        assert.equal(changes[0].changeType, ChangeType.Added);
        assert.equal(banList.userRules.filter(r => r.entity === '@old:localhost:9999').length, 1);
        modifyingEventId = await createPolicyRule(mjolnir.client, banListId, 'm.room.rule.user', '@old:localhost:9999', 'modified reason');
        changes = await banList.updateList();
        assert.equal(changes.length, 1);
        assert.equal(changes[0].changeType, ChangeType.Modified);
        assert.equal(changes[0].event['event_id'], modifyingEventId);
        assert.equal(changes[0].previousState['event_id'], originalEventId, 'There should be a previous state event for a modified rule');
        assert.equal(banList.userRules.filter(r => r.entity === '@old:localhost:9999').length, 1);
        modifyingAgainEventId = await createPolicyRule(mjolnir.client, banListId, RULE_USER, '@old:localhost:9999', 'changes again');
        changes = await banList.updateList();
        assert.equal(changes.length, 1);
        assert.equal(changes[0].changeType, ChangeType.Modified);
        assert.equal(changes[0].event['event_id'], modifyingAgainEventId);
        assert.equal(changes[0].previousState['event_id'], modifyingEventId, 'There should be a previous state event for a modified rule');
        assert.equal(banList.userRules.filter(r => r.entity === '@old:localhost:9999').length, 1);
    })
    it("Will remove rules with old types when they are 'soft redacted' with a different but more recent event type.", async function() {
        this.timeout(3000);
        const mjolnir: Mjolnir = this.mjolnir!
        const moderator = await newTestUser(this.config.homeserverUrl, { name: { contains: "moderator" }} );
        const banListId = await mjolnir.client.createRoom({ invite: [await moderator.getUserId()] });
        const banList = new PolicyList(banListId, banListId, mjolnir.client);
        await mjolnir.client.setUserPowerLevel(await moderator.getUserId(), banListId, 100);

        const entity = '@old:localhost:9999';
        let originalEventId = await createPolicyRule(mjolnir.client, banListId, 'm.room.rule.user', entity, '');
        let changes = await banList.updateList();
        assert.equal(changes.length, 1);
        assert.equal(changes[0].changeType, ChangeType.Added);
        assert.equal(banList.userRules.filter(rule => rule.entity === entity).length, 1, 'There should be a rule stored that we just added...')
        let softRedactingEventId = await mjolnir.client.sendStateEvent(banListId, RULE_USER, `rule:${entity}`, {});
        changes = await banList.updateList();
        assert.equal(changes.length, 1);
        assert.equal(changes[0].changeType, ChangeType.Removed);
        assert.equal(changes[0].event['event_id'], softRedactingEventId);
        assert.equal(changes[0].previousState['event_id'], originalEventId, 'There should be a previous state event for a modified rule');
        assert.equal(banList.userRules.filter(rule => rule.entity === entity).length, 0, 'The rule should no longer be stored.');
    })
    it("A rule of the most recent type won't be deleted when an old rule is deleted for the same entity.", async function() {
        const mjolnir: Mjolnir = this.mjolnir!
        const moderator = await newTestUser(this.config.homeserverUrl, { name: { contains: "moderator" } });
        const banListId = await mjolnir.client.createRoom({ invite: [await moderator.getUserId()] });
        const banList = new PolicyList(banListId, banListId, mjolnir.client);
        await mjolnir.client.setUserPowerLevel(await moderator.getUserId(), banListId, 100);

        const entity = '@old:localhost:9999';
        let originalEventId = await createPolicyRule(mjolnir.client, banListId, 'm.room.rule.user', entity, '');
        let changes = await banList.updateList();
        assert.equal(changes.length, 1);
        assert.equal(changes[0].changeType, ChangeType.Added);
        assert.equal(banList.userRules.filter(rule => rule.entity === entity).length, 1, 'There should be a rule stored that we just added...')
        let updatedEventId = await createPolicyRule(mjolnir.client, banListId, RULE_USER, entity, '');
        changes = await banList.updateList();
        // If in the future you change this and it fails, it's really subjective whether this constitutes a modification, since the only thing that has changed
        // is the rule type. The actual content is identical.
        assert.equal(changes.length, 1);
        assert.equal(changes[0].changeType, ChangeType.Modified);
        assert.equal(changes[0].event['event_id'], updatedEventId);
        assert.equal(changes[0].previousState['event_id'], originalEventId, 'There should be a previous state event for a modified rule');
        assert.equal(banList.userRules.filter(rule => rule.entity === entity).length, 1, 'Only the latest version of the rule gets returned.');

