diff --git a/src/MatrixClientPeg.ts b/src/MatrixClientPeg.ts
index e5ca4464ba..0ba2ec65d7 100644
--- a/src/MatrixClientPeg.ts
+++ b/src/MatrixClientPeg.ts
@@ -43,7 +43,6 @@ import { formatList } from "./utils/FormattingUtils";
 import SdkConfig from "./SdkConfig";
 import { Features } from "./settings/Settings";
 import { setDeviceIsolationMode } from "./settings/controllers/DeviceIsolationModeController.ts";
-import { ReadyWatchingStore } from "./stores/ReadyWatchingStore.ts";
 
 export interface IMatrixClientCreds {
     homeserverUrl: string;
@@ -310,7 +309,6 @@ class MatrixClientPegClass implements IMatrixClientPeg {
         MatrixActionCreators.start(this.matrixClient);
         MatrixClientBackedSettingsHandler.matrixClient = this.matrixClient;
         MatrixClientBackedController.matrixClient = this.matrixClient;
-        ReadyWatchingStore.matrixClient = this.matrixClient;
 
         return opts;
     }
diff --git a/src/stores/AsyncStoreWithClient.ts b/src/stores/AsyncStoreWithClient.ts
index d9facfc51a..7567eac9ac 100644
--- a/src/stores/AsyncStoreWithClient.ts
+++ b/src/stores/AsyncStoreWithClient.ts
@@ -36,13 +36,8 @@ export abstract class AsyncStoreWithClient<T extends Object> extends AsyncStore<
         })(dispatcher);
     }
 
-    protected async start(matrixClient: MatrixClient | null): Promise<void> {
-        await this.readyStore.start(matrixClient);
-    }
-
-    // XXX: This method is intended only for use in tests.
-    public async useUnitTestClient(cli: MatrixClient): Promise<void> {
-        await this.readyStore.useUnitTestClient(cli);
+    public async start(): Promise<void> {
+        await this.readyStore.start();
     }
 
     public get matrixClient(): MatrixClient | null {
diff --git a/src/stores/AutoRageshakeStore.ts b/src/stores/AutoRageshakeStore.ts
index e83baf5a9c..284c3e24a4 100644
--- a/src/stores/AutoRageshakeStore.ts
+++ b/src/stores/AutoRageshakeStore.ts
@@ -46,7 +46,9 @@ interface IState {
  */
 export default class AutoRageshakeStore extends AsyncStoreWithClient<IState> {
     private static readonly internalInstance = (() => {
-        return new AutoRageshakeStore();
+        const instance = new AutoRageshakeStore();
+        instance.start();
+        return instance;
     })();
 
     private constructor() {
diff --git a/src/stores/BreadcrumbsStore.ts b/src/stores/BreadcrumbsStore.ts
index 546f1e63ae..9859f24015 100644
--- a/src/stores/BreadcrumbsStore.ts
+++ b/src/stores/BreadcrumbsStore.ts
@@ -30,7 +30,9 @@ interface IState {
 
 export class BreadcrumbsStore extends AsyncStoreWithClient<IState> {
     private static readonly internalInstance = (() => {
-        return new BreadcrumbsStore();
+        const instance = new BreadcrumbsStore();
+        instance.start();
+        return instance;
     })();
 
     private waitingRooms: { roomId: string; addedTs: number }[] = [];
diff --git a/src/stores/CallStore.ts b/src/stores/CallStore.ts
index f0120ee6a6..115a56aced 100644
--- a/src/stores/CallStore.ts
+++ b/src/stores/CallStore.ts
@@ -31,6 +31,7 @@ export class CallStore extends AsyncStoreWithClient<{}> {
     public static get instance(): CallStore {
         if (!this._instance) {
             this._instance = new CallStore();
+            this._instance.start();
         }
         return this._instance;
     }
diff --git a/src/stores/ModalWidgetStore.ts b/src/stores/ModalWidgetStore.ts
index aa4d5d1466..59437db403 100644
--- a/src/stores/ModalWidgetStore.ts
+++ b/src/stores/ModalWidgetStore.ts
@@ -24,6 +24,7 @@ interface IState {
 export class ModalWidgetStore extends AsyncStoreWithClient<IState> {
     private static readonly internalInstance = (() => {
         const instance = new ModalWidgetStore();
+        instance.start();
         return instance;
     })();
     private modalInstance: IHandle<typeof ModalWidgetDialog> | null = null;
diff --git a/src/stores/OwnBeaconStore.ts b/src/stores/OwnBeaconStore.ts
index 4240d7b7df..f60dae07fe 100644
--- a/src/stores/OwnBeaconStore.ts
+++ b/src/stores/OwnBeaconStore.ts
@@ -87,6 +87,7 @@ const getLocallyCreatedBeaconEventIds = (): string[] => {
 export class OwnBeaconStore extends AsyncStoreWithClient<OwnBeaconStoreState> {
     private static readonly internalInstance = (() => {
         const instance = new OwnBeaconStore();
+        instance.start();
         return instance;
     })();
     // users beacons, keyed by event type
diff --git a/src/stores/OwnProfileStore.ts b/src/stores/OwnProfileStore.ts
index f0b94df553..be8c72aa23 100644
--- a/src/stores/OwnProfileStore.ts
+++ b/src/stores/OwnProfileStore.ts
@@ -28,6 +28,7 @@ const KEY_AVATAR_URL = "mx_profile_avatar_url";
 export class OwnProfileStore extends AsyncStoreWithClient<IState> {
     private static readonly internalInstance = (() => {
         const instance = new OwnProfileStore();
+        instance.start();
         return instance;
     })();
 
