refactor: mls group verification in `ZMUserSession` [WPB-9149]

[markusfassbender]

WPB-9149 iOS: refactor mls group verification in ZMUserSession

Motivation

The ZMUserSession's initialiser takes about 25 arguments. They can be categorised in two:

1. primary dependencies: foundational services, caches etc.. Ideally they should not use other dependencies.
2. secondary dependencies: derived objects that can be initialised by the primary dependencies.

The ObserveMLSGroupVerificationStatusUseCase belongs to category 2 and thus should not be passed to the initialiser of ZMUserSession to avoid a infinite growing of responsibilities.

The second point was, that the use case has a state. Therefore it was required to retain the whole use case and keep a task reference alive, again a responsibility of ZMUserSession until now. This is implicit and cannot be easily understand from the outer scope.

Refactoring

1. While working on it, I figured out that the logic broke into several smaller files, that kind of belong together, and overlapped in some points, logs etc.:

• ObserveMLSGroupVerificationStatusUseCase
• MLSConversationVerificationStatusUpdater
• UpdateMLSGroupVerificationStatusUseCase

ObserveMLSGroupVerificationStatusUseCase and MLSConversationVerificationStatusUpdater got merged into MLSGroupVerification. Extract extension to user session. Simplify mocking and unit tests.

2. Extract CertificateRevocationLists as extension to user session.

Review

[!NOTE] Start your review in ZMUserSession.swift to see the benefit there.

Maybe it's also helpful to checkout the whole branch and read classes in code.

Testing

• Simple test: breakpoints, run the app and login
• For the whole ticket we need to test the MLS group verification with @KaterinaWire and QA.

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Checklist

• [x] Title contains a reference JIRA issue number like [WPB-XXX].
• [x] Description is filled and free of optional paragraphs.
• [x] Adds/updates automated tests.

[github-actions[bot]]

Test Results

    5 files    894 suites   24m 10s :stopwatch: 7 270 tests 7 270 :white_check_mark: 0 :zzz: 0 :x: 7 278 runs  7 278 :white_check_mark: 0 :zzz: 0 :x:

Results for commit 4da25044.

:recycle: This comment has been updated with latest results.

[datadog-wireapp[bot]]

Datadog Report

Branch report: refactor/zmusersession-observeMLSGroupVerificationStatusUseCase Commit report: d03f80d Test service: wire-ios-mono

:white_check_mark: 0 Failed, 7270 Passed, 0 Skipped, 2m 59.94s Total Time