Refactor songs so its unit testable

.github/workflows/python-app.yml

@@ -8,7 +8,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        python-version: ["3.9", "3.10", "3.11", "3.12", "3.13"]
+        python-version: ["3.11", "3.12", "3.13"]
 
     steps:
       - uses: actions/checkout@v4

README.md

@@ -3,7 +3,7 @@
 > Given a song and artist, fetches lyrics from [Genius](https://genius.com), translates them to English using [Azure AI Translator](https://learn.microsoft.com/en-us/azure/ai-services/translator/), and displays original and translated lyrics side-by-side in the console.
 
 [![Python package](https://github.com/patkub/console-songs/actions/workflows/python-app.yml/badge.svg)](https://github.com/patkub/console-songs/actions/workflows/python-app.yml)
-![Python 3.x Required](https://img.shields.io/badge/python-3.x-brightgreen.svg)
+![Python 3.11+ Required](https://img.shields.io/badge/python-3.11+-brightgreen.svg)
 
 ### Idea
 1. Fetch song lyrics
@@ -13,6 +13,8 @@
 Enjoy listening to music and learning a new language!
 
 ### Setup
+Requires Python 3.11+
+
 Create an `.env` file with your API keys:
 ```
 GENIUS_ACCESS_TOKEN=...

songs.py

@@ -7,7 +7,7 @@
 # - Translate to English
 # - Display original and English translated lyrics side-by-side
 
-import argparse, os, sys
+import argparse, os
 from dotenv import load_dotenv
 
 # Class to get song lyrics from Genius
@@ -20,42 +20,62 @@
 # loading variables from .env file
 load_dotenv()
 
-#
-# Parse arguments
-#
 
-parser = argparse.ArgumentParser()
-parser.add_argument("song", nargs="+")
-parser.add_argument('--experimental',
-                    action=argparse.BooleanOptionalAction,
-                    help='Enable experimental features.\nUses a patched version of Genius API')
-args = parser.parse_args()
+def process_song(song, artist, access_keys, experimental):
+    """
+    Fetch song lyrics, translate to English, and display original and English side-by-side lyrics.
+    @param song: the name of the song
+    @param artist: the name of the artist
+    @param access_keys: dictionary of API access keys
+    @param experimental: use experimental features
+    """
+    #
+    # Fetch song lyrics from Genius
+    #
+    patched_genius = PatchedGenius if experimental else None
+    lyrics_fetcher = FetchLyrics(access_keys["GENIUS_ACCESS_TOKEN"], patched_genius)
+    song_info = lyrics_fetcher.fetch_lyrics(song, artist)
+    if song_info is None:
+        # song not found, end
+        return
 
-song = args.song[0]
-artist = args.song[1] if len(args.song) > 1 else None
+    song_lyrics = song_info.lyrics
 
-#
-# Fetch song lyrics from Genius
-#
+    #
+    # Translate lyrics to English using Microsoft Azure AI Translator
+    #
+    lyrics_translator = TranslateLyrics(access_keys["MS_TRANSLATOR_KEY"], access_keys["MS_TRANSLATOR_REGION"])
+    english_translation = lyrics_translator.translate_lyrics(song_lyrics)
 
-patched_genius = PatchedGenius if args.experimental else None
-lyrics_fetcher = FetchLyrics(os.getenv("GENIUS_ACCESS_TOKEN"), patched_genius)
-song_info = lyrics_fetcher.fetch_lyrics(song, artist)
-if song_info is None:
-    # song not found
-    sys.exit()
+    #
+    # Display original and English translated lyrics side-by-side
+    #
+    DisplayLyrics.display_lyrics(song_info, song_lyrics, english_translation)
 
-song_lyrics = song_info.lyrics
 
-#
-# Translate lyrics to English using Microsoft Azure AI Translator
-#
+if __name__ == '__main__':
+    #
+    # Parse arguments
+    #
 
-lyrics_translator = TranslateLyrics(os.getenv("MS_TRANSLATOR_KEY"), os.getenv("MS_TRANSLATOR_REGION"))
