test: add node:test coverage for active-note windowing/sustain fade logic

[OmikronApex]

Twenty-sixth repo from the org test-coverage audit. screen.js has no top-level wrapping IIFE for its function declarations; only the hooks block at the tail is wrapped. The module.exports hook wraps that block in an else-branch (same pattern as feedBack-plugin-sectionmap#9) so it never runs under Node.

10 tests against _fbGetActiveNotes, the function deciding which fretboard dots light up at a given playhead time:

• Standalone notes: within/outside the 80ms window, sustain fade toward a 0.3 floor, stays active through full sustain duration, the sorted-by-time early-break guard doesn't suppress an earlier reachable note
• Chords: members within window all included, a chord onset outside the 0.3s lookback excluded entirely, individual chord-member sustain still governs per-member inclusion once the chord-level gate passes
• Combines standalone notes + chords in one list; tolerates missing/undefined notes and chords

🤖 Generated with Claude Code

Summary by CodeRabbit

• Tests
  • Added automated coverage for note-selection behavior across timing windows, sustain fade handling, chord membership, and mixed note/chord output.
  • Included checks for edge cases such as missing data and efficient handling of far-future notes.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro Plus

Run ID: 3df72ad4-0609-4188-8afc-7a4be7180703

📥 Commits

Reviewing files that changed from the base of the PR and between cf92671 and ab383a7.

📒 Files selected for processing (2)

• screen.js
• tests/screen.test.js

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📝 Walkthrough

Walkthrough

screen.js adds a conditional Node/CommonJS export of the internal _fbGetActiveNotes helper, wrapping existing browser-only Hooks initialization in an else branch. A new test file, tests/screen.test.js, adds Node-based test coverage for note/chord activation, sustain behavior, iteration guards, and edge cases.

Changes

Node export and test coverage for _fbGetActiveNotes

Layer / File(s)	Summary
Node/CommonJS export guard screen.js	Adds a guard exporting _fbGetActiveNotes via module.exports in Node, moving browser Hooks/playSong initialization into an else branch.
Test setup and standalone note tests tests/screen.test.js	Adds test bootstrap (require-cache clearing, global.window) and tests for note activation window, exclusion, sustain fade with alpha floor, and duration cutoff.
Iteration break guard test tests/screen.test.js	Verifies early stopping over sorted-by-time notes when a far-future note is encountered.
Chord activation and sustain tests tests/screen.test.js	Tests chord inclusion/exclusion by lookback window and per-member sustain causing independent chord member drop-out.
Robustness and combined output tests tests/screen.test.js	Tests empty-array handling for missing notes/chords and correct merging of standalone notes with chord members.

Estimated code review effort: 2 (Simple) | ~12 minutes

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly summarizes the main change: new node:test coverage for active-note windowing and sustain fade logic.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
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.

✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch chore/add-basic-tests

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