Look at the device page and enable debug logging. Do your test and then look at the device events. Did doing a test trigger an event? If not, Hubitat isn't seeing it because the alarm isn't sending anything.
I would not be surprised if a test didn't raise an event, but a real fire would. That being said, don't get the idea to burn paper under the alarm to test it.
From what I remember the test button doesn't set an event. Take a paper towel, light it on fire (over sink) blow it out and wave it at the fire alarm so it goes off. It should now send an event.
Test never worked for me. Just an "onboard/local" function test I guess.
Hilariously, I light a paper towel and blow it out for some smoke haha. And, they are not fast at recognizing it. I guess reduces false alarms. Silly, but I've done it a lot as I have a few of the first alerts and after having a bad detached garage fire a few years ago, I'm SUPER paranoid about alerts and function.
The event is coming through to the hub, but because the event is "test", would not trigger HSM builtin smoke, but the real event should trigger the smoke event in HSM.