test: add CI-safe unit coverage across LockIMEKit

[BlackHole1]

What

Raises unit-test coverage of Sources/LockIMEKit so every non-off-limits file reaches ≥90% line coverage on a non-exempt basis. All new tests are CI-safe (no hardware/system access) and were written red-first.

Per-file coverage (xccov, before → after)

File	before	after (raw)	non-exempt
Rules/LockConfiguration.swift	82.86%	100%	100%
Localization/SupportedLanguage.swift	75.86%	100%	100%
Updates/UpdateChannel.swift	90.00%	100%	100%
LockEngine/LockEngine.swift	75.23%	88.99%	95.10% (97/102)
Logging/LogStore.swift	75.00%	84.62%	91.67% (44/48)
LockEngine/InputSourceChangeObserver.swift	65.00%	80.00%	92.31% (48/52)
LoginItem/LoginItemController.swift	38.46%	51.52%	94.44% (17/18)

Overall non-exempt coverage across non-off-limits files: 547/567 = 96.5%.

How

• Mock-driven via the existing seams (MockInputSourceProvider, MockFrontmostMonitor, MockBrowserURLProvider). No Carbon/TIS, NSWorkspace, Accessibility, SMAppService, or wall-clock access — passes on headless CI, never mutates machine state.
• Red-first: every test was seen failing before passing (value mutations for existing behavior; a pre-extraction compile error for the new logic). All mutations reverted.
• The only source change extracts the pure register/unregister decision out of LoginItemController.setEnabled into a testable action(desiredEnabled:current:). The switch maps 1:1 to the previous if/else — launch-at-login behavior is unchanged, and the new symbols are internal (invisible to the app module).

System-call exemptions (remaining uncovered lines)

Each is genuinely unexercisable CI-safe; verified by an adversarial audit pass:

• LoginItemController 38/40/53-65 — SMAppService.mainApp status/register/unregister.
• LockEngine 86-93 — private handlers wired only to the internally-constructed (non-injected) InputSourceChangeObservers, fired only by CFNotificationCenter.
• InputSourceChangeObserver 47-54 — the C callback body; only real distributed-notification delivery invokes it.
• LogStore 22-23 (real applicationSupportDirectory write) and 43/57 (SwiftData save/delete error catch — can't force a throw on a valid container).

The 5 off-limits shims (TISInputSourceProvider, FocusNudge, AppActivationMonitor, InstalledAppsScanner, AccessibilityBrowserURLReader) were not touched.

Verification

make test green — 133 tests, 0 failures, incl. LocalizationGuardTests.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro

Run ID: 33fd8a8b-08ff-4b3d-86b3-624c05a48223

📥 Commits

Reviewing files that changed from the base of the PR and between b4895c4 and c43b5d9.

📒 Files selected for processing (8)

• Sources/LockIMEKit/LoginItem/LoginItemController.swift
• Tests/LockIMEKitTests/InputSourceChangeObserverTests.swift
• Tests/LockIMEKitTests/LockConfigurationTests.swift
• Tests/LockIMEKitTests/LockEngineTests.swift
• Tests/LockIMEKitTests/LogStoreTests.swift
• Tests/LockIMEKitTests/LoginItemControllerTests.swift
• Tests/LockIMEKitTests/SupportedLanguageTests.swift
• Tests/LockIMEKitTests/UpdateChannelTests.swift

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Summary by CodeRabbit

• Refactor

  • Improved internal login-item registration logic with clearer decision handling.

• Tests

  • Expanded test coverage for input source observation, configuration management, engine lifecycle, logging, language support, and update channels.

Walkthrough

This PR adds a pure decision-logic helper to LoginItemController by extracting the enable/disable determination into a reusable action(desiredEnabled:current:) function that returns a LoginItemAction enum, allowing setEnabled(_:) to delegate its conditional registration logic. The change is accompanied by six new test suites validating identity invariants and public-facing behaviors across core components: InputSourceChangeObserver notification mappings, LockConfiguration rule lookup and Codable behavior, LockEngine lifecycle and accessor delegation, LogStore fallback resilience, SupportedLanguage locale identity and endonyms, and UpdateChannel id consistency.

🚥 Pre-merge checks | ✅ 4

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	The PR title 'test: add CI-safe unit coverage across LockIMEKit' follows the required format with type and subject, clearly describing the main change (adding unit test coverage).
Description check	✅ Passed	The PR description comprehensively explains the changes, coverage improvements, testing approach, and verification, directly relating to the changeset of new test files and a small refactoring.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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✨ Finishing Touches

✨ Simplify code

• Create PR with simplified code
• Commit simplified code in branch add-test

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