Examine all m.direct rooms to find a DM as fallback (#10127)

test/utils/DMRoomMap-test.ts

@@ -0,0 +1,54 @@
+/*
+Copyright 2023 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 { mocked, Mocked } from "jest-mock";
+import { EventType, IContent, MatrixClient } from "matrix-js-sdk/src/matrix";
+
+import DMRoomMap from "../../src/utils/DMRoomMap";
+import { mkEvent, stubClient } from "../test-utils";
+
+describe("DMRoomMap", () => {
+    const roomId1 = "!room1:example.com";
+    const roomId2 = "!room2:example.com";
+    const roomId3 = "!room3:example.com";
+    const roomId4 = "!room4:example.com";
+
+    const mDirectContent = {
+        "user@example.com": [roomId1, roomId2],
+        "@user:example.com": [roomId1, roomId3, roomId4],
+        "@user2:example.com": [] as string[],
+    } satisfies IContent;
+
+    let client: Mocked<MatrixClient>;
+    let dmRoomMap: DMRoomMap;
+
+    beforeEach(() => {
+        client = mocked(stubClient());
+
+        const mDirectEvent = mkEvent({
+            event: true,
+            type: EventType.Direct,
+            user: client.getSafeUserId(),
+            content: mDirectContent,
+        });
+        client.getAccountData.mockReturnValue(mDirectEvent);
+        dmRoomMap = new DMRoomMap(client);
+    });
+
+    it("getRoomIds should return the room Ids", () => {
+        expect(dmRoomMap.getRoomIds()).toEqual(new Set([roomId1, roomId2, roomId3, roomId4]));
+    });
+});