Добавить основную функциональность загрузки YouTube Shorts с использованием файла сессии и обработкой ошибок

tests/test_cli.py

@@ -0,0 +1,43 @@
+from __future__ import annotations
+
+from pathlib import Path
+
+import pytest
+
+from yt_shorts_downloader import cli
+from yt_shorts_downloader.exceptions import InvalidSessionError
+
+
+def test_cli_prints_downloaded_path(
+    monkeypatch: pytest.MonkeyPatch,
+    capsys: pytest.CaptureFixture[str],
+    tmp_path: Path,
+) -> None:
+    expected_path = tmp_path / "video.mp4"
+    monkeypatch.setattr(cli, "download", lambda **kwargs: expected_path)
+
+    exit_code = cli.main(
+        [
+            "https://youtube.com/shorts/example",
+            "cookies.txt",
+            "--output-dir",
+            str(tmp_path),
+        ]
+    )
+
+    captured = capsys.readouterr()
+
+    assert exit_code == 0
+    assert captured.out.strip() == str(expected_path)
+
+
+def test_cli_exits_with_error(monkeypatch: pytest.MonkeyPatch) -> None:
+    def raise_error(**kwargs: object) -> Path:
+        raise InvalidSessionError("session error")
+
+    monkeypatch.setattr(cli, "download", raise_error)
+
+    with pytest.raises(SystemExit) as exc_info:
+        cli.main(["https://youtube.com/shorts/example", "cookies.txt"])
+
+    assert exc_info.value.code == 1