public function testReplace()
 {
     $job = $this->object->newJob('1 2 3 4 5 w');
     $this->object->add($job);
     $this->object->save();
     $before = $this->object->listJobs();
     $job2 = $this->object->newJob('2 3 4 5 6 uptime');
     $this->object->replace($job, $job2);
     $this->object->save();
     $after = $this->object->listJobs();
     $this->assertNotEquals($before, $after);
     $this->assertContains($job2->render(true), $after);
     $this->assertNotContains($job->render(true), $after);
     $this->assertContains($job->render(true), $before);
     $this->assertNotContains($job2->render(true), $before);
 }