close the test gaps a QA pass found, and de-flake the flaky ones

Verify the Subsonic token hash and salt freshness, and fall back to per-album songs when the empty-search probe fails with an I/O error instead of aborting the whole sync. Add a real-server sync test that mirrors navidrome and gonic into Room and reads the rows back, plus SyncManager coverage for the success, coalescing and mid-sync-failure paths. Cover the sort mapping and delete/ping ViewModels, the download engine's request flags, the queue helpers, download prefs and migration data preservation. Drop the leaked collectors in the ViewModel/queue tests, document the screenshot tests as render smoke tests, bind a real search term in the trigram plan test, and assert a positive in-flight invariant alongside the concurrency timing checks.
2026-11-10 15:11:58 +01:00 · 2026-10-04 00:30:04 +00:00
parent 5cbe4c6839
commit 684cc5a287
27 changed files with 989 additions and 25 deletions
@@ -75,12 +75,16 @@ ksp {
    arg("room.schemaLocation", "$projectDir/schemas")
 }

-val integrationTestClassName = "com.subtracks.data.source.subsonic.SubsonicSourceIntegrationTest"
+val integrationTestClasses =
+    listOf(
+        "com.subtracks.data.source.subsonic.SubsonicSourceIntegrationTest",
+        "com.subtracks.data.sync.SyncServiceIntegrationTest",
+    )

 tasks.withType<Test>().configureEach {
    if (name.endsWith("UnitTest")) {
        filter {
-            excludeTestsMatching(integrationTestClassName)
+            integrationTestClasses.forEach { excludeTestsMatching(it) }
        }
    }
 }
@@ -93,7 +97,7 @@ tasks.register<Test>("integrationTest") {
    testClassesDirs = files(provider { unitTest.get().testClassesDirs })
    classpath = files(provider { unitTest.get().classpath })
    filter {
-        includeTestsMatching(integrationTestClassName)
+        integrationTestClasses.forEach { includeTestsMatching(it) }
    }
 }

@@ -0,0 +1,75 @@
+package com.subtracks.data.sync
+
+import android.content.Context
+import androidx.room3.Room
+import androidx.sqlite.driver.bundled.BundledSQLiteDriver
+import androidx.test.core.app.ApplicationProvider
+import androidx.test.ext.junit.runners.AndroidJUnit4
+import com.subtracks.data.db.SubtracksDatabase
+import com.subtracks.data.model.Source
+import com.subtracks.data.source.subsonic.SubsonicClient
+import com.subtracks.data.source.subsonic.SubsonicSource
+import kotlinx.coroutines.runBlocking
+import okhttp3.HttpUrl.Companion.toHttpUrl
+import okhttp3.OkHttpClient
+import org.junit.Assert.assertEquals
+import org.junit.Test
+import org.junit.runner.RunWith
+
+@RunWith(AndroidJUnit4::class)
+class SyncServiceIntegrationTest {
+    @Test
+    fun syncMirrorsTheLibraryIntoRoomForEveryServer() =
+        runBlocking {
+            servers.forEach { server ->
+                val context = ApplicationProvider.getApplicationContext<Context>()
+                val db =
+                    Room
+                        .inMemoryDatabaseBuilder(context, SubtracksDatabase::class.java)
+                        .setDriver(BundledSQLiteDriver())
+                        .build()
+                try {
+                    db.sourcesDao().upsertSource(
+                        Source(id = 1, name = server.name, address = server.baseUrl, isActive = true, createdAt = 0),
+                    )
+                    val source =
+                        SubsonicSource(
+                            id = 1,
+                            client =
+                                SubsonicClient(
+                                    baseUrl = server.baseUrl.toHttpUrl(),
+                                    username = server.username,
+                                    password = server.password,
+                                    useTokenAuth = false,
+                                    http = OkHttpClient(),
+                                ),
+                        )
+
+                    SyncService(db, source).sync()
+
+                    val library = db.libraryDao()
+                    assertEquals(server.name, 2, library.artistIds(1).size)
+                    assertEquals(server.name, 3, library.albumIds(1).size)
+                    assertEquals(server.name, 20, library.songIdsAfter(1, "", 1000).size)
+                    assertEquals(server.name, 1, library.playlistIds(1).size)
+                } finally {
+                    db.close()
+                }
+            }
+        }
+
+    private data class Server(
+        val name: String,
+        val baseUrl: String,
+        val username: String,
+        val password: String,
+    )
+
+    private companion object {
+        val servers =
+            listOf(
+                Server("navidrome", "http://localhost:4533/", "admin", "password"),
+                Server("gonic", "http://localhost:4747/", "admin", "admin"),
+            )
+    }
+}
@@ -14,6 +14,7 @@ import com.subtracks.data.repo.DownloadRepository
 import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.SupervisorJob
+import kotlinx.coroutines.cancel
 import kotlinx.coroutines.launch

 /**
@@ -42,6 +43,10 @@ class DownloadNotifier(
        }
    }

+    internal fun close() {
+        scope.cancel()
+    }
+
    private fun build(content: DownloadNotification): Notification =
        NotificationCompat
            .Builder(context, CHANNEL_ID)
@@ -35,6 +35,7 @@ import kotlinx.coroutines.flow.flowOf
 import kotlinx.coroutines.flow.flowOn
 import kotlinx.coroutines.flow.map
 import kotlinx.coroutines.launch
+import kotlinx.coroutines.runBlocking
 import kotlinx.coroutines.sync.Mutex
 import kotlinx.coroutines.sync.withLock
 import kotlinx.coroutines.withContext
@@ -78,7 +79,9 @@ class DownloadRepository(
    }

    fun close() {
+        val job = scope.coroutineContext[Job]
        scope.cancel()
+        runBlocking { job?.join() }
    }

    fun states(): StateFlow<Map<String, SongDownload>> = statesFlow
@@ -27,6 +27,7 @@ import kotlinx.coroutines.sync.Semaphore
 import kotlinx.coroutines.sync.withPermit
 import kotlinx.coroutines.withContext
 import org.xml.sax.Attributes
+import java.io.IOException

@OptIn(ExperimentalCoroutinesApi::class)
 class SubsonicSource(
@@ -272,6 +273,8 @@ class SubsonicSource(
                ) { input -> SubsonicXml.containsEntity(input, "song") }
            } catch (_: SubsonicException) {
                false
+            } catch (_: IOException) {
+                false
            }
        emptyQuerySearchSupported = supported
        return supported
@@ -159,8 +159,8 @@ class LibraryViewModel(
    fun sync() = syncManager.requestSync()
 }

-private fun ListQuery.albumSort(): AlbumSort = AlbumSort.entries.firstOrNull { it.name == sort } ?: AlbumSort.Name
+internal fun ListQuery.albumSort(): AlbumSort = AlbumSort.entries.firstOrNull { it.name == sort } ?: AlbumSort.Name

-private fun ListQuery.artistSort(): ArtistSort = ArtistSort.entries.firstOrNull { it.name == sort } ?: ArtistSort.Name
+internal fun ListQuery.artistSort(): ArtistSort = ArtistSort.entries.firstOrNull { it.name == sort } ?: ArtistSort.Name