-english_translation = lyrics_translator.translate_lyrics(song_lyrics)
+    parser = argparse.ArgumentParser()
+    parser.add_argument("song", nargs="+")
+    parser.add_argument('--experimental',
+                        action=argparse.BooleanOptionalAction,
+                        help='Enable experimental features.\nUses a patched version of Genius API')
+    args = parser.parse_args()
 
-#
-# Display original and English translated lyrics side-by-side
-#
+    song = args.song[0]
+    artist = args.song[1] if len(args.song) > 1 else None
 
-DisplayLyrics.display_lyrics(song_info, song_lyrics, english_translation)
+    access_keys = {
+        'GENIUS_ACCESS_TOKEN': os.getenv("GENIUS_ACCESS_TOKEN"),
+        'MS_TRANSLATOR_KEY': os.getenv("MS_TRANSLATOR_KEY"),
+        'MS_TRANSLATOR_REGION': os.getenv("MS_TRANSLATOR_REGION")
+    }
+
+    #
+    # Fetch song lyrics, translate to English, and display original and English side-by-side lyrics.
+    #
+
+    process_song(song, artist, access_keys, args.experimental)

test_songs.py

@@ -0,0 +1,65 @@
+from songs import process_song
+from unittest.mock import Mock, patch, ANY
+
+# mock object for reply from fetched lyrics
+mockedFetchLyrics = Mock()
+mockedFetchLyrics.lyrics = "mocked_lyrics"
+
+
+@patch('fetch_lyrics.FetchLyrics.FetchLyrics.fetch_lyrics', return_value=mockedFetchLyrics)
+@patch('translate_lyrics.TranslateLyrics.TranslateLyrics.translate_lyrics', return_value="english translation")
+@patch('display_lyrics.DisplayLyrics.DisplayLyrics.display_lyrics')
+def test_process_song(mocked_display_lyrics, mocked_translate_lyrics, mocked_fetch_lyrics):
+    """
+    Fetch song lyrics, translate to English, and display original and English side-by-side lyrics.
+    """
+
+    # Prepare
+    song = "test_song_name"
+    artist = "test_artist_name"
+    access_keys = {
+        'GENIUS_ACCESS_TOKEN': "fake_token_1",
+        'MS_TRANSLATOR_KEY': "fake_token_2",
+        'MS_TRANSLATOR_REGION': "fake_token_3"
+    }
+    experimental = False
+
+    # Act
+    process_song(song, artist, access_keys, experimental)
+
+    # Assert
+    # song searched by name and artist
+    mocked_fetch_lyrics.assert_called_with(song, artist)
+    # mocked lyrics get translated
+    mocked_translate_lyrics.assert_called_with("mocked_lyrics")
+    # display is called with song info, original and translated lyrics
+    mocked_display_lyrics.assert_called_with(ANY, "mocked_lyrics", "english translation")
+
+
+@patch('fetch_lyrics.FetchLyrics.FetchLyrics.fetch_lyrics', return_value=None)
+@patch('translate_lyrics.TranslateLyrics.TranslateLyrics.translate_lyrics', return_value="english translation")
+@patch('display_lyrics.DisplayLyrics.DisplayLyrics.display_lyrics')
+def test_process_song_null(mocked_display_lyrics, mocked_translate_lyrics, mocked_fetch_lyrics):
+    """
+    Null song fetched, translation and display are not called
+    """
+
+    # Prepare
+    song = "test_song_name"
+    artist = "test_artist_name"
+    access_keys = {
+        'GENIUS_ACCESS_TOKEN': "fake_token_1",
+        'MS_TRANSLATOR_KEY': "fake_token_2",
+        'MS_TRANSLATOR_REGION': "fake_token_3"
+    }
+    experimental = False
+
+    # Act
+    process_song(song, artist, access_keys, experimental)
+
+    # Assert
+    # song searched by name and artist
+    mocked_fetch_lyrics.assert_called_with(song, artist)
+    # fetched lyrics are null, so translation and display are not called
+    mocked_translate_lyrics.assert_not_called()
+    mocked_display_lyrics.assert_not_called()