diff --git a/tests/integration/headplane/machines.test.ts b/tests/integration/headplane/machines.test.ts
index 35308f5b..577bcb8e 100644
--- a/tests/integration/headplane/machines.test.ts
+++ b/tests/integration/headplane/machines.test.ts
@@ -26,7 +26,7 @@ describe("machines on a real tailnet", () => {
   });
 
   function machine(form: Record<string, string>) {
-    return app.call(machineAction as never, "/machines", { as: owner, form });
+    return app.call(machineAction, "/machines", { as: owner, form });
   }
 
   test("a waiting machine registered from its URL comes online for that user", async () => {
@@ -110,7 +110,7 @@ describe("DNS on a real tailnet", () => {
 
     const node = await tailnet.node({ name: "dns-client", user: "alice@" });
     const { cookie } = await app.signIn("owner");
-    const result = await app.call(dnsAction as never, "/dns", {
+    const result = await app.call(dnsAction, "/dns", {
       as: cookie,
       form: {
         intent: "add_record",
diff --git a/tests/support/app.ts b/tests/support/app.ts
index e649df52..525e6ad4 100644
--- a/tests/support/app.ts
+++ b/tests/support/app.ts
@@ -21,7 +21,8 @@ export interface TestAppOptions {
 
 export type TestApp = Awaited<ReturnType<typeof createTestApp>>;
 
-type RouteFunction = (args: LoaderFunctionArgs & ActionFunctionArgs) => unknown;
+// Any loader or action, whatever its generated argument types.
+type RouteFunction = (args: never) => unknown;
 
 export interface CallOptions {
   as?: string;
@@ -120,7 +121,9 @@ export async function createTestApp(options: TestAppOptions = {}) {
     };
 
     try {
-      return await fn(args as unknown as LoaderFunctionArgs & ActionFunctionArgs);
+      return await (fn as (args: LoaderFunctionArgs & ActionFunctionArgs) => unknown)(
+        args as unknown as LoaderFunctionArgs & ActionFunctionArgs,
+      );
     } catch (error) {
       return error;
     }
diff --git a/tests/unit/routes/auth-keys.test.ts b/tests/unit/routes/auth-keys.test.ts
index db7043af..358b87c5 100644
--- a/tests/unit/routes/auth-keys.test.ts
+++ b/tests/unit/routes/auth-keys.test.ts
@@ -20,7 +20,7 @@ afterEach(async () => {
 });
 
 function create(as: string, form: Record<string, string | string[]>) {
-  return app.call(action as never, "/settings/auth-keys", {
+  return app.call(action, "/settings/auth-keys", {
     as,
     form: { intent: "create", expiry: "90", ...form },
   });
@@ -90,7 +90,7 @@ describe("self-service auth keys", () => {
     await create(admin, { user_id: bob.id });
     await create(admin, { tags: "tag:prod" });
 
-    const data = (await app.call(loader as never, "/settings/auth-keys", {
+    const data = (await app.call(loader, "/settings/auth-keys", {
       as: await signInAsAlice(),
     })) as Awaited<ReturnType<typeof loader>>;
 
@@ -104,7 +104,7 @@ describe("self-service auth keys", () => {
     await create(cookie, { user_id: bob.id });
     await create(cookie, { tags: "tag:prod" });
 
-    const data = (await app.call(loader as never, "/settings/auth-keys", {
+    const data = (await app.call(loader, "/settings/auth-keys", {
       as: cookie,
     })) as Awaited<ReturnType<typeof loader>>;
 
diff --git a/tests/unit/routes/login.test.ts b/tests/unit/routes/login.test.ts
index 214d19ea..0c99b3bc 100644
--- a/tests/unit/routes/login.test.ts
+++ b/tests/unit/routes/login.test.ts
@@ -6,7 +6,7 @@ import { HEADSCALE_VERSIONS } from "../../harness/versions";
 import { createTestApp, type TestApp } from "../../support/app";
 
 async function signIn(app: TestApp, form: Record<string, string>) {
-  return app.call(action as never, "/login", { form });
+  return app.call(action, "/login", { form });
 }
 
 describe.for(HEADSCALE_VERSIONS)("API key sign-in on Headscale %s", (version) => {
diff --git a/tests/unit/routes/permissions.test.ts b/tests/unit/routes/permissions.test.ts
index 5dcd6af8..cc7bbf20 100644
--- a/tests/unit/routes/permissions.test.ts
+++ b/tests/unit/routes/permissions.test.ts
@@ -112,7 +112,7 @@ describe("route permissions", () => {
   });
 
   function callAction(entry: Entry, as?: string) {
-    return app.call(entry.module.action! as never, entry.path, {
+    return app.call(entry.module.action!, entry.path, {
       as,
       form: { ...form, ...(entry.intent ? { intent: entry.intent } : {}) },
       params: { id: form.node_id },
@@ -129,7 +129,7 @@ describe("route permissions", () => {
     async ([, entry]) => {
       const callers = MEMBER_VISIBLE.has(entry.file) ? [undefined] : [undefined, "member" as const];
       for (const role of callers) {
-        const result = await app.call(entry.module.loader! as never, entry.path, {
+        const result = await app.call(entry.module.loader!, entry.path, {
           as: role && cookies.get(role),
           params: { id: form.node_id },
         });