Fix acme.client.Client.__init__ (#5747)

* fixes #5738

* add test to prevent regressions

acme/acme/client.py

@@ -259,11 +259,12 @@ class Client(ClientBase):
         """
         # pylint: disable=too-many-arguments
         self.key = key
-        self.net = ClientNetwork(key, alg=alg, verify_ssl=verify_ssl) if net is None else net
+        if net is None:
+            net = ClientNetwork(key, alg=alg, verify_ssl=verify_ssl)
 
         if isinstance(directory, six.string_types):
             directory = messages.Directory.from_json(
-                self.net.get(directory).json())
+                net.get(directory).json())
         super(Client, self).__init__(directory=directory,
             net=net, acme_version=1)
 

acme/acme/client_test.py

@@ -299,6 +299,16 @@ class ClientTest(ClientTestBase):
             directory=uri, key=KEY, alg=jose.RS256, net=self.net)
         self.net.get.assert_called_once_with(uri)
 
+    @mock.patch('acme.client.ClientNetwork')
+    def test_init_without_net(self, mock_net):
+        mock_net.return_value = mock.sentinel.net
+        alg = jose.RS256
+        from acme.client import Client
+        self.client = Client(
+            directory=self.directory, key=KEY, alg=alg)
+        mock_net.called_once_with(KEY, alg=alg, verify_ssl=True)
+        self.assertEqual(self.client.net, mock.sentinel.net)
+
     def test_register(self):
         # "Instance of 'Field' has no to_json/update member" bug:
         # pylint: disable=no-member