feat: add similar songs functionality in agents, and Instant Mix (song-based) to UI (#4919)

* refactor: rename ArtistRadio to SimilarSongs for clarity and consistency Signed-off-by: Deluan <deluan@navidrome.org> * feat: implement GetSimilarSongsByTrack and related functionality for song similarity retrieval Signed-off-by: Deluan <deluan@navidrome.org> * feat: enhance GetSimilarSongsByTrack to include artist and album details and update tests Signed-off-by: Deluan <deluan@navidrome.org> * feat: enhance song matching by implementing title and artist filtering in loadTracksByTitleAndArtist Signed-off-by: Deluan <deluan@navidrome.org> * test: add unit tests for song matching functionality in provider Signed-off-by: Deluan <deluan@navidrome.org> * refactor: extract song matching functionality into its own file Signed-off-by: Deluan <deluan@navidrome.org> * docs: clarify similarSongsFallback function description in provider.go Signed-off-by: Deluan <deluan@navidrome.org> * refactor: initialize result slice for songs with capacity based on response length Signed-off-by: Deluan <deluan@navidrome.org> * refactor: simplify agent method calls for retrieving images and similar songs Signed-off-by: Deluan <deluan@navidrome.org> * refactor: simplify agent method calls for retrieving images and similar songs Signed-off-by: Deluan <deluan@navidrome.org> * refactor: remove outdated comments in GetSimilarSongs methods Signed-off-by: Deluan <deluan@navidrome.org> * fix: use composite key for song matches to handle duplicates by title and artist Signed-off-by: Deluan <deluan@navidrome.org> * refactor: consolidate expectations setup for similar songs tests Signed-off-by: Deluan <deluan@navidrome.org> * feat: add instant mix action to song context menu and update translations Signed-off-by: Deluan <deluan@navidrome.org> * fix(provider): handle unknown entity types in GetSimilarSongs Signed-off-by: Deluan <deluan@navidrome.org> * refactor: move playSimilar action to playbackActions and streamline song processing Signed-off-by: Deluan <deluan@navidrome.org> * format Signed-off-by: Deluan <deluan@navidrome.org> * feat: enhance instant mix functionality with loading notification and shuffle option Signed-off-by: Deluan <deluan@navidrome.org> * feat: implement fuzzy matching for similar songs based on configurable threshold Signed-off-by: Deluan <deluan@navidrome.org> * refactor: implement track matching with multiple specificity levels Signed-off-by: Deluan <deluan@navidrome.org> * refactor: enhance track matching by implementing unified scoring with specificity levels Signed-off-by: Deluan <deluan@navidrome.org> * feat: enhance deezer top tracks result with album Signed-off-by: Deluan <deluan@navidrome.org> * feat: enhance track matching with fuzzy album similarity for improved scoring Signed-off-by: Deluan <deluan@navidrome.org> * docs: document multi-phase song matching algorithm with detailed scoring and prioritization Signed-off-by: Deluan <deluan@navidrome.org> --------- Signed-off-by: Deluan <deluan@navidrome.org>
2026-01-25 16:16:43 -05:00
parent b455546fdf
commit 772d1f359b
29 changed files with 2082 additions and 525 deletions
@@ -0,0 +1,443 @@
+package external_test
+
+import (
+	"context"
+	"errors"
+
+	"github.com/Masterminds/squirrel"
+	"github.com/navidrome/navidrome/core/agents"
+	. "github.com/navidrome/navidrome/core/external"
+	"github.com/navidrome/navidrome/model"
+	"github.com/navidrome/navidrome/tests"
+	. "github.com/onsi/ginkgo/v2"
+	. "github.com/onsi/gomega"
+	"github.com/stretchr/testify/mock"
+)
+
+var _ = Describe("Provider - SimilarSongs", func() {
+	var ds model.DataStore
+	var provider Provider
+	var mockAgent *mockSimilarArtistAgent
+	var mockTopAgent agents.ArtistTopSongsRetriever
+	var mockSimilarAgent agents.ArtistSimilarRetriever
+	var agentsCombined *mockAgents