diff --git a/src/stores/ReadyWatchingStore.ts b/src/stores/ReadyWatchingStore.ts
index a2e8c278f0..a46a09899a 100644
--- a/src/stores/ReadyWatchingStore.ts
+++ b/src/stores/ReadyWatchingStore.ts
@@ -9,42 +9,27 @@
 import { MatrixClient, SyncState } from "matrix-js-sdk/src/matrix";
 import { EventEmitter } from "events";
 
+import { MatrixClientPeg } from "../MatrixClientPeg";
 import { ActionPayload } from "../dispatcher/payloads";
 import { IDestroyable } from "../utils/IDestroyable";
 import { Action } from "../dispatcher/actions";
 import { MatrixDispatcher } from "../dispatcher/dispatcher";
 
 export abstract class ReadyWatchingStore extends EventEmitter implements IDestroyable {
-    private static instances: ReadyWatchingStore[] = [];
-    protected _matrixClient: MatrixClient | null = null;
+    protected matrixClient: MatrixClient | null = null;
     private dispatcherRef: string | null = null;
 
-    public static set matrixClient(client: MatrixClient) {
-        for (const instance of ReadyWatchingStore.instances) {
-            instance.start(client);
-        }
-    }
-
     public constructor(protected readonly dispatcher: MatrixDispatcher) {
         super();
+    }
 
+    public async start(): Promise<void> {
         this.dispatcherRef = this.dispatcher.register(this.onAction);
 
-        ReadyWatchingStore.instances.push(this);
-    }
-
-    public get matrixClient(): MatrixClient | null {
-        return this._matrixClient;
-    }
-
-    public async start(matrixClient: MatrixClient | null): Promise<void> {
-        const oldClient = this._matrixClient;
-        this._matrixClient = matrixClient;
-
-        if (oldClient !== matrixClient) {
-            await this.onNotReady();
-        }
+        // MatrixClientPeg can be undefined in tests because of circular dependencies with other stores
+        const matrixClient = MatrixClientPeg?.get();
         if (matrixClient) {
+            this.matrixClient = matrixClient;
             await this.onReady();
         }
     }
@@ -53,10 +38,8 @@ export abstract class ReadyWatchingStore extends EventEmitter implements IDestro
         return this.matrixClient; // for external readonly access
     }
 
-    // XXX: This method is intended only for use in tests.
-    public async useUnitTestClient(cli: MatrixClient): Promise<void> {
-        this._matrixClient = cli;
-        await this.onReady();
+    public useUnitTestClient(cli: MatrixClient): void {
+        this.matrixClient = cli;
     }
 
     public destroy(): void {
@@ -91,13 +74,13 @@ export abstract class ReadyWatchingStore extends EventEmitter implements IDestro
                 if (this.matrixClient) {
                     await this.onNotReady();
                 }
-                this._matrixClient = payload.matrixClient;
+                this.matrixClient = payload.matrixClient;
                 await this.onReady();
             }
         } else if (payload.action === "on_client_not_viable" || payload.action === Action.OnLoggedOut) {
             if (this.matrixClient) {
                 await this.onNotReady();
-                this._matrixClient = null;
+                this.matrixClient = null;
             }
         }
     };
diff --git a/src/stores/VoiceRecordingStore.ts b/src/stores/VoiceRecordingStore.ts
index 7a9e3601cf..7cbb8ac120 100644
--- a/src/stores/VoiceRecordingStore.ts
+++ b/src/stores/VoiceRecordingStore.ts
@@ -30,6 +30,7 @@ export class VoiceRecordingStore extends AsyncStoreWithClient<IState> {
     public static get instance(): VoiceRecordingStore {
         if (!this.internalInstance) {
             this.internalInstance = new VoiceRecordingStore();
+            this.internalInstance.start();
         }
         return this.internalInstance;
     }
diff --git a/src/stores/WidgetStore.ts b/src/stores/WidgetStore.ts
index 071cf8bde9..cfb92360a0 100644
--- a/src/stores/WidgetStore.ts
+++ b/src/stores/WidgetStore.ts
@@ -45,6 +45,7 @@ interface IRoomWidgets {
 export default class WidgetStore extends AsyncStoreWithClient<IState> {
     private static readonly internalInstance = (() => {
         const instance = new WidgetStore();
+        instance.start();
         return instance;
     })();
 
