How to test if OEM12c (12.1.0.5) detect and alert archiver hung without actually create a archive hung - production database

I setup the oracle database instance target with metric DB Alert Log > Archiver Hung Alert Log Error with Critical Threshold as ORA-.

As Oracle document says that it "should" alert when log.xml under alert directory content the error.

Is there the way to inject the error so that OEM will detect and send out the alert.

It is production database so I can't not actually cause archive hung without getting fired.

I copied the error from other database log over but doesn't seem alert.

Thanks,
Binh
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