I know. I don't like either, but `setUpBeforeClass` is static and I need to pass the kernel to the helper. I could have configured the helper as a service, but it doesn't solve the problem, because to access the service I need to access the kernel anyway. 
`getKernel` is inherited from WebTestCase (basic brick provided by Symfony), and it's not static. Even if I had something like `getStaticKernel` it should complain the $this->kernel is not a static property.

Any suggestion?