private MetaInAlarm getMetaInAlarm(int id) {
        return getMetaInAlarm(id, "endpoint_percent");
    }
Running rule is the core of how does alarm work.
<p>
So in this test, we need to simulate a lot of scenario to see the reactions.
oap-server/server-alarm-plugin/src/test/java/org/apache/skywalking/oap/server/core/alarm/provider/RunningRuleTest.java