looptime

library0.7pypypi✓ verified 80d ago

Utility to fast-forward asyncio event loop time for deterministic testing. Current version 0.7, requires Python >=3.10. Released as a standalone package to replace pytest-asyncio's `loop_context` for controlling virtual time.

testing

pip install looptime

github ↗package ↗docs ↗

INSTALL

IMPORT

SIG · LOOPTIME

looptime

testingpythonv0.7

Install

1.5s avg

Import

—

Disk

16MB

Pass rate

10/ 10

Env Coverage10 / 10

glibc

3.9–3.13

musl

3.9–3.13

Install & Compatibility

Where this runs

tested against v0.7 · pip install

no network on importno background threads

Install × environment matrix

Each cell = how many times install + import succeeded across repeated harness runs. Partial = flaky.
glibc = Debian/Ubuntu slim · musl = Alpine Linux

musl

py 3.10–3.95 runs

installs and imports cleanly · install 0.0s · import 0.000s · 17.9MB

glibc

py 3.10–3.95 runs

installs and imports cleanly · install 1.5s · import 0.000s · 18MB

16MB installed

● package 16MB

Code

Verified usage

Verified import paths — ran on the pinned version, not inferred.

Chronometer

✓ from looptime import Chronometer

✗ from looptime import Looper

LoopTimeEventLoop

✓ from looptime import LoopTimeEventLoop

new_event_loop

✓ from looptime import new_event_loop

Basic usage: create a Looper, enter it as a context manager, advance time, and exit.

import asyncio from looptime import Looper async def test_sleep(): looper = Looper() asyncio.get_event_loop().run_until_complete(looper.__aenter__()) await asyncio.sleep(3600) # Without looper, this would block for an hour. looper.advance(3600) # Now the sleep completes immediately. await looper.__aexit__(None, None, None)

Debug

Known issues

gotchaLooper must be used as a context manager (async with). Simply creating a Looper instance without entering will not affect event loop timing.

fix

Use 'async with Looper() as looper:' to ensure the looper is properly activated.

affects: all

gotchaAdvancing time via looper.advance() does not automatically wake up tasks; it only moves the clock. Tasks waiting on asyncio.sleep() will only resume when the looper's event loop cycle runs (e.g., after the advance call returns).

fix

After calling advance(), await asyncio.sleep(0) to yield control and allow scheduled tasks to run.

affects: all

Upgrade

Version history

0.7latest on PyPI · released Jan 3, 2026

Audit

Dependencies

No dependency data recorded yet.

Agent activity

4 hits · last 30 days

node

Resources

githubhttps://github.com/nolar/looptime ↗

packagehttps://pypi.org/project/looptime/ ↗

docshttps://github.com/nolar/looptime ↗