Added etag checking when saving tasks & shots. Still a bit rough.

Needs nicer user interface stuff for explaining what's going on.

tests/test_tasks.py

@@ -4,6 +4,7 @@ import responses
 from bson import ObjectId
 
 import pillarsdk
+import pillarsdk.exceptions as sdk_exceptions
 import pillar.api.utils
 import pillar.tests
 import pillar.auth
@@ -59,11 +60,20 @@ class TaskWorkflowTest(AbstractAttractTest):
             pillar.auth.login_user(ctd.EXAMPLE_PROJECT_OWNER_ID)
 
             self.mock_blenderid_validate_happy()
+            self.assertRaises(sdk_exceptions.PreconditionFailed,
+                              self.mngr.edit_task,
+                              task._id,
+                              task_type=u'je møder',
+                              name=u'nööw name',
+                              description=u'€ ≠ ¥',
+                              status='todo',
+                              _etag='jemoeder')
             self.mngr.edit_task(task._id,
                                 task_type=u'je møder',
                                 name=u'nööw name',
                                 description=u'€ ≠ ¥',
-                                status='todo')
+                                status='todo',
+                                _etag=task._etag)
 
         # Test directly with MongoDB
         with self.app.test_request_context():