我有一些想要测试的异步Python代码,其中包括类似的内容
async def task(self):
while True:
await self.thing.change()
...
self.run_callbacks()
在我的测试文件中,我在 setUp() 函数中启动任务,如下所示:
def setUp(self):
...
self.loop = asyncio.get_event_loop()
self.task = self.loop.create_task(self.object_under_test.task())
然后想要验证回调是否运行:
def test_callback(self):
callback = mock.MagicMock()
self.object_under_test.add_callback('cb1', callback)
# ???
callback.assert_called_once()
我陷入困境的是如何在任务中模拟
thing.change()
。它需要阻塞,直到我告诉它(在???),此时它会返回。如果我在启动任务后模拟它,那么它不会有任何区别,因为任务已经在等待未模拟的函数返回。如果我在开始任务之前模拟它,那么它总是会返回一些东西而不是阻塞。
有什么建议我可以实现这一目标吗?
我已经弄清楚了如何使用 asyncio.Event 对象进行同步并作为模拟的副作用:
# my_task.py
import asyncio
async def async_task():
while True:
result = await trigger()
await asyncio.sleep(0)
async def trigger():
# Some asynchronous function you want to mock
await asyncio.sleep(1)
print('triggered')
return "Trigger Completed"
# test_my_task.py
import asyncio
import unittest
from unittest.mock import patch, AsyncMock
import my_task
class TestAsyncTask(unittest.TestCase):
def setUp(self):
self.trigger_event = asyncio.Event()
async def mocked_trigger():
await self.trigger_event.wait()
return "Mocked Trigger Completed"
my_task.trigger = AsyncMock(side_effect=mocked_trigger)
def test_async_task_with_mocked_trigger(self):
loop = asyncio.get_event_loop()
task = loop.create_task(my_task.async_task())
loop.run_until_complete(asyncio.sleep(1))
self.trigger_event.set()
loop.run_until_complete(asyncio.sleep(0))
self.assertGreaterEqual(my_task.trigger.await_count, 1)
if __name__ == "__main__":
unittest.main()