Tests

[bdlukaa]

Some errors are sneaky (like #127) and lead to unexpected crashes. These errors and crashes could be easily avoided with unit tests. In the future, widget testing could also be implemented.

Additional context

• flutter_test
• https://docs.flutter.dev/testing

[bdlukaa]

Added the Flutter Analysis/tests workflow. Now, every test under the test folder will run on every pull-request, merge or release.

[bdlukaa]

Some of the unit tests are:

• [ ] API
  • [ ] checkServerCredentials
  • [ ] Version Mismatch error
  • [ ] Successful response
  • [ ] getDevices
  • [ ] getEvents
  • [ ] ptz
• [ ] Downloads
  • [ ] Correctly read persisted values
  • [ ] Default download directory returns the correct value
  • [ ] Download event if its file doesn't exist on initialization
  • [ ] Correctly download event file
  • [ ] Correctly delete an event and its file
  • [ ] Correctly cancel a ongoing download
• [ ] Settings
  • [ ] Correctly persist data
  • [ ] Correctly read persisted data
• [ ] Other
  • [ ] Correctly convert timezone-aware dates
  • [ ] Find the correct device on List<Server>.findDevice(<id>)
  • [ ] Correctly sort Iterable<Device>.sorted according to the parameters