Testing

[michalrentka]

As discussed previously it would be nice to increase our test coverage. I'll list which places need improvement the most:

• SyncScheduler - scheduler itself doesn't have test coverage. We should add tests which check whether syncs are started properly when requested, appropriate delays are applied on retry, etc.
• Sync actions - there is some coverage, mostly of more complicated actions which revert changes. We can add tests for more actions where it makes sense. Most of them just fetch and store some data.
• Sync controller - has good coverage, but one thing is missing. When a conflict happens, user is asked to take next step (through ConflictCoordnator) and based on user action taken some sync steps are taken. We should add tests that check whether ConflictCoordinator is properly called when a conflict arises and when some option is picked then proper actions are called by SyncController.
• Test proper creation of annotations via CreateAnnotationsDbRequest. Check other ...DbRequest structs to test.
• ItemResponseSpec - we should include more options for item parsing, like parsing of annotations or attachments.
• TranslatorsAndStylesController - has some test coverage in TranslatorsControllerSpec, need to update tests for styles, which were added later.
• AnnotationSplitter - check whether rects/paths are split properly
• AttachmentCreator - check whether RItem is properly converted to Attachment
• CustomURLController - check whether URL is properly converted to CustomURLController.Kind
• ISBNParser
• View models - might be worth adding tests to view models of bigger/more complicated screens.

Feel free to add more places to the list or just add more tests as needed.