+	var artistRepo *mockArtistRepo
+	var mediaFileRepo *mockMediaFileRepo
+	var albumRepo *mockAlbumRepo
+	var ctx context.Context
+
+	BeforeEach(func() {
+		ctx = GinkgoT().Context()
+
+		artistRepo = newMockArtistRepo()
+		mediaFileRepo = newMockMediaFileRepo()
+		albumRepo = newMockAlbumRepo()
+
+		ds = &tests.MockDataStore{
+			MockedArtist:    artistRepo,
+			MockedMediaFile: mediaFileRepo,
+			MockedAlbum:     albumRepo,
+		}
+
+		mockAgent = &mockSimilarArtistAgent{}
+		mockTopAgent = mockAgent
+		mockSimilarAgent = mockAgent
+
+		agentsCombined = &mockAgents{
+			topSongsAgent: mockTopAgent,
+			similarAgent:  mockSimilarAgent,
+		}
+
+		provider = NewProvider(ds, agentsCombined)
+	})
+
+	Describe("dispatch by entity type", func() {
+		Context("when ID is a MediaFile (track)", func() {
+			It("calls GetSimilarSongsByTrack and returns matched songs", func() {
+				track := model.MediaFile{ID: "track-1", Title: "Just Can't Get Enough", Artist: "Depeche Mode", MbzRecordingID: "track-mbid"}
+				matchedSong := model.MediaFile{ID: "matched-1", Title: "Dreaming of Me", Artist: "Depeche Mode"}
+
+				// GetEntityByID tries Artist, Album, Playlist, then MediaFile
+				artistRepo.On("Get", "track-1").Return(nil, model.ErrNotFound).Once()
+				albumRepo.On("Get", "track-1").Return(nil, model.ErrNotFound).Once()
+				mediaFileRepo.On("Get", "track-1").Return(&track, nil).Once()
+
+				agentsCombined.On("GetSimilarSongsByTrack", mock.Anything, "track-1", "Just Can't Get Enough", "Depeche Mode", "track-mbid", 5).
+					Return([]agents.Song{
+						{Name: "Dreaming of Me", MBID: "", Artist: "Depeche Mode", ArtistMBID: "artist-mbid"},
+					}, nil).Once()
+
+				// Mock loadTracksByID - no ID matches
+				mediaFileRepo.On("GetAll", mock.MatchedBy(func(opt model.QueryOptions) bool {
+					_, ok := opt.Filters.(squirrel.Eq)
+					return ok
+				})).Return(model.MediaFiles{}, nil).Once()
+
+				// Mock loadTracksByMBID - no MBID matches (empty MBID means this won't be called)
+				mediaFileRepo.On("GetAll", mock.MatchedBy(func(opt model.QueryOptions) bool {
+					and, ok := opt.Filters.(squirrel.And)
+					if !ok || len(and) < 1 {
+						return false
+					}
+					eq, hasEq := and[0].(squirrel.Eq)
+					if !hasEq {
+						return false
+					}
+					_, hasMBID := eq["mbz_recording_id"]
+					return hasMBID
+				})).Return(model.MediaFiles{}, nil).Maybe()
+
+				// Mock loadTracksByTitleAndArtist - queries by artist name
+				mediaFileRepo.On("GetAll", mock.MatchedBy(func(opt model.QueryOptions) bool {
+					and, ok := opt.Filters.(squirrel.And)
+					if !ok || len(and) < 2 {
+						return false
+					}
+					eq, hasEq := and[0].(squirrel.Eq)
+					if !hasEq {
+						return false
+					}
+					_, hasArtist := eq["order_artist_name"]
+					return hasArtist
+				})).Return(model.MediaFiles{matchedSong}, nil).Maybe()
+
+				songs, err := provider.SimilarSongs(ctx, "track-1", 5)
+
+				Expect(err).ToNot(HaveOccurred())
+				Expect(songs).To(HaveLen(1))
+				Expect(songs[0].ID).To(Equal("matched-1"))
+			})
+
+			It("falls back to artist-based algorithm when GetSimilarSongsByTrack returns empty", func() {
+				track := model.MediaFile{ID: "track-1", Title: "Track", Artist: "Artist", ArtistID: "artist-1"}
+				artist := model.Artist{ID: "artist-1", Name: "Artist"}
+				song := model.MediaFile{ID: "song-1", Title: "Song One", ArtistID: "artist-1", MbzRecordingID: "mbid-1"}
+
+				// GetEntityByID for the initial call tries Artist, Album, Playlist, then MediaFile
+				artistRepo.On("Get", "track-1").Return(nil, model.ErrNotFound).Once()
+				albumRepo.On("Get", "track-1").Return(nil, model.ErrNotFound).Once()
+				mediaFileRepo.On("Get", "track-1").Return(&track, nil).Once()
+
+				agentsCombined.On("GetSimilarSongsByTrack", mock.Anything, "track-1", "Track", "Artist", "", mock.Anything).
