diff --git a/test/Authentication.test.ts b/test/Authentication.test.ts
index 4f91abc..032e24a 100644
--- a/test/Authentication.test.ts
+++ b/test/Authentication.test.ts
@@ -197,18 +197,19 @@ describe('Register with email (magic_link)', () => {
     });
 
     test('Cannot register without specifying username', async () => {
-        const res = await agent.get('/csrf').expect(200);
+        let res = await agent.get('/csrf').expect(200);
         const cookies = res.get('Set-Cookie');
         const csrf = res.text;
 
-        await agent.post('/auth/register')
+        res = await agent.post('/auth/register')
             .set('Cookie', cookies)
             .send({
                 csrf: csrf,
                 auth_method: 'magic_link',
-                identifier: 'glimmer@example.org',
+                identifier: 'no_user_name@example.org',
             })
             .expect(400);
+        expect(res.body.messages?.name?.name).toStrictEqual('UndefinedValueValidationError');
 
         expect(await popEmail()).toBeNull();
     });