public function testWorkerCanUnregister()
 {
     $worker = new Worker('*');
     $worker->registerWorker();
     $worker->unregisterWorker();
     $this->assertFalse(Worker::exists((string) $worker));
     $this->assertEquals(array(), Worker::all());
     $this->assertEquals(array(), $this->redis->smembers('resque:workers'));
 }