diff --git a/src/stores/local-echo/EchoStore.ts b/src/stores/local-echo/EchoStore.ts
index 41c92941ea..956eacb929 100644
--- a/src/stores/local-echo/EchoStore.ts
+++ b/src/stores/local-echo/EchoStore.ts
@@ -38,6 +38,7 @@ export class EchoStore extends AsyncStoreWithClient<IState> {
     public static get instance(): EchoStore {
         if (!this._instance) {
             this._instance = new EchoStore();
+            this._instance.start();
         }
         return this._instance;
     }
diff --git a/src/stores/notifications/RoomNotificationStateStore.ts b/src/stores/notifications/RoomNotificationStateStore.ts
index ebe9129989..87fb276c10 100644
--- a/src/stores/notifications/RoomNotificationStateStore.ts
+++ b/src/stores/notifications/RoomNotificationStateStore.ts
@@ -26,6 +26,7 @@ export const UPDATE_STATUS_INDICATOR = Symbol("update-status-indicator");
 export class RoomNotificationStateStore extends AsyncStoreWithClient<IState> {
     private static readonly internalInstance = (() => {
         const instance = new RoomNotificationStateStore();
+        instance.start();
         return instance;
     })();
     private roomMap = new Map<Room, RoomNotificationState>();
diff --git a/src/stores/right-panel/RightPanelStore.ts b/src/stores/right-panel/RightPanelStore.ts
index 4415852758..43a36e91b8 100644
--- a/src/stores/right-panel/RightPanelStore.ts
+++ b/src/stores/right-panel/RightPanelStore.ts
@@ -403,6 +403,7 @@ export default class RightPanelStore extends ReadyWatchingStore {
     public static get instance(): RightPanelStore {
         if (!this.internalInstance) {
             this.internalInstance = new RightPanelStore();
+            this.internalInstance.start();
         }
         return this.internalInstance;
     }
diff --git a/src/stores/room-list/MessagePreviewStore.ts b/src/stores/room-list/MessagePreviewStore.ts
index 1462826fe4..e0e06ec980 100644
--- a/src/stores/room-list/MessagePreviewStore.ts
+++ b/src/stores/room-list/MessagePreviewStore.ts
@@ -124,7 +124,11 @@ const mkMessagePreview = (text: string, event: MatrixEvent): MessagePreview => {
 };
 
 export class MessagePreviewStore extends AsyncStoreWithClient<IState> {
-    private static readonly internalInstance = (() => new MessagePreviewStore())();
+    private static readonly internalInstance = (() => {
+        const instance = new MessagePreviewStore();
+        instance.start();
+        return instance;
+    })();
 