        // Now we delete the old version of the rule without consequence.
        await mjolnir.client.sendStateEvent(banListId, 'm.room.rule.user', `rule:${entity}`, {});
        changes = await banList.updateList();
        assert.equal(changes.length, 0);
        assert.equal(banList.userRules.filter(rule => rule.entity === entity).length, 1, 'The rule should still be active.');

        // And we can still delete the new version of the rule.
        let softRedactingEventId = await mjolnir.client.sendStateEvent(banListId, RULE_USER, `rule:${entity}`, {});
        changes = await banList.updateList();
        assert.equal(changes.length, 1);
        assert.equal(changes[0].changeType, ChangeType.Removed);
        assert.equal(changes[0].event['event_id'], softRedactingEventId);
        assert.equal(changes[0].previousState['event_id'], updatedEventId, 'There should be a previous state event for a modified rule');
        assert.equal(banList.userRules.filter(rule => rule.entity === entity).length, 0, 'The rule should no longer be stored.');
    })
    it('Test: PolicyList Supports all entity types.', async function () {
        const mjolnir: Mjolnir = this.mjolnir!
        const banListId = await mjolnir.client.createRoom();
        const banList = new PolicyList(banListId, banListId, mjolnir.client);
        for (let i = 0; i < ALL_RULE_TYPES.length; i++) {
            await createPolicyRule(mjolnir.client, banListId, ALL_RULE_TYPES[i], `*${i}*`, '');
        }
        let changes: ListRuleChange[] = await banList.updateList();
        assert.equal(changes.length, ALL_RULE_TYPES.length);
        assert.equal(banList.allRules.length, ALL_RULE_TYPES.length);
    })
});

describe('Test: We will not be able to ban ourselves via ACL.', function() {
    it('We do not ban ourselves when we put ourselves into the policy list.', async function() {
        const mjolnir: Mjolnir = this.mjolnir
        const serverName = new UserID(await mjolnir.client.getUserId()).domain;
        const banListId = await mjolnir.client.createRoom();
        const banList = new PolicyList(banListId, banListId, mjolnir.client);
        const aclUnit = new AccessControlUnit([banList]);
        await createPolicyRule(mjolnir.client, banListId, RULE_SERVER, serverName, '');
        await createPolicyRule(mjolnir.client, banListId, RULE_SERVER, 'evil.com', '');
        await createPolicyRule(mjolnir.client, banListId, RULE_SERVER, '*', '');
        // We should still intern the matching rules rule.
        let changes: ListRuleChange[] = await banList.updateList();
        assert.equal(banList.serverRules.length, 3);
        // But when we construct an ACL, we should be safe.
        const acl = new ServerAcl(serverName)
        changes.forEach(change => acl.denyServer(change.rule.entity));
        assert.equal(acl.safeAclContent().deny.length, 1);
        assert.equal(acl.literalAclContent().deny.length, 3);

        const aclUnitAcl = aclUnit.compileServerAcl(serverName);
        assert.equal(aclUnitAcl.literalAclContent().deny.length, 1);

    })
})


describe('Test: ACL updates will batch when rules are added in succession.', function() {
    it('Will batch ACL updates if we spam rules into a PolicyList', async function() {
        const mjolnir: Mjolnir = this.mjolnir!
        const serverName: string = new UserID(await mjolnir.client.getUserId()).domain
        const moderator = await newTestUser(this.config.homeserverUrl, { name: { contains: "moderator" } });
        await moderator.joinRoom(mjolnir.managementRoomId);
        const mjolnirId = await mjolnir.client.getUserId();

        // Setup some protected rooms so we can check their ACL state later.
        const protectedRooms: string[] = [];
        for (let i = 0; i < 5; i++) {
            const room = await moderator.createRoom({ invite: [mjolnirId] });
            await mjolnir.client.joinRoom(room);
            await moderator.setUserPowerLevel(mjolnirId, room, 100);
            await mjolnir.addProtectedRoom(room);
            protectedRooms.push(room);
        }

