Exclude functional members from DM detection (#9124)

* Exclude functional members from DM detection

* Fix getRoomFunctionalMembers test

* Simplify getFunctionalMembers

* Remove unnecessary filter

test/utils/room/getRoomFunctionalMembers-test.ts

@@ -0,0 +1,53 @@
+/*
+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 { Room, UNSTABLE_ELEMENT_FUNCTIONAL_USERS } from "matrix-js-sdk/src/matrix";
+
+import { getFunctionalMembers } from "../../../src/utils/room/getFunctionalMembers";
+import { createTestClient, mkEvent } from "../../test-utils";
+
+describe("getRoomFunctionalMembers", () => {
+    const client = createTestClient();
+    const room = new Room("!room:example.com", client, client.getUserId());
+
+    it("should return an empty array if no functional members state event exists", () => {
+        expect(getFunctionalMembers(room)).toHaveLength(0);
+    });
+
+    it("should return an empty array if functional members state event does not have a service_members field", () => {
+        room.currentState.setStateEvents([mkEvent({
+            event: true,
+            type: UNSTABLE_ELEMENT_FUNCTIONAL_USERS.name,
+            user: "@user:example.com)",
+            room: room.roomId,
+            skey: "",
+            content: {},
+        })]);
+        expect(getFunctionalMembers(room)).toHaveLength(0);
+    });
+
+    it("should return service_members field of the functional users state event", () => {
+        room.currentState.setStateEvents([mkEvent({
+            event: true,
+            type: UNSTABLE_ELEMENT_FUNCTIONAL_USERS.name,
+            user: "@user:example.com)",
+            room: room.roomId,
+            skey: "",
+            content: { service_members: ["@user:example.com"] },
+        })]);
+        expect(getFunctionalMembers(room)).toEqual(["@user:example.com"]);
+    });
+});