Method test_bad_address

Lib/test/test_urllibnet.py:111–147

(self)

    @support.requires_resource('walltime')
    def test_bad_address(self):
        # Make sure proper exception is raised when connecting to a bogus
        # address.

        # Given that both VeriSign and various ISPs have in
        # the past or are presently hijacking various invalid
        # domain name requests in an attempt to boost traffic
        # to their own sites, finding a domain name to use
        # for this test is difficult.  RFC2606 leads one to
        # believe that '.invalid' should work, but experience
        # seemed to indicate otherwise.  Single character
        # TLDs are likely to remain invalid, so this seems to
        # be the best choice. The trailing '.' prevents a
        # related problem: The normal DNS resolver appends
        # the domain names from the search path if there is
        # no '.' the end and, and if one of those domains
        # implements a '*' rule a result is returned.
        # However, none of this will prevent the test from
        # failing if the ISP hijacks all invalid domain
        # requests.  The real solution would be to be able to
        # parameterize the framework with a mock resolver.
        bogus_domain = "sadflkjsasf.i.nvali.d."
        try:
            socket.gethostbyname(bogus_domain)
        except OSError:
            # socket.gaierror is too narrow, since getaddrinfo() may also
            # fail with EAI_SYSTEM and ETIMEDOUT (seen on Ubuntu 13.04),
            # i.e. Python's TimeoutError.
            pass
        else:
            # This happens with some overzealous DNS providers such as OpenDNS
            self.skipTest("%r should not resolve for test to work" % bogus_domain)
        failure_explanation = ('opening an invalid URL did not raise OSError; '
                               'can be caused by a broken DNS server '
                               '(e.g. returns 404 or hijacks page)')
        with self.assertRaises(OSError, msg=failure_explanation):
            urllib.request.urlopen("http://{}/".format(bogus_domain))


class urlretrieveNetworkTests(unittest.TestCase):