        // If a previous test hasn't cleaned up properly, these rooms will be populated by bogus ACLs at this point.
        await mjolnir.protectedRoomsTracker.syncLists(mjolnir.config.verboseLogging);
        await Promise.all(protectedRooms.map(async room => {
            // We're going to need timeline pagination I'm afraid.
            const roomAcl = await mjolnir.client.getRoomStateEvent(room, "m.room.server_acl", "");
            assert.equal(roomAcl?.deny?.length ?? 0, 0, 'There should be no entries in the deny ACL.');
        }));

        // Flood the watched list with banned servers, which should prompt Mjolnir to update server ACL in protected rooms.
        const banListId = await moderator.createRoom({ invite: [mjolnirId] });
        await mjolnir.client.joinRoom(banListId);
        await mjolnir.watchList(Permalinks.forRoom(banListId));
        const acl = new ServerAcl(serverName).denyIpAddresses().allowServer("*");
        const evilServerCount = 200;
        for (let i = 0; i < evilServerCount; i++) {
            const badServer = `${i}.evil.com`;
            acl.denyServer(badServer);
            await createPolicyRule(moderator, banListId, RULE_SERVER, badServer, `Rule #${i}`);
            // Give them a bit of a spread over time.
            await new Promise(resolve => setTimeout(resolve, 5));
        }
        // We do this because it should force us to wait until all the ACL events have been applied.
        // Even if that does mean the last few events will not go through batching...
        await mjolnir.protectedRoomsTracker.syncLists(mjolnir.config.verboseLogging);

        // At this point we check that the state within Mjolnir is internally consistent, this is just because debugging the following
        // is a pita.
        const list: PolicyList = this.mjolnir.policyLists[0]!;
        assert.equal(list.serverRules.length, evilServerCount, `There should be ${evilServerCount} rules in here`);

        // Check each of the protected rooms for ACL events and make sure they were batched and are correct.
        await Promise.all(protectedRooms.map(async room => {
            const roomAcl = await mjolnir.client.getRoomStateEvent(room, "m.room.server_acl", "");
            if (!acl.matches(roomAcl)) {
                assert.fail(`Room ${room} doesn't have the correct ACL: ${JSON.stringify(roomAcl, null, 2)}`)
            }
            let aclEventCount = 0;
            await getMessagesByUserIn(mjolnir.client, mjolnirId, room, 100, events => {
                events.forEach(event => event.type === 'm.room.server_acl' ? aclEventCount += 1 : null);
            });
            LogService.debug('PolicyListTest', `aclEventCount: ${aclEventCount}`);
            // If there's less than two then it means the ACL was updated by this test calling `this.mjolnir!.syncLists()`
            // and not the listener that detects changes to ban lists (that we want to test!).
            // It used to be 10, but it was too low, 30 seems better for CI.
            assert.equal(aclEventCount < 30 && aclEventCount > 2, true, 'We should have sent less than 30 ACL events to each room because they should be batched')
        }));
    })
})

describe('Test: unbaning entities via the PolicyList.', function() {
    afterEach(function() { this.moderator?.stop(); });
    it('Will remove rules that have legacy types', async function() {
        const mjolnir: Mjolnir = this.mjolnir!
        const serverName: string = new UserID(await mjolnir.client.getUserId()).domain
        const moderator: MatrixClient = await newTestUser(this.config.homeserverUrl, { name: { contains: "moderator" } });
        this.moderator = moderator;
        await moderator.joinRoom(mjolnir.managementRoomId);
        const mjolnirId = await mjolnir.client.getUserId();

        // We'll make 1 protected room to test ACLs in.
        const protectedRoom = await moderator.createRoom({ invite: [mjolnirId] });
        await mjolnir.client.joinRoom(protectedRoom);
        await moderator.setUserPowerLevel(mjolnirId, protectedRoom, 100);
        await mjolnir.addProtectedRoom(protectedRoom);

        // If a previous test hasn't cleaned up properly, these rooms will be populated by bogus ACLs at this point.
        await mjolnir.protectedRoomsTracker.syncLists(mjolnir.config.verboseLogging);
        // If this is not present, then it means the room isn't being protected, which is really bad.
        const roomAcl = await mjolnir.client.getRoomStateEvent(protectedRoom, "m.room.server_acl", "");
        assert.equal(roomAcl?.deny?.length ?? 0, 0, 'There should be no entries in the deny ACL.');

