feat: tested album artist relation

tests/collection.py

@@ -1,18 +1,13 @@
 import unittest
 
-import music_kraken
-from music_kraken.objects import Song, Album, Artist, Collection
+from music_kraken.objects import Song, Album, Artist, Collection, Country
 
 class TestCollection(unittest.TestCase):
-    def test_song_album_relation(self):
-        """
-        Tests that
-        album = album.any_song.one_album
-        is the same object
-        """
-
-        artist: Artist = Artist(
+    @staticmethod
+    def complicated_object() -> Artist:
+        return Artist(
             name="artist",
+            country=Country.by_alpha_2("DE"),
             main_album_list=[
                 Album(
                     title="album",
@@ -35,7 +30,14 @@ class TestCollection(unittest.TestCase):
             ]
         )
 
-        a = artist.main_album_collection[0]
+    def test_song_album_relation(self):
+        """
+        Tests that
+        album = album.any_song.one_album
+        is the same object
+        """
+
+        a = self.complicated_object().main_album_collection[0]
         b = a.song_collection[0].album_collection[0]
         c = a.song_collection[1].album_collection[0]
         d = b.song_collection[0].album_collection[0]
@@ -52,5 +54,37 @@ class TestCollection(unittest.TestCase):
 
         self.assertTrue(a.title == b.title == c.title == d.title == e.title == f.title == g.title == "new_title")
 
+    def test_album_artist_relation(self):
+        """
+        Tests that
+        artist = artist.any_album.any_song.one_artist
+        is the same object
+        """
+
+        a = self.complicated_object()
+        b = a.main_album_collection[0].artist_collection[0]
+        c = b.main_album_collection[0].artist_collection[0]
+        d = c.main_album_collection[0].artist_collection[0]
+
+        self.assertTrue(a.id == b.id == c.id == d.id)
+        self.assertTrue(a.name == b.name == c.name == d.name == "artist")
+        self.assertTrue(a.country == b.country == c.country == d.country)
+
+    def test_song_artist_relations(self):
+        """
+        Tests that
+        artist = artist.any_album.any_song.one_artist
+        is the same object
+        """
+
+        a = self.complicated_object()
+        b = a.main_album_collection[0].song_collection[0].main_artist_collection[0]
+        c = b.main_album_collection[0].song_collection[0].main_artist_collection[0]
+        d = c.main_album_collection[0].song_collection[0].main_artist_collection[0]
+
+        self.assertTrue(a.id == b.id == c.id == d.id)
+        self.assertTrue(a.name == b.name == c.name == d.name == "artist")
+        self.assertTrue(a.country == b.country == c.country == d.country)
+
 if __name__ == "__main__":
     unittest.main()