split up scenarios in multiple files as lazy-loading scenarios grow

src/scenarios/lazy-loading.js

@@ -0,0 +1,62 @@
+/*
+Copyright 2018 New Vector Ltd
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+        http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+
+const {delay} = require('../util');
+const join = require('../usecases/join');
+const sendMessage = require('../usecases/send-message');
+const {
+    checkTimelineContains,
+    scrollToTimelineTop
+} = require('../usecases/timeline');
+const createRoom = require('../usecases/create-room');
+const changeRoomSettings = require('../usecases/room-settings');
+const {enableLazyLoading} = require('../usecases/settings');
+
+module.exports = async function lazyLoadingScenarios(alice, bob, charlies) {
+    console.log(" creating a room for lazy loading member scenarios:");
+    await enableLazyLoading(alice);
+    const room = "Lazy Loading Test";
+    const alias = "#lltest:localhost";
+    const charlyMsg1 = "hi bob!";
+    const charlyMsg2 = "how's it going??";
+    await createRoom(bob, room);
+    await changeRoomSettings(bob, {directory: true, visibility: "public_no_guests", alias});
+    // wait for alias to be set by server after clicking "save"
+    // so the charlies can join it.
+    await bob.delay(500);
+    const charlyMembers = await charlies.join(alias);
+    await charlyMembers.talk(charlyMsg1);
+    await charlyMembers.talk(charlyMsg2);
+    bob.log.step("sends 20 messages").mute();
+    for(let i = 20; i >= 1; --i) {
+        await sendMessage(bob, `I will only say this ${i} time(s)!`);
+    }
+    bob.log.unmute().done();
+    await join(alice, alias);
+    await scrollToTimelineTop(alice);
+    //alice should see 2 messages from every charly with
+    //the correct display name
+    const expectedMessages = [charlyMsg1, charlyMsg2].reduce((messages, msgText) => {
+        return charlies.sessions.reduce((messages, charly) => {
+            return messages.concat({
+                sender: charly.displayName(),
+                body: msgText,
+            });
+        }, messages);
+    }, []);
+    await checkTimelineContains(alice, expectedMessages, "Charly #1-10");
+}