test(alerts): cover alert lifecycle and rendering

[frittlechasm]

Pull Request

Description

Adds test coverage for the TUI alerts package as part of #63.

Changes Made

• Added tests for alert creation, queuing, expiration, and timer handling
• Added tests for alert positioning, visibility, colors, icons, and rendered content
• Added clearly documented coverage-only tests for simple and defensive code paths

Testing

• Tested locally with example workflows
• Added new tests (if applicable)
• Tested with different filters, output, etc...

Commands run:

go test -race -cover ./internal/render/tui/alerts/

Checklist

• I have starred the repository
• My code follows the project's code style
• I have updated the documentation (README, cli-flags, etc...)
• My changes generate no new warnings
• I have tested my changes in a real workflow
• All tests pass locally

Greptile Summary

Adds comprehensive package-level tests for TUI alert behavior without changing production code.

• Covers queueing, expiration, timer scheduling, and ignored messages.
• Verifies alert positioning, overflow visibility, theme updates, colors, icons, and rendered content.
• The alert tests completed successfully across repeated normal and race-enabled runs, with full statement coverage.

Confidence Score: 5/5

Safe to merge; the added tests behave reliably under repeated execution and race detection.

No actionable issues were identified. Repeated alert-package test runs, race-enabled runs, and atomic coverage validation all completed successfully.

Files Needing Attention: None.

T-Rex Logs

What T-Rex did

• Validated the pre-PR baseline by running trex-artifacts/validate-alert-tests.sh and confirming the baseline commit 2512196^ had no alert-test files and exited successfully.
• Ran the alert-package tests 100 times and executed race-detection 25 times; all runs passed, no data races were reported, and per-test output for added lifecycle, layout, rendering, theme, and timer checks was retained.
• Executed atomic race coverage and confirmed all alert-package statements were covered.

_{Ran code and verified through T-Rex}

_{Reviews (1): Last reviewed commit: "test(alerts): organize coverage around b..." | Re-trigger Greptile}

Context used:

• Knowledge Base — Results presentation