/**
  * @test
  */
 public function it_verifies_if_a_service_exists_when_set_up_has_been_called()
 {
     $serviceContainer = new ServiceContainer();
     $serviceContainer['some_service'] = 'some value';
     $serviceContainer->setUp();
     $serviceExists = isset($serviceContainer['some_service']);
     $this->assertTrue($serviceExists);
 }