Merge pull request #611 from ddriddle/issue_610

Tests fallback to IPv4 if IPv6 fails

4 files changed, 41 insertions, 4 deletions

diff --git a/CONTRIBUTORS.txt b/CONTRIBUTORS.txt
index 58073075..9ce382e6 100644
--- a/CONTRIBUTORS.txt
+++ b/CONTRIBUTORS.txt
@@ -148,6 +148,9 @@ In chronological order:
 * tlynn <https://github.com/tlynn>
   * Respect the warning preferences at import.
 
+* David D. Riddle <ddriddle@illinois.edu>
+  * IPv6 bugfixes in testsuite
+
 * [Your name or handle] <[email or website]>
   * [Brief summary of your changes]
 
diff --git a/dummyserver/server.py b/dummyserver/server.py
index 63124d35..19994749 100755
--- a/dummyserver/server.py
+++ b/dummyserver/server.py
@@ -38,6 +38,35 @@ DEFAULT_CA = os.path.join(CERTS_PATH, 'cacert.pem')
 DEFAULT_CA_BAD = os.path.join(CERTS_PATH, 'client_bad.pem')
 NO_SAN_CA = os.path.join(CERTS_PATH, 'cacert.no_san.pem')
 
+def _has_ipv6(host):
+    """ Returns True if the system can bind an IPv6 address. """
+    sock = None
+    has_ipv6 = False
+
+    if socket.has_ipv6:
+        # has_ipv6 returns true if cPython was compiled with IPv6 support.
+        # It does not tell us if the system has IPv6 support enabled. To
+        # determine that we must bind to an IPv6 address.
+        # https://github.com/shazow/urllib3/pull/611
+        # https://bugs.python.org/issue658327
+        try:
+            sock = socket.socket(socket.AF_INET6)
+            sock.bind((host, 0))
+            has_ipv6 = True
+        except:
+            pass
+
+    if sock:
+        sock.close()
+    return has_ipv6
+
+# Some systems may have IPv6 support but DNS may not be configured
+# properly. We can not count that localhost will resolve to ::1 on all
+# systems. See https://github.com/shazow/urllib3/pull/611 and
+# https://bugs.python.org/issue18792
+HAS_IPV6_AND_DNS = _has_ipv6('localhost')
+HAS_IPV6 = _has_ipv6('::1')
+
 
 # Different types of servers we have:
 
@@ -64,7 +93,7 @@ class SocketServerThread(threading.Thread):
         self.ready_event = ready_event
 
     def _start_server(self):
-        if socket.has_ipv6:
+        if HAS_IPV6_AND_DNS:
             sock = socket.socket(socket.AF_INET6)
         else:
             warnings.warn("No IPv6 support. Falling back to IPv4.",
@@ -117,7 +146,7 @@ def bind_sockets(port, address=None, family=socket.AF_UNSPEC, backlog=128,
     sockets = []
     if address == "":
         address = None
-    if not socket.has_ipv6 and family == socket.AF_UNSPEC:
+    if not HAS_IPV6 and family == socket.AF_UNSPEC:
         # Python can be compiled with --disable-ipv6, which causes
         # operations on AF_INET6 sockets to fail, but does not
         # automatically exclude those results from getaddrinfo
diff --git a/test/with_dummyserver/test_connectionpool.py b/test/with_dummyserver/test_connectionpool.py
index d6cb1622..943db2ee 100644
--- a/test/with_dummyserver/test_connectionpool.py
+++ b/test/with_dummyserver/test_connectionpool.py
@@ -36,7 +36,7 @@ from urllib3.util.timeout import Timeout
 
 import tornado
 from dummyserver.testcase import HTTPDummyServerTestCase
-from dummyserver.server import NoIPv6Warning
+from dummyserver.server import NoIPv6Warning, HAS_IPV6_AND_DNS
 
 from nose.tools import timed
 
@@ -600,7 +600,7 @@ class TestConnectionPool(HTTPDummyServerTestCase):
 
     def test_source_address(self):
         for addr, is_ipv6 in VALID_SOURCE_ADDRESSES:
-            if is_ipv6 and not socket.has_ipv6:
+            if is_ipv6 and not HAS_IPV6_AND_DNS:
                 warnings.warn("No IPv6 support: skipping.",
                               NoIPv6Warning)
                 continue
diff --git a/test/with_dummyserver/test_poolmanager.py b/test/with_dummyserver/test_poolmanager.py
index 7e51c730..7553e70a 100644
--- a/test/with_dummyserver/test_poolmanager.py
+++ b/test/with_dummyserver/test_poolmanager.py
@@ -1,6 +1,8 @@
 import unittest
 import json
 
+from nose.plugins.skip import SkipTest
+from dummyserver.server import HAS_IPV6
 from dummyserver.testcase import (HTTPDummyServerTestCase,
                                   IPv6HTTPDummyServerTestCase)
 from urllib3.poolmanager import PoolManager
@@ -154,6 +156,9 @@ class TestPoolManager(HTTPDummyServerTestCase):
 
 
 class TestIPv6PoolManager(IPv6HTTPDummyServerTestCase):
+    if not HAS_IPV6:
+        raise SkipTest("IPv6 is not supported on this system.")
+
     def setUp(self):
         self.base_url = 'http://[%s]:%d' % (self.host, self.port)