-private fun ListQuery.playlistSort(): PlaylistSort = PlaylistSort.entries.firstOrNull { it.name == sort } ?: PlaylistSort.Name
+internal fun ListQuery.playlistSort(): PlaylistSort = PlaylistSort.entries.firstOrNull { it.name == sort } ?: PlaylistSort.Name
@@ -224,6 +224,8 @@ class LibraryDaoTest {
            }
        }

+    // These plan assertions depend on the query planner in the pinned androidx.sqlite:sqlite-bundled
+    // (see gradle/libs.versions.toml); re-check the expected index names when that engine is bumped.
    @Test
    fun albumOrdersAreIndexBacked() =
        runTest {
@@ -442,7 +444,11 @@ class LibraryDaoTest {
    @Test
    fun searchRunsThroughTheTrigramIndex() =
        runTest {
-            val plan = plan("SELECT * $ALBUMS_FILTER ORDER BY $ALBUM_ORDER_BY_NAME LIMIT 20 OFFSET 0")
+            val plan =
+                plan(
+                    "SELECT * ${ALBUMS_FILTER.replace(":search", "'abc'")} " +
+                        "ORDER BY $ALBUM_ORDER_BY_NAME LIMIT 20 OFFSET 0",
+                )

            assertTrue(plan, plan.contains("album_search"))
        }
@@ -87,7 +87,7 @@ class MigrationsTest {
                migrated.execSQL(
                    "INSERT INTO albums (sourceId, id, artistId, name, albumArtist, created, coverArt, genre, year, " +
                        "starred, songCount, frequentRank, recentRank) " +
-                        "VALUES (1, 'al1', 'ar1', 'The Album', 'The Artist', 101, NULL, NULL, 1999, NULL, 1, NULL, NULL)",
+                        "VALUES (1, 'al1', 'ar1', 'The Album', 'The Artist', 101, NULL, NULL, 1999, 555, 1, NULL, NULL)",
                )
                migrated.execSQL(
                    "INSERT INTO playlists (sourceId, id, name, comment, coverArt, songCount, created) " +
@@ -97,9 +97,24 @@ class MigrationsTest {
                MIGRATIONS.sortedBy { it.startVersion }.forEach { migration ->
                    migration.migrate(migrated)
                    when (migration.endVersion) {
-                        5 -> migrated.execSQL("UPDATE playlists SET duration = 987654 WHERE id = 'pl1'")
-                        8 -> migrated.execSQL("UPDATE playlists SET changed = 123456 WHERE id = 'pl1'")
-                        11 -> migrated.execSQL("INSERT INTO discs (sourceId, albumId, disc, title) VALUES (1, 'al1', 2, 'The Disc')")
+                        5 -> {
+                            migrated.execSQL("UPDATE playlists SET duration = 987654 WHERE id = 'pl1'")
+                        }
+
+                        8 -> {
+                            migrated.execSQL("UPDATE playlists SET changed = 123456 WHERE id = 'pl1'")
+                        }
+
+                        11 -> {
+                            migrated.execSQL("INSERT INTO discs (sourceId, albumId, disc, title) VALUES (1, 'al1', 2, 'The Disc')")
+                        }
+
+                        18 -> {
+                            migrated.execSQL(
+                                "INSERT INTO song_downloads (sourceId, songId, status, bytes, total) " +
+                                    "VALUES (1, 's1', 'Completed', 10, 20)",
+                            )
+                        }
                    }
                }

@@ -107,8 +122,11 @@ class MigrationsTest {
                assertEquals(123456L, long(migrated, "SELECT changed FROM playlists WHERE id = 'pl1'"))
                assertEquals(987654L, long(migrated, "SELECT duration FROM playlists WHERE id = 'pl1'"))
                assertEquals("The Album", text(migrated, "SELECT name FROM albums WHERE id = 'al1'"))
+                assertEquals(555L, long(migrated, "SELECT starred FROM albums WHERE id = 'al1'"))
                assertEquals("The Artist", text(migrated, "SELECT name FROM artists WHERE id = 'ar1'"))
                assertEquals("The Disc", text(migrated, "SELECT title FROM discs WHERE albumId = 'al1' AND disc = 2"))
+                assertEquals("Completed", text(migrated, "SELECT status FROM song_downloads WHERE songId = 's1'"))
+                assertEquals(10L, long(migrated, "SELECT bytes FROM song_downloads WHERE songId = 's1'"))
            }
        }

@@ -1,10 +1,30 @@
 package com.subtracks.data.download

 import android.app.DownloadManager
+import android.content.Context
+import androidx.test.core.app.ApplicationProvider
+import androidx.test.ext.junit.runners.AndroidJUnit4
 import org.junit.Assert.assertEquals
+import org.junit.Assert.assertFalse
+import org.junit.Assert.assertNotNull
+import org.junit.Assert.assertTrue
+import org.junit.Before
 import org.junit.Test
+import org.junit.runner.RunWith
+import org.robolectric.Shadows.shadowOf

+@RunWith(AndroidJUnit4::class)
 class SystemDownloadEngineTest {
+    private lateinit var engine: SystemDownloadEngine
+    private lateinit var downloadManager: DownloadManager
+
+    @Before
+    fun setUp() {
+        val context = ApplicationProvider.getApplicationContext<Context>()
+        engine = SystemDownloadEngine(context)
+        downloadManager = context.getSystemService(DownloadManager::class.java)
+    }
+
    @Test
    fun successfulRunningAndFailedStatusesAreMapped() {
        assertEquals(EngineStatus.Completed, engineStatus(DownloadManager.STATUS_SUCCESSFUL))
@@ -25,4 +45,66 @@ class SystemDownloadEngineTest {
        assertEquals("Storage is unavailable", failureMessage(DownloadManager.ERROR_DEVICE_NOT_FOUND))
        assertEquals("Download failed", failureMessage(DownloadManager.ERROR_UNKNOWN))
    }
+
+    @Test
+    fun enqueuedRequestIsStoredAndTargetsTheSourceAndSongDirectory() {
+        val id =
+            engine.enqueue(
+                EngineRequest(
+                    uri = "https://server.example/rest/stream?id=song-9",
+                    path = "downloads/7/song-9",
+                    title = "A Song",
+                ),
+            )
+
+        val downloads = shadowOf(downloadManager)
+        assertEquals(1, downloads.requestCount)
+
+        val request = shadowOf(downloads.getRequest(id))
+        assertEquals(id, request.id)
+        assertEquals("https://server.example/rest/stream?id=song-9", request.uri.toString())
+        assertEquals("A Song", request.title.toString())
+
+        val destination = request.destination
+        assertNotNull(destination)
+        val path = destination!!.path!!
+        assertTrue("destination $path is not under external files", path.contains("/external-files/"))
+        assertTrue(
+            "destination $path is not under the source/song downloads directory",
+            path.endsWith("/Music/downloads/7/song-9"),
+        )
+    }
+
+    @Test
+    fun meteredPreferenceIsAppliedForBothValues() {
+        val allowed =
+            engine.enqueue(
+                EngineRequest(
+                    uri = "https://server.example/a",
+                    path = "downloads/1/a",
+                    title = "a",
+                    allowMetered = true,
+                ),
+            )
+        val blocked =
+            engine.enqueue(
+                EngineRequest(
+                    uri = "https://server.example/b",
+                    path = "downloads/1/b",
+                    title = "b",
+                    allowMetered = false,
+                ),
+            )
+
+        val downloads = shadowOf(downloadManager)
+        assertEquals(2, downloads.requestCount)
+
+        val allowedRequest = shadowOf(downloads.getRequest(allowed))
+        assertTrue(allowedRequest.allowedOverMetered)
+        assertTrue(allowedRequest.allowedOverRoaming)
+
+        val blockedRequest = shadowOf(downloads.getRequest(blocked))
+        assertFalse(blockedRequest.allowedOverMetered)
+        assertFalse(blockedRequest.allowedOverRoaming)
+    }
 }
@@ -81,6 +81,25 @@ class UserPreferencesTest {
            file.delete()
        }

