What test scenarios are necessary and sufficient to exhaustively black box test a recurring appointment model?

Question

I have a django model for an appointment in a calendar that I am attempting to write a very comprehensive test driver for. The recurring appointment occurs at some point in time and can either run on infinitely or recur for a fixed number of times. The appointment mirrors the functionality available for a Google Calendar appointment (can recur monthly/annually/weekly, every two weeks, every 3 years.)

I'm trying to come up with a unit test that will exhaustively test the basics of this implementation. I am looking for the edge cases that will define the most basic tests.

I have a lot of basic ones, but am looking for suggestions to help identify the most important cases: 1) Create a single appointment 2) Create an appointment that recurs weekly 3) ... recurs monthly 4) recurs every 2 weeks 5) recurs every 2 months 6) recurs annually

Answer 1

Test with final days of months, leap years, and whether it will go crazy when the year has an extra second (this one hit a driver in the zune player).

Test it behaves well when crossing years.

That said, consider whether you are re-testing something that is part of the framework. Testing date logic can get ugly real fast, so you want to draw a line on what is part of your application and what is part of the framework.