**Replace Flake8 with Ruff, refactor type hints, and enhance archive processing logic**

- Removed `flake8` and `flake8-annotations` from dependencies, replaced by `ruff` for linting.
- Introduced cleaner type hinting and modern Python annotations (PEP 604 style) across multiple modules.
- Moved archive processing to a dedicated helper (`comic.archives`) for improved maintainability.
- Updated and simplified logic for archive file retrieval, directory cleaning, and user access validation.
- Improved error handling and added support for user classification restrictions in API responses.

comic/tests/test_models.py

@@ -0,0 +1,71 @@
+"""Tests for the comic models."""
+
+from pathlib import Path
+
+import pytest
+
+from comic import models
+from comic.tests.factories import make_cbz, make_pdf
+
+
+@pytest.mark.django_db
+def test_page_count_excludes_metadata(comic_volume: Path) -> None:
+    make_cbz(comic_volume / 'issue.cbz', pages=3, metadata=True)
+    book = models.ComicBook.objects.create(file_name='issue.cbz')
+    assert book.get_page_count() == 3
+
+
+@pytest.mark.django_db
+def test_pdf_page_count(comic_volume: Path) -> None:
+    make_pdf(comic_volume / 'issue.pdf', pages=2)
+    book = models.ComicBook.objects.create(file_name='issue.pdf')
+    assert book.get_page_count() == 2
+
+
+@pytest.mark.django_db
+def test_unreadable_archive_is_indexed_without_pages(comic_volume: Path) -> None:
+    path = comic_volume / 'broken.cbz'
+    path.write_bytes(b'this is not an archive')
+    result = models.ComicBook.process_comic_book(path)
+    assert isinstance(result, Path)
+    assert models.ComicBook.objects.get(file_name='broken.cbz').page_count == 0
+
+
+@pytest.mark.django_db
+def test_archive_path_uses_the_directory_tree(comic_volume: Path) -> None:
+    parent = models.Directory.objects.create(name='Series')
+    child = models.Directory.objects.create(name='Volume 1', parent=parent)
+    book = models.ComicBook.objects.create(file_name='issue.cbz', directory=child)
+    assert book.get_archive_path == comic_volume / 'Series' / 'Volume 1' / 'issue.cbz'
+
+
+@pytest.mark.django_db
+def test_book_without_a_directory_uses_the_volume_root(comic_volume: Path) -> None:
+    book = models.ComicBook.objects.create(file_name='issue.cbz')
+    assert book.get_archive_path == comic_volume / 'issue.cbz'
+
+
+@pytest.mark.django_db
+def test_directory_path_is_built_from_its_parents() -> None:
+    parent = models.Directory.objects.create(name='Series')
+    child = models.Directory.objects.create(name='Volume 1', parent=parent)
+    assert child.get_path() == Path('Series') / 'Volume 1'
+
+
+@pytest.mark.django_db
+def test_get_image_returns_the_requested_page(comic_volume: Path) -> None:
+    make_cbz(comic_volume / 'issue.cbz', pages=2, metadata=False)
+    book = models.ComicBook.objects.create(file_name='issue.cbz')
+    stream, mime_type = book.get_image(1)
+    assert mime_type == 'image/png'
+    assert stream.read()
+
+
+@pytest.mark.django_db
+def test_classification_comparison() -> None:
+    directory = models.Directory.objects.create(name='Rated', classification=models.Directory.Classification.C_18)
+    misc = models.UserMisc.objects.create(
+        user=models.User.objects.create_user('pg', 'pg@example.com', 'password12345'),
+        allowed_to_read=models.Directory.Classification.C_PG,
+    )
+    assert directory.classification > misc.allowed_to_read