public function testInvalidate()
 {
     $key = 'test';
     // create a fake list
     $this->cache->register($key, uniqid());
     $this->cache->register($key, uniqid());
     $this->ormCache->save($key, 'bar');
     $this->cache->invalidate($key);
     // now both the orm cache and our cache should not contain this list
     $this->assertFalse($this->ormCache->contains($key));
     $this->assertNotContains($key, $this->cache->getRegisteredKeys($key));
 }