TheAlgorithms-PHP/tests/Ciphers/CiphersTest.php

<?php

use PHPUnit\Framework\TestCase;

require_once __DIR__ . '/../../vendor/autoload.php';
require_once __DIR__ . '/../../Ciphers/CaesarCipher.php';
require_once __DIR__ . '/../../Ciphers/XORCipher.php';

class CiphersTest extends TestCase
{
    public function testCaesarCipher()
    {
        $this->assertEquals('Aopz pz h alza.', encrypt('This is a test.', 7));
        $this->assertEquals('Aopz pz h alza.', encrypt('This is a test.', 7 + 26));
        $this->assertEquals('This is a test.', decrypt('Aopz pz h alza.', 7));
        $this->assertEquals('This is a test.', decrypt('Aopz pz h alza.', 7 + 26));
    }

    public function testXorCipher()
    {
        $input_str = "test@string";
        $key = "test-key";
        $invalid_key = "wrong-key";
        $this->assertEquals($input_str, xorCipher(xorCipher($input_str, $key), $key));
        $this->assertNotEquals($input_str, xorCipher(xorCipher($input_str, $key), $invalid_key));
    }
}