address the bulk download review

- Cancelling a list while its download loop was still enqueueing missed every
  song queued after the cancel looked. The loop now holds the lock for the whole
  queue, so a cancel waits for it to finish and then removes all of it. That
  needed the enqueue helper split into a locked entry point and a body the loop
  can call while already holding the lock — calling the locked one from inside
  the lock deadlocked, which is what hung the tests.
- An empty resolved list now says so instead of doing nothing.
- One song failing to enqueue no longer aborts the rest of the batch.
- The artist actions resolve through the albums the artist page lists, matching
  what is on screen, rather than through songs.artistId, which for a guest on a
  compilation enqueued nothing.
- Bulk actions are one `applyAction` on the repository, so the three view models
  and both screens stop repeating the same dispatch.
- Tests: the playlist and artist resolve paths, a Running row counted as
  downloading, the action dispatch, and the action rule moved to a plain unit
  test.

app/src/test/kotlin/com/subtracks/data/repo/DownloadRepositoryTest.kt

@@ -12,6 +12,7 @@ import com.subtracks.data.download.ArtworkStore
 import com.subtracks.data.download.FakeDownloadEngine
 import com.subtracks.data.model.Album
 import com.subtracks.data.model.Artist
+import com.subtracks.data.model.BulkDownloadAction
 import com.subtracks.data.model.DownloadList
 import com.subtracks.data.model.DownloadStatus
 import com.subtracks.data.model.ListDownloadStatus
@@ -490,6 +491,10 @@ class DownloadRepositoryTest {
             db.downloadDao().upsert(SongDownload(1, "s2", DownloadStatus.Queued, engineId = 22))
 
             assertEquals(ListDownloadStatus(total = 2, downloaded = 1, downloading = 1), statusOf(DownloadList.Album, "al1"))
+
+            db.downloadDao().upsert(SongDownload(1, "s2", DownloadStatus.Running, engineId = 22))
+
+            assertEquals(ListDownloadStatus(total = 2, downloaded = 1, downloading = 1), statusOf(DownloadList.Album, "al1"))
         }
 
     @Test
@@ -514,6 +519,72 @@ class DownloadRepositoryTest {
         refId: String,
     ): ListDownloadStatus = runBlocking { repository.status(1, list, refId).first() }
 
+    @Test
+    fun downloadingAPlaylistQueuesEverySong() =
+        runTest {
+            seedLibrary()
+            runBlocking {
+                db.libraryDao().upsertPlaylists(listOf(Playlist(1, "pl1", "Playlist", null, null, 2, 0)))
+                db.libraryDao().upsertPlaylistSongs(
+                    listOf(
+                        PlaylistSong(1, "pl1", "s1", 0),
+                        PlaylistSong(1, "pl1", "s2", 1),
+                    ),
+                )
+            }
+
+            runBlocking { repository.downloadAll(1, DownloadList.Playlist, "pl1") }
+
+            assertEquals(listOf("s1", "s2"), requestedSongIds())
+        }
+
+    @Test
+    fun downloadingAnArtistQueuesTheSongsOfItsAlbums() =
+        runTest {
+            seedLibrary()
+            // s2 is a guest on the album, so its own artistId differs: the artist page lists the
+            // album, and the download follows what the page shows.
+            runBlocking {
+                db.libraryDao().upsertSongs(
+                    listOf(
+                        Song(
+                            sourceId = 1,
+                            id = "s2",
+                            albumId = "al1",
+                            artistId = "ar2",
+                            title = "Song 2",
+                            album = "Album",
+                            artist = "Guest",
+                            duration = 100,
+                            track = 2,
+                            disc = 1,
+                            starred = null,
+                            genre = null,
+                        ),
+                    ),
+                )
+            }
+
+            runBlocking { repository.downloadAll(1, DownloadList.Artist, "ar1") }
+
+            assertEquals(listOf("s1", "s2"), requestedSongIds())
+        }
+
+    @Test
+    fun applyActionRoutesToTheMatchingBulkAction() =
+        runTest {
+            seedLibrary()
+
+            runBlocking { repository.applyAction(1, DownloadList.Album, "al1", BulkDownloadAction.Download) }
+            assertEquals(2, engine.requests.size)
+
+            runBlocking { repository.applyAction(1, DownloadList.Album, "al1", BulkDownloadAction.Cancel) }
+
+            assertEquals(ListDownloadStatus(total = 2), statusOf(DownloadList.Album, "al1"))
+        }
+
+    private fun requestedSongIds(): List<String> = engine.requests.map { it.second.path.substringAfterLast('/') }
+
     private fun album(coverArt: String?) =
         Album(
             sourceId = 1,