+    @Test
+    fun downloadQualityAndMeteredRoundTrip() =
+        runTest {
+            val file = File.createTempFile("user-prefs", ".preferences_pb").apply { delete() }
+            val store = PreferenceDataStoreFactory.create(scope = backgroundScope) { file }
+            val prefs = UserPreferences(store)
+
+            assertEquals(StreamQuality(), prefs.downloadQuality().first())
+            assertEquals(false, prefs.downloadOverMetered().first())
+
+            prefs.setDownloadQuality(StreamQuality(192, "opus"))
+            prefs.setDownloadOverMetered(true)
+
+            assertEquals(StreamQuality(192, "opus"), prefs.downloadQuality().first())
+            assertEquals(true, prefs.downloadOverMetered().first())
+
+            file.delete()
+        }
+
    @Test
    fun syncConcurrencyDefaultsAndClampsToAtLeastOne() =
        runTest {
@@ -89,11 +89,15 @@ class LibraryRepositoryTest {
    fun starringUpdatesTheRowBeforeTheServerResponds() =
        runBlocking {
            withSource { server ->
-                server.enqueue(ok().setBodyDelay(10, TimeUnit.SECONDS))
+                server.enqueue(ok().setBodyDelay(250, TimeUnit.MILLISECONDS))

                val call = launch { repository.setStar(StarType.Song, "s1", true) }
                withTimeout(3_000) { while (starred() == null) delay(10) }
                call.cancel()
+                call.join()
+
+                assertNotNull(starred())
+                assertEquals(emptyList<String>(), messages)
            }
        }

@@ -8,6 +8,7 @@ import androidx.test.core.app.ApplicationProvider
 import androidx.test.ext.junit.runners.AndroidJUnit4
 import com.subtracks.data.db.SubtracksDatabase
 import com.subtracks.data.model.Album
+import com.subtracks.data.model.Playlist
 import com.subtracks.data.model.PlaylistSong
 import com.subtracks.data.model.QueueEntry
 import com.subtracks.data.model.QueueKind
@@ -734,6 +735,121 @@ class QueueRepositoryTest {
            }
        }

+    @Test
+    fun upNextCombinedIndexOfCountsFromTheAnchorIntoTheBlock() =
+        runTest {
+            seedLibrary()
+            val snapshot = repository.snapshotAfter(listOf(repository.albumEntry(1, "al1")))
+
+            repository.addUpNext(snapshot, currentPosition = 1, entry = repository.songEntry(1, "s4"), playNext = false)
+
+            val updated = repository.snapshot()
+            assertEquals(1L, updated.anchorPlay)
+            assertEquals(1L, updated.upNextSize)
+            assertEquals(2L, repository.combinedIndexOf(updated, "s4"))
+            assertEquals(1L, repository.combinedContextIndexOf(updated, "s2"))
+            assertEquals(3L, repository.combinedContextIndexOf(updated, "s3"))
+        }
+
+    @Test
+    fun combinedContextIndexOfTracksTheAnchorAsItMoves() =
+        runTest {
+            seedLibrary()
+            val snapshot = repository.snapshotAfter(listOf(repository.albumEntry(1, "al1")))
+            repository.addUpNext(snapshot, currentPosition = 0, entry = repository.songEntry(1, "s4"), playNext = false)
+
+            val before = repository.snapshot()
+            assertEquals(0L, before.anchorPlay)
+            assertEquals(3L, repository.combinedContextIndexOf(before, "s3"))
+
+            repository.setUpNextAnchor(2)
+
+            val after = repository.snapshot()
+            assertEquals(2L, after.anchorPlay)
+            assertEquals(2L, repository.combinedContextIndexOf(after, "s3"))
+            assertEquals(3L, repository.combinedIndexOf(after, "s4"))
+        }
+
+    @Test
+    fun combinedIndexOfPrefersTheUpNextCopyOverTheContextCopy() =
+        runTest {
+            seedLibrary()
+            val snapshot = repository.snapshotAfter(listOf(repository.songEntry(1, "s4")))
+            repository.addUpNext(snapshot, currentPosition = 0, entry = repository.songEntry(1, "s4"), playNext = false)
+
+            val updated = repository.snapshot()
+            assertEquals(0L, repository.combinedContextIndexOf(updated, "s4"))
+            assertEquals(1L, repository.combinedIndexOf(updated, "s4"))
+        }
+
+    @Test
+    fun sourceNameReadsTheAlbumPlaylistOrSongAlbum() =
+        runTest {
+            seedLibrary()
+            db.libraryDao().upsertPlaylists(listOf(playlist("p1", "Road Trip")))
+
+            assertEquals("First Album", repository.sourceName(QueueKind.Album, 1, "al1"))
+            assertEquals("Road Trip", repository.sourceName(QueueKind.Playlist, 1, "p1"))
+            assertEquals("Second Album", repository.sourceName(QueueKind.Song, 1, "s4"))
+            assertEquals(null, repository.sourceName(QueueKind.Song, 1, "ghost"))
+        }
+
+    @Test
+    fun aReorderedAlbumTrackKeepsItsAlbumAsSourceName() =
+        runTest {
+            seedLibrary()
+            repository.replace(listOf(repository.albumEntry(1, "al1")))
+
+            repository.move(repository.snapshot(), from = 0, to = 2)
+
+            val (entry, _) = repository.snapshot().locate(2)!!
+            assertEquals(QueueKind.Song, entry.kind)
+            assertEquals("s1", entry.refId)
+            assertEquals("First Album", repository.sourceName(entry.kind, entry.sourceId, entry.refId))
+        }
+
+    @Test
+    fun anAlbumSplitByRemovalIsStillLabeledByItsAlbum() =
+        runTest {
+            seedLibrary()
+            val snapshot = repository.snapshotAfter(listOf(repository.albumEntry(1, "al1")))
+
+            repository.removeAt(snapshot, 1)
+
+            val (entry, _) = repository.snapshot().locate(1)!!
+            assertEquals(QueueKind.Album, entry.kind)
+            assertEquals("First Album", repository.sourceName(entry.kind, entry.sourceId, entry.refId))
+        }
+
+    @Test
+    fun queueModesRoundTrip() =
+        runTest {
+            seedLibrary()
+            repository.replace(listOf(repository.albumEntry(1, "al1")))
+            assertEquals(QueueModes(shuffle = false, repeat = 0), repository.modes())
+
+            repository.setShuffle(4321L)
+            repository.setRepeat(2)
+            assertEquals(QueueModes(shuffle = true, repeat = 2), repository.modes())
+
+            repository.setShuffle(null)
+            repository.setRepeat(0)
+            assertEquals(QueueModes(shuffle = false, repeat = 0), repository.modes())
+        }
+
+    private fun playlist(
+        id: String,
+        name: String,
+    ) = Playlist(
+        sourceId = 1,
+        id = id,
+        name = name,
+        comment = null,
+        coverArt = null,
+        songCount = 0,
+        created = 0,
+    )
+
    private suspend fun seedLibrary() {
        db.sourcesDao().upsertSource(
            Source(id = 1, name = "test", address = "http://localhost", isActive = true, createdAt = 0),
@@ -167,6 +167,8 @@ class SourceRepositoryTest {
        runBlocking {
            withServer { server ->
                val dispatches = AtomicInteger()
+                val inFlight = AtomicInteger()
+                val maxInFlight = AtomicInteger()
                val secondStarted = CountDownLatch(1)
                val release = CountDownLatch(1)
                server.dispatcher =
@@ -175,7 +177,10 @@ class SourceRepositoryTest {
                            val url = request.requestUrl!!
                            if (url.encodedPath != "/rest/getPlaylist.view") return MockResponse().setResponseCode(404)
                            if (dispatches.incrementAndGet() == 2) secondStarted.countDown()
+                            val current = inFlight.incrementAndGet()
+                            maxInFlight.updateAndGet { maxOf(it, current) }
                            release.await(5, TimeUnit.SECONDS)
+                            inFlight.decrementAndGet()
                            val id = url.queryParameter("id")!!
                            return MockResponse().setBody(
                                "<subsonic-response status=\"ok\"><playlist id=\"$id\">" +
@@ -199,6 +204,7 @@ class SourceRepositoryTest {
                assertFalse(secondStarted.await(500, TimeUnit.MILLISECONDS))
                release.countDown()
                assertEquals(9, fetching.await().size)
+                assertEquals("only one fetch may be in flight at a time", 1, maxInFlight.get())
            }
        }

