[issue46568] non awaited coroutines on a IsolatedAsyncioTestCase results on a RuntimeWarning
bluecarrot added the comment: You are absolutely correct. Thank you very much! -- ___ Python tracker <https://bugs.python.org/issue46568> ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue46568] non awaited coroutines on a IsolatedAsyncioTestCase results on a RuntimeWarning
bluecarrot added the comment: Hi Andrew, thank you for your answer. I am experimenting with coroutines, as I am pretty new to them. My idea was to let the writer drain while other packets where read, and thus I am waiting for the writer_drain right before starting writer.write again. Isn't that the correct wait to overlap the readings and the writings? If I modify my initial code to look like: async def forward_stream(reader: StreamReader, writer: StreamWriter, event: asyncio.Event, source: str): writer_drain = writer.drain() # <--- awaitable is created here while not event.is_set(): try: data = await asyncio.wait_for(reader.read(1024), 1) # <-- CancelledError can be caught here, stack unwinds and writer_drain is never awaited, sure. except asyncio.TimeoutError: continue except asyncio.CancelledError: event.set() break ... # the rest is not important for this case await writer_drain so that in case the task is cancelled, writer_drain will be awaited outside of the loop. This works, at the cost of having to introduce code specific for testing purposes (which feels wrong). In "production", the workflow of this code will be to loose the connection, break out of the loop, and wait for the writer stream to finish... but I am not introducing any method allowing me to cancel the streams once the script is running. In the same way leaked tasks are "swallowed", which I have tested and works, shouldn't be these cases also handled by the tearDownClass method of IsolatedAsyncioTestCase? -- ___ Python tracker <https://bugs.python.org/issue46568> ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue46568] non awaited coroutines on a IsolatedAsyncioTestCase results on a RuntimeWarning
bluecarrot added the comment: Seems that, should I add an "await asyncio.sleep(1)" in asyncTearDown, so getting class TestConnections(IsolatedAsyncioTestCase): async def asyncSetUp(self) -> None: self.proxy = asyncio.create_task(EnergyAgentProxy(self.proxy_port, self.server_port, self.upstream_port)) async def asyncTearDown(self) -> None: await asyncio.sleep(1) is enough to "hide the problem under the carpet"... but sounds weird... -- ___ Python tracker <https://bugs.python.org/issue46568> ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue46568] non awaited coroutines on a IsolatedAsyncioTestCase results on a RuntimeWarning
New submission from bluecarrot :
I am unittesting a tcp proxy module using coroutines. This is the coroutine I
am using to do the forwarding, allowing the writer stream to drain while the
rest of the coroutines are proceeding:
async def forward_stream(reader: StreamReader, writer: StreamWriter, event:
asyncio.Event, source: str):
writer_drain = writer.drain()
while not event.is_set():
try:
data = await asyncio.wait_for(reader.read(1024), 1)
except asyncio.TimeoutError:
continue
if not data:
event.set()
break
# parse the data
if reading := parse(data):
# wait for the previous write to finish, and forward the data to
the other end, process the data in between
await writer_drain
writer.write(data)
writer_drain = writer.drain()
# wait for any outstanding write buffer to be flushed
await writer_drain
logger.info("{} reader forwarder finished.".format(source))
In my unit tests, I have the following (EnergyAgentProxy is the wrapper calling
the coroutine in the module that creates the proxy)
class TestConnections(IsolatedAsyncioTestCase):
async def asyncSetUp(self) -> None:
self.proxy = asyncio.create_task(EnergyAgentProxy(self.proxy_port,
self.server_port, self.upstream_port))
The problem is: When running these tests, I am getting the following error:
/usr/lib/python3.10/unittest/async_case.py:159: RuntimeWarning: coroutine
'StreamWriter.drain' was never awaited
Coroutine created at (most recent call last)
File "/usr/lib/python3.10/unittest/case.py", line 650, in __call__
return self.run(*args, **kwds)
[...]
File "/home/frubio/Documents/powermonitor_raspberrypi/EnergyAgent.py",
line 48, in forward_stream
writer_drain = writer.drain()
self._tearDownAsyncioLoop()
So... to me, it looks like when the tasks are being cancelled I am getting this
warning because the last "await writer_drain" in forward stream is not
executed, but I cannot ensure that. Am I doing something wrong? Is there any
way I can just prevent this warning from showing up in my tests?
--
components: Tests, asyncio
messages: 412060
nosy: asvetlov, bluecarrot, yselivanov
priority: normal
severity: normal
status: open
title: non awaited coroutines on a IsolatedAsyncioTestCase results on a
RuntimeWarning
type: behavior
versions: Python 3.10
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