WIP; needs put_class

Author: lgarber-akamai

test/unit/objects/linode_test.py

@@ -487,7 +487,6 @@ def test_get_interfaces(self):
 
     def test_get_interfaces_settings(self):
         instance = Instance(self.client, 124)
-
         iface_settings = instance.interfaces_settings
 
         assert iface_settings.network_helper
@@ -505,6 +504,25 @@ def test_get_interfaces_settings(self):
             456,
         ]
 
+    def test_update_interfaces_settings(self):
+        instance = Instance(self.client, 124)
+        iface_settings = instance.interfaces_settings
+
+        iface_settings.network_helper = False
+        iface_settings.default_route.ipv4_interface_id = 456
+        iface_settings.default_route.ipv6_interface_id = 123
+
+        with self.mock_put("/linode/instances/124/interfaces/settings") as m:
+            iface_settings.save()
+
+            assert m.call_data == {
+                "network_helper": False,
+                "default_route": {
+                    "ipv4_interface_id": 456,
+                    "ipv6_interface_id": 123,
+                }
+            }
+
 
 class DiskTest(ClientBaseCase):
     """