Can we have a test for it? The best would be for sync and async event emitters which fail without your change.

Can we have a test for it? The best would be for sync and async event emitters which fail without your change.

@mxschmitt Added test

When executing the test on my environment it leads to the following:

(env) ➜  playwright-python git:(master) ✗ pytest --browser chromium tests/common/test_events.py             
Test session starts (platform: darwin, Python 3.9.7, pytest 6.2.4, pytest-sugar 0.9.4)
cachedir: .pytest_cache
rootdir: /Users/max/development/playwright-python, configfile: setup.cfg
plugins: cov-2.12.1, sugar-0.9.4, asyncio-0.15.1, flaky-3.7.0, xdist-2.3.0, repeat-0.9.1, timeout-1.4.2, forked-1.3.0
collecting ... 
 tests/common/test_events.py::test_events[chromium] ✓                                                                                                                                                100% ██████████

Results (3.15s):
       1 passed
Exception ignored in: <function BaseSubprocessTransport.__del__ at 0x1060550d0>
Traceback (most recent call last):
  File "/Users/max/.pyenv/versions/3.9.7/lib/python3.9/asyncio/base_subprocess.py", line 126, in __del__
    self.close()
  File "/Users/max/.pyenv/versions/3.9.7/lib/python3.9/asyncio/base_subprocess.py", line 104, in close
    proto.pipe.close()
  File "/Users/max/.pyenv/versions/3.9.7/lib/python3.9/asyncio/unix_events.py", line 536, in close
    self._close(None)
  File "/Users/max/.pyenv/versions/3.9.7/lib/python3.9/asyncio/unix_events.py", line 560, in _close
    self._loop.call_soon(self._call_connection_lost, exc)
  File "/Users/max/.pyenv/versions/3.9.7/lib/python3.9/asyncio/base_events.py", line 746, in call_soon
    self._check_closed()
  File "/Users/max/.pyenv/versions/3.9.7/lib/python3.9/asyncio/base_events.py", line 510, in _check_closed
    raise RuntimeError('Event loop is closed')
RuntimeError: Event loop is closed

When executing the test on my environment it leads to the following:

(env) ➜  playwright-python git:(master) ✗ pytest --browser chromium tests/common/test_events.py             
Test session starts (platform: darwin, Python 3.9.7, pytest 6.2.4, pytest-sugar 0.9.4)
cachedir: .pytest_cache
rootdir: /Users/max/development/playwright-python, configfile: setup.cfg
plugins: cov-2.12.1, sugar-0.9.4, asyncio-0.15.1, flaky-3.7.0, xdist-2.3.0, repeat-0.9.1, timeout-1.4.2, forked-1.3.0
collecting ... 
 tests/common/test_events.py::test_events[chromium] ✓                                                                                                                                                100% ██████████

Results (3.15s):
       1 passed
Exception ignored in: <function BaseSubprocessTransport.__del__ at 0x1060550d0>
Traceback (most recent call last):
  File "/Users/max/.pyenv/versions/3.9.7/lib/python3.9/asyncio/base_subprocess.py", line 126, in __del__
    self.close()
  File "/Users/max/.pyenv/versions/3.9.7/lib/python3.9/asyncio/base_subprocess.py", line 104, in close
    proto.pipe.close()
  File "/Users/max/.pyenv/versions/3.9.7/lib/python3.9/asyncio/unix_events.py", line 536, in close
    self._close(None)
  File "/Users/max/.pyenv/versions/3.9.7/lib/python3.9/asyncio/unix_events.py", line 560, in _close
    self._loop.call_soon(self._call_connection_lost, exc)
  File "/Users/max/.pyenv/versions/3.9.7/lib/python3.9/asyncio/base_events.py", line 746, in call_soon
    self._check_closed()
  File "/Users/max/.pyenv/versions/3.9.7/lib/python3.9/asyncio/base_events.py", line 510, in _check_closed
    raise RuntimeError('Event loop is closed')
RuntimeError: Event loop is closed

@mxschmitt Fixed in latest commit