thermograph/tests/core/test_singleton.py
Emi Griffith 21f7ef4d19 Group regression tests by domain (#215)
Move the flat backend/tests/*.py into domain subfolders so the suite
mirrors the code's concerns:
  data/          climate, grading, scoring, grid, places, store
  web/           api, content, homepage, views
  notifications/ notify, digest, discord (+ dm/interactions/link)
  accounts/      api_accounts
  core/          metrics, singleton, dashboard

conftest.py stays at the tests/ root, so its sys.path setup and shared
fixtures still apply to every subfolder. The four tests that derive repo
paths from __file__ get their depth bumped one level to match their new
location. Pytest discovers the subfolders recursively; the CI command
(python -m pytest backend/tests) is unchanged.

Claude-Session: https://claude.ai/code/session_01XXxmNFy9cZ6Gh8Y9thZn62
2026-07-20 04:50:01 +00:00

64 lines
2 KiB
Python

"""Unit tests for the single-instance leader election (singleton.py)."""
import fcntl
import importlib
import os
import singleton
def _fresh():
# _held is module-level state; reload for an isolated starting point per test.
return importlib.reload(singleton)
def test_no_lock_path_is_always_leader():
s = _fresh()
assert s.claim(None) is True
assert s.claim("") is True
def test_first_claimer_wins_and_holds_the_lock(tmp_path):
s = _fresh()
lock = str(tmp_path / "notifier.lock")
assert s.claim(lock) is True
# Held for the process lifetime: the fd stays open and flock'd.
assert lock in s._held
def test_reclaiming_same_path_is_idempotent(tmp_path):
s = _fresh()
lock = str(tmp_path / "notifier.lock")
assert s.claim(lock) is True
fd = s._held[lock]
# Re-claiming must not re-open or drop the lock — same fd, still True.
assert s.claim(lock) is True
assert s._held[lock] == fd
def test_second_holder_stands_down(tmp_path):
"""When another holder already owns the lock, claim() returns False and leaks no
fd. Simulate the other worker by taking the exclusive flock on a separate open
file description (a fresh os.open, as a distinct process would)."""
s = _fresh()
lock = str(tmp_path / "notifier.lock")
other = os.open(lock, os.O_RDWR | os.O_CREAT, 0o644)
fcntl.flock(other, fcntl.LOCK_EX | fcntl.LOCK_NB)
try:
assert s.claim(lock) is False
assert lock not in s._held # did not record a role it doesn't own
finally:
fcntl.flock(other, fcntl.LOCK_UN)
os.close(other)
def test_reelection_after_holder_releases(tmp_path):
"""A restart drops the OS lock; the next claim() then wins."""
s = _fresh()
lock = str(tmp_path / "notifier.lock")
other = os.open(lock, os.O_RDWR | os.O_CREAT, 0o644)
fcntl.flock(other, fcntl.LOCK_EX | fcntl.LOCK_NB)
assert s.claim(lock) is False
# Prior leader exits -> OS releases the lock.
fcntl.flock(other, fcntl.LOCK_UN)
os.close(other)
assert s.claim(lock) is True