This test failure is due to test_zipimport_support loading and unloading modules, which leads to them being reloaded. Then the ssl.CertificateError which is checked for by assertRaises isn't the same as the one raised by the module under test (I have printed the type names and ids below):

$ ./python -E -bb -m test.regrtest test_http_cookies test_zipimport_support test_httplib
[1/3] test_http_cookies
[2/3] test_zipimport_support
[3/3] test_httplib
<class 'ssl.CertificateError'> 49243264
<class 'ssl.CertificateError'> 51134640
test test_httplib failed -- Traceback (most recent call last):
  File "/home/antoine/py3k/__svn__/Lib/test/test_httplib.py", line 481, in test_local_bad_hostname
    h.request('GET', '/')
  File "/home/antoine/py3k/__svn__/Lib/http/client.py", line 950, in request
    self._send_request(method, url, body, headers)
  File "/home/antoine/py3k/__svn__/Lib/http/client.py", line 988, in _send_request
    self.endheaders(body)
  File "/home/antoine/py3k/__svn__/Lib/http/client.py", line 946, in endheaders
    self._send_output(message_body)
  File "/home/antoine/py3k/__svn__/Lib/http/client.py", line 791, in _send_output
    self.send(msg)
  File "/home/antoine/py3k/__svn__/Lib/http/client.py", line 737, in send
    self.connect()
  File "/home/antoine/py3k/__svn__/Lib/http/client.py", line 1096, in connect
    ssl.match_hostname(self.sock.getpeercert(), self.host)
  File "/home/antoine/py3k/__svn__/Lib/ssl.py", line 142, in match_hostname
    % (hostname, dnsnames[0]))
ssl.CertificateError: hostname 'localhost' doesn't match 'fakehostname'


(witnessed in http://www.python.org/dev/buildbot/all/builders/AMD64%20Snow%20Leopard%203.x/builds/527/steps/test/logs/stdio )