Test modules in paperless, paperless_mail and documents imported filesystem assertions, the migration test base, the retry helper and the streaming-response reader out of documents/tests/utils.py, which kept each app's tests coupled to another app's test package.
They now live in paperless_testing, and the progress manager fake is renamed FakeProgressManager and now subclasses the real ProgressManager, overriding only the transport, so the payload it records is built by the production code. The twenty places that patched documents.tasks.ProgressManager by hand now use a fake_progress_manager fixture.
The unittest side of the suite built its temp directory tree with
tempfile.mkdtemp and a manually enabled override_settings, cleaned up only if
tearDown ran. That is now gone. DirectoriesMixin lives alongside the layout it
bridges and does nothing but hand the paperless_dirs fixture to TestCase
subclasses as self.dirs, so both halves of the suite get the same twelve
settings, the same directory shapes and cleanup owned by tmp_path.
The mixin moves to paperless_testing.dirs rather than staying in the documents
test utilities, because modules in paperless and paperless_mail import it
across the app boundary. The thirty-eight consuming modules change only their
import line; self.dirs.scratch_dir and its siblings keep working.