How to test alarm without horn blaring?

This is probably a silly question, and I do apologize. :) I live in an apartment complex and am installing a remote starter on my car. I have a tendency to stay up until 1-2am working on the car, which isn't a problem. The problem is that while doing the installing and testing everything, I keep accidentally setting the factory alarm off, which blares the horn and is quickly putting me atop the Most Hated resident list. While doing my install and initial troubleshooting, I am trying to think of an easy way to know when the alarm has been tripped without the sleep-disrupting horn blaring. Do car horns sound by getting a 12v pulses? If so, could I just disconnect the wires going to the horn and attach them to a strobelight or something like that instead?

Your horn has only 1 wire attached to it. It is a positive voltage. Yes you can disconnect that wire and attach it to a lamp.

You didn't say what type of car you have. My Ford truck has a relay for the horn in the dash board fuse center. When I'm programing or working on the system and don't want to annoy the neighbors, I put a relay with #30 bent over sideways in the horn position. I can hear the relay clicking to indicate horn activation, but there's no power sent to the horn because the pin is not making contact.

The car is a Honda Pilot. It has two horns. In the end, I disconnected one of the horns and shoved a sock in the other one. It quietened it down quite nicely. I will put everything back the way it was once the install is complete.