title: Can't find Yii2 classes in Codeception test
body: <p>I am beginning to use Codeception for Unit testing within Yii2. Great that Yii2 embraces it completely now, a major reason for me to upgrade!</p>
  
  <p>I am having difficulties letting Codeception find the classes. Controller classes that I have written e.g. These classes load fine by autoloading in the Yii2 application.</p>
  
  <p>E.g. this controller:</p>
  
  <pre><code>&lt;?php
  
  class RecipeControllerTest extends \Codeception\TestCase\Test
  {
     /**
      * @var \UnitTester
      */
      protected $tester;
  
      protected function _before()
      {
      }
  
      protected function _after()
      {
      }
  
      // tests
      public function testMe()
      {
        echo \app\controllers\RecipesController::getallrecipes();
      }
  
  }
  </code></pre>
  
  <p>Results when I do <code>codeception run unit</code> in the console in his output:</p>
  
  <blockquote>
    <p>FATAL ERROR. TESTS NOT FINISHED.</p>
    
    <p>Class '<code>app\controllers\RecipesController</code>' not found</p>
  </blockquote>
  
  <p>My <code>_bootstrap.php</code> file includes this:</p>
  
  <pre><code>require_once(__DIR__ . '/../../vendor/autoload.php');
  require_once(__DIR__ . '/../../vendor/yiisoft/yii2/Yii.php');
  </code></pre>
  
  <p>So I am sure I'm doing something wrong but am clueless.</p>