Flaky celery test

This is with Python 3.14:

=================================== FAILURES ===================================
__________________ TestCeleryInstrumentation.test_task_raises __________________

self = <tests.test_tasks.TestCeleryInstrumentation testMethod=test_task_raises>

    def test_task_raises(self):
        CeleryInstrumentor().instrument()
    
        result = task_raises.delay()
    
        timeout = time.time() + 60 * 1  # 1 minutes from now
        while not result.ready():
            if time.time() > timeout:
                break
            time.sleep(0.05)
    
        spans = self.sorted_spans(self.memory_exporter.get_finished_spans())
>       self.assertEqual(len(spans), 2)
E       AssertionError: 1 != 2

instrumentation/opentelemetry-instrumentation-celery/tests/test_tasks.py:123: AssertionError
----------------------------- Captured stdout call -----------------------------
 
 -------------- celery@runnervmgx7h7 v5.3.6 (emerald-rush)
--- ***** ----- 
-- ******* ---- Linux-6.17.0-1022-azure-x86_64-with-glibc2.39 2026-08-28 09:04:22
- *** --- * --- 
- ** ---------- [config]
- ** ---------- .> app:         __main__:0x7f29ba8b6510
- ** ---------- .> transport:   memory://localhost//
- ** ---------- .> results:     rpc://
- *** --- * --- .> concurrency: 1 (solo)
-- ******* ---- .> task events: OFF (enable -E to monitor tasks in this worker)
--- ***** ----- 
 -------------- [queues]
                .> celery           exchange=celery(direct) key=celery
                

----------------------------- Captured stderr call -----------------------------
[2026-08-28 09:04:22,731: WARNING/MainProcess] No hostname was supplied. Reverting to default 'localhost'
[2026-08-28 09:04:22,734: WARNING/MainProcess] No hostname was supplied. Reverting to default 'localhost'
[2026-08-28 09:04:23,742: ERROR/MainProcess] Task tests.celery_test_tasks.task_raises[b0d8851d-0ffb-467f-8721-c75b3d3703e9] raised unexpected: CustomError('The task failed!')
Traceback (most recent call last):
  File "/home/runner/work/opentelemetry-python-contrib/opentelemetry-python-contrib/.tox/py314-test-instrumentation-celery/lib/python3.14/site-packages/celery/app/trace.py", line 477, in trace_task
    R = retval = fun(*args, **kwargs)
                 ~~~^^^^^^^^^^^^^^^^^
  File "/home/runner/work/opentelemetry-python-contrib/opentelemetry-python-contrib/.tox/py314-test-instrumentation-celery/lib/python3.14/site-packages/celery/app/trace.py", line 760, in __protected_call__
    return self.run(*args, **kwargs)
           ~~~~~~~~^^^^^^^^^^^^^^^^^
  File "/home/runner/work/opentelemetry-python-contrib/opentelemetry-python-contrib/instrumentation/opentelemetry-instrumentation-celery/tests/celery_test_tasks.py", line 29, in task_raises
    raise CustomError("The task failed!")
tests.celery_test_tasks.CustomError: The task failed!
[2026-08-28 09:04:24,736: WARNING/MainProcess] Attempting to uninstrument while already uninstrumented
------------------------------ Captured log call -------------------------------
WARNING  kombu.connection:connection.py:669 No hostname was supplied. Reverting to default 'localhost'
WARNING  kombu.connection:connection.py:669 No hostname was supplied. Reverting to default 'localhost'
ERROR    celery.app.trace:trace.py:270 Task tests.celery_test_tasks.task_raises[b0d8851d-0ffb-467f-8721-c75b3d3703e9] raised unexpected: CustomError('The task failed!')
Traceback (most recent call last):
  File "/home/runner/work/opentelemetry-python-contrib/opentelemetry-python-contrib/.tox/py314-test-instrumentation-celery/lib/python3.14/site-packages/celery/app/trace.py", line 477, in trace_task
    R = retval = fun(*args, **kwargs)
                 ~~~^^^^^^^^^^^^^^^^^
  File "/home/runner/work/opentelemetry-python-contrib/opentelemetry-python-contrib/.tox/py314-test-instrumentation-celery/lib/python3.14/site-packages/celery/app/trace.py", line 760, in __protected_call__
    return self.run(*args, **kwargs)
           ~~~~~~~~^^^^^^^^^^^^^^^^^
  File "/home/runner/work/opentelemetry-python-contrib/opentelemetry-python-contrib/instrumentation/opentelemetry-instrumentation-celery/tests/celery_test_tasks.py", line 29, in task_raises
    raise CustomError("The task failed!")
tests.celery_test_tasks.CustomError: The task failed!
WARNING  opentelemetry.instrumentation.instrumentor:instrumentor.py:130 Attempting to uninstrument while already uninstrumented

Start with instrumentation/opentelemetry-instrumentation-celery/tests/test_tasks.py:123 and the task_raises definition in tests/celery_test_tasks.py:29. Run TestCeleryInstrumentation.test_task_raises under Python 3.14 and inspect why only one span is collected. Done means the test reliably observes the expected two spans without weakening its assertion.