PHPUnit Basics (Write Your First Unit Test)

Testing protects your code from regressions. ## Step 1: Install PHPUnit (Composer) ```bash composer require --dev phpunit/phpunit ``` ## Step 2: Create a simple function File: `src/Math.php` ```php <?php function add(int $a, int $b): int { return $a + $b; } ``` ## Step 3: Write a test File: `tests/MathTest.php` ```php <?php use PHPUnit\Framework\TestCase; require_once __DIR__ . "/../src/Math.php"; class MathTest extends TestCase { public function testAdd() { $this->assertEquals(5, add(2, 3)); } } ``` ## Step 4: Run tests ```bash ./vendor/bin/phpunit ``` > Next: Mocking dependencies, test services without real database calls.