>  I suggest simply skipping the test, unless we find a remote IMAP server that accepts random TLS certs.

I tried "imap.gmail.com" server: first, it fails with:

imaplib.IMAP4.error: b'[AUTHENTICATIONFAILED] Invalid credentials (Failure)'

And then:

imaplib.IMAP4.error: b'[ALERT] Web login required: https://support.google.com/mail/answer/78754 (Failure)'

Well, I don't see why an IMAP server would accept our client cert?

Lib/test/keycert3.pem was added by the commit 58ddc9d743d09ee93d5cf46a4de62eab30dad79d (made by Antoine Pitrou): the certificated was *generated* randomly by Lib/test/make_ssl_certs.py (also added by the same commit).

RemoteIMAP_SSLTest was added by commit b1436f185dac249f0f6dc342b2a543ae2d1db63d (Antoine Pitrou) in 2010 with the server: cyrus.andrew.cmu.edu.

So since 2010 until a few days ago, cyrus.andrew.cmu.edu accepted random client certificate, but now the server started to fail... as expected?