In order to test LoginNotify in a single-IP environment (such as a VM on which a developer is testing the code), we need a way to create fake login attempts from an arbitrary IP address. I think the best solution is a maintenance script used as such:
maintenance/loginAttempt.php --user Admin --IP 18.104.22.168 --UA "Some User Agent" --success 1
Where user is the username for which a login attempt will be made, IP and UA are self-explanatory, and success is 0 if the login failed, and 1 if it succeeded.
By default, success is 0, and UA also defaults to something like Login attempt by LoginNotify maintenance script. The user and IP parameters would be mandatory.