[Observium] Alert checking on port state change

Hi all, I'm starting to get my head around Observium alerts.

I want to be alerted if a switch port that was previously down comes up, and vice versa. I don't want to get repeatedly alerted when a port is down (or up), only when it changes state. At the moment I'm using tests "ifAdminStatus equals up" and "ifOperStatus notequals up" for one alert, but I appear to be getting notifications each time the poller runs. Any suggestions on how I can get what I want?

Cheers,

Tim