The test_wrong_cert_tls13 unit tests checks the behavior when the server rejects the client's ceritficate. On macOS, this can sometimes lead to a "Broken pipe" on the client instead of a "Connection reset by peer" when the connection is closed during the s.write() call.

This happens frequently in the free-threaded build, but can also be reproduced on the default (with GIL) build by adding a short time.sleep(0.1) immediately before the s.write(b'data').

Linked PRs

• gh-117483: Accept "Broken pipe" as valid error message in test_wrong_cert_tls13 #117484