php中PHPUnit框架如何使用？

composer require --dev phpunit/phpunit

{

  "autoload": {

    "psr-4": {

      "Controller\\": "controller/",

      "Model\\": "model/",

      "Service\\": "service/",

      "Test\\": "test/",

    }

  },

}

namespace Service;

class CalculateService

{

    public function abs($num)

    {

      return abs($num);

    }

}