The Tests actually caught an error :)

If shortcuts were set, these were added as duplicates to the list.

core/subsonic-api/src/test/kotlin/org/moire/ultrasonic/api/subsonic/models/AlbumListTypeTest.kt

@@ -1,5 +1,6 @@
 package org.moire.ultrasonic.api.subsonic.models
 
+import java.util.Locale
 import org.amshove.kluent.`should be equal to`
 import org.amshove.kluent.`should throw`
 import org.junit.Test
@@ -10,7 +11,7 @@ import org.junit.Test
 class AlbumListTypeTest {
     @Test
     fun `Should create type from string ignoring case`() {
-        val type = AlbumListType.SORTED_BY_NAME.typeName.toLowerCase()
+        val type = AlbumListType.SORTED_BY_NAME.typeName.lowercase(Locale.ROOT)
 
         val albumListType = AlbumListType.fromName(type)
 

ultrasonic/src/main/kotlin/org/moire/ultrasonic/domain/APIIndexesConverter.kt

@@ -7,15 +7,29 @@ import org.moire.ultrasonic.api.subsonic.models.Index as APIIndex
 import org.moire.ultrasonic.api.subsonic.models.Indexes as APIIndexes
 
 fun APIIndexes.toArtistList(): List<Artist> {
-    val list = this.shortcutList.map { it.toDomainEntity() }.toMutableList()
+    val shortcuts = this.shortcutList.map { it.toDomainEntity() }.toMutableList()
-    list.addAll(this.indexList.foldIndexToArtistList())
+    val indexes = this.indexList.foldIndexToArtistList()
-    return list
+
+    indexes.forEach {
+        if (!shortcuts.contains(it)) {
+            shortcuts.add(it)
+        }
+    }
+
+    return shortcuts
 }
 
 fun APIIndexes.toIndexList(musicFolderId: String?): List<Index> {
-    val list = this.shortcutList.map { it.toIndexEntity() }.toMutableList()
+    val shortcuts = this.shortcutList.map { it.toIndexEntity() }.toMutableList()
-    list.addAll(this.indexList.foldIndexToIndexList(musicFolderId))
+    val indexes = this.indexList.foldIndexToIndexList(musicFolderId)
-    return list
+
+    indexes.forEach {
+        if (!shortcuts.contains(it)) {
+            shortcuts.add(it)
+        }
+    }
+
+    return shortcuts
 }
 
 private fun List<APIIndex>.foldIndexToArtistList(): List<Artist> = this.fold(

ultrasonic/src/test/kotlin/org/moire/ultrasonic/domain/APIIndexConverterTest.kt

@@ -31,7 +31,7 @@ class APIIndexConverterTest {
             shortcutList = artistsA
         )
 
-        val convertedEntity = entity.toIndexList(null)
+        val convertedEntity = entity.toArtistList()
 
         val expectedArtists = (artistsA + artistsT).map { it.toDomainEntity() }.toMutableList()
         with(convertedEntity) {