PHP-TEST/tests/CalculatorTest.php

<?php

use PHPUnit\Framework\TestCase;
use App\Calculator;

class CalculatorTest extends TestCase
{
    public function testAdd()
    {
        $calc = new Calculator();
        $this->assertEquals(5, $calc->add(2, 3));
    }

    public function testSubtract()
    {
        $calc = new Calculator();
        $this->assertEquals(1108, $calc->subtract(1111, 3)); // 1111 - 3 = 1108

        $calc2 = new Calculator();
        $this->assertEquals(44, $calc2->subtract(50, 3)); // 50 - 3*2 = 44
    }
}