Refactor test configurations and enhance testing framework

- Replace TempConfig with DummyConfig across tests for consistency
- Introduce unit tests workflow configuration
- Add pytest configuration for standardized test discovery
- Implement comprehensive tests for config loading and downloader behavior
- Clean up unused temp_config.py and related references

tests/test_cli_flags.py

@@ -1,23 +1,23 @@
 import logging
 from ytplaylist.manager import PlaylistManager
-from tests.temp_config import TempConfig
+from tests.dummy_config import DummyConfig
 
 
-class TestConfig(TempConfig):
-    playlists = [{"url": None, "save_path": "./tmp_test", "archive": "archive.txt"}]
-
-if __name__ == '__main__':
+def test_run_with_prune_disabled():
     logging.basicConfig(level=logging.INFO, format="%(levelname)s:%(message)s")
-    print('--- Running with prune=False ---')
-    cfg=TestConfig()
-    m=PlaylistManager(cfg, debug=False)
+    cfg = DummyConfig()
+    cfg.playlists = [{"url": None, "save_path": "tests/tmp_test", "archive": "archive.txt"}]
+    m = PlaylistManager(cfg, debug=False)
+    # should complete without raising
     m.run()
-    print('Run complete prune=False')
 
-    print('\n--- Running with prune=True, non_interactive=True ---')
-    cfg2=TestConfig()
-    cfg2.prune=True
-    cfg2.non_interactive=True
-    m2=PlaylistManager(cfg2, debug=False)
-    m2.run()
-    print('Run complete prune=True non_interactive=True')
+
+def test_run_with_prune_enabled_non_interactive():
+    logging.basicConfig(level=logging.INFO, format="%(levelname)s:%(message)s")
+    cfg = DummyConfig()
+    cfg.playlists = [{"url": None, "save_path": "tests/tmp_test", "archive": "archive.txt"}]
+    cfg.prune = True
+    cfg.non_interactive = True
+    m = PlaylistManager(cfg, debug=False)
+    # should complete without raising
+    m.run()