     /**
      * @internal Public for test only
diff --git a/src/stores/room-list/RoomListLayoutStore.ts b/src/stores/room-list/RoomListLayoutStore.ts
index d305bacffb..ea85860554 100644
--- a/src/stores/room-list/RoomListLayoutStore.ts
+++ b/src/stores/room-list/RoomListLayoutStore.ts
@@ -28,6 +28,7 @@ export default class RoomListLayoutStore extends AsyncStoreWithClient<IState> {
     public static get instance(): RoomListLayoutStore {
         if (!this.internalInstance) {
             this.internalInstance = new RoomListLayoutStore();
+            this.internalInstance.start();
         }
         return RoomListLayoutStore.internalInstance;
     }
diff --git a/src/stores/room-list/RoomListStore.ts b/src/stores/room-list/RoomListStore.ts
index bb7cf15e8e..53377e0a01 100644
--- a/src/stores/room-list/RoomListStore.ts
+++ b/src/stores/room-list/RoomListStore.ts
@@ -643,9 +643,11 @@ export default class RoomListStore {
             if (SettingsStore.getValue("feature_sliding_sync")) {
                 logger.info("using SlidingRoomListStoreClass");
                 const instance = new SlidingRoomListStoreClass(defaultDispatcher, SdkContextClass.instance);
+                instance.start();
                 RoomListStore.internalInstance = instance;
             } else {
                 const instance = new RoomListStoreClass(defaultDispatcher);
+                instance.start();
                 RoomListStore.internalInstance = instance;
             }
         }
diff --git a/src/stores/spaces/SpaceStore.ts b/src/stores/spaces/SpaceStore.ts
index 1c3afeaf85..90358f3310 100644
--- a/src/stores/spaces/SpaceStore.ts
+++ b/src/stores/spaces/SpaceStore.ts
@@ -17,7 +17,6 @@ import {
     MatrixEvent,
     ClientEvent,
     ISendEventResponse,
-    MatrixClient,
 } from "matrix-js-sdk/src/matrix";
 import { KnownMembership } from "matrix-js-sdk/src/types";
 import { logger } from "matrix-js-sdk/src/logger";
@@ -1398,6 +1397,7 @@ export class SpaceStoreClass extends AsyncStoreWithClient<IState> {
 export default class SpaceStore {
     private static readonly internalInstance = (() => {
         const instance = new SpaceStoreClass();
+        instance.start();
         return instance;
     })();
 
@@ -1408,9 +1408,9 @@ export default class SpaceStore {
     /**
      * @internal for test only
      */
-    public static testInstance(client: MatrixClient): SpaceStoreClass {
+    public static testInstance(): SpaceStoreClass {
         const store = new SpaceStoreClass();
-        store.useUnitTestClient(client);
+        store.start();
         return store;
     }
 }
diff --git a/src/stores/widgets/WidgetLayoutStore.ts b/src/stores/widgets/WidgetLayoutStore.ts
index 00b27a1aa1..cefbee0f6b 100644
--- a/src/stores/widgets/WidgetLayoutStore.ts
+++ b/src/stores/widgets/WidgetLayoutStore.ts
@@ -60,6 +60,7 @@ export class WidgetLayoutStore extends ReadyWatchingStore {
     public static get instance(): WidgetLayoutStore {
         if (!this.internalInstance) {
             this.internalInstance = new WidgetLayoutStore();
+            this.internalInstance.start();
         }
         return this.internalInstance;
     }
diff --git a/src/stores/widgets/WidgetMessagingStore.ts b/src/stores/widgets/WidgetMessagingStore.ts
index 404049ab36..0388aeacb4 100644
--- a/src/stores/widgets/WidgetMessagingStore.ts
+++ b/src/stores/widgets/WidgetMessagingStore.ts
@@ -27,6 +27,7 @@ export enum WidgetMessagingStoreEvent {
 export class WidgetMessagingStore extends AsyncStoreWithClient<{}> {
     private static readonly internalInstance = (() => {
         const instance = new WidgetMessagingStore();
+        instance.start();
         return instance;
     })();
 
diff --git a/test/MatrixClientPeg-test.ts b/test/MatrixClientPeg-test.ts
index 4d7f769d04..9634a6a54f 100644
--- a/test/MatrixClientPeg-test.ts
+++ b/test/MatrixClientPeg-test.ts
@@ -6,8 +6,8 @@ SPDX-License-Identifier: AGPL-3.0-only OR GPL-3.0-only
 Please see LICENSE files in the repository root for full details.
 */
 
-import * as MatrixJs from "matrix-js-sdk/src/matrix";
 import { logger } from "matrix-js-sdk/src/logger";
+import fetchMockJest from "fetch-mock-jest";
 
 import { advanceDateAndTime, stubClient } from "./test-utils";
 import { IMatrixClientPeg, MatrixClientPeg as peg } from "../src/MatrixClientPeg";
@@ -19,14 +19,9 @@ jest.useFakeTimers();
 const PegClass = Object.getPrototypeOf(peg).constructor;
 
 describe("MatrixClientPeg", () => {
-    let mockClient: MatrixJs.MatrixClient;
-
     beforeEach(() => {
         // stub out Logger.log which gets called a lot and clutters up the test output
         jest.spyOn(logger, "log").mockImplementation(() => {});
-
-        mockClient = stubClient();
-        jest.spyOn(MatrixJs, "createClient").mockReturnValue(mockClient);
     });
 
     afterEach(() => {
@@ -38,6 +33,7 @@ describe("MatrixClientPeg", () => {
     });
 
     it("setJustRegisteredUserId", () => {
+        stubClient();
         (peg as any).matrixClient = peg.get();
         peg.setJustRegisteredUserId("@userId:matrix.org");
         expect(peg.safeGet().credentials.userId).toBe("@userId:matrix.org");
@@ -56,6 +52,7 @@ describe("MatrixClientPeg", () => {
     });
 