+					Return([]agents.Song{}, nil).Once()
+
+				// Fallback calls getArtist(id) which calls GetEntityByID again - this time it finds the mediafile
+				// and recursively calls getArtist(v.ArtistID)
+				artistRepo.On("Get", "track-1").Return(nil, model.ErrNotFound).Once()
+				albumRepo.On("Get", "track-1").Return(nil, model.ErrNotFound).Once()
+				mediaFileRepo.On("Get", "track-1").Return(&track, nil).Once()
+
+				// Then it recurses with the artist-1 ID
+				artistRepo.On("Get", "artist-1").Return(&artist, nil).Maybe()
+				artistRepo.On("GetAll", mock.MatchedBy(func(opt model.QueryOptions) bool {
+					return opt.Max == 1 && opt.Filters != nil
+				})).Return(model.Artists{artist}, nil).Maybe()
+
+				mockAgent.On("GetSimilarArtists", mock.Anything, "artist-1", "Artist", "", 15).
+					Return([]agents.Artist{}, nil).Once()
+
+				artistRepo.On("GetAll", mock.MatchedBy(func(opt model.QueryOptions) bool {
+					return opt.Max == 0 && opt.Filters != nil
+				})).Return(model.Artists{}, nil).Once()
+
+				mockAgent.On("GetArtistTopSongs", mock.Anything, "artist-1", "Artist", "", mock.Anything).
+					Return([]agents.Song{{Name: "Song One", MBID: "mbid-1"}}, nil).Once()
+
+				mediaFileRepo.On("GetAll", mock.AnythingOfType("model.QueryOptions")).Return(model.MediaFiles{song}, nil).Once()
+
+				songs, err := provider.SimilarSongs(ctx, "track-1", 5)
+
+				Expect(err).ToNot(HaveOccurred())
+				Expect(songs).To(HaveLen(1))
+				Expect(songs[0].ID).To(Equal("song-1"))
+			})
+		})
+
+		Context("when ID is an Album", func() {
+			It("calls GetSimilarSongsByAlbum and returns matched songs", func() {
+				album := model.Album{ID: "album-1", Name: "Speak & Spell", AlbumArtist: "Depeche Mode", MbzAlbumID: "album-mbid"}
+				matchedSong := model.MediaFile{ID: "matched-1", Title: "New Life", Artist: "Depeche Mode", MbzRecordingID: "song-mbid"}
+
+				// GetEntityByID tries Artist, Album, Playlist, then MediaFile
+				artistRepo.On("Get", "album-1").Return(nil, model.ErrNotFound).Once()
+				albumRepo.On("Get", "album-1").Return(&album, nil).Once()
+
+				agentsCombined.On("GetSimilarSongsByAlbum", mock.Anything, "album-1", "Speak & Spell", "Depeche Mode", "album-mbid", 5).
