Add testing to TCA

[Liqs-v2]

Problem

TCA is currently, for the most part untested. To ensure that we deliver a quality application with good usability, I would like to extend the app's test suite.

Since I have already worked with the calendar module for two other PRs and it is one of the more vital features, I would start with adding testing for this module. If you'd prefer me to test some other code (eg. backend) let me know in the comments.

Prioritization

I would suggest focusing on the part of the application responsible for fetching the events and displaying them to the user, as these are the most vital.

I would thus work on: CalendarActivity, CalendarController, CalendarFragment initially. After that features such as displaying the details of a calendar item and creating a new private calendar item can be tested.

Suggested Enhancement ✨

Testing suite covers calendar module. Unit and Integration tests.

I would pick this issue up immediately and work on it.

[Liqs-v2]

Okay so sadly I still cannot login right now, so I can't access the calendar component. Does anyone know if this is a TUMOnline issue? The codebase didn't change as far as I'm aware and it hasn't been working since yesterday.

[Liqs-v2]

After some digging it seems that is to do with has to do with API, as the app crashes when the tumCabeClient.verifyKey() is called in OnboardingExtrasFragment.kt:134

I will thus work on another issue until this is resolved.

[Liqs-v2]

Nevermind, clearing the app storage on the device fixed the issue. Not sure what exactly is going on there.

[joschahenningsen]

Nevermind, clearing the app storage on the device fixed the issue. Not sure what exactly is going on there.

Seems to be a regression of #1395 #1389