     it("setJustRegisteredUserId(null)", () => {
+        stubClient();
         (peg as any).matrixClient = peg.get();
         peg.setJustRegisteredUserId(null);
         expect(peg.currentUserIsJustRegistered()).toBe(false);
@@ -74,6 +71,7 @@ describe("MatrixClientPeg", () => {
         beforeEach(() => {
             // instantiate a MatrixClientPegClass instance, with a new MatrixClient
             testPeg = new PegClass();
+            fetchMockJest.get("http://example.com/_matrix/client/versions", {});
             testPeg.replaceUsingCreds({
                 accessToken: "SEKRET",
                 homeserverUrl: "http://example.com",
@@ -85,10 +83,13 @@ describe("MatrixClientPeg", () => {
         it("should initialise the rust crypto library by default", async () => {
             const mockSetValue = jest.spyOn(SettingsStore, "setValue").mockResolvedValue(undefined);
 
+            const mockInitCrypto = jest.spyOn(testPeg.safeGet(), "initCrypto").mockResolvedValue(undefined);
+            const mockInitRustCrypto = jest.spyOn(testPeg.safeGet(), "initRustCrypto").mockResolvedValue(undefined);
+
             const cryptoStoreKey = new Uint8Array([1, 2, 3, 4]);
             await testPeg.start({ rustCryptoStoreKey: cryptoStoreKey });
-            expect(mockClient.initCrypto).not.toHaveBeenCalled();
-            expect(mockClient.initRustCrypto).toHaveBeenCalledWith({ storageKey: cryptoStoreKey });
+            expect(mockInitCrypto).not.toHaveBeenCalled();
+            expect(mockInitRustCrypto).toHaveBeenCalledWith({ storageKey: cryptoStoreKey });
 
             // we should have stashed the setting in the settings store
             expect(mockSetValue).toHaveBeenCalledWith("feature_rust_crypto", null, SettingLevel.DEVICE, true);
@@ -96,9 +97,10 @@ describe("MatrixClientPeg", () => {
 
         it("Should migrate existing login", async () => {
             const mockSetValue = jest.spyOn(SettingsStore, "setValue").mockResolvedValue(undefined);
+            const mockInitRustCrypto = jest.spyOn(testPeg.safeGet(), "initRustCrypto").mockResolvedValue(undefined);
 
             await testPeg.start();
-            expect(mockClient.initRustCrypto).toHaveBeenCalledTimes(1);
+            expect(mockInitRustCrypto).toHaveBeenCalledTimes(1);
 
             // we should have stashed the setting in the settings store
             expect(mockSetValue).toHaveBeenCalledWith("feature_rust_crypto", null, SettingLevel.DEVICE, true);
diff --git a/test/stores/AutoRageshakeStore-test.ts b/test/stores/AutoRageshakeStore-test.ts
index 7ed317fc81..f321e909a4 100644
--- a/test/stores/AutoRageshakeStore-test.ts
+++ b/test/stores/AutoRageshakeStore-test.ts
@@ -47,7 +47,7 @@ describe("AutoRageshakeStore", () => {
 
         // @ts-ignore bypass private ctor for tests
         autoRageshakeStore = new AutoRageshakeStore();
-        autoRageshakeStore.useUnitTestClient(client);
+        autoRageshakeStore.start();
 
         utdEvent = mkEvent({
             event: true,
diff --git a/test/stores/OwnProfileStore-test.ts b/test/stores/OwnProfileStore-test.ts
index 628706372d..0f4f2d325a 100644
--- a/test/stores/OwnProfileStore-test.ts
+++ b/test/stores/OwnProfileStore-test.ts
@@ -40,7 +40,7 @@ describe("OwnProfileStore", () => {
             displayname: "Display Name",
             avatar_url: "mxc://example.com/abc123",
         });
-        await ownProfileStore.useUnitTestClient(client);
+        await ownProfileStore.start();
 
         expect(onUpdate).toHaveBeenCalled();
         expect(ownProfileStore.displayName).toBe("Display Name");
@@ -54,7 +54,7 @@ describe("OwnProfileStore", () => {
                 errcode: "M_NOT_FOUND",
             }),
         );
-        await ownProfileStore.useUnitTestClient(client);
+        await ownProfileStore.start();
 
         expect(onUpdate).toHaveBeenCalled();
         expect(ownProfileStore.displayName).toBe(client.getSafeUserId());
@@ -69,7 +69,7 @@ describe("OwnProfileStore", () => {
             }),
         );
         try {
-            await ownProfileStore.useUnitTestClient(client);
+            await ownProfileStore.start();
         } catch (ignore) {}
 
