# PHP Unit Testing (PHPUnit)

**PHPUnit** is a programmer-oriented testing framework for PHP. It is an instance of the xUnit architecture for unit testing frameworks.

---

## 1. Installation
The recommended way to install PHPUnit is via Composer.

```bash
composer require --dev phpunit/phpunit
```

## 2. Writing a Test
Tests are usually written in a class that extends `PHPUnit\Framework\TestCase`. The test methods must be public and start with `test`.

```php
use PHPUnit\Framework\TestCase;

class StackTest extends TestCase {
    public function testPushAndPop() {
        $stack = [];
        $this->assertSame(0, count($stack));

        array_push($stack, 'foo');
        $this->assertSame('foo', $stack[count($stack)-1]);
        $this->assertSame(1, count($stack));

        $this->assertSame('foo', array_pop($stack));
        $this->assertSame(0, count($stack));
    }
}
```

## 3. Common Assertions
Assertions are the checks that determine if the code behaves as expected.

*   `$this->assertTrue($condition)`: Check if true.
*   `$this->assertFalse($condition)`: Check if false.
*   `$this->assertEquals($expected, $actual)`: Check if values are equal.
*   `$this->assertSame($expected, $actual)`: Check if values and types are equal (===).
*   `$this->assertCount($count, $haystack)`: Check array count.

## 4. Running Tests
You can run tests using the PHPUnit binary installed by Composer.

```bash
./vendor/bin/phpunit tests/StackTest.php
```

[[programming/php/php]] [[programming/php/php-composer]]