---
phase: 05-database-library-tests
plan: 02
subsystem: testing
tags: [library, entity-cache, sqlite, unit-tests, scan, orphan-cleanup]

# Dependency graph
requires:
  - phase: 03-test-infrastructure
    provides: "NewTestDB(t) helper for in-memory SQLite test databases"
  - phase: 04-queue-config-player-tests
    provides: "Established test patterns: t.Parallel(), internal tests, table-driven subtests"
provides:
  - "13 library scan tests covering entity cache, pure helpers, and orphan cleanup"
  - "setupTestLibrary helper for Library + test DB construction"
  - "Safety net for Phase 7 (PERF-01) performance optimization of scan logic"
affects: [06-sql-consolidation, 07-performance-optimization]

# Tech tracking
tech-stack:
  added: []
  patterns: ["direct Library struct construction for internal tests (bypasses Config.Validate)", "setupTestLibrary helper: NewTestDB + direct Library construction"]

key-files:
  created:
    - backend/library/scan_test.go
  modified: []

key-decisions:
  - "Construct Library directly in tests (bypass Config.Validate os.Stat) — entity cache functions only need ctx + db"
  - "Document contentless FTS5 DeleteSearchIndex limitation — DELETE fails on content='' tables, production code logs warning"
  - "Empty artist credit name creates a valid DB record — documents actual behavior"

patterns-established:
  - "setupTestLibrary pattern: NewTestDB + direct Library struct with t.Context() (no Wails dependency)"
  - "Entity cache tests: fresh newEntityCache() per test, verify cache map sizes after operations"

requirements-completed: [TEST-06]

# Metrics
duration: 4min
completed: 2026-03-04
---

# Phase 05 Plan 02: Library Scan Tests Summary

**13 unit tests for entity cache functions (cachedUpsertArtistCredit, cachedLinkArtist, cachedUpsertGenre, resolveReleaseGroup), pure helpers (getRecordingName, toNullInt64, toNullString, splitGenres, mapTrackRow), and orphan deletion with contentless FTS5 characterization**

## Performance

- **Duration:** 4 min
- **Started:** 2026-03-04T21:33:23Z
- **Completed:** 2026-03-04T21:38:02Z
- **Tasks:** 2
- **Files modified:** 1

## Accomplishments
- 5 pure helper tests: getRecordingName (title present, filename fallback, complex path), toNullInt64 (zero/positive/negative), toNullString (empty/non-empty), splitGenres (empty/single/multiple), mapTrackRow (all 16 columns + NullInt64 null handling)
- 7 entity cache tests: cachedUpsertArtistCredit cache hit, cachedLinkArtist dedup + multi-credit, cachedUpsertGenre cache hit, resolveReleaseGroup with cover art update + empty album, resolveReleaseGroup cache hit with pre-populated cache
- 1 orphan cleanup test: DeleteAudioFile removes row, documents contentless FTS5 DeleteSearchIndex limitation
- All 13 tests use t.Parallel() and pass with -race flag
- Entity cache tests use plain context.Context via t.Context() — no Wails runtime dependency

## Task Commits

Each task was committed atomically:

1. **Task 1: Pure helper tests (no DB needed)** - `6f96a94` (test)
2. **Task 2: Entity cache + orphan cleanup tests (DB-backed)** - `fa6c378` (test)

## Files Created/Modified
- `backend/library/scan_test.go` - 718 lines: pure helper tests, entity cache tests, orphan cleanup test, empty metadata test, setupTestLibrary helper

## Decisions Made
- Constructed Library directly in tests (`&Library{ctx: t.Context(), ...}`) rather than using `NewLibrary()` — avoids `Config.Validate()` calling `os.Stat` on a directory, and entity cache functions only need `l.ctx` and `l.db`
- Documented contentless FTS5 limitation: `DeleteSearchIndex` errors on `content=''` tables — production orphan cleanup code logs this as a warning; stale FTS entries are harmless because JOINs to deleted audio_files return no results
- Empty artist credit name creates a valid DB record (`UpsertArtistCredit("")` succeeds) — test documents actual behavior rather than asserting an error

## Deviations from Plan

None - plan executed exactly as written.

## Issues Encountered
- Contentless FTS5 table (`content=''`) does not support `DELETE FROM search_index WHERE rowid = ?` — adapted orphan deletion test to document this limitation rather than assert successful deletion. The production code handles this gracefully by logging a warning.

## User Setup Required

None - no external service configuration required.

## Next Phase Readiness
- Phase 05 complete — both database query tests (plan 01) and library scan tests (plan 02) delivered
- 13 new library scan tests provide safety net for Phase 7 performance optimization
- Contentless FTS5 limitation documented — relevant for Phase 6 SQL consolidation

## Self-Check: PASSED

- [x] backend/library/scan_test.go exists
- [x] Commit 6f96a94 found
- [x] Commit fa6c378 found

---
*Phase: 05-database-library-tests*
*Completed: 2026-03-04*