music_library/backlog/tasks/ml-192 - Add-high-value-behavioral-test-coverage.md

id, title, status, assignee, created_date, updated_date, labels, dependencies, documentation, priority, ordinal

id	title	status	assignee	created_date	updated_date	labels	dependencies	documentation	priority	ordinal
ML-192	Add high-value behavioral test coverage	To Do		2026-05-20 17:19	2026-05-20 21:54	testing coverage		docs/architecture.md docs/project-conventions.md .agents/skills/testing/SKILL.md .agents/skills/ui-framework/SKILL.md .agents/skills/sqlite-optimization/SKILL.md	high	35000

Description

Increase coverage where current tests would catch meaningful regressions in user-facing workflows and core data transformations. Focus on the high-value gaps identified from the coverage triage: RecordForm genre and cover-search behavior, BarcodeScanner component state and import branches, Notes component create/update/read-edit behavior, ScrobbleRules subset application, and Assets.Image conversion/error handling. Avoid tests that only assert markup exists without exercising behavior.

Acceptance Criteria

• #1 Record editing tests cover genre search suggestions, adding a new normalized genre, preventing duplicate/blank genres, and removing an existing genre through the LiveComponent path.
• #2 Record editing tests cover Brave cover search success, search failure with a friendly message, selecting a search result, and persisting the downloaded cover hash on the record.
• #3 Barcode scanner tests cover a scan failure toast, removing one scanned result, clearing all scanned results, and the 2+ new-release async import branch including expected enqueued import jobs.
• #4 Notes component tests cover creating a new record or artist note, rendering an existing note in read mode, updating note content, and persisting the result through the Notes context.
• #5 Scrobble rules tests prove apply_all_rules/1 only updates the supplied track subset and leaves non-supplied matching tracks unchanged.
• #6 Assets image tests cover convert/3 same-format passthrough, successful JPEG/WebP conversion as supported by the app, and invalid image data returning an error tuple.

Implementation Plan

1. Read docs/architecture.md, docs/project-conventions.md, .agents/skills/testing/SKILL.md, and the relevant UI/SQLite guidance before changing tests.

2. Add RecordForm genre behavioral coverage through existing record edit paths in test/music_library_web/live/collection_live/show_test.exs and/or test/music_library_web/live/wishlist_live/show_test.exs. Prefer PhoenixTest, using unwrap/2 + LiveViewTest only for non-standard click targets (Fluxon custom selects, <li> elements with phx-click). The record edit form is reached via click_link("Edit") from either show page and renders the RecordForm LiveComponent. Cover genre search suggestions (type into #genre-input, assert #genre-suggestions list items appear), creating a normalized new genre (click "Create" suggestion, assert badge appears), duplicate/blank genre no-ops (attempt adding same genre twice, assert no duplicate badge; attempt adding empty string, assert badges unchanged), and removing an existing genre (click badge's remove icon, assert badge disappears). Assert both visible form state and persisted record state through MusicLibrary.Records.get_record!/1 after form save.

3. Add RecordForm cover-search/download coverage through the same edit path. The RecordForm uses start_async for both BraveSearch image search and image download, which runs in a separate Task process. Req.Test.stub/2 stores stubs per-process by default and will not be visible inside the Task. Use mode: :global on all BraveSearch stubs to make them available across process boundaries:

   # Successful search stub
   Req.Test.stub(BraveSearch.API, fn conn ->
     Req.Test.json(conn, %{
       "results" => [
         %{
           "thumbnail" => %{"src" => "https://example.com/thumb1.jpg"},
           "properties" => %{
             "url" => "https://example.com/full1.jpg",
             "width" => 800, "height" => 600
           },
           "title" => "Test Cover 1", "source" => "example.com"
         },
         %{
           "thumbnail" => %{"src" => "https://example.com/thumb2.jpg"},
           "properties" => %{
             "url" => "https://example.com/full2.jpg",
             "width" => 1024, "height" => 1024
           },
           "title" => "Test Cover 2", "source" => "example.com"
         }
       ]
     })
   end, mode: :global)
   
