diff --git a/extensions/matrix/src/matrix/actions/client.test.ts b/extensions/matrix/src/matrix/actions/client.test.ts
index 7a397cb27f2..5f7f122a823 100644
--- a/extensions/matrix/src/matrix/actions/client.test.ts
+++ b/extensions/matrix/src/matrix/actions/client.test.ts
@@ -1,19 +1,22 @@
 import { afterEach, beforeEach, describe, expect, it, vi } from "vitest";
-import type { MatrixClient } from "../sdk.js";
+import {
+  createMockMatrixClient,
+  matrixClientResolverMocks,
+  primeMatrixClientResolverMocks,
+} from "../client-resolver.test-helpers.js";
 
-const loadConfigMock = vi.fn(() => ({}));
-const getActiveMatrixClientMock = vi.fn();
-const createMatrixClientMock = vi.fn();
-const isBunRuntimeMock = vi.fn(() => false);
-const resolveMatrixAuthMock = vi.fn();
-const resolveMatrixAuthContextMock = vi.fn();
+const {
+  loadConfigMock,
+  getMatrixRuntimeMock,
+  getActiveMatrixClientMock,
+  createMatrixClientMock,
+  isBunRuntimeMock,
+  resolveMatrixAuthMock,
+  resolveMatrixAuthContextMock,
+} = matrixClientResolverMocks;
 
 vi.mock("../../runtime.js", () => ({
-  getMatrixRuntime: () => ({
-    config: {
-      loadConfig: loadConfigMock,
-    },
-  }),
+  getMatrixRuntime: () => getMatrixRuntimeMock(),
 }));
 
 vi.mock("../active-client.js", () => ({
@@ -29,44 +32,10 @@ vi.mock("../client.js", () => ({
 
 let resolveActionClient: typeof import("./client.js").resolveActionClient;
 
-function createMockMatrixClient(): MatrixClient {
-  return {
-    prepareForOneOff: vi.fn(async () => undefined),
-    start: vi.fn(async () => undefined),
-  } as unknown as MatrixClient;
-}
-
 describe("resolveActionClient", () => {
   beforeEach(async () => {
     vi.resetModules();
-    vi.clearAllMocks();
-    getActiveMatrixClientMock.mockReturnValue(null);
-    isBunRuntimeMock.mockReturnValue(false);
-    resolveMatrixAuthMock.mockResolvedValue({
-      accountId: "default",
-      homeserver: "https://matrix.example.org",
-      userId: "@bot:example.org",
-      accessToken: "token",
-      password: undefined,
-      deviceId: "DEVICE123",
-      encryption: false,
-    });
-    resolveMatrixAuthContextMock.mockImplementation(
-      ({ cfg, accountId }: { cfg: unknown; accountId?: string | null }) => ({
-        cfg,
-        env: process.env,
-        accountId: accountId ?? "default",
-        resolved: {
-          homeserver: "https://matrix.example.org",
-          userId: "@bot:example.org",
-          accessToken: "token",
-          password: undefined,
-          deviceId: "DEVICE123",
-          encryption: false,
-        },
-      }),
-    );
-    createMatrixClientMock.mockResolvedValue(createMockMatrixClient());
+    primeMatrixClientResolverMocks();
 
