Ignore unraisable & unhandled exceptions in pytest

Refs:
* #355
* https://docs.pytest.org/en/stable/usage.html#unraisable
* pytest-dev/pytest#5299

pytest.ini

@@ -29,6 +29,15 @@ addopts =
 doctest_optionflags = ALLOW_UNICODE ELLIPSIS
 filterwarnings =
     error
+
+    # pytest>=6.2.0 under Python 3.8:
+    # Ref: https://docs.pytest.org/en/stable/usage.html#unraisable
+    # Ref: https://github.com/pytest-dev/pytest/issues/5299
+    ignore:Exception in thread CP Server Thread-:pytest.PytestUnhandledThreadExceptionWarning:_pytest.threadexception
+    ignore:Exception in thread Thread-:pytest.PytestUnhandledThreadExceptionWarning:_pytest.threadexception
+    ignore:Exception ignored in. <socket.socket fd=-1, family=AddressFamily.AF_INET, type=SocketKind.SOCK_STREAM, proto=6>:pytest.PytestUnraisableExceptionWarning:_pytest.unraisableexception
+    ignore:Exception ignored in. <socket.socket fd=-1, family=AddressFamily.AF_INET6, type=SocketKind.SOCK_STREAM, proto=6>:pytest.PytestUnraisableExceptionWarning:_pytest.unraisableexception
+
     # cryptography==3.0 warning:
     # `cryptography.utils.CryptographyDeprecationWarning` happens but we
     # cannot import it because of the chicken-egg nature of its