Describe the bug

I had to cancel this test run (Python 3.12) after 5 minutes:

The second attempt succeeded just fine, but still shows a deprecation warning, which is likely related to the issue:

   /opt/hostedtoolcache/Python/3.12.0/x64/lib/python3.12/multiprocessing/popen_fork.py:66: DeprecationWarning: This process (pid=1909) is multi-threaded, use of fork() may lead to deadlocks in the child.
    self.pid = os.fork()

To Reproduce

1. Run test_should_execute_pipeline_return_valid_placeholder repeatedly
2. Eventually, the process gets stuck in wait_for_messages.

Expected behavior

Tests should always run through. As an extra safeguard, we might want to limit the runtime of some "dangerous" tests and fail them after x seconds. This can be done using pytest-timeout.

Screenshots (optional)

No response

Additional Context (optional)

This issue also occurred in this run.