---
phase: 04-queue-config-player-tests
plan: 01
subsystem: testing
tags: [queue, sqlite, unit-tests, shuffle, repeat, persistence]

# Dependency graph
requires:
  - phase: 03-test-infrastructure
    provides: "NewTestDB(t) helper for in-memory SQLite test databases"
provides:
  - "29 queue tests covering core ops, navigation, and persistence roundtrip"
  - "Mock TrackLoader and seedAudioFiles test helpers in queue package"
  - "Safety net for Phase 7 (PERF-01) queue persistence refactoring"
affects: [07-performance-optimization]

# Tech tracking
tech-stack:
  added: []
  patterns: ["internal package tests (package queue, not queue_test)", "direct field manipulation for pure logic tests (no DB)", "seedAudioFiles helper with FK chain for DB-backed tests"]

key-files:
  created:
    - backend/queue/queue_test.go
    - backend/queue/navigation_test.go
    - backend/queue/persistence_test.go
  modified: []

key-decisions:
  - "Internal tests (package queue) to access unexported fields like shuffleOrder, mu"
  - "Navigation tests use direct struct construction (no DB) for fast pure-logic testing"
  - "Persistence roundtrip test verifies ALL state fields including shuffleOrder JSON"

patterns-established:
  - "mockTrackLoader pattern: no-op TrackLoader with loadedFile tracking"
  - "seedAudioFiles helper: creates FK chain (artist_credit → recordings → audio_files) for N tracks"
  - "newTestQueueDirect: direct Queue construction for navigation/logic tests without DB"

requirements-completed: [TEST-02]

# Metrics
duration: 3min
completed: 2026-03-03
---

# Phase 04 Plan 01: Queue Unit Tests Summary

**29 unit tests for queue core operations (SetQueue, Add, Insert, Move, Remove, Shuffle, Repeat), navigation logic (Next/Previous in all modes), and SaveState/RestoreState persistence roundtrip**

## Performance

- **Duration:** 3 min
- **Started:** 2026-03-03T21:57:38Z
- **Completed:** 2026-03-03T22:00:46Z
- **Tasks:** 2
- **Files modified:** 3

## Accomplishments
- 14 core operation tests: SetQueue (3 variants), AddTrack, InsertTracksAt (before/after current), MoveQueueTracks (forward/backward/current), RemoveTrack (normal/current), Clear, ToggleShuffle, CycleRepeat
- 9 navigation tests: nextIndex/previousIndex in RepeatOff/RepeatAll/RepeatOne modes, shuffle navigation, generateShuffleOrder property validation (all indices, no duplicates, current at [0])
- 6 persistence roundtrip tests: full state fidelity, empty/single/10-track edge cases, overwrite semantics, no-prior-save safety
- All 29 tests pass with `-race` flag

## Task Commits

Each task was committed atomically:

1. **Task 1: Queue core operations and navigation tests** - `8d60dc0` (test)
2. **Task 2: Queue persistence round-trip tests** - `77cc993` (test)

## Files Created/Modified
- `backend/queue/queue_test.go` - Core operation tests + mock TrackLoader + setupTestQueue/seedAudioFiles helpers
- `backend/queue/navigation_test.go` - Navigation edge case tests + shuffle order property tests
- `backend/queue/persistence_test.go` - SaveState/RestoreState roundtrip fidelity tests

## Decisions Made
- Used internal tests (`package queue`) to access unexported fields (shuffleOrder, mu) — necessary for shuffle verification and roundtrip assertions
- Navigation tests bypass DB entirely using direct struct construction for fast, focused tests
- Roundtrip test asserts on shuffleOrder (JSON-serialized) to ensure Phase 7 refactoring won't silently lose shuffle state

## Deviations from Plan

None - plan executed exactly as written.

## Issues Encountered
None

## User Setup Required

None - no external service configuration required.

## Next Phase Readiness
- Queue test safety net complete — ready for Phase 7 (PERF-01) incremental persistence refactoring
- Test helpers (mockTrackLoader, seedAudioFiles) available for reuse in Plan 04-02 (config/player tests)
- Ready for Plan 04-02 execution

---
*Phase: 04-queue-config-player-tests*
*Completed: 2026-03-03*