Symfony\Component\HttpKernel\Kernel::getContainerBaseClass PHP Method

    protected function getContainerBaseClass()
    {
        return 'Container';
    }

 /**
  * {@inheritdoc}
  */
 protected function getContainerBaseClass()
 {
     if (in_array($this->getEnvironment(), ['test', 'test_cached'], true)) {
         return MockerContainer::class;
     }
     return parent::getContainerBaseClass();
 }