downloads: address review on the cancel/progress rows

Name the cancel and delete buttons after the row so screen readers can
tell them apart, show an indeterminate bar when a running track has no
known total, and drop the no-op media refresh on cancel. Trim the dead
size alias and a redundant guard, and cover a queued row with no engine
id plus a failed track in the progress denominator.

app/src/test/kotlin/com/subtracks/ui/downloads/DownloadTreeTest.kt

@@ -58,6 +58,20 @@ class DownloadTreeTest {
         assertNull(nodeProgress(listOf(song("s3", "Three", "ar1", "Artist", "al1", "Album", size = 1))))
     }
 
+    @Test
+    fun nodeProgressCountsAFailedTrackInTheDenominator() {
+        val songs =
+            listOf(
+                song("s1", "One", "ar1", "Artist", "al1", "Album", size = 100),
+                song("s2", "Two", "ar1", "Artist", "al1", "Album", size = 100)
+                    .copy(status = DownloadStatus.Failed),
+                song("s3", "Three", "ar1", "Artist", "al1", "Album", size = 100)
+                    .copy(status = DownloadStatus.Running, bytes = 50, total = 100),
+            )
+
+        assertEquals(0.5f, nodeProgress(songs)!!, 0.0001f)
+    }
+
     private fun song(
         id: String,
         title: String,

app/src/test/kotlin/com/subtracks/ui/downloads/DownloadsScreenTest.kt

@@ -53,10 +53,10 @@ class DownloadsScreenTest {
             onCancel = { cancelled = it },
         )
 
-        composeRule.onAllNodesWithContentDescription("Cancel download").assertCountEquals(1)
-        composeRule.onAllNodesWithContentDescription("Delete downloads").assertCountEquals(1)
+        composeRule.onAllNodesWithContentDescription("Cancel download", substring = true).assertCountEquals(1)
+        composeRule.onAllNodesWithContentDescription("Delete downloads", substring = true).assertCountEquals(1)
 
-        composeRule.onNodeWithContentDescription("Cancel download").performClick()
+        composeRule.onNodeWithContentDescription("Cancel download of Active").performClick()
         assertEquals(listOf("s1"), cancelled)
     }
 
@@ -66,8 +66,8 @@ class DownloadsScreenTest {
 
         expandArtistAndAlbum()
 
-        composeRule.onAllNodesWithContentDescription("Cancel download").assertCountEquals(3)
-        composeRule.onAllNodesWithContentDescription("Delete download").assertCountEquals(1)
+        composeRule.onAllNodesWithContentDescription("Cancel download", substring = true).assertCountEquals(3)
+        composeRule.onAllNodesWithContentDescription("Delete download of Done").assertCountEquals(1)
     }
 
     private fun artist(

app/src/test/kotlin/com/subtracks/ui/downloads/DownloadsViewModelTest.kt

@@ -150,6 +150,17 @@ class DownloadsViewModelTest {
         assertNotNull("a completed download should survive a cancel", row("s2"))
     }
 
+    @Test
+    fun cancelSongsRemovesAQueuedDownloadWithoutAnEngineId() {
+        seedDownloads()
+        runBlocking { db.downloadDao().upsert(SongDownload(sourceId, "s1", DownloadStatus.Queued, engineId = null)) }
+
+        viewModel.cancelSongs(listOf("s1"))
+        await { row("s1") == null }
+
+        assertNull(row("s1"))
+    }
+
     private fun seedDownloads() {
         sourceId =
             runBlocking {