}

    /**
     * Test constructor with an empty token.
     * Empty token causes readObject() to return null, which leads to NullPointerException.
     */
    @Test
    void testConstructor_EmptyToken() {
        // 1. GIVEN
        byte[] emptyToken = new byte[0];
        Map<Integer, KerberosKey> keys = new HashMap<>();

        // 2. WHEN & 3. THEN