cover the drag drop target mapping

app/src/main/kotlin/com/subtracks/ui/playback/QueueScreen.kt

@@ -395,7 +395,7 @@ fun QueueScreen(
     }
 }
 
-private fun dropTarget(
+internal fun dropTarget(
     rows: List<QueueRow>,
     index: Int,
     from: Long,

app/src/test/kotlin/com/subtracks/ui/playback/QueueViewModelTest.kt

@@ -7,6 +7,7 @@ import androidx.test.core.app.ApplicationProvider
 import androidx.test.ext.junit.runners.AndroidJUnit4
 import com.subtracks.data.db.SubtracksDatabase
 import com.subtracks.data.model.Song
+import com.subtracks.data.model.SongListItem
 import com.subtracks.data.model.Source
 import com.subtracks.data.prefs.fakeUserPreferences
 import com.subtracks.data.repo.QueueRepository
@@ -98,6 +99,13 @@ class QueueViewModelTest {
         assertEquals((139L..199L).toList(), viewModel.rows.map { it.position })
     }
 
+    @Test
+    fun dropTargetUsesStablePositionsAcrossDirectionChanges() {
+        assertEquals(1L, dropTarget(listOf(row(1), row(0), row(2), row(3)), index = 1, from = 0))
+        assertEquals(3L, dropTarget(listOf(row(1), row(2), row(3), row(0)), index = 3, from = 0))
+        assertEquals(1L, dropTarget(listOf(row(0), row(3), row(1), row(2)), index = 1, from = 3))
+    }
+
     @Test
     fun reorderingMovesTheRowLocally() {
         runBlocking { seedSongs(200) }
@@ -113,6 +121,30 @@ class QueueViewModelTest {
         assertEquals(listOf(101L, 102L, 100L), positions.take(3))
     }
 
+    private fun row(position: Int) =
+        QueueRow(
+            position.toLong(),
+            position.toLong(),
+            SongListItem(
+                song =
+                    Song(
+                        sourceId = 1,
+                        id = "s$position",
+                        albumId = "al1",
+                        artistId = "ar1",
+                        title = "Song $position",
+                        album = "Album",
+                        artist = "Artist",
+                        duration = 100,
+                        track = 1,
+                        disc = 1,
+                        starred = null,
+                        genre = null,
+                    ),
+                coverArt = null,
+            ),
+        )
+
     private suspend fun seedSongs(count: Int) {
         db.sourcesDao().upsertSource(
             Source(id = 1, name = "test", address = "http://localhost", isActive = true, createdAt = 0),