         expect(onUpdate).not.toHaveBeenCalled();
diff --git a/test/stores/SpaceStore-test.ts b/test/stores/SpaceStore-test.ts
index 53172f946a..35ec275c49 100644
--- a/test/stores/SpaceStore-test.ts
+++ b/test/stores/SpaceStore-test.ts
@@ -1428,7 +1428,7 @@ describe("SpaceStore", () => {
 
         it("passes that value in calls to getVisibleRooms during getSpaceFilteredRoomIds", () => {
             // Given a store
-            const store = SpaceStore.testInstance(client);
+            const store = SpaceStore.testInstance();
 
             // When we ask for filtered room ids
             store.getSpaceFilteredRoomIds(MetaSpace.Home);
@@ -1478,7 +1478,7 @@ describe("SpaceStore", () => {
 
         it("passes that value in calls to getVisibleRooms during getSpaceFilteredRoomIds", () => {
             // Given a store
-            const store = SpaceStore.testInstance(client);
+            const store = SpaceStore.testInstance();
             // When we ask for filtered room ids
             store.getSpaceFilteredRoomIds(MetaSpace.Home);
 
diff --git a/test/stores/VoiceRecordingStore-test.ts b/test/stores/VoiceRecordingStore-test.ts
index 9af96914e8..6974e6063e 100644
--- a/test/stores/VoiceRecordingStore-test.ts
+++ b/test/stores/VoiceRecordingStore-test.ts
@@ -31,7 +31,7 @@ describe("VoiceRecordingStore", () => {
 
     const mkStore = (): VoiceRecordingStore => {
         const store = new VoiceRecordingStore();
-        store.useUnitTestClient(stubClient);
+        store.start();
         return store;
     };
 
diff --git a/test/stores/WidgetLayoutStore-test.ts b/test/stores/WidgetLayoutStore-test.ts
index 4ac397a121..72418dda5f 100644
--- a/test/stores/WidgetLayoutStore-test.ts
+++ b/test/stores/WidgetLayoutStore-test.ts
@@ -167,7 +167,7 @@ describe("WidgetLayoutStore", () => {
 
     it("should recalculate all rooms when the client is ready", async () => {
         mocked(client.getVisibleRooms).mockReturnValue([mockRoom]);
-        await store.start(client);
+        await store.start();
 
         expect(roomUpdateListener).toHaveBeenCalled();
         expect(store.getContainerWidgets(mockRoom, Container.Top)).toEqual([]);
@@ -243,7 +243,7 @@ describe("WidgetLayoutStore", () => {
     });
 
     it("should copy the layout to the room", async () => {
-        await store.start(client);
+        await store.start();
         store.recalculateRoom(mockRoom);
         store.moveToContainer(mockRoom, mockApps[0], Container.Top);
         store.copyLayoutToRoom(mockRoom);
@@ -297,7 +297,7 @@ describe("WidgetLayoutStore", () => {
             mocked(client.getVisibleRooms).mockReturnValue([]);
             // @ts-ignore bypass private ctor for tests
             const store = new WidgetLayoutStore();
-            await store.start(client);
+            await store.start();
             expect(client.getVisibleRooms).toHaveBeenCalledWith(false);
         });
     });
@@ -314,7 +314,7 @@ describe("WidgetLayoutStore", () => {
             mocked(client.getVisibleRooms).mockReturnValue([]);
             // @ts-ignore bypass private ctor for tests
             const store = new WidgetLayoutStore();
-            await store.start(client);
+            await store.start();
             expect(client.getVisibleRooms).toHaveBeenCalledWith(true);
         });
     });
diff --git a/test/stores/room-list/MessagePreviewStore-test.ts b/test/stores/room-list/MessagePreviewStore-test.ts
index 603f4713e9..976c822253 100644
--- a/test/stores/room-list/MessagePreviewStore-test.ts
+++ b/test/stores/room-list/MessagePreviewStore-test.ts
@@ -80,7 +80,7 @@ describe("MessagePreviewStore", () => {
         mocked(client.getRoom).mockReturnValue(room);
 
         store = MessagePreviewStore.testInstance();
-        await store.useUnitTestClient(client);
+        await store.start();
         await setupAsyncStoreWithClient(store, client);
     });
 
diff --git a/test/stores/room-list/RoomListStore-test.ts b/test/stores/room-list/RoomListStore-test.ts
index 4fe59a6222..fd5562753e 100644
--- a/test/stores/room-list/RoomListStore-test.ts
+++ b/test/stores/room-list/RoomListStore-test.ts
@@ -29,9 +29,6 @@ import DMRoomMap from "../../../src/utils/DMRoomMap";
 import { flushPromises, stubClient, upsertRoomStateEvents, mkRoom } from "../../test-utils";
 import { DEFAULT_PUSH_RULES, makePushRule } from "../../test-utils/pushRules";
 
