[chore] write unit tests

[diegoberaldin]

Tests are being added module by module in the androidUnitTest source set. This card has been created to keep track of the progress so far:

• [x] :core:api (does not need to be tested, mostly generated code)
• [x] :core:appearance
• [x] :core:architecture (does not need to be tested, just framework)
• [ ] :core:commonui:components
• [x] :core:commonui:detailopener-api (does not need to be tested, only public API)
• [x] :core:commonui:detailopener-impl
• [ ] :core:commonui:lemmyui
• [ ] :core:commonui:modals
• [x] :core:l10n (does not need to be tested, generated code)
• [ ] :core:markdown
• [x] :core:navigation
• [x] :core:notifications
• [x] :core:persistence
• [x] :core:preferences
• [x] :core:resources (does not need to be tested, just exposes resources)
• [x] :core:testutils (does not need to be tested)
• [x] :core:utils
• [x] :domain:identity
• [x] :domain:inbox
• [x] :domain:lemmy:data (does not need to be tested, just data classes)
• [x] :domain:lemmy:pagination
• [ ] :domain:lemmy:repository (partially done)
• [ ] :feature:home
• [ ] :feature:inbox
• [ ] :feature:profile
• [ ] :feature:search
• [ ] :feature:settings
• [ ] :unit:about
• [ ] :unit:accountsettings
• [ ] :unit:ban
• [ ] :unit:chat
• [ ] :unit:choosecolor
• [ ] :unit:choosefont
• [ ] :unit:communitydetail
• [ ] :unit:communityinfo
• [ ] :unit:configurecontentview
• [ ] :unit:configureswipeactions
• [ ] :unit:createcomment
• [ ] :unit:createpost
• [ ] :unit:createreport
• [ ] :unit:drafts
• [ ] :unit:drawer
• [ ] :unit:editcommunity
• [ ] :unit:explore
• [ ] :unit:filteredcontents
• [ ] :unit:instanceinfo
• [ ] :unit:licences
• [ ] :unit:login
• [ ] :unit:manageaccounts
• [ ] :unit:manageban
• [ ] :unit:managesubscriptions
• [ ] :unit:mentions
• [ ] :unit:messages
• [ ] :unit:moderatewithreason
• [ ] :unit:modlog
• [ ] :unit:multicommunity
• [ ] :unit:myaccount
• [ ] :unit:postdetail
• [ ] :unit:postlist
• [ ] :unit:rawcontent
• [ ] :unit:replies
• [ ] :unit:reportlist
• [ ] :unit:selectcommunity
• [ ] :unit:selectinstance
• [ ] :unit:userdetail
• [ ] :unit:userinfo
• [ ] :unit:web
• [ ] :unit:zoomableimage