@@ -5,11 +5,13 @@ import okhttp3.mockwebserver.MockResponse
 import okhttp3.mockwebserver.MockWebServer
 import org.junit.After
 import org.junit.Assert.assertEquals
+import org.junit.Assert.assertNotEquals
 import org.junit.Assert.assertNotNull
 import org.junit.Assert.assertNull
 import org.junit.Assert.assertThrows
 import org.junit.Before
 import org.junit.Test
+import java.security.MessageDigest

 class SubsonicClientTest {
    private lateinit var server: MockWebServer
@@ -57,6 +59,36 @@ class SubsonicClientTest {
        assertNull(url.queryParameter("p"))
    }

+    @Test
+    fun tokenHashIsMd5OfPasswordAndSalt() {
+        server.enqueue(MockResponse().setBody("<subsonic-response status=\"ok\" version=\"1.16.1\"/>"))
+
+        client(tokenAuth = true).check("ping")
+
+        val url = server.takeRequest().requestUrl!!
+        val salt = url.queryParameter("s")!!
+        assertEquals(md5Hex("secret$salt"), url.queryParameter("t"))
+    }
+
+    @Test
+    fun tokenSaltIsFreshPerRequest() {
+        repeat(2) { server.enqueue(MockResponse().setBody("<subsonic-response status=\"ok\" version=\"1.16.1\"/>")) }
+        val client = client(tokenAuth = true)
+
+        client.check("ping")
+        client.check("ping")
+
+        val first = server.takeRequest().requestUrl!!.queryParameter("s")
+        val second = server.takeRequest().requestUrl!!.queryParameter("s")
+        assertNotEquals(first, second)
+    }
+
+    private fun md5Hex(input: String): String =
+        MessageDigest
+            .getInstance("MD5")
+            .digest(input.toByteArray(Charsets.UTF_8))
+            .joinToString("") { "%02x".format(it) }
+
    @Test
    fun plaintextAuthSendsPassword() {
        server.enqueue(MockResponse().setBody("<subsonic-response status=\"ok\" version=\"1.16.1\"/>"))
@@ -12,6 +12,7 @@ import okhttp3.mockwebserver.Dispatcher
 import okhttp3.mockwebserver.MockResponse
 import okhttp3.mockwebserver.MockWebServer
 import okhttp3.mockwebserver.RecordedRequest
+import okhttp3.mockwebserver.SocketPolicy
 import org.junit.After
 import org.junit.Assert.assertEquals
 import org.junit.Assert.assertFalse
@@ -74,6 +75,42 @@ class SubsonicSourceTest {
            )
        }

+    @Test
+    fun getSongsFallsBackToAlbumsWhenEmptySearchProbeFails() =
+        runBlocking {
+            server.dispatcher =
+                object : Dispatcher() {
+                    override fun dispatch(request: RecordedRequest): MockResponse =
+                        when {
+                            request.path?.startsWith("/rest/search3.view") == true -> {
+                                MockResponse().setSocketPolicy(SocketPolicy.DISCONNECT_AFTER_REQUEST)
+                            }
+
+                            request.path?.startsWith("/rest/getAlbumList2.view") == true -> {
+                                MockResponse().setBody(ALBUM_LIST)
+                            }
+
+                            request.path?.startsWith("/rest/getAlbum.view") == true -> {
+                                MockResponse().setBody(ALBUM)
+                            }
+
+                            else -> {
+                                MockResponse().setResponseCode(404)
+                            }
+                        }
+                }
+            val source = SubsonicSource(1, client())
+
+            assertEquals(
+                listOf("s1", "s2"),
+                source
+                    .songs()
+                    .toList()
+                    .flatten()
+                    .map { it.id },
+            )
+        }
+
    @Test
    fun artistsAreEmittedInBoundedBatches() =
        runBlocking {
@@ -353,6 +390,8 @@ class SubsonicSourceTest {
            val bound = 2
            val started = CountDownLatch(bound)
            val beyondBound = CountDownLatch(bound + 1)
+            val inFlight = AtomicInteger()
+            val maxInFlight = AtomicInteger()
            val release = CountDownLatch(1)
            server.dispatcher =
                object : Dispatcher() {
@@ -361,7 +400,10 @@ class SubsonicSourceTest {
                        if (url.encodedPath != "/rest/getPlaylist.view") return MockResponse().setResponseCode(404)
                        beyondBound.countDown()
                        started.countDown()
+                        val current = inFlight.incrementAndGet()
+                        maxInFlight.updateAndGet { maxOf(it, current) }
                        release.await(5, TimeUnit.SECONDS)
+                        inFlight.decrementAndGet()
                        return MockResponse().setBody(playlistResponse(url.queryParameter("id")!!))
                    }
                }
@@ -384,6 +426,7 @@ class SubsonicSourceTest {
            val entries = fetching.await()

            assertEquals(12, entries.size)
+            assertEquals("the bound must cap concurrent fetches", bound, maxInFlight.get())
        }

    @Test
@@ -14,6 +14,11 @@ import kotlinx.coroutines.flow.first
 import kotlinx.coroutines.runBlocking
 import kotlinx.coroutines.withTimeout
 import okhttp3.OkHttpClient
+import okhttp3.mockwebserver.Dispatcher
+import okhttp3.mockwebserver.MockResponse
+import okhttp3.mockwebserver.MockWebServer
+import okhttp3.mockwebserver.RecordedRequest
+import okhttp3.mockwebserver.SocketPolicy
 import org.junit.After
 import org.junit.Assert.assertEquals
 import org.junit.Assert.assertTrue
@@ -22,6 +27,9 @@ import org.junit.Test
 import org.junit.runner.RunWith
 import java.io.File
 import java.util.concurrent.CopyOnWriteArrayList
+import java.util.concurrent.CountDownLatch
+import java.util.concurrent.TimeUnit
+import java.util.concurrent.atomic.AtomicInteger

