OUT-4068: residual service-branch tests (resync helper, root-move, delta, folder recovery)

[SandipBajracharya]

Stacked on #135 (OUT-4066). Base is OUT-4066 so this diff shows only the L3b tests; GitHub will retarget it to main once #135 merges. Review/merge #135 first.

What & why

The final ticket of the Unit & Integration test milestone. Covers the residual service branches left after L1/L2/L3a — the ones no happy-path flow reaches and the sibling unit tests only partially exercise. Test-only: no production changes, reuses the existing MSW harness.

Linear: OUT-4068

Coverage (35 new tests)

Resync-helper guard/error branches (resync-sweep.integration.test.ts, +22) — cases 132–137

• retryDeleteInAssembly / retryDeleteInDropbox: missing-field + already-gone (Copilot 404 / Dropbox 409 path_lookup_not_found) → markDeleted; other → markFailure.
• retryCreateInDropbox: missing assemblyFileId/itemPath/channelSync → markFailure; retrieve 404 → markDeleted; still-pending → markFailure.
• retryCreateInAssembly + reconcileExistingAssemblyFile: missing fields → markFailure; Dropbox not_found/deleted-tag → markDeleted; non-not_found metadata error → markFailure; recreate on null/404 assemblyFileId; non-404 reconcile error → markFailure; abandoned path nulls assemblyFileId before deleting the stale file (ordering).

Root-move + delta (dropbox-webhook-internals.integration.test.ts, new, +6) — cases 108/109, 114/115/116

• handleDbxRootPathMove: 409 path-gone → re-fetch by dbxRootId, refresh cursor, update map, skip cycle; non-409 rethrows.
• getDropboxChanges: deleted entry with no mapped row / no dbxFileId → dropped; malformed entry → throws; root-scope prefix filter (case-insensitive).

Sync.service residuals (+7) — cases 46, 79, 84, 85, 86

• createAndUploadFileInDropbox existing-file → rename via filesMoveV2 + re-upload.
• createFolderInAssembly "Folder already exists": row found → stamp only; non-matching error → rethrow.
• recoverUnmappedAssemblyFolder: multi-page nextToken traversal; never-found → give up.
• handleFolderCreatedCase: no-op when not the last folder item.
• resyncLeafOnContentChange: recreate carries assemblyPathOverride = existing.assemblyPath.

Notes

• Two seams to call out: 108/109 inject the metadata outcome at getDropboxFileMetadata (its withRetry adds ~20s backoff, impractical through MSW); the 136e ordering test uses a delete-mock that reads the row's live assemblyFileId at call-time to prove null-before-delete.
• The 12h stuck-pending boundary micro-test was intentionally dropped (no clock control → flaky; existing 11h/13h tests already bracket the threshold) — recorded in the design doc.

Testing

• pnpm typecheck ✅ · pnpm lint ✅ · pnpm test → 203 passed ✅
• pnpm test:integration → 170 passed ✅ (was 141; +29)

🤖 Generated with Claude Code

[linear-code]

OUT-4068

[vercel]

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Project	Deployment	Actions	Updated (UTC)
dropbox-integration	Ready	Preview	Aug 20, 2026 5:15am

[greptile-apps]

Greptile Summary

This test-only PR expands coverage for residual sync-service branches, including resync recovery, Dropbox root moves and delta filtering, folder recovery, and content-change recreation.

• Adds resync guard, error-classification, reconciliation, and operation-ordering coverage.
• Adds integration coverage for Dropbox root-path moves and delta-entry handling.
• Adds folder recovery pagination and existing-row behavior tests.
• Verifies Assembly-path preservation and Dropbox rename-before-reupload behavior.

Confidence Score: 5/5

The PR appears safe to merge because it changes only tests and no concrete test correctness or isolation issue remains.

The added tests reach the intended production branches, use the repository’s per-test database and MSW isolation, and introduce no production behavior changes.

Important Files Changed

Filename	Overview
src/features/sync/lib/tests/Sync.folderRecovery.test.ts	Adds focused unit coverage for folder-exists recovery, pagination, concurrent insertion, error propagation, and the non-final-folder guard.
src/features/sync/lib/tests/Sync.resyncLeaf.test.ts	Verifies that content-change recreation preserves the existing Assembly path override.
test/flows/dropbox-webhook-internals.integration.test.ts	Adds isolated integration coverage for root-move recovery and Dropbox delta validation, deletion resolution, and root filtering.
test/flows/resync-sweep.integration.test.ts	Substantially expands resync branch coverage across missing fields, already-deleted objects, API failures, recreation, and stale-file cleanup ordering.
test/flows/sync-error-shape.integration.test.ts	Adds coverage for the existing-file rename-and-reupload flow and its expected Dropbox operations.

_{Reviews (1): Last reviewed commit: "test(OUT-4068): cover Dropbox rename + f..." | Re-trigger Greptile}

[priosshrsth]

lgtm