1. If alerts is empty after `relabelAlerts`, just return to avoid subsequent unnecessary operations 2. minor fix in notifier's test case 3. minor fix in comment Signed-off-by: YaoZengzeng <yaozengzeng@zju.edu.cn>
1. If alerts is empty after `relabelAlerts`, just return to avoid subsequent unnecessary operations 2. minor fix in notifier's test case 3. minor fix in comment Signed-off-by: YaoZengzeng <yaozengzeng@zju.edu.cn>