AES 256 CBC unit test

        assert!(p1 == p0);

    }

    #[test]

    fn test_aes_256_cbc_decrypt() {

        let cr = super::Crypter::new(super::AES_256_CBC);

        let iv = vec![

            4_u8, 223_u8, 153_u8, 219_u8, 28_u8, 142_u8, 234_u8, 68_u8, 227_u8,

            69_u8, 98_u8, 107_u8, 208_u8, 14_u8, 236_u8, 60_u8, 0_u8, 0_u8,

            0_u8, 0_u8, 0_u8, 0_u8, 0_u8, 0_u8, 0_u8, 0_u8, 0_u8, 0_u8, 0_u8,

            0_u8, 0_u8, 0_u8

        ];

        let data = [

            143_u8, 210_u8, 75_u8, 63_u8, 214_u8, 179_u8, 155_u8,

            241_u8, 242_u8, 31_u8, 154_u8, 56_u8, 198_u8, 145_u8, 192_u8, 64_u8,

            2_u8, 245_u8, 167_u8, 220_u8, 55_u8, 119_u8, 233_u8, 136_u8, 139_u8,

            27_u8, 71_u8, 242_u8, 119_u8, 175_u8, 65_u8, 207_u8

        ];

        let ciphered_data = [

            0x4a_u8, 0x2e_u8, 0xe5_u8, 0x6_u8, 0xbf_u8, 0xcf_u8, 0xf2_u8, 0xd7_u8,

            0xea_u8, 0x2d_u8, 0xb1_u8, 0x85_u8, 0x6c_u8, 0x93_u8, 0x65_u8, 0x6f_u8

            ];

        cr.init(super::Decrypt, data, iv);

        cr.pad(false);

        let unciphered_data_1 = cr.update(ciphered_data);

        let unciphered_data_2 = cr.finalize();

        // A string translating to "I love turtles." with a trailing

        // 0x1 as last byte.

        let expected_unciphered_data = vec![

            0x49_u8, 0x20_u8, 0x6c_u8, 0x6f_u8, 0x76_u8, 0x65_u8, 0x20_u8, 0x74_u8, 

            0x75_u8, 0x72_u8, 0x74_u8, 0x6c_u8, 0x65_u8, 0x73_u8, 0x2e_u8, 0x1_u8

        ];

        assert!(unciphered_data_2.len() == 0);

        assert_eq!(

            unciphered_data_1,

            expected_unciphered_data

        );

    }

    fn cipher_test(ciphertype: super::Type, pt: &str, ct: &str, key: &str, iv: &str) {

        use serialize::hex::ToHex;