ValueError: The future belongs to a different loop than the one specified as the loop argument

[WolfgangFahl]

First Check

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Example Code

# @unittest.skipIf(Basetest.inPublicCI(), "Skip in public CI environment")
    def testWebServerPaths(self):
        print("\n=== START testWebServerPaths DEBUG ===")
        self.check_server("initial_state")

        frontend = self.get_frontend("www")
        self.check_server("after_get_frontend")

        test_cases = [
            ("/www/Joker", "Joker"),
            ("/", "<title>pyWikiCMS</title>"),
            ("/www/{Illegal}", "invalid char"),
        ]

        for i, (query, ehtml) in enumerate(test_cases):
            print(f"\n--- Request {i+1}: {query} ---")
            self.check_server(f"pre_request_{i}")
            try:
                html = self.get_html(query)
                self.check_server(f"post_request_{i}_success")
                self.assertIn(ehtml, html)
            except Exception as e:
                self.check_server(f"post_request_{i}_error: {str(e)}")
                raise

        print("=== END testWebServerPaths DEBUG ===")

Description

run https://github.com/BITPlan/pyWikiCMS/blob/master/tests/test_frontend.py in github CI
it works locally but not in the CI.

I wonder how i can mitigate this eventloop issue and for a start properly debug it.

NiceGUI Version

2.21.1.dev0

Python Version

3.10

Browser

Firefox

Operating System

Linux

Additional Context

We get very lengthy stacktrace that is unfortunately not helpful.

