DeprecationWarning: reactor.iterate cannot be used inside unit tests. In the future, using iterate will fail the test and may crash or hang the test run.

[altendky]

https://github.com/pytest-dev/pytest-twisted/pull/94/checks?check_run_id=692810777

============================= test session starts ==============================
platform linux -- Python 3.6.10, pytest-5.4.2, py-1.8.1, pluggy-0.13.1 -- /__w/pytest-twisted/pytest-twisted/.tox/py36-qt5reactor/bin/python
cachedir: .pytest_cache
PyQt5 5.14.2 -- Qt runtime 5.14.2 -- Qt compiled 5.14.2
rootdir: /tmp/pytest-of-root/pytest-0/test_scrapy____something0
plugins: qt-3.3.0, xvfb-1.2.0, twisted-1.12
collecting ... collected 1 item

test_scrapy____something.py::Test::test PASSED                           [100%]

=============================== warnings summary ===============================
test_scrapy____something.py::Test::test
  /__w/pytest-twisted/pytest-twisted/.tox/py36-qt5reactor/lib/python3.6/site-packages/qt5reactor/core.py:292: DeprecationWarning: reactor.iterate cannot be used inside unit tests. In the future, using iterate will fail the test and may crash or hang the test run.
    self.iterate(delay=delay, fromqt=True)

-- Docs: https://docs.pytest.org/en/latest/warnings.html
========================= 1 passed, 1 warning in 0.10s =========================

https://github.com/sunu/qt5reactor/blob/8aaf354ef5d5ec07aca4fbe3c4ec9fba2c476ee9/src/qt5reactor/core.py#L291-L292

[altendky]

https://github.com/twisted/twisted/blob/e17604416eadc58e90f28806968e267a06c38909/src/twisted/trial/_asynctest.py#L230-L242

    def _makeReactorMethod(self, name):
        """
        Create a method which wraps the reactor method C{name}. The new
        method issues a deprecation warning and calls the original.
        """
        def _(*a, **kw):
            warnings.warn("reactor.%s cannot be used inside unit tests. "
                          "In the future, using %s will fail the test and may "
                          "crash or hang the test run."
                          % (name, name),
                          stacklevel=2, category=DeprecationWarning)
            return self._reactorMethods[name](*a, **kw)
        return _

[altendky]

This was noticed over in pytest-dev/pytest-twisted#94 (for pytest-dev/pytest-twisted#93) after pytest 5.4.2 fixed (or hid or...) the other issue that related to test teardown and re-entering the reactor. I don't know if this is ... a sign of an additional pytest issue? a false alarm where this is just 'misdetected' as 'inside unit tests'? or a real qt5reactor issue.