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vllm-project--vllm/tests/v1/worker/test_sleep_mode_backend.py
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chore: import upstream snapshot with attribution
2026-07-13 12:55:37 +08:00

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Python

# SPDX-License-Identifier: Apache-2.0
# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
"""CPU-only unit tests for the sleep-mode backend abstraction (RFC #34303).
These cover the registry/factory contract and capability flags. They do not
touch CUDA - the ``cumem`` suspend/resume path is exercised end-to-end on GPU
in ``tests/basic_correctness/test_cumem.py``.
"""
import pytest
from vllm.device_allocator.sleep_mode_backend import (
CuMemBackend,
SleepModeBackend,
SleepModeBackendFactory,
)
def test_cumem_is_the_default_registered_backend():
backend_cls = SleepModeBackendFactory.get_backend_class("cumem")
assert backend_cls is CuMemBackend
assert issubclass(backend_cls, SleepModeBackend)
def test_cumem_capability_flags():
# cumem leaves communicators untouched but does not preserve compiled
# artifacts, graphs, or durable state - these flags are what the executor and
# /health introspect to decide reinit / persistence behavior.
assert CuMemBackend.is_supported() is True
assert CuMemBackend.preserves_communicators() is True
assert CuMemBackend.preserves_compiled_artifacts() is False
assert CuMemBackend.preserves_graphs_with_communicators() is False
assert CuMemBackend.supports_durable_storage() is False
def test_new_backend_starts_in_running_state():
# Constructing a backend must not touch the GPU; only suspend/resume do.
assert CuMemBackend().state() == "RUNNING"
def test_unknown_backend_raises():
with pytest.raises(ValueError, match="Unsupported sleep-mode backend"):
SleepModeBackendFactory.get_backend_class("does-not-exist")
def test_duplicate_registration_raises():
with pytest.raises(ValueError, match="already registered"):
SleepModeBackendFactory.register_backend(
"cumem",
"vllm.device_allocator.sleep_mode_backend",
"CuMemBackend",
)
def test_third_party_backend_registration_and_resolution():
"""A plugin registers a backend by name; the factory resolves it lazily."""
name = "_pytest_dummy_backend"
try:
SleepModeBackendFactory.register_backend(
name,
"tests.v1.worker.test_sleep_mode_backend",
"DummyBackend",
)
resolved = SleepModeBackendFactory.get_backend_class(name)
assert resolved is DummyBackend
assert resolved.supports_durable_storage() is True
finally:
SleepModeBackendFactory._registry.pop(name, None)
def test_suspend_resume_state_transitions():
"""Lifecycle state advances RUNNING -> SUSPENDED -> RUNNING without GPU."""
backend = DummyBackend()
assert backend.state() == "RUNNING"
backend.suspend(level=1)
assert backend.state() == "SUSPENDED"
backend.resume()
assert backend.state() == "RUNNING"
class DummyBackend(SleepModeBackend):
"""A no-GPU backend used to exercise lifecycle + registration in CPU tests."""
def suspend(self, level: int = 1) -> None:
self._state = "SUSPENDED"
def resume(self, tags: list[str] | None = None) -> None:
self._state = "RUNNING"
@classmethod
def supports_durable_storage(cls) -> bool:
return True