[Python-Dev] Test failures in test_timeout

Thomas Wouters thomas at xs4all.net
Thu Feb 16 18:43:26 CET 2006

I'm seeing spurious test failures in test_timeout, on my own workstation and
on macteagle.python.org (now that it crashes less; Apple sent over some new
memory.) The problem is pretty simple: both macteagle and my workstation
live too closely, network-wise, to www.python.org:

class TimeoutTestCase(unittest.TestCase):
    def setUp(self):
        self.addr_remote = ('www.python.org', 80)
    def testConnectTimeout(self):
        # Test connect() timeout
        _timeout = 0.001

        _t1 = time.time()
        self.failUnlessRaises(socket.error, self.sock.connect,

In other words, the test fails because www.python.org responds too quickly.

The test on my workstation only fails occasionally, but I do expect
macteagle's failure to be more common (since it's connected to
www.python.org through (literally) a pair of gigabit switches, whereas my
workstation has to pass through a few more switches, two Junipers and some
dark fiber.) Lowering the timeout has no effect, as far as I can tell, which
is probably a granularity issue.

I'm thinking that it could probably try to connect to a less reliable
website, but that's just moving the problem around (and possibly harassing
an unsuspecting website, particularly around release-time.) Perhaps the test
should try to connect to a known unconnecting site, like a firewalled port
on www.python.org? Not something that refuses connections, just something
that times out.

Thomas Wouters <thomas at xs4all.net>

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