Configuración de PHPUnit y primera prueba

¿Qué es PHPUnit?

Instalar PHPUnit

$ composer require --dev phpunit/phpunit "^11.0"

Configuración de phpunit.xml

<?xml version="1.0" encoding="UTF-8"?>
<phpunit xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:noNamespaceSchemaLocation="vendor/phpunit/phpunit/phpunit.xsd"
         bootstrap="vendor/autoload.php">
    <testsuites>
        <testsuite name="Unit">
            <directory>tests/</directory>
        </testsuite>
    </testsuites>
</phpunit>

Escribir una clase de prueba

<?php
use PHPUnit\Framework\TestCase;

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

La clase que se está probando

<?php
class Calculator
{
    public function add(int $a, int $b): int
    {
        return $a + $b;
    }
}

Ejecutar las pruebas

$ vendor/bin/phpunit
...
OK (1 test, 1 assertion)

Convenciones para nombrar pruebas

<?php
/** @test */
public function addition_returns_correct_sum(): void
{
    $this->assertEquals(5, (new Calculator())->add(2, 3));
}

Estructura de directorios

src/Calculator.php       → Calculator
tests/CalculatorTest.php → CalculatorTest

setUp() y tearDown()

<?php
protected function setUp(): void
{
    $this->calc = new Calculator();
}

public function test_add(): void
{
    $this->assertEquals(7, $this->calc->add(3, 4));
}

setUpBeforeClass() y tearDownAfterClass()

Cobertura de código

$ vendor/bin/phpunit --coverage-html coverage/

Resumen

Comprobación rápida