Ticket created as a result of https://mynms.opennms.com/Ticket/Display.html?id=1972
Steps to reproduce, in web UI:
1. Admin -> Configure Users, Groups, and Roles -> Configure Users
2. Click the Modify control for any user
3. At bottom of page in Duty Schedule area, select "1" and click "Add this many schedules"
4. Check at least one day. Leave the default "0" value for both start and end times. Click Finish.
Some kind of error message indicating that the start and end time are the same
Happily commits a schedule that puts the user on duty for a single minute out of the specified day or days (probably not what I wanted)
I think we need to leave intact the possibility to have a single-minute period in the duty schedule, but should both:
A. Warn the user that this is happening
B. Default the end time to a value of 2359 rather than 0