======================================================================
ERROR: testWebServerPaths (tests.test_frontend.TestFrontend)
----------------------------------------------------------------------
  + Exception Group Traceback (most recent call last):
  |   File "/opt/hostedtoolcache/Python/3.10.18/x64/lib/python3.10/site-packages/starlette/_utils.py", line 77, in collapse_excgroups
  |     yield
  |   File "/opt/hostedtoolcache/Python/3.10.18/x64/lib/python3.10/site-packages/starlette/middleware/base.py", line 183, in __call__
  |     async with anyio.create_task_group() as task_group:
  |   File "/opt/hostedtoolcache/Python/3.10.18/x64/lib/python3.10/site-packages/anyio/_backends/_asyncio.py", line 772, in __aexit__
  |     raise BaseExceptionGroup(
  | exceptiongroup.ExceptionGroup: unhandled errors in a TaskGroup (1 sub-exception)
  +-+---------------- 1 ----------------
    | Traceback (most recent call last):
    |   File "/opt/hostedtoolcache/Python/3.10.18/x64/lib/python3.10/unittest/case.py", line 59, in testPartExecutor
    |     yield
    |   File "/opt/hostedtoolcache/Python/3.10.18/x64/lib/python3.10/unittest/case.py", line 591, in run
    |     self._callTestMethod(testMethod)
    |   File "/opt/hostedtoolcache/Python/3.10.18/x64/lib/python3.10/unittest/case.py", line 549, in _callTestMethod
    |     method()
    |   File "/home/runner/work/pyWikiCMS/pyWikiCMS/tests/test_frontend.py", line 184, in testWebServerPaths
    |     html = self.get_html(query)
    |   File "/opt/hostedtoolcache/Python/3.10.18/x64/lib/python3.10/site-packages/ngwidgets/test_base_webserver.py", line 175, in get_html
    |     response = self.get_response(path, expected_status_code)
    |   File "/opt/hostedtoolcache/Python/3.10.18/x64/lib/python3.10/site-packages/ngwidgets/webserver_test.py", line 82, in get_response
    |     response = self.client.get(path)
    |   File "/opt/hostedtoolcache/Python/3.10.18/x64/lib/python3.10/site-packages/starlette/testclient.py", line 479, in get
    self.gen.throw(typ, value, traceback)
  File "/opt/hostedtoolcache/Python/3.10.18/x64/lib/python3.10/site-packages/starlette/_utils.py", line 83, in collapse_excgroups
    raise exc
  File "/opt/hostedtoolcache/Python/3.10.18/x64/lib/python3.10/site-packages/starlette/middleware/base.py", line 184, in __call__
    response = await self.dispatch_func(request, call_next)
  File "/opt/hostedtoolcache/Python/3.10.18/x64/lib/python3.10/site-packages/nicegui/middlewares.py", line 13, in dispatch
    response = await call_next(request)
  File "/opt/hostedtoolcache/Python/3.10.18/x64/lib/python3.10/site-packages/starlette/middleware/base.py", line 159, in call_next
    raise app_exc
  File "/opt/hostedtoolcache/Python/3.10.18/x64/lib/python3.10/site-packages/starlette/middleware/base.py", line 144, in coro
    await self.app(scope, receive_or_disconnect, send_no_error)
  File "/opt/hostedtoolcache/Python/3.10.18/x64/lib/python3.10/site-packages/starlette/middleware/gzip.py", line 29, in __call__
    await responder(scope, receive, send)
  File "/opt/hostedtoolcache/Python/3.10.18/x64/lib/python3.10/site-packages/starlette/middleware/gzip.py", line 130, in __call__
    await super().__call__(scope, receive, send)
  File "/opt/hostedtoolcache/Python/3.10.18/x64/lib/python3.10/site-packages/starlette/middleware/gzip.py", line 46, in __call__
    await self.app(scope, receive, self.send_with_compression)
  File "/opt/hostedtoolcache/Python/3.10.18/x64/lib/python3.10/site-packages/starlette/middleware/exceptions.py", line 63, in __call__
    await wrap_app_handling_exceptions(self.app, conn)(scope, receive, send)
  File "/opt/hostedtoolcache/Python/3.10.18/x64/lib/python3.10/site-packages/starlette/_exception_handler.py", line 53, in wrapped_app
    raise exc
  File "/opt/hostedtoolcache/Python/3.10.18/x64/lib/python3.10/site-packages/starlette/_exception_handler.py", line 42, in wrapped_app
    await app(scope, receive, sender)
  File "/opt/hostedtoolcache/Python/3.10.18/x64/lib/python3.10/site-packages/starlette/routing.py", line 716, in __call__
    await self.middleware_stack(scope, receive, send)
  File "/opt/hostedtoolcache/Python/3.10.18/x64/lib/python3.10/site-packages/starlette/routing.py", line 736, in app
    await route.handle(scope, receive, send)
  File "/opt/hostedtoolcache/Python/3.10.18/x64/lib/python3.10/site-packages/starlette/routing.py", line 290, in handle
    await self.app(scope, receive, send)
  File "/opt/hostedtoolcache/Python/3.10.18/x64/lib/python3.10/site-packages/starlette/routing.py", line 78, in app
    await wrap_app_handling_exceptions(app, request)(scope, receive, send)
  File "/opt/hostedtoolcache/Python/3.10.18/x64/lib/python3.10/site-packages/starlette/_exception_handler.py", line 53, in wrapped_app
    raise exc
  File "/opt/hostedtoolcache/Python/3.10.18/x64/lib/python3.10/site-packages/starlette/_exception_handler.py", line 42, in wrapped_app
    await app(scope, receive, sender)
  File "/opt/hostedtoolcache/Python/3.10.18/x64/lib/python3.10/site-packages/starlette/routing.py", line 75, in app
    response = await f(request)
  File "/opt/hostedtoolcache/Python/3.10.18/x64/lib/python3.10/site-packages/fastapi/routing.py", line 302, in app
    raw_response = await run_endpoint_function(
  File "/opt/hostedtoolcache/Python/3.10.18/x64/lib/python3.10/site-packages/fastapi/routing.py", line 213, in run_endpoint_function
    return await dependant.call(**values)
  File "/opt/hostedtoolcache/Python/3.10.18/x64/lib/python3.10/site-packages/nicegui/page.py", line 161, in decorated
    await asyncio.wait([
  File "/opt/hostedtoolcache/Python/3.10.18/x64/lib/python3.10/asyncio/tasks.py", line 382, in wait
    fs = {ensure_future(f, loop=loop) for f in fs}
  File "/opt/hostedtoolcache/Python/3.10.18/x64/lib/python3.10/asyncio/tasks.py", line 382, in <setcomp>
    fs = {ensure_future(f, loop=loop) for f in fs}
  File "/opt/hostedtoolcache/Python/3.10.18/x64/lib/python3.10/asyncio/tasks.py", line 615, in ensure_future
    return _ensure_future(coro_or_future, loop=loop)
  File "/opt/hostedtoolcache/Python/3.10.18/x64/lib/python3.10/asyncio/tasks.py", line 621, in _ensure_future
    raise ValueError('The future belongs to a different loop than '
ValueError: The future belongs to a different loop than the one specified as the loop argument

[falkoschindler]

@WolfgangFahl Can you, please, create a minimum reproducible code example? Thanks!
Why is it important to provide a minimal reproducible example?