Just call 911, and when connected state that it's a test call and hang up. 911 calls have plenty of capacity for occasional test calls, and the need to test them clearly is important to reduce the risk of them not working when needed.
If you need to do automated tests, there is a test flag in the android dialer API which will make the call but mark it with some test flag so you get a recorded message not a human answering.
If you need to do automated tests, there is a test flag in the android dialer API which will make the call but mark it with some test flag so you get a recorded message not a human answering.