        // Create some legacy rules on a PolicyList.
        const banListId = await moderator.createRoom({ invite: [mjolnirId] });
        await moderator.setUserPowerLevel(await mjolnir.client.getUserId(), banListId, 100);
        await moderator.sendStateEvent(banListId, 'org.matrix.mjolnir.shortcode', '', { shortcode: "unban-test" });
        await mjolnir.client.joinRoom(banListId);
        await mjolnir.watchList(Permalinks.forRoom(banListId));
        // we use this to compare changes.
        const banList = new PolicyList(banListId, banListId, moderator);
        // we need two because we need to test the case where an entity has all rule types in the list
        // and another one that only has one (so that we would hit 404 while looking up state)
        const olderBadServer = "old.evil.example"
        const newerBadServer = "new.evil.example"
        await Promise.all(SERVER_RULE_TYPES.map(type => createPolicyRule(moderator, banListId, type, olderBadServer, 'gregg rulz ok')));
        await createPolicyRule(moderator, banListId, RULE_SERVER, newerBadServer, 'this is bad sort it out.');
        await createPolicyRule(moderator, banListId, RULE_SERVER, newerBadServer, 'hidden with a non-standard state key', undefined, "rule_1");
        // Wait for the ACL event to be applied to our protected room.
        await mjolnir.protectedRoomsTracker.syncLists();

        await banList.updateList();
        // rules are normalized by rule type, that's why there should only be 3.
        assert.equal(banList.allRules.length, 3);

        // Check that we have setup our test properly and therefore evil.example is banned.
        const acl = new ServerAcl(serverName).denyIpAddresses().allowServer("*").denyServer(olderBadServer).denyServer(newerBadServer);
        const protectedAcl = await mjolnir.client.getRoomStateEvent(protectedRoom, "m.room.server_acl", "");
        if (!acl.matches(protectedAcl)) {
            assert.fail(`Room ${protectedRoom} doesn't have the correct ACL: ${JSON.stringify(roomAcl, null, 2)}`);
        }

        // Now unban the servers, we will go via the unban command for completeness sake.
        try {
            await moderator.start();
            for (const server of [olderBadServer, newerBadServer]) {
                await getFirstReaction(moderator, mjolnir.managementRoomId, '✅', async () => {
                    return await moderator.sendMessage(mjolnir.managementRoomId, { msgtype: 'm.text', body: `!mjolnir unban unban-test server ${server}` });
                });
            }
        } finally {
            moderator.stop();
        }

        // Wait for mjolnir to sync protected rooms to update ACL.
        await mjolnir.protectedRoomsTracker.syncLists(mjolnir.config.verboseLogging);
        // Confirm that the server is unbanned.
        await banList.updateList();
        assert.equal(banList.allRules.length, 0);
        const aclAfter = await mjolnir.client.getRoomStateEvent(protectedRoom, "m.room.server_acl", "");
        assert.equal(aclAfter.deny.length, 0, 'Should be no servers denied anymore');
    })
})

describe('Test: should apply bans to the most recently active rooms first', function() {
    it('Applies bans to the most recently active rooms first', async function() {
        this.timeout(180000)
        const mjolnir: Mjolnir = this.mjolnir!
        const serverName: string = new UserID(await mjolnir.client.getUserId()).domain
        const moderator = await newTestUser(this.config.homeserverUrl, { name: { contains: "moderator" } });
        await moderator.joinRoom(mjolnir.managementRoomId);
        const mjolnirId = await mjolnir.client.getUserId();

        // Setup some protected rooms so we can check their ACL state later.
        const protectedRooms: string[] = [];
        for (let i = 0; i < 10; i++) {
            const room = await moderator.createRoom({ invite: [mjolnirId] });
            await mjolnir.client.joinRoom(room);
            await moderator.setUserPowerLevel(mjolnirId, room, 100);
            await mjolnir.addProtectedRoom(room);
            protectedRooms.push(room);
        }

