Add tests for encoders

and some refactoring

spotdl/lyrics/tests/test_lyric_base.py

@@ -0,0 +1,29 @@
+from spotdl.lyrics import LyricBase
+
+import pytest
+
+
+class TestAbstractBaseClass:
+    def test_error_abstract_base_class_lyricbase(self):
+        artist = "awesome artist"
+        track = "amazing track"
+
+        with pytest.raises(TypeError):
+            # This abstract base class must be inherited from
+            # for instantiation
+            LyricBase(artist, track)
+
+
+    def test_inherit_abstract_base_class_encoderbase(self):
+        class LyricKid(LyricBase):
+            def __init__(self, artist, track):
+                super().__init__(artist, track)
+
+            def get_lyrics(self):
+                pass
+
+
+        artist = "awesome artist"
+        track = "amazing track"
+
+        LyricKid(artist, track)