     ({ resolveActionClient } = await import("./client.js"));
   });
diff --git a/extensions/matrix/src/matrix/client-resolver.test-helpers.ts b/extensions/matrix/src/matrix/client-resolver.test-helpers.ts
new file mode 100644
index 00000000000..7a2d9c0e3b2
--- /dev/null
+++ b/extensions/matrix/src/matrix/client-resolver.test-helpers.ts
@@ -0,0 +1,92 @@
+import { vi } from "vitest";
+import type { MatrixClient } from "./sdk.js";
+
+export const matrixClientResolverMocks = {
+  loadConfigMock: vi.fn(() => ({})),
+  getMatrixRuntimeMock: vi.fn(),
+  getActiveMatrixClientMock: vi.fn(),
+  createMatrixClientMock: vi.fn(),
+  isBunRuntimeMock: vi.fn(() => false),
+  resolveMatrixAuthMock: vi.fn(),
+  resolveMatrixAuthContextMock: vi.fn(),
+};
+
+export function createMockMatrixClient(): MatrixClient {
+  return {
+    prepareForOneOff: vi.fn(async () => undefined),
+    start: vi.fn(async () => undefined),
+  } as unknown as MatrixClient;
+}
+
+export function primeMatrixClientResolverMocks(params?: {
+  cfg?: unknown;
+  accountId?: string;
+  resolved?: Record<string, unknown>;
+  auth?: Record<string, unknown>;
+  client?: MatrixClient;
+}): MatrixClient {
+  const {
+    loadConfigMock,
+    getMatrixRuntimeMock,
+    getActiveMatrixClientMock,
+    createMatrixClientMock,
+    isBunRuntimeMock,
+    resolveMatrixAuthMock,
+    resolveMatrixAuthContextMock,
+  } = matrixClientResolverMocks;
+
+  const cfg = params?.cfg ?? {};
+  const accountId = params?.accountId ?? "default";
+  const defaultResolved = {
+    homeserver: "https://matrix.example.org",
+    userId: "@bot:example.org",
+    accessToken: "token",
+    password: undefined,
+    deviceId: "DEVICE123",
+    encryption: false,
+  };
+  const defaultAuth = {
+    accountId,
+    homeserver: "https://matrix.example.org",
+    userId: "@bot:example.org",
+    accessToken: "token",
+    password: undefined,
+    deviceId: "DEVICE123",
+    encryption: false,
+  };
+  const client = params?.client ?? createMockMatrixClient();
+
+  vi.clearAllMocks();
+  loadConfigMock.mockReturnValue(cfg);
+  getMatrixRuntimeMock.mockReturnValue({
+    config: {
+      loadConfig: loadConfigMock,
+    },
+  });
+  getActiveMatrixClientMock.mockReturnValue(null);
+  isBunRuntimeMock.mockReturnValue(false);
+  resolveMatrixAuthContextMock.mockImplementation(
+    ({
+      cfg: explicitCfg,
+      accountId: explicitAccountId,
+    }: {
+      cfg: unknown;
+      accountId?: string | null;
+    }) => ({
+      cfg: explicitCfg,
+      env: process.env,
+      accountId: explicitAccountId ?? accountId,
+      resolved: {
+        ...defaultResolved,
+        ...params?.resolved,
+      },
+    }),
+  );
+  resolveMatrixAuthMock.mockResolvedValue({
+    ...defaultAuth,
+    ...params?.auth,
+  });
+  createMatrixClientMock.mockResolvedValue(client);
+
+  return client;
+}
diff --git a/extensions/matrix/src/matrix/send/client.test.ts b/extensions/matrix/src/matrix/send/client.test.ts
index 828fd6dd8de..7a8147cecef 100644
--- a/extensions/matrix/src/matrix/send/client.test.ts
+++ b/extensions/matrix/src/matrix/send/client.test.ts
@@ -1,12 +1,18 @@
 import { afterEach, beforeEach, describe, expect, it, vi } from "vitest";
-import type { MatrixClient } from "../sdk.js";
+import {
+  createMockMatrixClient,
+  matrixClientResolverMocks,
+  primeMatrixClientResolverMocks,
+} from "../client-resolver.test-helpers.js";
 
-const getActiveMatrixClientMock = vi.fn();
-const createMatrixClientMock = vi.fn();
-const isBunRuntimeMock = vi.fn(() => false);
-const resolveMatrixAuthMock = vi.fn();
-const resolveMatrixAuthContextMock = vi.fn();
-const getMatrixRuntimeMock = vi.fn();
+const {
+  getMatrixRuntimeMock,
+  getActiveMatrixClientMock,
+  createMatrixClientMock,
+  isBunRuntimeMock,
+  resolveMatrixAuthMock,
+  resolveMatrixAuthContextMock,
+} = matrixClientResolverMocks;
 
 vi.mock("../active-client.js", () => ({
   getActiveMatrixClient: (...args: unknown[]) => getActiveMatrixClientMock(...args),
@@ -25,39 +31,12 @@ vi.mock("../../runtime.js", () => ({
 
 let resolveMatrixClient: typeof import("./client.js").resolveMatrixClient;
 
-function createMockMatrixClient(): MatrixClient {
-  return {
-    prepareForOneOff: vi.fn(async () => undefined),
-  } as unknown as MatrixClient;
-}
-
 describe("resolveMatrixClient", () => {
   beforeEach(async () => {
     vi.resetModules();
-    vi.clearAllMocks();
-    getActiveMatrixClientMock.mockReturnValue(null);
-    isBunRuntimeMock.mockReturnValue(false);
-    getMatrixRuntimeMock.mockReturnValue({
-      config: {
-        loadConfig: () => ({}),
-      },
-    });
-    resolveMatrixAuthContextMock.mockReturnValue({
-      cfg: {},
-      env: process.env,
-      accountId: "default",
+    primeMatrixClientResolverMocks({
       resolved: {},
     });
-    resolveMatrixAuthMock.mockResolvedValue({
-      accountId: "default",
-      homeserver: "https://matrix.example.org",
-      userId: "@bot:example.org",
-      accessToken: "token",
-      password: undefined,
-      deviceId: "DEVICE123",
-      encryption: false,
-    });
-    createMatrixClientMock.mockResolvedValue(createMockMatrixClient());
 
     ({ resolveMatrixClient } = await import("./client.js"));
   });