test: reorganize core suite into explicit domain files

tests/downloads/test_download_manager_cache_and_validation.py

@@ -0,0 +1,57 @@
+from __future__ import annotations
+
+from pathlib import Path
+
+import pytest
+
+from auditui.constants import MIN_FILE_SIZE
+from auditui.downloads import DownloadManager
+
+
+def _manager_with_cache_dir(tmp_path: Path) -> DownloadManager:
+    """Build a lightweight DownloadManager instance without real HTTP clients."""
+    manager = DownloadManager.__new__(DownloadManager)
+    manager.cache_dir = tmp_path
+    manager.chunk_size = 1024
+    return manager
+
+
+def test_sanitize_filename_replaces_invalid_characters() -> None:
+    """Ensure filesystem-invalid symbols are replaced with underscores."""
+    manager = DownloadManager.__new__(DownloadManager)
+    assert manager._sanitize_filename('a<>:"/\\|?*b') == "a_________b"
+
+
+def test_validate_download_url_accepts_only_http_schemes() -> None:
+    """Ensure download URL validation only accepts HTTP and HTTPS links."""
+    manager = DownloadManager.__new__(DownloadManager)
+    assert manager._validate_download_url("https://example.com/file") is True
+    assert manager._validate_download_url("http://example.com/file") is True
+    assert manager._validate_download_url("ftp://example.com/file") is False
+
+
+def test_get_cached_path_and_remove_cached(
+    tmp_path: Path, monkeypatch: pytest.MonkeyPatch
+) -> None:
+    """Ensure cache lookup and cache deletion work for valid files."""
+    manager = _manager_with_cache_dir(tmp_path)
+    monkeypatch.setattr(manager, "_get_name_from_asin", lambda asin: "My Book")
+    cached_path = tmp_path / "My Book.aax"
+    cached_path.write_bytes(b"0" * MIN_FILE_SIZE)
+    messages: list[str] = []
+    assert manager.get_cached_path("ASIN123") == cached_path
+    assert manager.is_cached("ASIN123") is True
+    assert manager.remove_cached("ASIN123", notify=messages.append) is True
+    assert not cached_path.exists()
+    assert "Removed from cache" in messages[-1]
+
+
+def test_get_cached_path_ignores_small_files(
+    tmp_path: Path, monkeypatch: pytest.MonkeyPatch
+) -> None:
+    """Ensure undersized files are not treated as valid cache entries."""
+    manager = _manager_with_cache_dir(tmp_path)
+    monkeypatch.setattr(manager, "_get_name_from_asin", lambda asin: "My Book")
+    cached_path = tmp_path / "My Book.aax"
+    cached_path.write_bytes(b"0" * (MIN_FILE_SIZE - 1))
+    assert manager.get_cached_path("ASIN123") is None