        // If a previous test hasn't cleaned up properly, these rooms will be populated by bogus ACLs at this point.
        await mjolnir.protectedRoomsTracker.syncLists(mjolnir.config.verboseLogging);
        await Promise.all(protectedRooms.map(async room => {
            const roomAcl = await mjolnir.client.getRoomStateEvent(room, "m.room.server_acl", "").catch(e => e.statusCode === 404 ? { deny: [] } : Promise.reject(e));
            assert.equal(roomAcl?.deny?.length ?? 0, 0, 'There should be no entries in the deny ACL.');
        }));

        // Flood the watched list with banned servers, which should prompt Mjolnir to update server ACL in protected rooms.
        const banListId = await moderator.createRoom({ invite: [mjolnirId] });
        await mjolnir.client.joinRoom(banListId);
        await mjolnir.watchList(Permalinks.forRoom(banListId));

        await mjolnir.protectedRoomsTracker.syncLists(mjolnir.config.verboseLogging);

        // shuffle protected rooms https://stackoverflow.com/a/12646864, we do this so we can create activity "randomly" in them.
        for (let i = protectedRooms.length - 1; i > 0; i--) {
            const j = Math.floor(Math.random() * (i + 1));
            [protectedRooms[i], protectedRooms[j]] = [protectedRooms[j], protectedRooms[i]];
        }
        // create some activity in the same order.
        for (const roomId of protectedRooms.slice().reverse()) {
            await moderator.sendMessage(roomId, { body: `activity`, msgtype: 'm.text' });
            await new Promise(resolve => setTimeout(resolve, 100));
        }

        // check the rooms are in the expected order
        for (let i = 0; i < protectedRooms.length; i++) {
            assert.equal(mjolnir.protectedRoomsTracker.protectedRoomsByActivity()[i], protectedRooms[i]);
        }

        // just ban one server
        const badServer = `evil.com`;
        const acl = new ServerAcl(serverName).denyIpAddresses().allowServer("*").denyServer(badServer);
        // collect all the rooms that received an ACL event.
        const aclRooms: any[] = await new Promise(async resolve => {
            const rooms: any[] = [];
            this.mjolnir.client.on('room.event', (room: string, event: any) => {
                if (protectedRooms.includes(room)) {
                    rooms.push(room);
                }
                if (rooms.length === protectedRooms.length) {
                    resolve(rooms)
                }
            });
            // create the rule that will ban the server.
            await createPolicyRule(moderator, banListId, RULE_SERVER, badServer, `Rule ${badServer}`);
        })

        // Wait until all the ACL events have been applied.
        await mjolnir.protectedRoomsTracker.syncLists(mjolnir.config.verboseLogging);

        for (let i = 0; i < protectedRooms.length; i++) {
            assert.equal(aclRooms[i], protectedRooms[i], "The ACL should have been applied to the active rooms first.");
        }

        // Check that the most recently active rooms got the ACL update first.
        let last_event_ts = 0;
        for (const roomId of protectedRooms) {
            let roomAclEvent: null | any;
            // Can't be the best way to get the whole event, but ok.
            await getMessagesByUserIn(mjolnir.client, mjolnirId, roomId, 1, events => roomAclEvent = events[0]);
            const roomAcl = roomAclEvent!.content;
            if (!acl.matches(roomAcl)) {
                assert.fail(`Room ${roomId} doesn't have the correct ACL: ${JSON.stringify(roomAcl, null, 2)}`)
            }
            assert.equal(roomAclEvent.origin_server_ts > last_event_ts, true, `This room was more recently active so should have the more recent timestamp`);
            last_event_ts = roomAclEvent.origin_server_ts;
        }
    })
})

/**
 * Assert that the AccessUnitOutcome entity test has the right access.
 * @param expected The Access we expect the entity to have, See Access.
 * @param query The result of a test on AccessControlUnit e.g. `unit.getAccessForUser'@meow:localhost')`
 * @param message A message for the console if the entity doesn't have the expected access.
 */
function assertAccess(expected: Access, query: EntityAccess, message?: string) {
    assert.equal(query.outcome, expected, message);
}

describe('Test: AccessControlUnit interaction with policy lists.', function() {
    it('The AccessControlUnit correctly reflects the policies that have been set in its watched lists.', async function() {
        const mjolnir: Mjolnir = this.mjolnir!
        const policyListId = await mjolnir.client.createRoom();
        const policyList = new PolicyList(policyListId, Permalinks.forRoom(policyListId), mjolnir.client);
        const aclUnit = new AccessControlUnit([policyList]);
        assertAccess(Access.Allowed, aclUnit.getAccessForUser('@anyone:anywhere.example.com', "CHECK_SERVER"), 'Empty lists should implicitly allow.');