   # Search failure stub
   Req.Test.stub(BraveSearch.API, fn conn ->
     conn
     |> Plug.Conn.put_status(429)
     |> Req.Test.json(conn, %{"error" => "Rate limit exceeded"})
   end, mode: :global)
   
   # Image download stub
   Req.Test.stub(BraveSearch.API, fn conn ->
     Plug.Conn.send_resp(conn, 200, Image.fallback_data())
   end, mode: :global)
   

   Important: Register on_exit cleanup to remove global stubs after each test to maintain test isolation:

   on_exit(fn ->
     Req.Test.stub(BraveSearch.API, nil, mode: :global)
   end)
   

   Test flow: navigate to edit form → type query into cover search input → click "Search" button → call render_async() to wait for the async task → assert cover search result thumbnails render in #cover-search-results → click a result thumbnail → call render_async() again to wait for download async → assert success toast and verify record.cover_hash changed via MusicLibrary.Records.get_record!/1. For search failure: stub an error response, click search, call render_async(), and assert the friendly error text appears in the p.text-red-600 selector containing "Search failed". For selecting a search result: stub both search and download, verify the downloaded cover hash is persisted on the record and an asset exists via MusicLibrary.Assets.get(hash).

4. Add BarcodeScanner coverage in test/music_library_web/live/collection_live/index_test.exs under the existing "Add via barcode scan" describe block (or a new describe block). Use trigger_hook/3 to simulate scan events, following the existing pattern in that file:

   • Scan failure toast: Stub MusicBrainz.API to return a Req.Test.transport_error(conn, :timeout), trigger trigger_hook("#barcode-scanner", "barcode_scanned", %{"number" => "123"}), assert error toast appears (matching gettext("Failed to search release for barcode %{number}", number: "123")).
   • Remove one scanned result: Stub a successful scan, trigger hook, assert cart item appears. Trigger render_hook with "remove_result" event and %{"number" => "123"}, assert that item is removed while other items remain.
   • Clear all scanned results: Add multiple scan results, trigger render_hook with "clear_results", assert all cart items are gone.
   • 2+ new-release async import branch: Add 2+ new scan results, click "Add N releases" button. Assert assert_enqueued(worker: MusicLibrary.Worker.ImportFromMusicbrainzRelease, args: %{"release_id" => _, "format" => _, "purchased_at" => _, "selected_release_id" => _}) with one job per new scan result. Assert no Records.Record rows were synchronously inserted via MusicLibrary.Repo.all(Record).

   For the successful scan stub, follow the existing pattern in the "Add via barcode scan" test that stubs MusicBrainz.API for both the barcode search and the release/release-group endpoints. The plan only needs the barcode search path for scan-result display; full import requires release/release-group/cover stubs as well.

5. Add Notes component coverage through the test/music_library_web/live/collection_live/show_test.exs record show page. The Notes component is rendered as a Fluxon <.sheet> dialog opened via phx-click={MusicLibraryWeb.Components.Notes.open("record-notes-sheet")} from a standard <button> with text "Notes". Use click_button("Notes") to open the sheet. After opening:

   • Creating a note: The sheet opens in "edit" mode (tab "Edit" active) when no note exists. Fill in the textarea via fill_in or unwrap with form/3 + render_change/1, click "Save", assert success toast and persistence via MusicLibrary.Notes.get_note(:record, record.musicbrainz_id).
   • Reading an existing note: Pre-create a note via Notes.create_note/2, then reopen the sheet. Assert the "Read" tab is active and content is rendered.
   • Editing a note: Switch to "Edit" tab via click_button("Edit"), modify content, save, assert persistence.
   • Persistence verification: After create/update, call MusicLibrary.Notes.get_note/2 to verify the note exists with expected content and entity.

   If click_button("Notes") targeting the sheet-open button does not work (e.g., the button is inside a scoped container), use unwrap with element/2 + render_click/1 as fallback. The assert_has selectors should target content inside the .sheet container.

