Noobie.. How can I tell if my humidifer works?

I bought my first humidor, which is a 10 cigar travel humidor. It doesn't have a hygrometer, and I have a tiny humidifier. My cigars have only been in there for about 3 days, and they still smell fresh, but I don't really know how to tell if they're fresh or if the humidifer is working.

Is there any sort of a test or any way i can tell if it's working? I just feel uneasy without being able to visually see that its doing its job. I soaked it in a bag of distilled water for 3 minutes, and then put it in the humidor for an hour, then put all my cigars in the humidor.