}
    }

    @Nested
    @DisplayName("toString() Tests")
    class ToStringTests {

        @Test
        @DisplayName("toString with valid data produces expected format")
        void testToStringWithValidData() {
            byte[] challenge = new byte[] { (byte) 0x01, (byte) 0x02, (byte) 0x03, (byte) 0xFF };
            UniAddress dc = mock(UniAddress.class);
            when(dc.toString()).thenReturn("SERVER123");