        await createPolicyRule(mjolnir.client, policyListId, RULE_SERVER, 'matrix.org', '', { recommendation: Recommendation.Allow });
        // we want to imagine that the banned server was never taken off the allow after being banned.
        await createPolicyRule(mjolnir.client, policyListId, RULE_SERVER, 'bad.example.com', '', { recommendation: Recommendation.Allow }, 'something-else');
        await createPolicyRule(mjolnir.client, policyListId, RULE_SERVER, 'bad.example.com', '', { recommendation: Recommendation.Ban });
        await createPolicyRule(mjolnir.client, policyListId, RULE_SERVER, '*.ddns.example.com', '', { recommendation: Recommendation.Ban });

        await policyList.updateList();

        assertAccess(Access.Allowed, aclUnit.getAccessForServer('matrix.org'));
        assertAccess(Access.Allowed, aclUnit.getAccessForUser('@someone:matrix.org', "CHECK_SERVER"));
        assertAccess(Access.NotAllowed, aclUnit.getAccessForServer('anywhere.else.example.com'));
        assertAccess(Access.NotAllowed, aclUnit.getAccessForUser('@anyone:anywhere.else.example.com', "CHECK_SERVER"));
        assertAccess(Access.Banned, aclUnit.getAccessForServer('bad.example.com'));
        assertAccess(Access.Banned, aclUnit.getAccessForUser('@anyone:bad.example.com', "CHECK_SERVER"));
        // They're not allowed in the first place, never mind that they are also banned.
        assertAccess(Access.NotAllowed, aclUnit.getAccessForServer('meow.ddns.example.com'));
        assertAccess(Access.NotAllowed, aclUnit.getAccessForUser('@anyone:meow.ddns.example.com', "CHECK_SERVER"));

        assertAccess(Access.Allowed, aclUnit.getAccessForUser('@spam:matrix.org', "CHECK_SERVER"));
        await createPolicyRule(mjolnir.client, policyListId, RULE_USER, '@spam:matrix.org', '', { recommendation: Recommendation.Ban });
        await policyList.updateList();
        assertAccess(Access.Banned, aclUnit.getAccessForUser('@spam:matrix.org', "CHECK_SERVER"));
        assertAccess(Access.Allowed, aclUnit.getAccessForUser('@someone:matrix.org', "CHECK_SERVER"));

        // protect a room and check that only bad.example.com, *.ddns.example.com are in the deny ACL and not matrix.org
        await mjolnir.watchList(policyList.roomRef);
        const protectedRoom = await mjolnir.client.createRoom();
        await mjolnir.protectedRoomsTracker.addProtectedRoom(protectedRoom);
        await mjolnir.protectedRoomsTracker.syncLists();
        const roomAcl = await mjolnir.client.getRoomStateEvent(protectedRoom, "m.room.server_acl", "");
        assert.equal(roomAcl?.deny?.length ?? 0, 2, 'There should be two entries in the deny ACL.');
        for (const serverGlob of ["*.ddns.example.com", "bad.example.com"]) {
            assert.equal((roomAcl?.deny ?? []).includes(serverGlob), true);
        }
        assert.equal(roomAcl.deny.includes("matrix.org"), false);
        assert.equal(roomAcl.allow.includes("matrix.org"), true);

        // Now we remove the rules and hope that everything functions noramally.
        await removePolicyRule(mjolnir.client, policyListId, RULE_SERVER, 'matrix.org');
        await removePolicyRule(mjolnir.client, policyListId, RULE_SERVER, 'bad.example.com', 'something-else');
        await removePolicyRule(mjolnir.client, policyListId, RULE_SERVER, 'bad.example.com');
        await removePolicyRule(mjolnir.client, policyListId, RULE_SERVER, '*.ddns.example.com');
        await removePolicyRule(mjolnir.client, policyListId, RULE_USER, "@spam:matrix.org");
        const changes = await policyList.updateList()
        await mjolnir.protectedRoomsTracker.syncLists();