+					Return([]agents.Song{
+						{Name: "New Life", MBID: "song-mbid", Artist: "Depeche Mode"},
+					}, nil).Once()
+
+				// Mock loadTracksByID - no ID matches
+				mediaFileRepo.On("GetAll", mock.MatchedBy(func(opt model.QueryOptions) bool {
+					_, ok := opt.Filters.(squirrel.Eq)
+					return ok
+				})).Return(model.MediaFiles{}, nil).Once()
+
+				// Mock loadTracksByMBID - MBID match
+				mediaFileRepo.On("GetAll", mock.MatchedBy(func(opt model.QueryOptions) bool {
+					and, ok := opt.Filters.(squirrel.And)
+					if !ok || len(and) < 1 {
+						return false
+					}
+					_, hasEq := and[0].(squirrel.Eq)
+					return hasEq
+				})).Return(model.MediaFiles{matchedSong}, nil).Once()
+
+				songs, err := provider.SimilarSongs(ctx, "album-1", 5)
+
+				Expect(err).ToNot(HaveOccurred())
+				Expect(songs).To(HaveLen(1))
+				Expect(songs[0].ID).To(Equal("matched-1"))
+			})
+
+			It("falls back when GetSimilarSongsByAlbum returns ErrNotFound", func() {
+				album := model.Album{ID: "album-1", Name: "Album", AlbumArtist: "Artist", AlbumArtistID: "artist-1"}
+				artist := model.Artist{ID: "artist-1", Name: "Artist"}
+				song := model.MediaFile{ID: "song-1", Title: "Song One", ArtistID: "artist-1", MbzRecordingID: "mbid-1"}
+
+				// GetEntityByID for the initial call tries Artist, Album, Playlist, then MediaFile
+				artistRepo.On("Get", "album-1").Return(nil, model.ErrNotFound).Once()
+				albumRepo.On("Get", "album-1").Return(&album, nil).Once()
+
+				agentsCombined.On("GetSimilarSongsByAlbum", mock.Anything, "album-1", "Album", "Artist", "", mock.Anything).
+					Return(nil, agents.ErrNotFound).Once()
+
+				// Fallback calls getArtist(id) which calls GetEntityByID again - this time it finds the album
+				// and recursively calls getArtist(v.AlbumArtistID)
+				artistRepo.On("Get", "album-1").Return(nil, model.ErrNotFound).Once()
+				albumRepo.On("Get", "album-1").Return(&album, nil).Once()
+
+				// Then it recurses with the artist-1 ID
+				artistRepo.On("Get", "artist-1").Return(&artist, nil).Maybe()
+				artistRepo.On("GetAll", mock.MatchedBy(func(opt model.QueryOptions) bool {
+					return opt.Max == 1 && opt.Filters != nil
+				})).Return(model.Artists{artist}, nil).Maybe()
+
+				mockAgent.On("GetSimilarArtists", mock.Anything, "artist-1", "Artist", "", 15).
+					Return([]agents.Artist{}, nil).Once()
+
+				artistRepo.On("GetAll", mock.MatchedBy(func(opt model.QueryOptions) bool {
+					return opt.Max == 0 && opt.Filters != nil
+				})).Return(model.Artists{}, nil).Once()
+
+				mockAgent.On("GetArtistTopSongs", mock.Anything, "artist-1", "Artist", "", mock.Anything).
+					Return([]agents.Song{{Name: "Song One", MBID: "mbid-1"}}, nil).Once()
+
+				mediaFileRepo.On("GetAll", mock.AnythingOfType("model.QueryOptions")).Return(model.MediaFiles{song}, nil).Once()
+
+				songs, err := provider.SimilarSongs(ctx, "album-1", 5)
+
+				Expect(err).ToNot(HaveOccurred())
+				Expect(songs).To(HaveLen(1))
+				Expect(songs[0].ID).To(Equal("song-1"))
+			})
+		})
+
+		Context("when ID is an Artist", func() {
+			It("calls GetSimilarSongsByArtist and returns matched songs", func() {
+				artist := model.Artist{ID: "artist-1", Name: "Depeche Mode", MbzArtistID: "artist-mbid"}
+				matchedSong := model.MediaFile{ID: "matched-1", Title: "Enjoy the Silence", Artist: "Depeche Mode", MbzRecordingID: "song-mbid"}
+
+				artistRepo.On("Get", "artist-1").Return(&artist, nil).Once()
+				agentsCombined.On("GetSimilarSongsByArtist", mock.Anything, "artist-1", "Depeche Mode", "artist-mbid", 5).
