Python fake sleep fixture for pytest.

fake_sleep_decorator.py

import functools
from datetime import datetime, timedelta
from unittest import mock

from freezegun import freeze_time


def fake_sleep(func):
    freezegun_control = None

    def fake_sleep(seconds):
        nonlocal freezegun_control
        utcnow = datetime.utcnow()
        if freezegun_control is not None:
            freezegun_control.stop()
        freezegun_control = freeze_time(utcnow + timedelta(seconds=seconds))
        freezegun_control.start()

    @functools.wraps(func)
    def wrapper(*args, **kwargs):
        with mock.patch('time.sleep', fake_sleep):
            rv = func(*args, **kwargs)

            if freezegun_control is not None:
                freezegun_control.stop()
            return rv

    return wrapper


@fake_sleep
def test_sleep():
    import time
    now = datetime.utcnow()

    for sleep_seconds in range(10):
        for i in range(1, 10):

            time.sleep(sleep_seconds)

            assert datetime.utcnow() - now >= timedelta(
                seconds=i * sleep_seconds)

fake_sleep_pytest.py

from datetime import datetime, timedelta

import freezegun
import pytest


@pytest.fixture
def sleep():
    freezegun_control = None

    def fake_sleep(seconds):
        nonlocal freezegun_control
        utcnow = datetime.utcnow()
        if freezegun_control is not None:
            freezegun_control.stop()
        freezegun_control = freezegun.freeze_time(
            utcnow + timedelta(seconds=seconds))
        freezegun_control.start()

    yield fake_sleep

    if freezegun_control is not None:
        freezegun_control.stop()


def test_fake_sleep(sleep):
    now = datetime.utcnow()

    for sleep_seconds in range(10):
        for i in range(1, 10):

            sleep(sleep_seconds)

            assert datetime.utcnow() - now >= timedelta(
                seconds=i * sleep_seconds)