ejecutar phpunit

desde la carpeta Test en la terminal:

../vendor/bin/phpunit AnimalTest

donde 

<?php

require_once('Animal.php');

use PHPUnit\Framework\TestCase;

class AnimalTest extends PHPUnit_Framework_TestCase {

protected function setUp(){

$this->animal = new Animal('','','',11);

}

public function testSonido(){

$this->assertEquals('Guaau',$this->animal->sonido());

}

}