6. Add a ScrobbleRules.apply_all_rules/1 subset context test in test/music_library/scrobble_rules_test.exs under the existing "rule application" describe block. Create:

   • An enabled album rule matching "Test Album"
   • Two tracks with album.title == "Test Album" but different scrobbled_at_uts values (set explicitly to avoid SQLite second-precision ordering issues, per testing skill)
   • One track kept outside the supplied list (the non-supplied matching track)

   Call apply_all_rules([supplied_track]) and verify:

   • The supplied track's album.musicbrainz_id was updated to the rule's target
   • The non-supplied matching track's album.musicbrainz_id remains unchanged

7. Add Assets.Image.convert/3 tests in test/music_library/assets/image_test.exs. Use Image.fallback_data/0 (~2KB JPEG, fast to process):

   • Same-format passthrough: assert {:ok, data} = Image.convert(fallback_data, "image/jpeg", "image/jpeg") and assert data == fallback_data (returns original binary unchanged, no Vips processing).
   • JPEG → WebP conversion: assert {:ok, webp_data} = Image.convert(fallback_data, "image/jpeg", "image/webp") and assert webp_data != fallback_data (different binary, successfully converted by libvips).
   • Invalid image data: Pass an arbitrary binary (e.g., "not an image") and assert {:error, _reason} with a specific error tuple shape (Vix returns an error struct on invalid input).

8. Keep the implementation test-only. Do not refactor production code unless a new test exposes an actual bug; if a production fix is needed, pause and update the plan before continuing.

Performance profile

• No production runtime performance changes are expected because this task adds behavioral tests only.
• Keep test runtime reasonable: use existing fixtures/fallback image data (Image.fallback_data/0), avoid real network calls (all external APIs stubbed with Req.Test), keep image conversions minimal (Vix operations on ~2KB images are fast), and prefer targeted LiveView interactions over full end-to-end import flows unless required by an acceptance criterion.

Benchmarks

• Benchmarks are not required for the planned test-only implementation.
• Reconsider only if production image-processing, SQL, or import logic changes during implementation.

Paid resources / external calls

• No paid resources should be used.
• All external API interactions, including BraveSearch and MusicBrainz, must be stubbed with Req.Test; no live API calls should occur.
• BraveSearch stubs use mode: :global to cross the start_async Task process boundary and must be cleaned up in on_exit to maintain test isolation.

Production / manual infrastructure steps

• None expected. No environment variables, provisioning, deployment configuration, or manual production actions are required.

Documentation

• No documentation updates are expected for test-only coverage.
• Exception: The mode: :global Req.Test stub pattern for APIs consumed via start_async Tasks is new to this project. If this pattern is used in the implementation, add a section to .agents/skills/testing/SKILL.md under "API Stubs (Req.Test)" documenting when and how to use global stubs, the cleanup requirement, and the interaction with start_async/render_async.

Verification

1. Run targeted tests for every touched file, for example:
   • mix test test/music_library_web/live/collection_live/show_test.exs test/music_library_web/live/collection_live/index_test.exs test/music_library/scrobble_rules_test.exs test/music_library/assets/image_test.exs
   • Include test/music_library_web/live/artist_live/show_test.exs or test/music_library_web/live/wishlist_live/show_test.exs if Notes or RecordForm coverage lands there.
2. Run mise run dev:lint for formatting/static checks after Elixir test changes.
3. Run mise run test as the CI-equivalent full suite when feasible. If it is skipped because of time or environment limits, record that explicitly in the task notes/final summary with the targeted commands that did pass.

Implementation Notes

Plan review (2026-05-20)

Reviewed against 10 review criteria. Five issues found, all addressed:

1. Critical — Fixed Req.Test stub process boundary gap. BraveSearch is called via start_async Tasks; Req.Test.stub/2 is per-process. Plan now specifies mode: :global with on_exit cleanup.
2. Medium — Added Notes sheet interaction details: button text, tab names, fill_in/unwrap fallback strategy.
3. Medium — Added full BraveSearch stub response shapes (search result map, download binary) and the render_async() calls needed after async triggers.
4. Minor — Step 4 now cross-references the existing barcode scan test as a pattern for MusicBrainz.API stubbing.
5. Advisory — Documentation section now mandates updating the testing skill if mode: :global stubs are introduced.