You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
m123/.venv/Lib/site-packages/trio/_tests/test_scheduler_determinism.py

50 lines
1.3 KiB

from __future__ import annotations
from typing import TYPE_CHECKING
import trio
if TYPE_CHECKING:
import pytest
async def scheduler_trace() -> tuple[tuple[str, int], ...]:
"""Returns a scheduler-dependent value we can use to check determinism."""
trace = []
async def tracer(name: str) -> None:
for i in range(50):
trace.append((name, i))
await trio.sleep(0)
async with trio.open_nursery() as nursery:
for i in range(5):
nursery.start_soon(tracer, str(i))
return tuple(trace)
def test_the_trio_scheduler_is_not_deterministic() -> None:
# At least, not yet. See https://github.com/python-trio/trio/issues/32
traces = []
for _ in range(10):
traces.append(trio.run(scheduler_trace))
assert len(set(traces)) == len(traces)
def test_the_trio_scheduler_is_deterministic_if_seeded(
monkeypatch: pytest.MonkeyPatch,
) -> None:
monkeypatch.setattr(trio._core._run, "_ALLOW_DETERMINISTIC_SCHEDULING", True)
traces = []
for _ in range(10):
state = trio._core._run._r.getstate()
try:
trio._core._run._r.seed(0)
traces.append(trio.run(scheduler_trace))
finally:
trio._core._run._r.setstate(state)
assert len(traces) == 10
assert len(set(traces)) == 1