diff --git a/src/lib/logoutFlow.test.ts b/src/lib/logoutFlow.test.ts
index d437ef9..3cbaccb 100644
--- a/src/lib/logoutFlow.test.ts
+++ b/src/lib/logoutFlow.test.ts
@@ -2,12 +2,15 @@ import { completeLogout, reportLogoutAudit } from "./logoutFlow";
 
 describe("reportLogoutAudit", () => {
   it("starts an authenticated keepalive request", async () => {
-    const fetcher = jest.fn(async () => ({ ok: true }) as Response);
+    const fetcher = jest.fn(
+      async (_input: RequestInfo | URL, _init?: RequestInit) =>
+        ({ ok: true }) as Response,
+    );
 
     await reportLogoutAudit({
       endpoint: "https://server.example/api/v1/audit-events",
       accessToken: "access-token",
-      fetcher,
+      fetcher: fetcher as typeof fetch,
     });
 
     expect(fetcher).toHaveBeenCalledTimes(1);