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

tests/test_api.py

@@ -0,0 +1,50 @@
+from __future__ import annotations
+
+from pathlib import Path
+
+import pytest
+
+from yt_shorts_downloader import api
+from yt_shorts_downloader.exceptions import InvalidSessionError, InvalidUrlError
+from yt_shorts_downloader.models import SessionValidation
+
+
+def test_download_returns_path_from_downloader(
+    monkeypatch: pytest.MonkeyPatch, tmp_path: Path
+) -> None:
+    expected_path = tmp_path / "video.mp4"
+
+    monkeypatch.setattr(
+        api,
+        "validate_session_file",
+        lambda path: SessionValidation(True, True, True, True, str(path)),
+    )
+    monkeypatch.setattr(
+        api,
+        "download_video",
+        lambda *, url, output_dir, session_path: expected_path,
+    )
+
+    downloaded_path = api.download(
+        "https://youtube.com/shorts/example",
+        session_path="cookies.txt",
+        output_dir=tmp_path,
+    )
+
+    assert downloaded_path == expected_path
+
+
+def test_download_rejects_invalid_url() -> None:
+    with pytest.raises(InvalidUrlError):
+        api.download("https://example.com/watch?v=1", session_path="cookies.txt")
+
+
+def test_download_rejects_invalid_session(monkeypatch: pytest.MonkeyPatch) -> None:
+    monkeypatch.setattr(
+        api,
+        "validate_session_file",
+        lambda path: SessionValidation(False, False, False, False, "bad session"),
+    )
+
+    with pytest.raises(InvalidSessionError, match="bad session"):
+        api.download("https://youtube.com/shorts/example", session_path="cookies.txt")