Start verification sessions in an E2E DM where possible

Fixes https://github.com/vector-im/riot-web/issues/12187

test/createRoom-test.js

@@ -0,0 +1,41 @@
+import {_waitForMember} from '../src/createRoom';
+import {EventEmitter} from 'events';
+
+/* Shorter timeout, we've got tests to run */
+const timeout = 30;
+
+describe("waitForMember", () => {
+    let client;
+
+    beforeEach(() => {
+        client = new EventEmitter();
+    });
+
+    it("resolves with false if the timeout is reached", (done) => {
+        _waitForMember(client, "", "", { timeout: 0 }).then((r) => {
+            expect(r).toBe(false);
+            done();
+        });
+    });
+
+    it("resolves with false if the timeout is reached, even if other RoomState.newMember events fire", (done) => {
+        const roomId = "!roomId:domain";
+        const userId = "@clientId:domain";
+        _waitForMember(client, roomId, userId, { timeout }).then((r) => {
+            expect(r).toBe(false);
+            done();
+        });
+        client.emit("RoomState.newMember", undefined, undefined, { roomId, userId: "@anotherClient:domain" });
+    })
+
+    it("resolves with true if RoomState.newMember fires", (done) => {
+        const roomId = "!roomId:domain";
+        const userId = "@clientId:domain";
+        _waitForMember(client, roomId, userId, { timeout }).then((r) => {
+            expect(r).toBe(true);
+            expect(client.listeners("RoomState.newMember").length).toBe(0);
+            done();
+        });
+        client.emit("RoomState.newMember", undefined, undefined, { roomId, userId });
+    })
+});