[CLX-3740][S] Add tests cases inbox

[Ahmed-Naguib93]

refs: CLX-3740
builds: Student
affects: Student
release note: none

test plan: none

[claude]

Claude Code Review

Updated: 2026-01-08

✅ Approved. Changes are correct.

Summary:

• InboxMessageModel refactored from computed to stored properties - all initializations properly updated via convenience initializers (lines 56-68, 292-305)
• AnnouncementInteractor guard statement prevents redundant work when announcement already marked read
• ViewModel refactoring: business logic extracted to testable helper methods (shouldIncludeAnnouncements, filterAnnouncementsByReadStatus, messageMatchesPeopleFilter)
• AnnouncementsPublisher correctly uses CurrentValueSubject with proper replay semantics
• Class declarations updated to final for performance optimization
• Comprehensive test coverage added (672 lines in HInboxViewModelTests)
• All publisher subscriptions properly composed and stored

No critical issues found.

[inst-danger]

	Warnings
⚠️	This pull request will not generate a release note.
⚠️	One or more files are below the minimum test coverage 50%

Affected Apps: Student

Builds: Student

Coverage	New %	Master %	Delta
Canvas iOS	91.33%	81.06%	10.27%
Core/Core/Common/Extensions/PDFKit/PDFDocumentExtensions.swift	0%	--	--

Generated by 🚫 dangerJS against f232651

[inst-danger]

Builds

Commit: fix: code review comments (f232651)
Build Number: 1116
Built At: Jan 08 15:27 CET (01/08 07:27 AM MST)

Student

[claude]

Claude Code Review

Critical Issue Found

Race Condition in Announcements Publisher (HInboxViewModel.swift:54,235-254)

• announcementsPublisher is a PassthroughSubject without replay capability
• In listenForMessagesAndAnnouncements(), CombineLatest4 won't emit until all four publishers emit
• Initial announcements from init may be lost if other streams haven't emitted yet
• Symptom: Announcements missing on initial load, especially under slow network
• Fix: Use CurrentValueSubject instead or restructure initialization order

✅ Remaining changes acceptable (model refactoring, test additions, class->final)