⏰ SleepFake

SleepFake is a compact Python package (under 100 lines) that provides a context manager to simulate the time.sleep and asyncio.sleep functions during tests. This is useful for testing time-dependent code without the need to actually wait for time to pass. The real magic behind this package comes from freezegun. 🎩✨

Installation

pip install sleepfake

🚀 Usage

Context Manager

import asyncio
import time

from sleepfake import SleepFake


def test_example():
    real_start = time.time()
    with SleepFake():
        start = time.time()
        time.sleep(10)
        end = time.time()
        assert end - start == 10
    real_end = time.time()
    assert real_end - real_start < 1

@pytest.mark.asyncio
async def test_async_example():
    real_start = asyncio.get_event_loop().time()
    with SleepFake():
        start = asyncio.get_event_loop().time()
        await asyncio.gather(asyncio.sleep(5), asyncio.sleep(5), asyncio.sleep(5))
        end = asyncio.get_event_loop().time()
        assert end - start <= 5.5  # almost 5 seconds  # noqa: PLR2004
        assert end - start >= 5  # almost 5 seconds  # noqa: PLR2004
    real_end = asyncio.get_event_loop().time()
    assert real_end - real_start < 1  # almost 0 seconds

With Fixture (Beta)

import asyncio
import time

from sleepfake import SleepFake

def test_example(sleepfake: SleepFake):
    start = time.time()
    time.sleep(10)
    end = time.time()
    assert end - start == 10

@pytest.mark.asyncio
async def test_async_example(sleepfake: SleepFake):
    start = asyncio.get_event_loop().time()
    await asyncio.gather(asyncio.sleep(5), asyncio.sleep(5), asyncio.sleep(5))
    end = asyncio.get_event_loop().time()
    assert end - start <= 5.5  # almost 5 seconds  # noqa: PLR2004
    assert end - start >= 5  # almost 5 seconds  # noqa: PLR2004

Local Development

Prerequisites

Install rye

curl -sSf https://rye.astral.sh/get | bash

Install dep

rye sync

Run tests

rye run test

Run linter

rye run lint

Acknowledgments 🙏

• freezegun