@RunWith(AndroidJUnit4::class)
 class SyncManagerTest {
@@ -30,6 +38,7 @@ class SyncManagerTest {
    private lateinit var queueRepository: QueueRepository
    private lateinit var manager: SyncManager
    private val messages = CopyOnWriteArrayList<String>()
+    private lateinit var server: MockWebServer

    @Before
    fun setUp() {
@@ -42,12 +51,15 @@ class SyncManagerTest {
        sourceRepository = SourceRepository(db, OkHttpClient(), fakeUserPreferences(), ArtworkStore(File(context.cacheDir, "art")))
        queueRepository = QueueRepository(db)
        manager = SyncManager(db, sourceRepository, queueRepository, showMessage = { messages += it })
+        server = MockWebServer()
+        server.start()
    }

    @After
    fun tearDown() {
        sourceRepository.close()
        db.close()
+        server.shutdown()
    }

    @Test
@@ -70,4 +82,146 @@ class SyncManagerTest {
            assertTrue(status is SyncStatus.Failed)
            assertEquals(before + 1, queueRepository.snapshot().version)
        }
+
+    @Test
+    fun aSuccessfulSyncMirrorsTheLibraryIntoRoom() =
+        runBlocking {
+            server.dispatcher = healthyDispatcher()
+            sourceRepository.addSource("Local", server.url("/").toString(), "u", "p", useTokenAuth = false)
+
+            manager.requestSync()
+            withTimeout(10_000) { manager.status.first { it is SyncStatus.Success } }
+
+            assertEquals(listOf("ar1"), db.libraryDao().artistIds(1))
+            assertEquals(listOf("al1"), db.libraryDao().albumIds(1))
+        }
+
+    @Test
+    fun aMidSyncFailureKeepsCommittedRowsAndRecovers() =
+        runBlocking {
+            server.dispatcher =
+                object : Dispatcher() {
+                    override fun dispatch(request: RecordedRequest): MockResponse =
+                        when {
+                            request.path?.startsWith("/rest/getArtists.view") == true -> {
+                                MockResponse().setBody(ARTISTS)
+                            }
+
+                            request.path?.startsWith("/rest/getAlbumList2.view") == true -> {
+                                MockResponse().setBody(ALBUM_LIST)
+                            }
+
+                            request.path?.startsWith("/rest/search3.view") == true -> {
+                                MockResponse().setSocketPolicy(SocketPolicy.DISCONNECT_AT_START)
+                            }
+
+                            request.path?.startsWith("/rest/getAlbum.view") == true -> {
+                                MockResponse().setSocketPolicy(SocketPolicy.DISCONNECT_AT_START)
+                            }
+
+                            else -> {
+                                MockResponse().setResponseCode(404)
+                            }
+                        }
+                }
+            sourceRepository.addSource("Local", server.url("/").toString(), "u", "p", useTokenAuth = false)
+
+            manager.requestSync()
+            withTimeout(10_000) { manager.status.first { it is SyncStatus.Failed } }
+
+            assertEquals(listOf("ar1"), db.libraryDao().artistIds(1))
+
+            server.dispatcher = healthyDispatcher()
+            manager.requestSync()
+            withTimeout(10_000) { manager.status.first { it is SyncStatus.Success } }
+
+            assertEquals(listOf("ar1"), db.libraryDao().artistIds(1))
+            assertEquals(listOf("al1"), db.libraryDao().albumIds(1))
+        }
+
+    @Test
+    fun requestsWhileRunningCoalesceIntoOneSync() =
+        runBlocking {
+            val artistRequests = AtomicInteger()
+            val firstArtistStarted = CountDownLatch(1)
+            val secondArtistStarted = CountDownLatch(1)
+            val releaseFirst = CountDownLatch(1)
+            server.dispatcher =
+                object : Dispatcher() {
+                    override fun dispatch(request: RecordedRequest): MockResponse {
+                        if (request.path?.startsWith("/rest/getArtists.view") == true) {
+                            when (artistRequests.incrementAndGet()) {
+                                1 -> {
+                                    firstArtistStarted.countDown()
+                                    releaseFirst.await(10, TimeUnit.SECONDS)
+                                }
+
+                                2 -> {
+                                    secondArtistStarted.countDown()
+                                }
+                            }
+                        }
+                        return healthyDispatcher().dispatch(request)
+                    }
+                }
+            sourceRepository.addSource("Local", server.url("/").toString(), "u", "p", useTokenAuth = false)
+
+            manager.requestSync()
+            assertTrue(firstArtistStarted.await(10, TimeUnit.SECONDS))
+            manager.requestSync()
+            manager.requestSync()
+            releaseFirst.countDown()
+
+            withTimeout(10_000) { manager.status.first { it is SyncStatus.Success } }
+            assertTrue("the coalesced sync should start", secondArtistStarted.await(10, TimeUnit.SECONDS))
+            assertEquals(2, artistRequests.get())
+        }
+
+    private fun healthyDispatcher() =
+        object : Dispatcher() {
+            override fun dispatch(request: RecordedRequest): MockResponse =
+                when {
+                    request.path?.startsWith("/rest/getArtists.view") == true -> {
+                        MockResponse().setBody(ARTISTS)
+                    }
+
+                    request.path?.startsWith("/rest/getAlbumList2.view") == true -> {
+                        val type = request.requestUrl?.queryParameter("type")
+                        MockResponse().setBody(if (type == "newest") ALBUM_LIST else emptyAlbumList())
+                    }
+
+                    request.path?.startsWith("/rest/search3.view") == true -> {
+                        MockResponse().setBody(SONG)
+                    }
+
+                    request.path?.startsWith("/rest/getPlaylists.view") == true -> {
+                        MockResponse().setBody(emptyPlaylists())
+                    }
+
+                    else -> {
+                        MockResponse().setResponseCode(404)
+                    }
+                }
+        }
+
+    private fun emptyAlbumList() = "<subsonic-response status=\"ok\"><albumList2></albumList2></subsonic-response>"
+
+    private fun emptyPlaylists() = "<subsonic-response status=\"ok\"><playlists></playlists></subsonic-response>"
+
+    private companion object {
+        const val ARTISTS =
+            "<subsonic-response status=\"ok\" version=\"1.16.1\"><artists>" +
+                "<artist id=\"ar1\" name=\"Artist One\" albumCount=\"1\"/>" +
+                "</artists></subsonic-response>"
+
+        const val ALBUM_LIST =
+            "<subsonic-response status=\"ok\" version=\"1.16.1\"><albumList2>" +
+                "<album id=\"al1\" artistId=\"ar1\" name=\"Album One\" artist=\"Artist One\" songCount=\"1\"/>" +
+                "</albumList2></subsonic-response>"
+
+        const val SONG =
+            "<subsonic-response status=\"ok\" version=\"1.16.1\"><searchResult3>" +
+                "<song id=\"s1\" title=\"Song One\" albumId=\"al1\" artistId=\"ar1\" track=\"1\"/>" +
+                "</searchResult3></subsonic-response>"
+    }
 }
@@ -3,31 +3,49 @@ package com.subtracks.di
 import android.content.Context
 import androidx.test.core.app.ApplicationProvider
 import androidx.test.ext.junit.runners.AndroidJUnit4
+import com.subtracks.data.download.DownloadNotifier
 import com.subtracks.data.repo.DownloadRepository
+import com.subtracks.data.repo.SourceRepository
 import com.subtracks.playback.PlaybackController
 import okhttp3.OkHttpClient
 import org.junit.After
-import org.junit.Assert.assertNotNull
+import org.junit.Assert.assertSame
 import org.junit.Before
 import org.junit.Test
 import org.junit.runner.RunWith
+import org.koin.core.Koin
 import org.koin.core.context.startKoin
 import org.koin.core.context.stopKoin

