Move Lazy Loading tests from Puppeteer to Cypress (#8982)

* Remove Puppeteer Lazy Loading tests

* Remove Puppeteer Lazy Loading tests

* Remove Puppeteer Lazy Loading tests

* Stash lazy loading cypress tests

* Stash lazy loading cypress tests

* Update cypress-real-events

* Stash offline-less test

* Add offline/online'ing

cypress/support/timeline.ts

@@ -0,0 +1,68 @@
+/*
+Copyright 2022 The Matrix.org Foundation C.I.C.
+
+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.
+*/
+
+/// <reference types="cypress" />
+
+import Chainable = Cypress.Chainable;
+
+declare global {
+    // eslint-disable-next-line @typescript-eslint/no-namespace
+    namespace Cypress {
+        interface Chainable {
+            // Scroll to the top of the timeline
+            scrollToTop(): void;
+            // Find the event tile matching the given sender & body
+            findEventTile(sender: string, body: string): Chainable<JQuery>;
+        }
+    }
+}
+
+export interface Message {
+    sender: string;
+    body: string;
+    encrypted: boolean;
+    continuation: boolean;
+}
+
+Cypress.Commands.add("scrollToTop", (): void => {
+    cy.get(".mx_RoomView_timeline .mx_ScrollPanel").scrollTo("top", { duration: 100 }).then(ref => {
+        if (ref.scrollTop() > 0) {
+            return cy.scrollToTop();
+        }
+    });
+});
+
+Cypress.Commands.add("findEventTile", (sender: string, body: string): Chainable<JQuery> => {
+    // We can't just use a bunch of `.contains` here due to continuations meaning that the events don't
+    // have their own rendered sender displayname so we have to walk the list to keep track of the sender.
+    return cy.get(".mx_RoomView_MessageList .mx_EventTile").then(refs => {
+        let latestSender: string;
+        for (let i = 0; i < refs.length; i++) {
+            const ref = refs.eq(i);
+            const displayName = ref.find(".mx_DisambiguatedProfile_displayName");
+            if (displayName) {
+                latestSender = displayName.text();
+            }
+
+            if (latestSender === sender && ref.find(".mx_EventTile_body").text() === body) {
+                return ref;
+            }
+        }
+    });
+});
+
+// Needed to make this file a module
+export { };