Added playlist tracks count and modification date in API

api/tests/playlists/test_models.py

@@ -5,6 +5,7 @@ from django import forms
 
 def test_can_insert_plt(factories):
     plt = factories['playlists.PlaylistTrack']()
+    modification_date = plt.playlist.modification_date
 
     assert plt.index is None
 
@@ -12,6 +13,7 @@ def test_can_insert_plt(factories):
     plt.refresh_from_db()
 
     assert plt.index == 0
+    assert plt.playlist.modification_date > modification_date
 
 
 def test_insert_use_last_idx_by_default(factories):

api/tests/playlists/test_views.py

@@ -23,6 +23,16 @@ def test_can_create_playlist_via_api(logged_in_api_client):
     assert playlist.privacy_level == 'everyone'
 
 
+def test_serializer_includes_tracks_count(factories, logged_in_api_client):
+    playlist = factories['playlists.Playlist']()
+    plt = factories['playlists.PlaylistTrack'](playlist=playlist)
+
+    url = reverse('api:v1:playlists-detail', kwargs={'pk': playlist.pk})
+    response = logged_in_api_client.get(url)
+
+    assert response.data['tracks_count'] == 1
+
+
 def test_playlist_inherits_user_privacy(logged_in_api_client):
     url = reverse('api:v1:playlists-list')
     user = logged_in_api_client.user