@RunWith(AndroidJUnit4::class)
 class AppModuleTest {
+    private lateinit var koin: Koin
+
    @Before
    fun setUp() = stopKoin()

    @After
-    fun tearDown() = stopKoin()
+    fun tearDown() {
+        if (::koin.isInitialized) {
+            runCatching {
+                koin.get<DownloadNotifier>().close()
+                koin.get<PlaybackController>().close()
+                koin.get<DownloadRepository>().close()
+                koin.get<SourceRepository>().close()
+            }
+        }
+        stopKoin()
+    }

    @Test
    fun theModuleResolvesThePlaybackGraph() {
        val context = ApplicationProvider.getApplicationContext<Context>()
-        val koin = startKoin { modules(appModule(context, OkHttpClient())) }.koin
+        koin = startKoin { modules(appModule(context, OkHttpClient())) }.koin

-        assertNotNull(koin.get<DownloadRepository>())
-        assertNotNull(koin.get<PlaybackController>())
+        val downloads = koin.get<DownloadRepository>()
+        val controller = koin.get<PlaybackController>()
+
+        assertSame(downloads, koin.get<DownloadRepository>())
+        assertSame(controller, koin.get<PlaybackController>())
    }
 }
@@ -27,6 +27,7 @@ import kotlinx.coroutines.delay
 import kotlinx.coroutines.flow.MutableStateFlow
 import kotlinx.coroutines.launch
 import kotlinx.coroutines.runBlocking
+import kotlinx.coroutines.withContext
 import okhttp3.OkHttpClient
 import org.junit.After
 import org.junit.Assert.assertEquals
@@ -1236,11 +1237,10 @@ class PlaybackControllerTest {
        await { controller.state.value.isPlaying }

        handle.startBuffering()
-        Thread.sleep(300)
-        assertFalse(controller.state.value.isBuffering)
+        runBlocking { withContext(dispatcher) { } }
+        assertFalse("buffering must be debounced, not reported immediately", controller.state.value.isBuffering)

-        Thread.sleep(1_200)
-        assertTrue(controller.state.value.isBuffering)
+        await { controller.state.value.isBuffering }

        handle.becomeReady()
        await { !controller.state.value.isBuffering }
@@ -71,6 +71,11 @@ import org.robolectric.annotation.Config
 import org.robolectric.annotation.GraphicsMode
 import kotlin.random.Random

+/**
+ * Render smoke tests: these render each screen and assert the awaited node exists, then write a PNG
+ * for local review. No golden images are committed and `verifyRoborazziDebug` is not run in CI, so
+ * pixel/layout regressions are NOT caught here. Use `recordRoborazziDebug` to inspect output.
+ */
@OptIn(DelicateCoilApi::class)
@RunWith(AndroidJUnit4::class)
@GraphicsMode(GraphicsMode.Mode.NATIVE)
@@ -27,6 +27,7 @@ import org.junit.runner.RunWith
 import org.robolectric.annotation.Config
 import org.robolectric.annotation.GraphicsMode

+/** Render smoke test: asserts the awaited node exists and writes a PNG for local review; it does not verify pixels. */
@RunWith(AndroidJUnit4::class)
@GraphicsMode(GraphicsMode.Mode.NATIVE)
@Config(qualifiers = RobolectricDeviceQualifiers.PixelXL)
@@ -28,6 +28,7 @@ import org.junit.runner.RunWith
 import org.robolectric.annotation.Config
 import org.robolectric.annotation.GraphicsMode

