After merging https://github.com/python/cpython/pull/9296 asyncio test suite prints a lot of warnings like
Exception ignored in: <coroutine object AsyncMockMixin._mock_call at 0x7fb648a1c170>
Traceback (most recent call last):
File "/home/andrew/projects/cpython/Lib/warnings.py", line 510, in _warn_unawaited_coroutine
warn(msg, category=RuntimeWarning, stacklevel=2, source=coro)
RuntimeWarning: coroutine 'AsyncMockMixin._mock_call' was never awaited
I believe this is not a sign of AsyncMock problem but asyncio tests should be fixed.
Need more investigations though.