Files
vrsub/tests/test_adaptive_pool.py
T

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Python

"""自适应线程池测试。
覆盖决策函数(增/减/保持/边界)、map 顺序返回、worker 异常隔离,
以及"10s 窗口内平均响应 < 0.3s 加线程 / > 1.0s 减线程"的弹性行为
(通过注入假时钟做确定性验证)。
"""
import threading
import time
from nodes.adaptive_pool import AdaptiveThreadPool, decide
class FakeClock:
"""可手动拨动的假时钟,用于确定性验证弹性窗口逻辑。"""
def __init__(self, now: float = 0.0) -> None:
self.now = now
def __call__(self) -> float:
return self.now
def advance(self, seconds: float) -> None:
self.now += seconds
def test_decide_increase_when_fast() -> None:
"""平均响应低于 fast_threshold 且未达上限:线程数 +1。"""
assert decide(1, 0.1, 1, 16, 0.3, 1.0) == 2
def test_decide_decrease_when_slow() -> None:
"""平均响应高于 slow_threshold 且高于下限:线程数 -1。"""
assert decide(3, 2.0, 1, 16, 0.3, 1.0) == 2
def test_decide_keep_when_mid() -> None:
"""平均响应介于两阈值之间:保持不变。"""
assert decide(2, 0.5, 1, 16, 0.3, 1.0) == 2
def test_decide_bounds() -> None:
"""已达上限不再增、已达下限不再减。"""
assert decide(16, 0.1, 1, 16, 0.3, 1.0) == 16
assert decide(1, 2.0, 1, 16, 0.3, 1.0) == 1
def test_pool_map_ordered_results() -> None:
"""map 按输入顺序返回结果,worker 简单映射。"""
pool = AdaptiveThreadPool(worker=lambda item: item * 2)
assert pool.map([1, 2, 3, 4]) == [2, 4, 6, 8]
def test_pool_on_progress_callback() -> None:
"""进度回调:每次完成触发一次,携带已完成数/总数/速度/平均耗时/线程数。"""
progress: list[tuple[int, int, float, float, int]] = []
pool = AdaptiveThreadPool(
worker=lambda item: item,
on_progress=lambda done, total, rate, avg_time, workers: progress.append(
(done, total, rate, avg_time, workers)
),
)
pool.map([10, 20, 30])
assert [item[0] for item in progress] == [1, 2, 3] # 已完成数递增。
assert all(item[1] == 3 for item in progress) # 总数固定。
assert all(item[2] > 0 for item in progress) # 速度为正值。
# 窗口未满时平均耗时回退为累计平均(>0);线程数 ∈ [1, 上限]。
assert all(item[3] > 0 for item in progress)
assert all(1 <= item[4] <= pool.max_workers for item in progress)
def test_pool_progress_reports_window_avg_after_first_window() -> None:
"""窗口评估后:回调携带最近窗口平均耗时(扩缩容依据)与扩容后的线程数。
覆盖 `_current_avg_time` 两个分支:窗口评估前回退累计平均,评估后使用
最近窗口平均(0.0s,响应远快于 fast_threshold 0.3s → 线程 +1)。
"""
clock = FakeClock()
seen: list[tuple[int, int, float, float, int]] = []
def progress(done, total, rate, avg_time, workers):
# 推进窗口时钟但不增加 worker 耗时,确定性触发快响应扩容。
seen.append((done, total, rate, avg_time, workers))
if done == 1:
clock.advance(11)
pool = AdaptiveThreadPool(
worker=lambda item: item,
min_workers=1, max_workers=16,
window_seconds=10.0, fast_threshold=0.3,
clock=clock, on_progress=progress,
)
pool.map(list(range(5)))
# 第一个完成的任务回调在窗口评估前:真实 worker 耗时为 0,均值也为 0。
assert seen[0][3] == 0.0
# 窗口评估后:回调携带最近窗口平均(≈0.0),且线程已扩容到 2。
assert any(item[3] == 0.0 for item in seen)
assert any(item[4] == 2 for item in seen)
assert pool.max_concurrency == 2
def test_pool_cancel_suppresses_progress() -> None:
"""worker 触发 cancel(如检测到暂停信号)后:剩余任务不再触发进度回调。
暂停场景:队列中剩余的大量帧会逐帧快速失败退出,若每完成一项都打印
进度日志,会在数秒内打出上万行日志;cancel 后抑制后续进度回调。
"""
progress: list[tuple[int, int, float, float, int]] = []
def worker(item):
if item == 1:
pool.cancel() # 模拟某帧检测到暂停信号。
return item
pool = AdaptiveThreadPool(
worker=worker,
on_progress=lambda done, total, rate, avg_time, workers: progress.append(
(done, total, rate, avg_time, workers)
),
)
pool.map([0, 1, 2, 3])
# 只有 cancel 之前的任务(item=0)触发了进度回调。
assert len(progress) == 1