+					Return([]agents.Song{
+						{Name: "Enjoy the Silence", MBID: "song-mbid", Artist: "Depeche Mode"},
+					}, nil).Once()
+
+				// Mock loadTracksByID - no ID matches
+				mediaFileRepo.On("GetAll", mock.MatchedBy(func(opt model.QueryOptions) bool {
+					_, ok := opt.Filters.(squirrel.Eq)
+					return ok
+				})).Return(model.MediaFiles{}, nil).Once()
+
+				// Mock loadTracksByMBID - MBID match
+				mediaFileRepo.On("GetAll", mock.MatchedBy(func(opt model.QueryOptions) bool {
+					and, ok := opt.Filters.(squirrel.And)
+					if !ok || len(and) < 1 {
+						return false
+					}
+					_, hasEq := and[0].(squirrel.Eq)
+					return hasEq
+				})).Return(model.MediaFiles{matchedSong}, nil).Once()
+
+				songs, err := provider.SimilarSongs(ctx, "artist-1", 5)
+
+				Expect(err).ToNot(HaveOccurred())
+				Expect(songs).To(HaveLen(1))
+				Expect(songs[0].ID).To(Equal("matched-1"))
+			})
+		})
+	})
+
+	It("returns similar songs from main artist and similar artists", func() {
+		artist1 := model.Artist{ID: "artist-1", Name: "Artist One"}
+		similarArtist := model.Artist{ID: "artist-3", Name: "Similar Artist"}
+		song1 := model.MediaFile{ID: "song-1", Title: "Song One", ArtistID: "artist-1", MbzRecordingID: "mbid-1"}
+		song2 := model.MediaFile{ID: "song-2", Title: "Song Two", ArtistID: "artist-1", MbzRecordingID: "mbid-2"}
+		song3 := model.MediaFile{ID: "song-3", Title: "Song Three", ArtistID: "artist-3", MbzRecordingID: "mbid-3"}
+
+		artistRepo.On("Get", "artist-1").Return(&artist1, nil).Maybe()
+		artistRepo.On("Get", "artist-3").Return(&similarArtist, nil).Maybe()
+
+		artistRepo.On("GetAll", mock.MatchedBy(func(opt model.QueryOptions) bool {
+			return opt.Max == 1 && opt.Filters != nil
+		})).Return(model.Artists{artist1}, nil).Once()
+
+		// New similar songs by artist returns ErrNotFound to trigger fallback
+		agentsCombined.On("GetSimilarSongsByArtist", mock.Anything, "artist-1", "Artist One", "", mock.Anything).
+			Return(nil, agents.ErrNotFound).Once()
+
+		similarAgentsResp := []agents.Artist{
+			{Name: "Similar Artist", MBID: "similar-mbid"},
+		}
+		mockAgent.On("GetSimilarArtists", mock.Anything, "artist-1", "Artist One", "", 15).
+			Return(similarAgentsResp, nil).Once()
+
+		// Mock the three-phase artist lookup: ID (skipped - no IDs), MBID, then Name
+		// MBID lookup returns empty (no match)
+		artistRepo.On("GetAll", mock.MatchedBy(func(opt model.QueryOptions) bool {
+			_, ok := opt.Filters.(squirrel.Eq)
+			return opt.Max == 0 && ok
+		})).Return(model.Artists{}, nil).Once()
+		// Name lookup returns the similar artist
+		artistRepo.On("GetAll", mock.MatchedBy(func(opt model.QueryOptions) bool {
+			_, ok := opt.Filters.(squirrel.Or)
+			return opt.Max == 0 && ok
+		})).Return(model.Artists{similarArtist}, nil).Once()
+
+		mockAgent.On("GetArtistTopSongs", mock.Anything, "artist-1", "Artist One", "", mock.Anything).