+/** Render smoke test: asserts the awaited node exists and writes a PNG for local review; it does not verify pixels. */
@RunWith(AndroidJUnit4::class)
@GraphicsMode(GraphicsMode.Mode.NATIVE)
@Config(qualifiers = RobolectricDeviceQualifiers.PixelXL)
@@ -0,0 +1,179 @@
+package com.subtracks.ui.downloads
+
+import android.content.Context
+import androidx.lifecycle.viewModelScope
+import androidx.room3.Room
+import androidx.sqlite.driver.bundled.BundledSQLiteDriver
+import androidx.test.core.app.ApplicationProvider
+import androidx.test.ext.junit.runners.AndroidJUnit4
+import com.subtracks.data.db.SubtracksDatabase
+import com.subtracks.data.download.ArtworkStore
+import com.subtracks.data.download.FakeDownloadEngine
+import com.subtracks.data.model.DownloadList
+import com.subtracks.data.model.DownloadStatus
+import com.subtracks.data.model.Song
+import com.subtracks.data.model.SongDownload
+import com.subtracks.data.prefs.fakeUserPreferences
+import com.subtracks.data.repo.DownloadRepository
+import com.subtracks.data.repo.LibraryRepository
+import com.subtracks.data.repo.NetworkServerActionSink
+import com.subtracks.data.repo.QueueRepository
+import com.subtracks.data.repo.SourceRepository
+import com.subtracks.playback.FakePlayerConnection
+import com.subtracks.playback.FakePlayerHandle
+import com.subtracks.playback.PlaybackController
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.ExperimentalCoroutinesApi
+import kotlinx.coroutines.asCoroutineDispatcher
+import kotlinx.coroutines.cancel
+import kotlinx.coroutines.runBlocking
+import kotlinx.coroutines.test.resetMain
+import kotlinx.coroutines.test.setMain
+import okhttp3.OkHttpClient
+import org.junit.After
+import org.junit.Assert.assertNotNull
+import org.junit.Assert.assertNull
+import org.junit.Assert.assertTrue
+import org.junit.Before
+import org.junit.Test
+import org.junit.runner.RunWith
+import java.io.File
+import java.util.concurrent.Executors
+
+@OptIn(ExperimentalCoroutinesApi::class)
+@RunWith(AndroidJUnit4::class)
+class DownloadsViewModelTest {
+    private val dispatcher = Executors.newSingleThreadExecutor().asCoroutineDispatcher()
+
+    private lateinit var db: SubtracksDatabase
+    private lateinit var sourceRepository: SourceRepository
+    private lateinit var downloadRepository: DownloadRepository
+    private lateinit var controller: PlaybackController
+    private lateinit var viewModel: DownloadsViewModel
+    private var sourceId: Long = 0
+
+    @Before
+    fun setUp() {
+        Dispatchers.setMain(dispatcher)
+        val context = ApplicationProvider.getApplicationContext<Context>()
+        db =
+            Room
+                .inMemoryDatabaseBuilder(context, SubtracksDatabase::class.java)
+                .setDriver(BundledSQLiteDriver())
+                .build()
+        val artwork = ArtworkStore(File(context.cacheDir, "art-${System.nanoTime()}"))
+        sourceRepository = SourceRepository(db, OkHttpClient(), fakeUserPreferences(), artwork)
+        downloadRepository =
+            DownloadRepository(
+                db,
+                sourceRepository,
+                FakeDownloadEngine(),
+                File(context.cacheDir, "downloads-${System.nanoTime()}"),
+                artworkStore = artwork,
+                artworkFetcher = { ByteArray(0) },
+            )
+        controller =
+            PlaybackController(
+                sourceRepository,
+                QueueRepository(db),
+                FakePlayerConnection(FakePlayerHandle()),
+                downloadRepository,
+                dispatcher = dispatcher,
+            )
+        viewModel =
+            DownloadsViewModel(
+                LibraryRepository(db, sourceRepository, NetworkServerActionSink(sourceRepository)),
+                downloadRepository,
+                controller,
+            )
+    }
+
+    @After
+    fun tearDown() {
+        viewModel.viewModelScope.cancel()
+        controller.close()
+        downloadRepository.close()
+        sourceRepository.close()
+        db.close()
+        Dispatchers.resetMain()
+        dispatcher.close()
+    }
+
+    @Test
+    fun deleteAllRemovesEveryDownloadOfTheSource() {
+        seedDownloads()
+
+        viewModel.deleteAll()
+        await { allRows().isEmpty() }
+
+        assertTrue("every download row should be gone", allRows().isEmpty())
+    }
+
+    @Test
+    fun deleteRemovesOnlyTheSongsOfThatAlbum() {
+        seedDownloads()
+
+        viewModel.delete(DownloadList.Album, "al1")
+        await { row("s1") == null && row("s2") == null }
+
+        assertNull(row("s1"))
+        assertNull(row("s2"))
+        assertNotNull("a song from another album should survive", row("s3"))
+    }
+
+    @Test
+    fun deleteSongsRemovesOnlyTheGivenSongs() {
+        seedDownloads()
+
+        viewModel.deleteSongs(listOf("s1"))
+        await { row("s1") == null }
+
+        assertNull(row("s1"))
+        assertNotNull("an unnamed song should survive", row("s2"))
+    }
+
+    private fun seedDownloads() {
+        sourceId =
+            runBlocking {
+                val id = sourceRepository.addSource("nav", "http://localhost/", "u", "p", false)
+                db.libraryDao().upsertSongs(
+                    listOf(
+                        song(id, "s1", "al1"),
+                        song(id, "s2", "al1"),
+                        song(id, "s3", "al2"),
+                    ),
+                )
+                listOf("s1", "s2", "s3").forEach { db.downloadDao().upsert(SongDownload(id, it, DownloadStatus.Completed)) }
+                id
+            }
+    }
+
+    private fun song(
+        sourceId: Long,
+        songId: String,
+        albumId: String,
+    ) = Song(
+        sourceId = sourceId,
+        id = songId,
+        albumId = albumId,
+        artistId = "ar1",
+        title = songId,
+        album = "Album",
+        artist = "Artist",
+        duration = 100,
+        track = 1,
+        disc = 1,
+        starred = null,
+        genre = null,
+    )
+
+    private fun row(songId: String): SongDownload? = runBlocking { db.downloadDao().find(sourceId, songId) }
+
+    private fun allRows(): List<SongDownload> = runBlocking { db.downloadDao().all() }
+
+    private fun await(predicate: () -> Boolean) {
+        val deadline = System.nanoTime() + 5_000_000_000L
+        while (!predicate() && System.nanoTime() < deadline) Thread.sleep(10)
+        assertTrue("Timed out waiting for the expected state", predicate())
+    }
+}
@@ -0,0 +1,27 @@
+package com.subtracks.ui.library
+
+import androidx.test.ext.junit.runners.AndroidJUnit4
+import com.subtracks.data.prefs.AlbumSort
+import com.subtracks.data.prefs.ArtistSort
+import com.subtracks.data.prefs.ListQuery
+import com.subtracks.data.prefs.PlaylistSort
+import org.junit.Assert.assertEquals
+import org.junit.Test
+import org.junit.runner.RunWith
+
+@RunWith(AndroidJUnit4::class)
+class LibraryViewModelTest {
+    @Test
+    fun aKnownSortStringDecodesToItsEnum() {
+        assertEquals(AlbumSort.Year, ListQuery("Year").albumSort())
+        assertEquals(ArtistSort.AlbumCount, ListQuery("AlbumCount").artistSort())
+        assertEquals(PlaylistSort.Updated, ListQuery("Updated").playlistSort())
+    }
+
+    @Test
+    fun anUnknownSortStringFallsBackToName() {
+        assertEquals(AlbumSort.Name, ListQuery("LegacyAlbumOrder").albumSort())
+        assertEquals(ArtistSort.Name, ListQuery("LegacyArtistOrder").artistSort())
+        assertEquals(PlaylistSort.Name, ListQuery("LegacyPlaylistOrder").playlistSort())
+    }
+}
@@ -1,6 +1,7 @@
 package com.subtracks.ui.playback

 import android.content.Context
+import androidx.lifecycle.viewModelScope
 import androidx.room3.Room
 import androidx.sqlite.driver.bundled.BundledSQLiteDriver
 import androidx.test.core.app.ApplicationProvider
@@ -22,6 +23,7 @@ import com.subtracks.playback.PlaybackController
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.ExperimentalCoroutinesApi
 import kotlinx.coroutines.asCoroutineDispatcher
+import kotlinx.coroutines.cancel
 import kotlinx.coroutines.runBlocking
 import kotlinx.coroutines.test.resetMain
 import kotlinx.coroutines.test.setMain
@@ -43,6 +45,8 @@ class QueueViewModelTest {
    private val dispatcher = Executors.newSingleThreadExecutor().asCoroutineDispatcher()

    private lateinit var db: SubtracksDatabase
+    private lateinit var sources: SourceRepository
+    private lateinit var downloads: DownloadRepository
    private lateinit var queues: QueueRepository
    private lateinit var controller: PlaybackController
    private lateinit var viewModel: QueueViewModel
@@ -56,10 +60,10 @@ class QueueViewModelTest {
                .inMemoryDatabaseBuilder(context, SubtracksDatabase::class.java)
                .setDriver(BundledSQLiteDriver())
                .build()
-        val sources = SourceRepository(db, OkHttpClient(), fakeUserPreferences(), ArtworkStore(File(context.cacheDir, "art")))
+        sources = SourceRepository(db, OkHttpClient(), fakeUserPreferences(), ArtworkStore(File(context.cacheDir, "art")))
        queues = QueueRepository(db)
        val artwork = ArtworkStore(File(context.cacheDir, "art"))
-        val downloads =
+        downloads =
            DownloadRepository(
                db,
                sources,
@@ -74,7 +78,10 @@ class QueueViewModelTest {

