diff --git a/src/matrix/e2ee/DeviceTracker.js b/src/matrix/e2ee/DeviceTracker.js
index 0068a1f9..c640b04a 100644
--- a/src/matrix/e2ee/DeviceTracker.js
+++ b/src/matrix/e2ee/DeviceTracker.js
@@ -363,3 +363,125 @@ export class DeviceTracker {
         return await txn.deviceIdentities.getByCurve25519Key(curve25519Key);
     }
 }
+
+import {createMockStorage} from "../../mocks/Storage";
+import {Instance as NullLoggerInstance} from "../../logging/NullLogger";
+
+export function tests() {
+
+    function createUntrackedRoomMock(roomId, joinedUserIds, invitedUserIds = []) {
+        return {
+            isTrackingMembers: false,
+            isEncrypted: true,
+            loadMemberList: () => {
+                const joinedMembers = joinedUserIds.map(userId => {return {membership: "join", roomId, userId};});
+                const invitedMembers = invitedUserIds.map(userId => {return {membership: "invite", roomId, userId};});
+                const members = joinedMembers.concat(invitedMembers);
+                const memberMap = members.reduce((map, member) => {
+                    map.set(member.userId, member);
+                    return map;
+                }, new Map());
+                return {members: memberMap, release() {}}
+            },
+            writeIsTrackingMembers(isTrackingMembers) {
+                if (this.isTrackingMembers !== isTrackingMembers) {
+                    return isTrackingMembers;
+                }
+                return undefined;
+            },
+            applyIsTrackingMembersChanges(isTrackingMembers) {
+                if (isTrackingMembers !== undefined) {
+                    this.isTrackingMembers = isTrackingMembers;
+                }
+            },
+        }
+    }
+
+    function createQueryKeysHSApiMock(createKey = (algorithm, userId, deviceId) => `${algorithm}:${userId}:${deviceId}:key`) {
+        return {
+            queryKeys(payload) {
+                const {device_keys: deviceKeys} = payload;
+                const userKeys = Object.entries(deviceKeys).reduce((userKeys, [userId, deviceIds]) => {
+                    if (deviceIds.length === 0) {
+                        deviceIds = ["device1"];
+                    }
+                    userKeys[userId] = deviceIds.filter(d => d === "device1").reduce((deviceKeys, deviceId) => {
+                        deviceKeys[deviceId] = {
+                            "algorithms": [
+                              "m.olm.v1.curve25519-aes-sha2",
+                              "m.megolm.v1.aes-sha2"
+                            ],
+                            "device_id": deviceId,
+                            "keys": {
+                                [`curve25519:${deviceId}`]: createKey("curve25519", userId, deviceId),
+                                [`ed25519:${deviceId}`]: createKey("ed25519", userId, deviceId),
+                            },
+                            "signatures": {
+                                [userId]: {
+                                    [`ed25519:${deviceId}`]: `ed25519:${userId}:${deviceId}:signature`
+                                }
+                            },
+                            "unsigned": {
+                              "device_display_name": `${userId} Phone`
+                            },
+                            "user_id": userId
+                        };
+                        return deviceKeys;
+                    }, {});
+                    return userKeys;
+                }, {});
+                const response = {device_keys: userKeys};
+                return {
+                    async response() {
+                        return response;
+                    }
+                };
+            }
+        };
+    }
+    const roomId = "!abc:hs.tld";
+
+    return {
+        "trackRoom only writes joined members": async assert => {
+            const storage = await createMockStorage();
+            const tracker = new DeviceTracker({
+                storage,
+                getSyncToken: () => "token",
+                olmUtil: {ed25519_verify: () => {}}, // valid if it does not throw
+                ownUserId: "@alice:hs.tld",
+                ownDeviceId: "ABCD",
+            });
+            const room = createUntrackedRoomMock(roomId, ["@alice:hs.tld", "@bob:hs.tld"], ["@charly:hs.tld"]);
+            await tracker.trackRoom(room, NullLoggerInstance.item);
+            const txn = await storage.readTxn([storage.storeNames.userIdentities]);
+            assert.deepEqual(await txn.userIdentities.get("@alice:hs.tld"), {
+                userId: "@alice:hs.tld",
+                roomIds: [roomId],
+                deviceTrackingStatus: TRACKING_STATUS_OUTDATED
+            });
+            assert.deepEqual(await txn.userIdentities.get("@bob:hs.tld"), {
+                userId: "@bob:hs.tld",
+                roomIds: [roomId],
+                deviceTrackingStatus: TRACKING_STATUS_OUTDATED
+            });
+            assert.equal(await txn.userIdentities.get("@charly:hs.tld"), undefined);
+        },
+        "getting devices for tracked room yields correct keys": async assert => {
+            const storage = await createMockStorage();
+            const tracker = new DeviceTracker({
+                storage,
+                getSyncToken: () => "token",
+                olmUtil: {ed25519_verify: () => {}}, // valid if it does not throw
+                ownUserId: "@alice:hs.tld",
+                ownDeviceId: "ABCD",
+            });
+            const room = createUntrackedRoomMock(roomId, ["@alice:hs.tld", "@bob:hs.tld"]);
+            await tracker.trackRoom(room, NullLoggerInstance.item);
+            const hsApi = createQueryKeysHSApiMock();
+            const devices = await tracker.devicesForRoomMembers(roomId, ["@alice:hs.tld", "@bob:hs.tld"], hsApi, NullLoggerInstance.item);
+            assert.equal(devices.length, 2);
+            assert.equal(devices.find(d => d.userId === "@alice:hs.tld").ed25519Key, "ed25519:@alice:hs.tld:device1:key");
+            assert.equal(devices.find(d => d.userId === "@bob:hs.tld").ed25519Key, "ed25519:@bob:hs.tld:device1:key");
+        },
+    }
+}