Ensure Model.update accounts for REMOVE expressions on in-memory object (#741)

Author: conjmurph

pynamodb/models.py

@@ -390,11 +390,7 @@ def update(self, actions, condition=None):
         kwargs.update(actions=actions)
 
         data = self._get_connection().update_item(*args, **kwargs)
-        for name, value in data[ATTRIBUTES].items():
-            attr_name = self._dynamo_to_python_attr(name)
-            attr = self.get_attributes().get(attr_name)
-            if attr:
-                setattr(self, attr_name, attr.deserialize(attr.get_value(value)))
+        self._deserialize(data[ATTRIBUTES])
         return data
 
     def save(self, condition=None):

tests/test_model.py

@@ -837,7 +837,7 @@ def test_update(self, mock_time):
         """
         mock_time.side_effect = [1559692800]  # 2019-06-05 00:00:00 UTC
         self.init_table_meta(SimpleUserModel, SIMPLE_MODEL_TABLE_DATA)
-        item = SimpleUserModel('foo', is_active=True, email='foo@example.com', signature='foo')
+        item = SimpleUserModel(user_name='foo', is_active=True, email='foo@example.com', signature='foo', views=100)
 
         with patch(PATCH_METHOD) as req:
             req.return_value = {}
@@ -848,12 +848,18 @@ def test_update(self, mock_time):
         with patch(PATCH_METHOD) as req:
             req.return_value = {
                 ATTRIBUTES: {
+                    "user_name": {
+                        "S": "foo",
+                    },
                     "email": {
                         "S": "foo@example.com",
                     },
                     "is_active": {
                         "NULL": None,
                     },
+                    "signature": {
+                        "NULL": None,
+                    },
                     "aliases": {
                         "SS": {"bob"},
                     }