+			Return([]agents.Song{
+				{Name: "Song One", MBID: "mbid-1"},
+				{Name: "Song Two", MBID: "mbid-2"},
+			}, nil).Once()
+
+		mockAgent.On("GetArtistTopSongs", mock.Anything, "artist-3", "Similar Artist", "", mock.Anything).
+			Return([]agents.Song{
+				{Name: "Song Three", MBID: "mbid-3"},
+			}, nil).Once()
+
+		mediaFileRepo.On("GetAll", mock.AnythingOfType("model.QueryOptions")).Return(model.MediaFiles{song1, song2}, nil).Once()
+		mediaFileRepo.On("GetAll", mock.AnythingOfType("model.QueryOptions")).Return(model.MediaFiles{song3}, nil).Once()
+
+		songs, err := provider.SimilarSongs(ctx, "artist-1", 3)
+
+		Expect(err).ToNot(HaveOccurred())
+		Expect(songs).To(HaveLen(3))
+		for _, song := range songs {
+			Expect(song.ID).To(BeElementOf("song-1", "song-2", "song-3"))
+		}
+	})
+
+	It("returns ErrNotFound when artist is not found", func() {
+		artistRepo.On("Get", "artist-unknown-artist").Return(nil, model.ErrNotFound)
+		mediaFileRepo.On("Get", "artist-unknown-artist").Return(nil, model.ErrNotFound)
+		albumRepo.On("Get", "artist-unknown-artist").Return(nil, model.ErrNotFound)
+
+		artistRepo.On("GetAll", mock.MatchedBy(func(opt model.QueryOptions) bool {
+			return opt.Max == 1 && opt.Filters != nil
+		})).Return(model.Artists{}, nil).Maybe()
+
+		songs, err := provider.SimilarSongs(ctx, "artist-unknown-artist", 5)
+
+		Expect(err).To(Equal(model.ErrNotFound))
+		Expect(songs).To(BeNil())
+	})
+
+	It("returns songs from main artist when GetSimilarArtists returns error", func() {
+		artist1 := model.Artist{ID: "artist-1", Name: "Artist One"}
+		song1 := model.MediaFile{ID: "song-1", Title: "Song One", ArtistID: "artist-1", MbzRecordingID: "mbid-1"}
+
+		artistRepo.On("Get", "artist-1").Return(&artist1, nil).Maybe()
+		artistRepo.On("GetAll", mock.MatchedBy(func(opt model.QueryOptions) bool {
+			return opt.Max == 1 && opt.Filters != nil
+		})).Return(model.Artists{artist1}, nil).Maybe()
+
+		// New similar songs by artist returns ErrNotFound to trigger fallback
+		agentsCombined.On("GetSimilarSongsByArtist", mock.Anything, "artist-1", "Artist One", "", mock.Anything).
+			Return(nil, agents.ErrNotFound).Once()
+
+		mockAgent.On("GetSimilarArtists", mock.Anything, "artist-1", "Artist One", "", 15).
+			Return(nil, errors.New("error getting similar artists")).Once()
+
+		artistRepo.On("GetAll", mock.MatchedBy(func(opt model.QueryOptions) bool {
+			return opt.Max == 0 && opt.Filters != nil
+		})).Return(model.Artists{}, nil).Once()
+
+		mockAgent.On("GetArtistTopSongs", mock.Anything, "artist-1", "Artist One", "", mock.Anything).
