public function testSetPrefix()
 {
     $builder = new ServiceIdBuilder();
     $this->assertSame('config', $builder->getPrefix());
     $builder->setPrefix($expected = 'zzz');
     $this->assertSame($expected, $builder->getPrefix());
 }
 protected function getCacheId()
 {
     if (is_null($this->cacheId)) {
         $builder = new ServiceIdBuilder();
         $this->cacheId = $builder->getPrefix();
     }
     return $this->cacheId;
 }