Extract archives when zip/rar are enabled as supported formats (#1343)

The default audiobook formats include `zip` and `rar`.
`scan_directory_tree` checks the supported-format list before checking
for archives, so a downloaded archive lands in `book_files` and is
imported as-is. The extraction branch in `collect_directory_files` is
never reached.

This keeps archives out of `book_files`, so they always take the archive
path: extracted when extraction is allowed, imported as-is when it isn't
(unchanged).

Tests added in `tests/download/test_postprocess_scan_archives.py`; three
of the four fail without the change.

shelfmark/download/postprocess/scan.py

@@ -187,7 +187,9 @@ def scan_directory_tree(
                 file_path = Path(root) / filename
                 suffix = file_path.suffix.lower()
 
-                if suffix in supported_exts:
+                # zip/rar can also be enabled as supported formats. Keep archives
+                # out of book_files so they are extracted rather than imported whole.
+                if suffix in supported_exts and not is_archive(file_path):
                     book_files.append(file_path)
                 elif suffix in trackable_exts:
                     rejected_files.append(file_path)

tests/download/test_postprocess_scan_archives.py

@@ -0,0 +1,102 @@
+from __future__ import annotations
+
+import zipfile
+
+from shelfmark.core.models import DownloadTask
+from shelfmark.core.utils import ARCHIVE_FORMATS, AUDIOBOOK_FORMATS
+from shelfmark.download import archive as archive_mod
+from shelfmark.download.postprocess import scan as scan_mod
+
+# The shipped default for SUPPORTED_AUDIOBOOK_FORMATS, which includes archives.
+_DEFAULT_AUDIOBOOK_FORMATS = [*AUDIOBOOK_FORMATS, *ARCHIVE_FORMATS]
+
+
+def _audiobook_task() -> DownloadTask:
+    return DownloadTask(task_id="t", source="audiobookbay", title="Test", content_type="audiobook")
+
+
+def _use_default_audiobook_formats(monkeypatch, tmp_path) -> None:
+    monkeypatch.setattr(
+        scan_mod, "get_supported_audiobook_formats", lambda: list(_DEFAULT_AUDIOBOOK_FORMATS)
+    )
+    monkeypatch.setattr(
+        archive_mod, "get_supported_audiobook_formats", lambda: list(_DEFAULT_AUDIOBOOK_FORMATS)
+    )
+    staging = tmp_path / "staging"
+
+    def build_staging_dir(prefix, _task_id):
+        path = staging / str(prefix)
+        path.mkdir(parents=True, exist_ok=True)
+        return path
+
+    monkeypatch.setattr(scan_mod, "build_staging_dir", build_staging_dir)
+
+
+def _write_series_zip(directory):
+    directory.mkdir()
+    archive = directory / "Series - Books 1-3.zip"
+    with zipfile.ZipFile(archive, "w") as zf:
+        for n in (1, 2, 3):
+            zf.writestr(f"Series/Book {n}/Book {n}.mp3", b"audio")
+    return archive
+
+
+def test_archive_is_not_counted_as_book_file(tmp_path, monkeypatch) -> None:
+    _use_default_audiobook_formats(monkeypatch, tmp_path)
+    download = tmp_path / "download"
+    archive = _write_series_zip(download)
+
+    book_files, _rejected, archive_files, error = scan_mod.scan_directory_tree(
+        download, "audiobook"
+    )
+
+    assert error is None
+    assert book_files == []
+    assert archive_files == [archive]
+
+
+def test_archive_is_extracted_with_default_audiobook_formats(tmp_path, monkeypatch) -> None:
+    _use_default_audiobook_formats(monkeypatch, tmp_path)
+    download = tmp_path / "download"
+    _write_series_zip(download)
+
+    files, _rejected, _cleanup, error = scan_mod.collect_directory_files(
+        download,
+        _audiobook_task(),
+        allow_archive_extraction=True,
+    )
+
+    assert error is None
+    assert sorted(f.name for f in files) == ["Book 1.mp3", "Book 2.mp3", "Book 3.mp3"]
+
+
+def test_archive_imported_as_is_when_extraction_disabled(tmp_path, monkeypatch) -> None:
+    _use_default_audiobook_formats(monkeypatch, tmp_path)
+    download = tmp_path / "download"
+    archive = _write_series_zip(download)
+
+    files, _rejected, _cleanup, error = scan_mod.collect_directory_files(
+        download,
+        _audiobook_task(),
+        allow_archive_extraction=False,
+    )
+
+    assert error is None
+    assert files == [archive]
+
+
+def test_loose_audio_still_preferred_over_archives(tmp_path, monkeypatch) -> None:
+    _use_default_audiobook_formats(monkeypatch, tmp_path)
+    download = tmp_path / "download"
+    _write_series_zip(download)
+    loose = download / "Book.m4b"
+    loose.write_bytes(b"audio")
+
+    files, _rejected, _cleanup, error = scan_mod.collect_directory_files(
+        download,
+        _audiobook_task(),
+        allow_archive_extraction=True,
+    )
+
+    assert error is None
+    assert files == [loose]