assertNotNull(auth, "Authenticator should remain usable after refresh");
    }

    @Test
    @DisplayName("handle: sets NameCallback and PasswordCallback on happy path")
    void testHandleSetsNameAndPasswordHappyPath() throws Exception {
        JAASAuthenticator auth = new JAASAuthenticator("DOM", "user", "pass");
        NameCallback nc = new NameCallback("user:");