routes.email_helpers._decode_header joined the runs from
email.header.decode_header() with " ". Those runs carry their own
surrounding whitespace (e.g. (b"Re: ", None)), and RFC 2047 §6.2 requires
the whitespace between two adjacent encoded-words to be dropped, so the
join produced a double space after an ASCII prefix ("Re: Jóse"), a
spurious space in "Name <addr>" senders, and a stray space between two
adjacent encoded-words ("Café 日本"). _decode_header backs the inbox list,
message read, search, and the background pollers, so the corruption hit
essentially every non-ASCII subject/sender.
Use email.header.make_header(...) for RFC-correct concatenation, keeping
the existing lossy per-part fallback for malformed/unknown MIME charsets
(make_header raises LookupError there) so the unknown-charset contract in
tests/test_email_decode_header.py still holds.
The sibling mcp_servers.email_server._decode_header was already fixed the
same way (commit cfdeec4); this brings the routes.email_helpers copy in
line, with regression coverage.
Supported by Claude Opus 4.8
Co-authored-by: SurprisedDuck <288741682+SurprisedDuck@users.noreply.github.com>
This file documents the shared test helpers and the review expectations that go
with them. The suite is being refactored incrementally, so this is a working
reference for that effort — not a claim that the suite is already fully
organized. Read it before adding a new helper or before reviewing a PR that
touches tests/helpers/.
Core principles
Keep PRs small and homogeneous: one kind of change per PR.
Prefer explicit local setup over hidden global fixtures.
Avoid expanding the root conftest.py unless absolutely necessary.
Do not mix file moves with logic changes in the same PR.
Do not weaken tests with skip/xfail just to make CI pass.
Validate the focused files you changed, plus any neighboring or
order-sensitive groups they interact with.
Helper conventions
The helpers below live under tests/helpers/. They exist to remove repeated
boilerplate that already appeared across multiple tests. Reach for one only when
your test matches its intended use; do not stretch a helper to cover a new case.
tests.helpers.cli_loader.load_script
Use when a test needs to import a script under scripts/ without repeating
SourceFileLoader / importlib.util boilerplate.
Intended for script/CLI tests that load a single file from scripts/.
Not for arbitrary package imports — use a normal import for those.
When migrating an existing test to it, keep the existing stubs and assertions
unchanged. Any sys.modules stubs the script needs at import time must still
be injected (e.g. via monkeypatch) before calling load_script.
tests.helpers.import_state.clear_module
Use when a test must drop one cached module and its parent-package attribute
before a fresh import.
Clears sys.modules[name].
Clears the parent-package attribute when present.
Good replacement for local sys.modules.pop(...) + delattr(parent, child)
blocks.
tests.helpers.import_state.preserve_import_state
Use when a test temporarily installs stubs into sys.modules and needs
deterministic cleanup afterward.
Context manager: restores both sys.modules entries and parent-package
attributes on exit (normal or exception).
Useful around module-level stubs or temporary imports.
Prefer narrow, explicit module names over broad ones.
SurprisedDuck
2c4c77be5a