-// Mock out the SpaceWatcher as it messes with the prefilterConditions
-jest.mock("../../../src/stores/room-list/SpaceWatcher.ts");
-
 describe("RoomListStore", () => {
     const client = stubClient();
     const newRoomId = "!roomid:example.com";
@@ -94,10 +91,6 @@ describe("RoomListStore", () => {
         await (RoomListStore.instance as RoomListStoreClass).makeReady(client);
     });
 
-    beforeEach(() => {
-        DMRoomMap.makeShared(client);
-    });
-
     it.each(OrderedDefaultTagIDs)("defaults to importance ordering for %s=", (tagId) => {
         expect(RoomListStore.instance.getTagSorting(tagId)).toBe(SortAlgorithm.Recent);
     });
@@ -109,11 +102,11 @@ describe("RoomListStore", () => {
     function createStore(): { store: RoomListStoreClass; handleRoomUpdate: jest.Mock<any, any> } {
         const fakeDispatcher = { register: jest.fn() } as unknown as MatrixDispatcher;
         const store = new RoomListStoreClass(fakeDispatcher);
+        // @ts-ignore accessing private member to set client
+        store.readyStore.matrixClient = client;
         const handleRoomUpdate = jest.fn();
         // @ts-ignore accessing private member to mock it
         store.algorithm.handleRoomUpdate = handleRoomUpdate;
-        // @ts-ignore accessing private member to set client
-        store.readyStore.useUnitTestClient(client);
 
         return { store, handleRoomUpdate };
     }
@@ -164,6 +157,7 @@ describe("RoomListStore", () => {
         room1.updateMyMembership(KnownMembership.Join);
         room2.updateMyMembership(KnownMembership.Join);
         room3.updateMyMembership(KnownMembership.Join);
+        DMRoomMap.makeShared(client);
         const { store } = createStore();
         client.getVisibleRooms = jest.fn().mockReturnValue([room1, room2, room3]);
 
@@ -275,6 +269,7 @@ describe("RoomListStore", () => {
 
         it("Passes the feature flag on to the client when asking for visible rooms", () => {
             // Given a store that we can ask for a room list
+            DMRoomMap.makeShared(client);
             const { store } = createStore();
             client.getVisibleRooms = jest.fn().mockReturnValue([]);
 
@@ -290,7 +285,7 @@ describe("RoomListStore", () => {
     describe("room updates", () => {
         const makeStore = async () => {
             const store = new RoomListStoreClass(defaultDispatcher);
-            await store.useUnitTestClient(client);
+            await store.start();
             return store;
         };
 
diff --git a/test/stores/room-list/SlidingRoomListStore-test.ts b/test/stores/room-list/SlidingRoomListStore-test.ts
index 926d1fd2f3..f667ef7dca 100644
--- a/test/stores/room-list/SlidingRoomListStore-test.ts
+++ b/test/stores/room-list/SlidingRoomListStore-test.ts
@@ -65,7 +65,7 @@ describe("SlidingRoomListStore", () => {
 
     describe("spaces", () => {
         it("alters 'filters.spaces' on the DefaultTagID.Untagged list when the selected space changes", async () => {
-            await store.useUnitTestClient(context.client!); // call onReady
+            await store.start(); // call onReady
             const spaceRoomId = "!foo:bar";
 
             const p = untilEmission(store, LISTS_LOADING_EVENT, (listName, isLoading) => {
@@ -92,7 +92,7 @@ describe("SlidingRoomListStore", () => {
                 },
             );
             activeSpace = MetaSpace.Home;
-            await store.useUnitTestClient(context.client!); // call onReady
+            await store.start(); // call onReady
 
             expect(context._SlidingSyncManager!.ensureListRegistered).toHaveBeenCalledWith(DefaultTagID.Untagged, {
                 filters: expect.objectContaining({
@@ -108,7 +108,7 @@ describe("SlidingRoomListStore", () => {
             const p = untilEmission(store, LISTS_LOADING_EVENT, (listName, isLoading) => {
                 return listName === DefaultTagID.Untagged && !isLoading;
             });
-            await store.useUnitTestClient(context.client!); // call onReady
+            await store.start(); // call onReady
             await p;
             expect(context._SlidingSyncManager!.ensureListRegistered).toHaveBeenCalledWith(
                 DefaultTagID.Untagged,
@@ -121,7 +121,7 @@ describe("SlidingRoomListStore", () => {
         });
 
