Handle missing vevent attributes

[devmount]

Description of the Change

This change ignores all remote events, that don't have a dtstart or neither a dtend nor duration. Also the event title gets a default value, if summary is missing.

Benefits

Wider range of supported caldav servers.

Applicable Issues

Fixes #741

[devmount]

How can we actually test this? Our current tests (correct me if I'm wrong) always fake the list_events() function. Is there a way to acutally test the caldav connector?

[MelissaAutumn]

How can we actually test this? Our current tests (correct me if I'm wrong) always fake the list_events() function. Is there a way to acutally test the caldav connector?

We can create some mock ical files, and have list_events return those files initialized into icalendar (iirc) instead. It's a little confusing because I think python-caldav handles the server requests and responses, but then it uses icalendar for the calendar/event objects...I think.

[MelissaAutumn]

Thanks!

[devmount]

Good idea, I'll play around with that a bit and create some tests. Those should live in test_calendar.py rather than test_appointment.py, right?

[MelissaAutumn]

Yep probably as a unit test if you want to test the functions directly. Let me know if you run into any issues there!

[devmount]

Postponed the test creation for now.