DESTest.java

package com.thealgorithms.ciphers;

import static org.junit.jupiter.api.Assertions.*;

import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.Test;

// Test example taken from https://page.math.tu-berlin.de/~kant/teaching/hess/krypto-ws2006/des.htm
public class DESTest {

    DES des;

    @BeforeEach
    public void setUp() {
        des = new DES("0000111000110010100100100011001011101010011011010000110101110011");
    }

    @Test
    void testEncrypt() {
        // given
        String plainText = "Your lips are smoother than vaseline\r\n";
        // This is equal to
        // c0999fdde378d7ed727da00bca5a84ee47f269a4d6438190d9d52f78f5358499828ac9b453e0e653 in
        // hexadecimal
        String expectedOutput = "11000000100110011001111111011101111000110111100011010111111"
            + "011010111001001111101101000000000101111001010010110101000010011101110010001111111001"
            + "001101001101001001101011001000011100000011001000011011001110101010010111101111000111"
            + "101010011010110000100100110011000001010001010110010011011010001010011111000001110011001010011";

        // when
        String cipherText = des.encrypt(plainText);

        // then
        assertEquals(expectedOutput, cipherText);
    }

    @Test
    void testDecrypt() {
        // given
        // This is equal to
        // c0999fdde378d7ed727da00bca5a84ee47f269a4d6438190d9d52f78f5358499828ac9b453e0e653 in
        // hexadecimal
        String cipherText = "11000000100110011001111111011101111000110111100011010111111"
            + "011010111001001111101101000000000101111001010010110101000010011101110010001111111001"
            + "001101001101001001101011001000011100000011001000011011001110101010010111101111000111"
            + "101010011010110000100100110011000001010001010110010011011010001010011111000001110011001010011";
        String expectedOutput = "Your lips are smoother than vaseline\r\n";

        // when
        String plainText = des.decrypt(cipherText);

        // then
        assertEquals(expectedOutput, plainText);
    }
}