Add a test for URL previews being disabled in e2e rooms (#8270)

* Add a test for URL previews being disabled in e2e rooms

Regression test for https://github.com/matrix-org/matrix-react-sdk/pull/8227

* Fix the types

test/components/structures/RoomView-test.tsx

@@ -0,0 +1,115 @@
+/*
+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.
+*/
+
+import React from "react";
+import TestRenderer from "react-test-renderer";
+import { Room, RoomEvent } from "matrix-js-sdk/src/models/room";
+import { MatrixEvent } from "matrix-js-sdk/src/models/event";
+
+import { MatrixClientPeg } from "../../../src/MatrixClientPeg";
+import { stubClient } from "../../test-utils";
+import { Action } from "../../../src/dispatcher/actions";
+import dis from "../../../src/dispatcher/dispatcher";
+import { ViewRoomPayload } from "../../../src/dispatcher/payloads/ViewRoomPayload";
+import MatrixClientContext from "../../../src/contexts/MatrixClientContext";
+import { RoomView } from "../../../src/components/structures/RoomView";
+import ResizeNotifier from "../../../src/utils/ResizeNotifier";
+import { RoomViewStore } from "../../../src/stores/RoomViewStore";
+import DMRoomMap from "../../../src/utils/DMRoomMap";
+
+describe("RoomView", () => {
+    it("updates url preview visibility on encryption state change", async () => {
+        stubClient();
+        const cli = MatrixClientPeg.get();
+        cli.hasLazyLoadMembersEnabled = () => false;
+        cli.isInitialSyncComplete = () => true;
+        cli.stopPeeking = () => undefined;
+
+        const r1 = new Room("r1", cli, "@name:example.com");
+        cli.getRoom = () => r1;
+        r1.getPendingEvents = () => [];
+
+        DMRoomMap.makeShared();
+
+        const switchRoomPromise = new Promise<void>(resolve => {
+            const subscription = RoomViewStore.instance.addListener(() => {
+                if (RoomViewStore.instance.getRoomId()) {
+                    subscription.remove();
+                    resolve();
+                }
+            });
+        });
+
+        dis.dispatch<ViewRoomPayload>({
+            action: Action.ViewRoom,
+            room_id: r1.roomId,
+            metricsTrigger: null,
+        });
+
+        await switchRoomPromise;
+
+        const renderer = TestRenderer.create(<MatrixClientContext.Provider value={cli}>
+            <RoomView mxClient={cli}
+                threepidInvite={null}
+                oobData={null}
+                resizeNotifier={new ResizeNotifier()}
+                justCreatedOpts={null}
+                forceTimeline={false}
+                onRegistered={null}
+            />
+        </MatrixClientContext.Provider>);
+
+        const roomViewInstance = renderer.root.findByType(RoomView).instance;
+
+        // in a default (non-encrypted room, it should start out with url previews enabled)
+        // This is a white-box test in that we're asserting things about the state, which
+        // is not ideal, but asserting that a URL preview just isn't there could risk the
+        // test being invalid because the previews just hasn't rendered yet. This feels
+        // like the safest way I think?
+        // This also relies on the default settings being URL previews on normally and
+        // off for e2e rooms because 1) it's probably useful to assert this and
+        // 2) SettingsStore is a static class and so very hard to mock out.
+        expect(roomViewInstance.state.showUrlPreview).toBe(true);
+
+        // now enable encryption (by mocking out the tests for whether a room is encrypted)
+        cli.isCryptoEnabled = () => true;
+        cli.isRoomEncrypted = () => true;
+
+        // and fake an encryption event into the room to prompt it to re-check
+        // wait until the event has been added
+        const eventAddedPromise = new Promise<void>(resolve => {
+            r1.once(RoomEvent.Timeline, (...args) => {
+                // we're also using mock client that doesn't re-emit, so
+                // we emit the event to client manually
+                cli.emit(RoomEvent.Timeline, ...args);
+                resolve();
+            });
+        });
+
+        r1.addLiveEvents([new MatrixEvent({
+            type: "m.room.encryption",
+            sender: cli.getUserId(),
+            content: {},
+            event_id: "someid",
+            room_id: r1.roomId,
+        })]);
+
+        await eventAddedPromise;
+
+        // URL previews should now be disabled
+        expect(roomViewInstance.state.showUrlPreview).toBe(false);
+    });
+});