diff --git a/core/artwork_test.go b/core/artwork_test.go
index a8a0d41d..289bca84 100644
--- a/core/artwork_test.go
+++ b/core/artwork_test.go
@@ -22,8 +22,15 @@ var _ = Describe("Artwork", func() {
 
 	BeforeEach(func() {
 		ds = &persistence.MockDataStore{MockedTranscoding: &mockTranscodingRepository{}}
-		ds.Album(ctx).(*persistence.MockAlbum).SetData(`[{"id": "222", "coverArtId": "123", "coverArtPath":"tests/fixtures/test.mp3"}, {"id": "333", "coverArtId": ""}, {"id": "444", "coverArtId": "444", "coverArtPath": "tests/fixtures/cover.jpg"}]`)
-		ds.MediaFile(ctx).(*persistence.MockMediaFile).SetData(`[{"id": "123", "albumId": "222", "path": "tests/fixtures/test.mp3", "hasCoverArt": true, "updatedAt":"2020-04-02T21:29:31.6377Z"},{"id": "456", "albumId": "222", "path": "tests/fixtures/test.ogg", "hasCoverArt": false, "updatedAt":"2020-04-02T21:29:31.6377Z"}]`)
+		ds.Album(ctx).(*persistence.MockAlbum).SetData(model.Albums{
+			{ID: "222", CoverArtId: "123", CoverArtPath: "tests/fixtures/test.mp3"},
+			{ID: "333", CoverArtId: ""},
+			{ID: "444", CoverArtId: "444", CoverArtPath: "tests/fixtures/cover.jpg"},
+		})
+		ds.MediaFile(ctx).(*persistence.MockMediaFile).SetData(model.MediaFiles{
+			{ID: "123", AlbumID: "222", Path: "tests/fixtures/test.mp3", HasCoverArt: true},
+			{ID: "456", AlbumID: "222", Path: "tests/fixtures/test.ogg", HasCoverArt: false},
+		})
 	})
 
 	Context("Cache is configured", func() {
diff --git a/core/media_streamer_test.go b/core/media_streamer_test.go
index ddb1b0ae..4a5ed6e8 100644
--- a/core/media_streamer_test.go
+++ b/core/media_streamer_test.go
@@ -26,7 +26,9 @@ var _ = Describe("MediaStreamer", func() {
 		conf.Server.DataFolder, _ = ioutil.TempDir("", "file_caches")
 		conf.Server.TranscodingCacheSize = "100MB"
 		ds = &persistence.MockDataStore{MockedTranscoding: &mockTranscodingRepository{}}
-		ds.MediaFile(ctx).(*persistence.MockMediaFile).SetData(`[{"id": "123", "path": "tests/fixtures/test.mp3", "suffix": "mp3", "bitRate": 128, "duration": 257.0}]`)
+		ds.MediaFile(ctx).(*persistence.MockMediaFile).SetData(model.MediaFiles{
+			{ID: "123", Path: "tests/fixtures/test.mp3", Suffix: "mp3", BitRate: 128, Duration: 257.0},
+		})
 		testCache := NewTranscodingCache()
 		Eventually(func() bool { return testCache.Ready() }).Should(BeTrue())
 		streamer = NewMediaStreamer(ds, ffmpeg, testCache)
diff --git a/persistence/mock_album_repo.go b/persistence/mock_album_repo.go
index c4c82a94..437b81f3 100644
--- a/persistence/mock_album_repo.go
+++ b/persistence/mock_album_repo.go
@@ -1,9 +1,7 @@
 package persistence
 
 import (
-	"encoding/json"
 	"errors"
-	"fmt"
 
 	"github.com/deluan/navidrome/model"
 )
@@ -24,13 +22,9 @@ func (m *MockAlbum) SetError(err bool) {
 	m.err = err
 }
 
-func (m *MockAlbum) SetData(j string) {
+func (m *MockAlbum) SetData(albums model.Albums) {
 	m.data = make(map[string]model.Album)
-	m.all = model.Albums{}
-	err := json.Unmarshal([]byte(j), &m.all)
-	if err != nil {
-		fmt.Println("ERROR: ", err)
-	}
+	m.all = albums
 	for _, a := range m.all {
 		m.data[a.ID] = a
 	}
diff --git a/persistence/mock_artist_repo.go b/persistence/mock_artist_repo.go
index 2a159d61..0fadf520 100644
--- a/persistence/mock_artist_repo.go
+++ b/persistence/mock_artist_repo.go
@@ -1,9 +1,7 @@
 package persistence
 
 import (
-	"encoding/json"
 	"errors"
-	"fmt"
 
 	"github.com/deluan/navidrome/model"
 )
@@ -22,14 +20,9 @@ func (m *MockArtist) SetError(err bool) {
 	m.err = err
 }
 
-func (m *MockArtist) SetData(j string) {
+func (m *MockArtist) SetData(artists model.Artists) {
 	m.data = make(map[string]model.Artist)
-	var l = model.Artists{}
-	err := json.Unmarshal([]byte(j), &l)
-	if err != nil {
-		fmt.Println("ERROR: ", err)
-	}
-	for _, a := range l {
+	for _, a := range artists {
 		m.data[a.ID] = a
 	}
 }
diff --git a/persistence/mock_mediafile_repo.go b/persistence/mock_mediafile_repo.go
index 7897f545..410ab36c 100644
--- a/persistence/mock_mediafile_repo.go
+++ b/persistence/mock_mediafile_repo.go
@@ -1,9 +1,7 @@
 package persistence
 
 import (
-	"encoding/json"
 	"errors"
-	"fmt"
 
 	"github.com/deluan/navidrome/model"
 )
@@ -22,15 +20,10 @@ func (m *MockMediaFile) SetError(err bool) {
 	m.err = err
 }
 
-func (m *MockMediaFile) SetData(j string) {
+func (m *MockMediaFile) SetData(mfs model.MediaFiles) {
 	m.data = make(map[string]model.MediaFile)
-	var l = model.MediaFiles{}
-	err := json.Unmarshal([]byte(j), &l)
-	if err != nil {
-		fmt.Println("ERROR: ", err)
-	}
-	for _, a := range l {
-		m.data[a.ID] = a
+	for _, mf := range mfs {
+		m.data[mf.ID] = mf
 	}
 }
 
diff --git a/server/subsonic/album_lists_test.go b/server/subsonic/album_lists_test.go
index 8e4c6c8d..d1ed6047 100644
--- a/server/subsonic/album_lists_test.go
+++ b/server/subsonic/album_lists_test.go
@@ -28,7 +28,9 @@ var _ = Describe("AlbumListController", func() {
 	Describe("GetAlbumList", func() {
 		It("should return list of the type specified", func() {
 			r := newGetRequest("type=newest", "offset=10", "size=20")
-			mockRepo.SetData(`[{"id": "1"},{"id": "2"}]`)
+			mockRepo.SetData(model.Albums{
+				{ID: "1"}, {ID: "2"},
+			})
 			resp, err := controller.GetAlbumList(w, r)
 
 			Expect(err).To(BeNil())
@@ -58,7 +60,9 @@ var _ = Describe("AlbumListController", func() {
 	Describe("GetAlbumList2", func() {
 		It("should return list of the type specified", func() {
 			r := newGetRequest("type=newest", "offset=10", "size=20")
-			mockRepo.SetData(`[{"id": "1"},{"id": "2"}]`)
+			mockRepo.SetData(model.Albums{
+				{ID: "1"}, {ID: "2"},
+			})
 			resp, err := controller.GetAlbumList2(w, r)
 
 			Expect(err).To(BeNil())