+			Return([]agents.Song{
+				{Name: "Song One", MBID: "mbid-1"},
+			}, nil).Once()
+
+		mediaFileRepo.On("GetAll", mock.AnythingOfType("model.QueryOptions")).Return(model.MediaFiles{song1}, nil).Once()
+
+		songs, err := provider.SimilarSongs(ctx, "artist-1", 5)
+
+		Expect(err).ToNot(HaveOccurred())
+		Expect(songs).To(HaveLen(1))
+		Expect(songs[0].ID).To(Equal("song-1"))
+	})
+
+	It("returns empty list when GetArtistTopSongs returns error", func() {
+		artist1 := model.Artist{ID: "artist-1", Name: "Artist One"}
+
+		artistRepo.On("Get", "artist-1").Return(&artist1, nil).Maybe()
+		artistRepo.On("GetAll", mock.MatchedBy(func(opt model.QueryOptions) bool {
+			return opt.Max == 1 && opt.Filters != nil
+		})).Return(model.Artists{artist1}, nil).Maybe()
+
+		// New similar songs by artist returns ErrNotFound to trigger fallback
+		agentsCombined.On("GetSimilarSongsByArtist", mock.Anything, "artist-1", "Artist One", "", mock.Anything).
+			Return(nil, agents.ErrNotFound).Once()
+
+		mockAgent.On("GetSimilarArtists", mock.Anything, "artist-1", "Artist One", "", 15).
+			Return([]agents.Artist{}, nil).Once()
+
+		artistRepo.On("GetAll", mock.MatchedBy(func(opt model.QueryOptions) bool {
+			return opt.Max == 0 && opt.Filters != nil
+		})).Return(model.Artists{}, nil).Once()
+
+		mockAgent.On("GetArtistTopSongs", mock.Anything, "artist-1", "Artist One", "", mock.Anything).
+			Return(nil, errors.New("error getting top songs")).Once()
+
+		songs, err := provider.SimilarSongs(ctx, "artist-1", 5)
+
+		Expect(err).ToNot(HaveOccurred())
+		Expect(songs).To(BeEmpty())
+	})
+
+	It("respects count parameter", func() {
+		artist1 := model.Artist{ID: "artist-1", Name: "Artist One"}
+		song1 := model.MediaFile{ID: "song-1", Title: "Song One", ArtistID: "artist-1", MbzRecordingID: "mbid-1"}
+		song2 := model.MediaFile{ID: "song-2", Title: "Song Two", ArtistID: "artist-1", MbzRecordingID: "mbid-2"}
+
+		artistRepo.On("Get", "artist-1").Return(&artist1, nil).Maybe()
+		artistRepo.On("GetAll", mock.MatchedBy(func(opt model.QueryOptions) bool {
+			return opt.Max == 1 && opt.Filters != nil
+		})).Return(model.Artists{artist1}, nil).Maybe()
+
+		// New similar songs by artist returns ErrNotFound to trigger fallback
+		agentsCombined.On("GetSimilarSongsByArtist", mock.Anything, "artist-1", "Artist One", "", mock.Anything).
+			Return(nil, agents.ErrNotFound).Once()
+
+		mockAgent.On("GetSimilarArtists", mock.Anything, "artist-1", "Artist One", "", 15).
+			Return([]agents.Artist{}, nil).Once()
+
+		artistRepo.On("GetAll", mock.MatchedBy(func(opt model.QueryOptions) bool {
+			return opt.Max == 0 && opt.Filters != nil
+		})).Return(model.Artists{}, nil).Once()
+
+		mockAgent.On("GetArtistTopSongs", mock.Anything, "artist-1", "Artist One", "", mock.Anything).
+			Return([]agents.Song{
+				{Name: "Song One", MBID: "mbid-1"},
+				{Name: "Song Two", MBID: "mbid-2"},
+			}, nil).Once()
+
+		mediaFileRepo.On("GetAll", mock.AnythingOfType("model.QueryOptions")).Return(model.MediaFiles{song1, song2}, nil).Once()
+
+		songs, err := provider.SimilarSongs(ctx, "artist-1", 1)
+
+		Expect(err).ToNot(HaveOccurred())
+		Expect(songs).To(HaveLen(1))
+		Expect(songs[0].ID).To(BeElementOf("song-1", "song-2"))
+	})
+})