    @After
    fun tearDown() {
+        viewModel.viewModelScope.cancel()
        controller.close()
+        downloads.close()
+        sources.close()
        db.close()
        Dispatchers.resetMain()
        dispatcher.close()
@@ -0,0 +1,152 @@
+package com.subtracks.ui.settings
+
+import android.content.Context
+import androidx.lifecycle.viewModelScope
+import androidx.room3.Room
+import androidx.sqlite.driver.bundled.BundledSQLiteDriver
+import androidx.test.core.app.ApplicationProvider
+import androidx.test.ext.junit.runners.AndroidJUnit4
+import com.subtracks.data.db.SubtracksDatabase
+import com.subtracks.data.download.ArtworkStore
+import com.subtracks.data.download.FakeDownloadEngine
+import com.subtracks.data.prefs.fakeUserPreferences
+import com.subtracks.data.repo.DownloadRepository
+import com.subtracks.data.repo.QueueRepository
+import com.subtracks.data.repo.SourceRepository
+import com.subtracks.data.sync.SyncManager
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.ExperimentalCoroutinesApi
+import kotlinx.coroutines.asCoroutineDispatcher
+import kotlinx.coroutines.cancel
+import kotlinx.coroutines.runBlocking
+import kotlinx.coroutines.test.resetMain
+import kotlinx.coroutines.test.setMain
+import okhttp3.OkHttpClient
+import okhttp3.mockwebserver.MockResponse
+import okhttp3.mockwebserver.MockWebServer
+import org.junit.After
+import org.junit.Assert.assertEquals
+import org.junit.Assert.assertFalse
+import org.junit.Assert.assertNotNull
+import org.junit.Assert.assertTrue
+import org.junit.Before
+import org.junit.Test
+import org.junit.runner.RunWith
+import java.io.File
+import java.util.concurrent.Executors
+
+@OptIn(ExperimentalCoroutinesApi::class)
+@RunWith(AndroidJUnit4::class)
+class AddSourceViewModelTest {
+    private val dispatcher = Executors.newSingleThreadExecutor().asCoroutineDispatcher()
+
+    private lateinit var db: SubtracksDatabase
+    private lateinit var sourceRepository: SourceRepository
+    private lateinit var downloadRepository: DownloadRepository
+    private lateinit var server: MockWebServer
+    private val createdViewModels = mutableListOf<AddSourceViewModel>()
+
+    @Before
+    fun setUp() {
+        Dispatchers.setMain(dispatcher)
+        val context = ApplicationProvider.getApplicationContext<Context>()
+        db =
+            Room
+                .inMemoryDatabaseBuilder(context, SubtracksDatabase::class.java)
+                .setDriver(BundledSQLiteDriver())
+                .build()
+        val artwork = ArtworkStore(File(context.cacheDir, "art-${System.nanoTime()}"))
+        sourceRepository = SourceRepository(db, OkHttpClient(), fakeUserPreferences(), artwork)
+        downloadRepository =
+            DownloadRepository(
+                db,
+                sourceRepository,
+                FakeDownloadEngine(),
+                File(context.cacheDir, "downloads-${System.nanoTime()}"),
+                artworkStore = artwork,
+                artworkFetcher = { ByteArray(0) },
+            )
+        server = MockWebServer()
+        server.start()
+    }
+
+    @After
+    fun tearDown() {
+        createdViewModels.forEach { it.viewModelScope.cancel() }
+        server.shutdown()
+        downloadRepository.close()
+        sourceRepository.close()
+        db.close()
+        Dispatchers.resetMain()
+        dispatcher.close()
+    }
+
+    @Test
+    fun aRejectedPingSetsTheErrorAndClearsBusy() {
+        val viewModel = viewModel()
+        viewModel.setAddress(server.url("/").toString())
+        viewModel.setUsername("u")
+        viewModel.setPassword("p")
+        server.enqueue(failed())
+
+        viewModel.testConnection()
+        await { !viewModel.state.value.busy }
+
+        val state = viewModel.state.value
+        assertFalse(state.busy)
+        assertTrue("a rejected ping should be an error", state.isError)
+        assertEquals("Failed: Wrong username", state.message)
+    }
+
+    @Test
+    fun aSuccessfulPingClearsAnEarlierError() {
+        val viewModel = viewModel()
+        viewModel.setAddress(server.url("/").toString())
+        viewModel.setUsername("u")
+        viewModel.setPassword("p")
+        server.enqueue(failed())
+        viewModel.testConnection()
+        await { !viewModel.state.value.busy && viewModel.state.value.isError }
+
+        server.enqueue(ok())
+        viewModel.testConnection()
+        await { !viewModel.state.value.busy && !viewModel.state.value.isError }
+
+        val state = viewModel.state.value
+        assertEquals("Connection OK", state.message)
+        assertFalse(state.isError)
+    }
+
+    @Test
+    fun theActiveSourceCannotBeDeleted() =
+        runBlocking {
+            val sourceId = sourceRepository.addSource("nav", server.url("/").toString(), "u", "p", false)
+            val viewModel = viewModel(sourceId)
+            await { !viewModel.state.value.canDelete }
+
+            viewModel.delete {}
+            await { !viewModel.state.value.busy && viewModel.state.value.message != null }
+
+            val state = viewModel.state.value
+            assertTrue(state.isError)
+            assertTrue(state.message!!.contains("active server can't be deleted"))
+            assertNotNull("the active source must survive the refused delete", db.sourcesDao().sourceOnce(sourceId))
+        }
+
+    private fun viewModel(sourceId: Long? = null): AddSourceViewModel =
+        AddSourceViewModel(sourceRepository, SyncManager(db, sourceRepository, QueueRepository(db)), downloadRepository, sourceId)
+            .also { createdViewModels += it }
+
+    private fun ok() = MockResponse().setBody("<subsonic-response status=\"ok\" version=\"1.16.1\"/>")
+
+    private fun failed() =
+        MockResponse().setBody(
+            "<subsonic-response status=\"failed\"><error code=\"40\" message=\"Wrong username\"/></subsonic-response>",
+        )
+
+    private fun await(predicate: () -> Boolean) {
+        val deadline = System.nanoTime() + 5_000_000_000L
+        while (!predicate() && System.nanoTime() < deadline) Thread.sleep(10)
+        assertTrue("Timed out waiting for the expected state", predicate())
+    }
+}
@@ -65,7 +65,7 @@ class ArtworkExtractionTest {

    @Test
    fun resolvesColorsFromCoverArt() {
-        val ref = CoverArtRef(url = "art", cacheKey = "art-${System.nanoTime()}")
+        val ref = CoverArtRef(url = "art", cacheKey = "art")
        var colors: ArtworkColors? = null
        composeRule.setContent {
            colors = rememberArtworkColors(ref)
@@ -113,7 +113,7 @@ class ArtworkExtractionTest {

    @Test
    fun keepsTheStoredSeedWhenTheArtCannotBeDecoded() {
-        val key = "missing-${System.nanoTime()}"
+        val key = "missing"
        val stored = ArtworkSeed(key, 0xFF3A7BD5.toInt(), 0xFFD53A3A.toInt(), null)
        ArtworkSeedCache.install(
            object : ArtworkSeedStore {
@@ -1 +1,5 @@
 sdk=35
+# The real Application starts app-scoped Koin singletons (download repo/notifier) whose collectors
+# are never cancelled between tests, so they query a torn-down database at teardown. Tests build
+# their own graphs; AppModuleTest starts Koin explicitly.
+application=android.app.Application