         it("includes subspaces in 'filters.spaces' when the selected space has subspaces", async () => {
-            await store.useUnitTestClient(context.client!); // call onReady
+            await store.start(); // call onReady
             const spaceRoomId = "!foo:bar";
             const subSpace1 = "!ss1:bar";
             const subSpace2 = "!ss2:bar";
@@ -168,7 +168,7 @@ describe("SlidingRoomListStore", () => {
     });
 
     it("getTagsForRoom gets the tags for the room", async () => {
-        await store.useUnitTestClient(context.client!);
+        await store.start();
         const roomA = "!a:localhost";
         const roomB = "!b:localhost";
         const keyToListData: Record<string, { joinedCount: number; roomIndexToRoomId: Record<number, string> }> = {
@@ -200,7 +200,7 @@ describe("SlidingRoomListStore", () => {
     });
 
     it("emits LISTS_UPDATE_EVENT when slidingSync lists update", async () => {
-        await store.useUnitTestClient(context.client!);
+        await store.start();
         const roomA = "!a:localhost";
         const roomB = "!b:localhost";
         const roomC = "!c:localhost";
@@ -236,7 +236,7 @@ describe("SlidingRoomListStore", () => {
     });
 
     it("sets the sticky room on the basis of the viewed room in RoomViewStore", async () => {
-        await store.useUnitTestClient(context.client!);
+        await store.start();
         // seed the store with 3 rooms
         const roomIdA = "!a:localhost";
         const roomIdB = "!b:localhost";
@@ -301,7 +301,7 @@ describe("SlidingRoomListStore", () => {
     });
 
     it("gracefully handles unknown room IDs", async () => {
-        await store.useUnitTestClient(context.client!);
+        await store.start();
         const roomIdA = "!a:localhost";
         const roomIdB = "!b:localhost"; // does not exist
         const roomIdC = "!c:localhost";
diff --git a/test/test-utils/test-utils.ts b/test/test-utils/test-utils.ts
index fe9d078f3a..ebfc6b221b 100644
--- a/test/test-utils/test-utils.ts
+++ b/test/test-utils/test-utils.ts
@@ -86,14 +86,13 @@ export function createTestClient(): MatrixClient {
     let txnId = 1;
 
     const client = {
-        startClient: jest.fn(),
         getHomeserverUrl: jest.fn(),
         getIdentityServerUrl: jest.fn(),
         getDomain: jest.fn().mockReturnValue("matrix.org"),
         getUserId: jest.fn().mockReturnValue("@userId:matrix.org"),
         getSafeUserId: jest.fn().mockReturnValue("@userId:matrix.org"),
         getUserIdLocalpart: jest.fn().mockResolvedValue("userId"),
-        getUser: jest.fn().mockReturnValue({ on: jest.fn(), off: jest.fn(), removeListener: jest.fn() }),
+        getUser: jest.fn().mockReturnValue({ on: jest.fn(), off: jest.fn() }),
         getDevice: jest.fn(),
         getDeviceId: jest.fn().mockReturnValue("ABCDEFGHI"),
         getStoredCrossSigningForUser: jest.fn(),
@@ -134,8 +133,6 @@ export function createTestClient(): MatrixClient {
             getVerificationRequestsToDeviceInProgress: jest.fn().mockReturnValue([]),
             setDeviceIsolationMode: jest.fn(),
         }),
-        initCrypto: jest.fn(),
-        initRustCrypto: jest.fn(),
 
         getPushActionsForEvent: jest.fn(),
         getRoom: jest.fn().mockImplementation((roomId) => mkStubRoom(roomId, "My room", client)),
@@ -183,7 +180,6 @@ export function createTestClient(): MatrixClient {
         getSyncState: jest.fn().mockReturnValue("SYNCING"),
         generateClientSecret: () => "t35tcl1Ent5ECr3T",
         isGuest: jest.fn().mockReturnValue(false),
-        setGuest: jest.fn(),
         getRoomHierarchy: jest.fn().mockReturnValue({
             rooms: [],
         }),
@@ -281,7 +277,6 @@ export function createTestClient(): MatrixClient {
         isFallbackICEServerAllowed: jest.fn().mockReturnValue(false),
         getAuthIssuer: jest.fn(),
         getOrCreateFilter: jest.fn(),
-        setNotifTimelineSet: jest.fn(),
     } as unknown as MatrixClient;
 
     client.reEmitter = new ReEmitter(client);