* fix(caldav): don't prune the whole window when no objects could be parsed
The post-sync prune deletes local origin=="caldav" rows in the window whose UID
the server didn't just return. With an empty seen_uids it falls back to
`uid.isnot(None)` — a match-all delete. That's right when the calendar is
genuinely empty, but when the server returns objects and every one fails to
parse (malformed iCal / an icalendar error), seen_uids is empty only because
nothing could be read, so the match-all branch silently deletes every local
event in the 90-day-back/365-day-forward window.
Track whether any object failed to parse and gate the prune with a small pure
helper `_should_prune_window(seen_uids, parse_failed)`: prune when something was
read, or when the calendar is genuinely empty (no objects, no parse errors), but
never when objects came back unreadable.
Adds tests/test_caldav_prune_parse_failure.py for the three cases.
* fix(caldav): skip the prune on any parse failure, not just total
Review follow-up (#3454): _should_prune_window returned True whenever seen_uids
was non-empty, so a partial parse failure (say 48 of 50 objects parse) still
pruned the 2 unreadable-but-still-upstream events, because their UIDs were absent
from seen_uids. Any parse failure makes seen_uids an incomplete view of the
server, so pruning against it is unsafe whether the failure is total or partial.
Skip the prune on any parse failure (return not parse_failed); only prune on a
clean read (a genuinely empty window is still safe to prune). Tradeoff: one
permanently-unparseable event pauses deletion mirroring until it is fixed, which
is the safe direction (false-keep beats false-delete).
Replace the now-incorrect "partial failure still prunes" assertion with a
partial-failure regression: one object parses, one fails, so the prune is
skipped and the unparsed event's local copy is not deleted.
---------
Co-authored-by: Kenny Van de Maele <kenny@kvandemaele.be>
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/.
For the broader rules - test taxonomy, determinism/isolation rules, the
behavioral-vs-source-text policy, and helper/factory extraction rules - see
TESTING_STANDARD.md. This file is the concrete helper
reference; that file is the standard the refactor works toward.
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.
Mazen Tamer Salah
1209f258d7