assert progress[0][1] == 4 # 总数仍是 4。
def test_pool_cancel_resets_between_maps() -> None:
"""取消状态按批(map)重置:下一批任务进度回调恢复正常。"""
progress: list[tuple[int, int, float, float, int]] = []
def worker(item):
if item == "stop":
pool.cancel()
return item
pool = AdaptiveThreadPool(
worker=worker,
on_progress=lambda done, total, rate, avg_time, workers: progress.append(
(done, total, rate, avg_time, workers)
),
)
pool.map(["a", "stop", "b"])
assert len(progress) == 1 # 只有 cancel 前的 a 触发回调。
pool.map(["c", "d"])
# 新一批恢复回调(done 从 1 重新计数):共 3 次回调(1 + 2)。
assert [item[0] for item in progress] == [1, 1, 2]
def test_pool_map_empty() -> None:
"""空输入:不启动任务,直接返回空列表。"""
pool = AdaptiveThreadPool(worker=lambda item: item)
assert pool.map([]) == []
def test_pool_worker_exception_isolated() -> None:
"""worker 抛异常时以异常对象作为结果,不拖垮整体。"""
def boom(item):
raise RuntimeError("boom")
pool = AdaptiveThreadPool(worker=boom)
results = pool.map([1, 2])
assert len(results) == 2
assert all(isinstance(result, RuntimeError) for result in results)
def test_pool_grows_when_fast() -> None:
"""10s 窗口内平均响应 < 0.3s:线程数从 1 增至 2(弹性扩容)。"""
clock = FakeClock()
pool = AdaptiveThreadPool(
worker=lambda item: item,
min_workers=1, max_workers=16,
window_seconds=10.0, fast_threshold=0.3,
clock=clock,
on_progress=lambda done, *_: clock.advance(11) if done == 1 else None,
)
# 首个任务完成后越过窗口 → 平均响应≈0 < 0.3 → +1 个在途额度。
pool.map(list(range(4)))
assert pool.max_concurrency == 2
def test_pool_shrink_when_slow() -> None:
"""窗口平均响应 > 1.0s:线程数从 2 减至 1(弹性退避)。"""
clock = FakeClock()
pool = AdaptiveThreadPool(
worker=lambda item: item,
min_workers=1, max_workers=16,
window_seconds=10.0, fast_threshold=0.3, slow_threshold=1.0,
clock=clock,
)
pool._resize(2) # 先扩到 2 个线程。
clock.advance(11)
pool._tick(2.0) # 窗口内平均 2.0 > 1.0 → 缩回 1。
# 缩容只调整提交额度;实际积压任务行为由下方并发回归测试验证。
assert pool._target_workers == 1
def test_resize_shrink_idempotent() -> None:
"""回归:重复缩容到同一目标不会重复放哨兵(曾因并发缩容毒死全部线程而死锁)。"""
pool = AdaptiveThreadPool(worker=lambda item: item, min_workers=1, max_workers=8)
pool._resize(3)
assert pool._target_workers == 3
pool._resize(2)
pool._resize(2) # 目标已是 2:幂等,不再放哨兵。
assert pool._target_workers == 2
# 重复缩容不会遗留哨兵影响下一批,真实 map 必须返回全部输入。
assert pool.map(list(range(20))) == list(range(20))
def test_pool_survives_mixed_grow_shrink() -> None:
"""回归:扩容+缩容混合场景 map 必须完成且保序(修复前会死锁挂起)。"""
clock = FakeClock()
state = {"count": 0}
def worker(item):
state["count"] += 1
clock.advance(0.06 if state["count"] <= 20 else 0.6)
return item
pool = AdaptiveThreadPool(
worker=worker, min_workers=1, max_workers=4,
window_seconds=0.5, fast_threshold=0.2, slow_threshold=0.4,
clock=clock,
)
out = pool.map(list(range(60)))
assert out == list(range(60))
def test_pool_report_failure_lowers_effective_max() -> None:
"""消费错误(如 API 限流)临时降低有效最大线程数,下限为 min_workers。
自适应:并发打到配额线触发 429 时,report_failure 收紧有效上限,
后续请求减少从而避开持续限流。
"""
pool = AdaptiveThreadPool(worker=lambda item: item, min_workers=1, max_workers=16)
assert pool._effective_max_workers == 16
pool.report_failure()
assert pool._effective_max_workers == 15
for _ in range(30):
pool.report_failure()
assert pool._effective_max_workers == 1 # 下限 min_workers。
def test_pool_effective_max_recovers_after_clean_window() -> None:
"""连续无错误窗口后有效上限逐步回升到 max_workers。"""
clock = FakeClock()