        assert.equal(changes.length, 5, "The rules should have correctly been removed");
        assertAccess(Access.Allowed, aclUnit.getAccessForServer('matrix.org'));
        assertAccess(Access.Allowed, aclUnit.getAccessForUser('@someone:matrix.org', "CHECK_SERVER"));
        assertAccess(Access.Allowed, aclUnit.getAccessForServer('anywhere.else.example.com'));
        assertAccess(Access.Allowed, aclUnit.getAccessForUser('@anyone:anywhere.else.example.com', "CHECK_SERVER"));
        assertAccess(Access.Allowed, aclUnit.getAccessForServer('bad.example.com'));
        assertAccess(Access.Allowed, aclUnit.getAccessForUser('@anyone:bad.example.com', "CHECK_SERVER"));
        assertAccess(Access.Allowed, aclUnit.getAccessForServer('meow.ddns.example.com'));
        assertAccess(Access.Allowed, aclUnit.getAccessForUser('@anyone:meow.ddns.example.com', "CHECK_SERVER"));
        assertAccess(Access.Allowed, aclUnit.getAccessForUser('@spam:matrix.org', "CHECK_SERVER"));

        const roomAclAfter = await mjolnir.client.getRoomStateEvent(protectedRoom, "m.room.server_acl", "");
        assert.equal(roomAclAfter.deny?.length ?? 0, 0, 'There should be no entries in the deny ACL.');
        assert.equal(roomAclAfter.allow?.length ?? 0, 1, 'There should be 1 entry in the allow ACL.');
        assert.equal(roomAclAfter.allow.includes("*"), true);
    })
    it('removing a rule from a different list will not clobber anything.', async function() {
        const mjolnir: Mjolnir = this.mjolnir!
        const policyLists = await Promise.all([...Array(2).keys()].map(async _ => {
            const policyListId = await mjolnir.client.createRoom();
            return new PolicyList(policyListId, Permalinks.forRoom(policyListId), mjolnir.client);
        }));
        const banMeServer = 'banme.example.com';
        const aclUnit = new AccessControlUnit(policyLists);
        await Promise.all(policyLists.map(policyList => {
            return createPolicyRule(mjolnir.client, policyList.roomId, RULE_SERVER, banMeServer, '', { recommendation: Recommendation.Ban })
        }));
        await Promise.all(policyLists.map(list => list.updateList()));
        assertAccess(Access.Banned, aclUnit.getAccessForServer(banMeServer));

        // remove the rule that bans `banme.example.com` from just one of the lists.
        await removePolicyRule(mjolnir.client, policyLists[0].roomId, RULE_SERVER, banMeServer);
        await Promise.all(policyLists.map(list => list.updateList()));
        assertAccess(Access.Banned, aclUnit.getAccessForServer(banMeServer), "Should still be banned at this point.");
        await removePolicyRule(mjolnir.client, policyLists[1].roomId, RULE_SERVER, banMeServer);
        await Promise.all(policyLists.map(list => list.updateList()));
        assertAccess(Access.Allowed, aclUnit.getAccessForServer(banMeServer), "Should not longer be any rules");
    })
})

describe('Test: Creating policy lists.', function() {
    it('Will automatically invite and op users from invites', async function() {
        const mjolnir: Mjolnir = this.mjolnir;
        const testUsers = await Promise.all([...Array(2)].map(_ => newTestUser(this.config.homeserverUrl, { name: { contains: "moderator" } })))
        const invite = await Promise.all(testUsers.map(client => client.getUserId()));
        const policyListId = await PolicyList.createList(
            mjolnir.client,
            randomUUID(),
            invite
        );
        // Check power levels are right.
        const powerLevelEvent = await mjolnir.client.getRoomStateEvent(policyListId, "m.room.power_levels", "");
        assert.equal(Object.keys(powerLevelEvent.users ?? {}).length, invite.length + 1);
        // Check create event for MSC3784 support.
        const createEvent = await mjolnir.client.getRoomStateEvent(policyListId, "m.room.create", "");
        assert.equal(createEvent.type, PolicyList.ROOM_TYPE);
        // We can't create rooms without forgetting the type.
        await assert.rejects(
            async () => {
                await PolicyList.createList(mjolnir.client, randomUUID(), [], {
                    creation_content: {}
                })
            },
            TypeError
        );
    })
})