}

    @Test
    @DisplayName("isAnonymous: depends on subject presence and super")
    void isAnonymous_behaviour() {
        Kerb5Authenticator anon = new Kerb5Authenticator((Subject) null);
        assertTrue(anon.isAnonymous(), "Null subject with default super should be anonymous");

        Kerb5Authenticator nonAnon = new Kerb5Authenticator(new Subject());
        assertFalse(nonAnon.isAnonymous());