zeo: Fix parsing URI with IPv6 address

The code was crashing this way:

---- 8< ----
======================================================================
ERROR: test_call_ipv6 (zodburi.tests.test_resolvers.TestClientStorageURIResolver)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/kirr/src/wendelin/venv/z-dev/local/lib/python2.7/site-packages/mock/mock.py", line 1305, in patched
    return func(*args, **keywargs)
  File "/home/kirr/src/wendelin/z/zodburi/zodburi/tests/test_resolvers.py", line 265, in test_call_ipv6
    factory, dbkw = resolver('zeo://[::1]:9090?debug=true')
  File "/home/kirr/src/wendelin/z/zodburi/zodburi/resolvers.py", line 141, in __call__
    host, port = netloc.split(':')
ValueError: too many values to unpack

======================================================================
ERROR: test_call_ipv6_no_port (zodburi.tests.test_resolvers.TestClientStorageURIResolver)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/kirr/src/wendelin/venv/z-dev/local/lib/python2.7/site-packages/mock/mock.py", line 1305, in patched
    return func(*args, **keywargs)
  File "/home/kirr/src/wendelin/z/zodburi/zodburi/tests/test_resolvers.py", line 258, in test_call_ipv6_no_port
    factory, dbkw = resolver('zeo://[::1]?debug=true')
  File "/home/kirr/src/wendelin/z/zodburi/zodburi/resolvers.py", line 141, in __call__
    host, port = netloc.split(':')
ValueError: too many values to unpack
---- 8< ----

Fix it by leveraging the fact that urlparse.urlsplit return() tuple-like object
with additional .hostname and .port attributes which already parse IPv6 correctly:

In [2]: u = urlsplit('http://[::1]:5553')

In [3]: u
Out[3]: SplitResult(scheme='http', netloc='[::1]:5553', path='', query='', fragment='')

In [4]: u.netloc
Out[4]: '[::1]:5553'

In [5]: u.hostname
Out[5]: '::1'

In [6]: u.port
Out[6]: 5553

In [7]: u = urlsplit('http://[::1]')

In [8]: u.hostname
Out[8]: '::1'

In [9]: u.port

In [10]: repr(u.port)
Out[10]: 'None'

CHANGES.txt

@@ -8,6 +8,8 @@
 
 - Add support for Python 3.6.
 
+- Fix parsing of ``zeo://`` URI with IPv6 address.
+
 2.2.2 (2017-05-05)
 ------------------
 

zodburi/resolvers.py

@@ -134,21 +134,19 @@ class ClientStorageURIResolver(Resolver):
         # urlsplit doesnt understand zeo URLs so force to something that
         # doesn't break
         uri = uri.replace('zeo://', 'http://', 1)
-        (scheme, netloc, path, query, frag) = urlsplit(uri)
-        if netloc:
+        u = urlsplit(uri)
+        if u.netloc:
             # TCP URL
-            if ':' in netloc:
-                host, port = netloc.split(':')
-                port = int(port)
-            else:
-                host = netloc
+            host = u.hostname
+            port = u.port
+            if port is None:
                 port = 9991
             args = ((host, port),)
         else:
             # Unix domain socket URL
-            path = os.path.normpath(path)
+            path = os.path.normpath(u.path)
             args = (path,)
-        kw = dict(parse_qsl(query))
+        kw = dict(parse_qsl(u.query))
         kw, unused = self.interpret_kwargs(kw)
         if 'demostorage' in kw:
             kw.pop('demostorage')

zodburi/tests/test_resolvers.py

@@ -252,6 +252,20 @@ class TestClientStorageURIResolver(unittest.TestCase):
         factory()
         ClientStorage.assert_called_once_with(('localhost', 8080), debug=1)
 
+    @mock.patch('zodburi.resolvers.ClientStorage')
+    def test_call_ipv6_no_port(self, ClientStorage):
+        resolver = self._makeOne()
+        factory, dbkw = resolver('zeo://[::1]?debug=true')
+        factory()
+        ClientStorage.assert_called_once_with(('::1', 9991), debug=1)
+
+    @mock.patch('zodburi.resolvers.ClientStorage')
+    def test_call_ipv6(self, ClientStorage):
+        resolver = self._makeOne()
+        factory, dbkw = resolver('zeo://[::1]:9090?debug=true')
+        factory()
+        ClientStorage.assert_called_once_with(('::1', 9090), debug=1)
+
     @mock.patch('zodburi.resolvers.ClientStorage')
     def test_call_unix(self, ClientStorage):
         resolver = self._makeOne()