pool = AdaptiveThreadPool(
worker=lambda item: item, min_workers=1, max_workers=16,
window_seconds=10.0, fast_threshold=0.3, clock=clock,
)
pool.report_failure() # 有效上限 16 -> 15。
clock.advance(11)
pool._tick(0.01) # 错误所在窗口:上限不恢复。
assert pool._effective_max_workers == 15
clock.advance(11)
pool._tick(0.01) # 下一个干净窗口:恢复 +1。
assert pool._effective_max_workers == 16
pool._tick(0.01) # 窗口未满早退,上限不变。
assert pool._effective_max_workers == 16
def test_failure_at_single_worker_never_expands() -> None:
"""真实 map 内报告限流:1 个在途任务不能因上限 20 变 19 而突然扩容。"""
targets = []
def worker(item):
if item == 0:
pool.report_failure()
targets.append(pool._target_workers)
return item
pool = AdaptiveThreadPool(worker=worker, max_workers=20, window_seconds=1000)
assert pool.map(list(range(30))) == list(range(30))
assert targets == [1]
def test_failure_shrink_limits_backlogged_work() -> None:
"""积压任务中从 4 降到 1:已开始任务可完成,后续实际并发必须为 1。"""
barrier = threading.Barrier(4, timeout=3)
reduced = threading.Event()
lock = threading.Lock()
active = 0
subsequent_peaks = []
def worker(item):
nonlocal active
with lock:
active += 1
if item >= 5:
subsequent_peaks.append(active)
try:
if 1 <= item <= 4:
barrier.wait()
if item == 1:
# 连续限流将有效上限压到下限,存量请求不强制中断。
for _ in range(3):
pool.report_failure()
reduced.set()
assert reduced.wait(3)
elif item >= 5:
# 模拟 I/O 等待,给其他工作线程实际进入任务的机会。
time.sleep(0.005)
return item
finally:
with lock:
active -= 1
def progress(done, *_):
if done == 1:
pool._resize(4)
pool = AdaptiveThreadPool(worker=worker, max_workers=4, window_seconds=1000,
on_progress=progress)
items = list(range(40))
assert pool.map(items) == items
assert subsequent_peaks and max(subsequent_peaks) == 1
def test_error_window_does_not_regrow() -> None:
"""报告限流的同一窗口即使响应很快,也不能重新加并发。"""
clock = FakeClock()
pool = AdaptiveThreadPool(worker=lambda item: item, max_workers=4, clock=clock)
pool.report_failure()
clock.advance(11)
pool._tick(0.01)
assert pool._target_workers <= 1
def test_retry_map_preserves_reduced_limit() -> None:
"""两轮真实 map:首轮连续限流后,重试期间实际并发及进度都遵守新上限。"""
lock = threading.Lock()
active = 0
peak = 0
progress_counts = []
def worker(item):
nonlocal active, peak
with lock:
active += 1
peak = max(peak, active)
try:
if item == "limited":
for _ in range(3):
pool.report_failure()
raise RuntimeError("rate limited")
time.sleep(0.002)
return item
finally:
with lock:
active -= 1
pool = AdaptiveThreadPool(
worker=worker, max_workers=4, window_seconds=1000,
on_progress=lambda done, *_: progress_counts.append(done),
)
assert isinstance(pool.map(["limited"])[0], RuntimeError)
assert pool._effective_max_workers == 1
# 主动申请扩容也受已收紧额度约束,下一轮不能重置有效上限。
pool._resize(4)
assert pool._target_workers == 1
assert pool.map(list(range(12))) == list(range(12))
assert peak == 1
assert progress_counts == [1] + list(range(1, 13))
def test_pool_decide_uses_effective_max() -> None:
"""扩容上限按有效最大线程数:错误窗口内即使响应快也不超过收紧后的上限。"""
clock = FakeClock()
pool = AdaptiveThreadPool(
worker=lambda item: item, min_workers=1, max_workers=16,
window_seconds=10.0, fast_threshold=0.3, clock=clock,
)
pool.report_failure() # 有效上限 16 -> 15。
pool._resize(15)
pool._window_failures = 1 # 本窗口内仍有错误 → 不恢复上限。
clock.advance(11)
pool._tick(0.01) # 响应快,但 15 已是有效上限 → 不扩。
assert pool._target_workers == 15
assert pool._effective_max_workers == 15