app/src/test/kotlin/com/subtracks/ui/components/BulkDownloadActionTest.kt

@@ -0,0 +1,29 @@
+package com.subtracks.ui.components
+
+import com.subtracks.data.model.BulkDownloadAction
+import com.subtracks.data.model.ListDownloadStatus
+import org.junit.Assert.assertEquals
+import org.junit.Test
+
+class BulkDownloadActionTest {
+    @Test
+    fun anUndownloadedListOffersDownload() {
+        assertEquals(BulkDownloadAction.Download, ListDownloadStatus(total = 3).action())
+        assertEquals(BulkDownloadAction.Download, ListDownloadStatus().action())
+    }
+
+    @Test
+    fun aPartiallyDownloadedListStillOffersDownload() {
+        assertEquals(BulkDownloadAction.Download, ListDownloadStatus(total = 3, downloaded = 1).action())
+    }
+
+    @Test
+    fun aListWithDownloadsInFlightOffersCancel() {
+        assertEquals(BulkDownloadAction.Cancel, ListDownloadStatus(total = 3, downloaded = 1, downloading = 1).action())
+    }
+
+    @Test
+    fun aFullyDownloadedListOffersDelete() {
+        assertEquals(BulkDownloadAction.Delete, ListDownloadStatus(total = 3, downloaded = 3).action())
+    }
+}

app/src/test/kotlin/com/subtracks/ui/components/HeroDownloadTest.kt

@@ -7,6 +7,7 @@ import androidx.compose.ui.test.onNodeWithContentDescription
 import androidx.compose.ui.test.performClick
 import androidx.compose.ui.unit.dp
 import androidx.test.ext.junit.runners.AndroidJUnit4
+import com.subtracks.data.model.BulkDownloadAction
 import com.subtracks.data.model.ListDownloadStatus
 import com.subtracks.ui.theme.SubtracksTheme
 import org.junit.Assert.assertEquals
@@ -21,27 +22,6 @@ class HeroDownloadTest {
     @get:Rule
     val composeRule = createAndroidComposeRule<ComponentActivity>()
 
-    @Test
-    fun anUndownloadedListOffersDownload() {
-        assertEquals(BulkDownloadAction.Download, ListDownloadStatus(total = 3).action())
-        assertEquals(BulkDownloadAction.Download, ListDownloadStatus().action())
-    }
-
-    @Test
-    fun aPartiallyDownloadedListStillOffersDownload() {
-        assertEquals(BulkDownloadAction.Download, ListDownloadStatus(total = 3, downloaded = 1).action())
-    }
-
-    @Test
-    fun aListWithDownloadsInFlightOffersCancel() {
-        assertEquals(BulkDownloadAction.Cancel, ListDownloadStatus(total = 3, downloaded = 1, downloading = 1).action())
-    }
-
-    @Test
-    fun aFullyDownloadedListOffersDelete() {
-        assertEquals(BulkDownloadAction.Delete, ListDownloadStatus(total = 3, downloaded = 3).action())
-    }
-
     @Test
     fun tappingTheButtonReportsTheActionItsStateOffers() {
         val actions = mutableListOf<BulkDownloadAction>()